Very informative and helpful. Thank you. I have an EdgeHD 8 and look forward to getting the .7 reducer as the next upgrade. Pointer - when threading on filters, adapters, etc. try doing a left-loosy (CCW) rotation first to seat the threads, then righty-tighty (CW) to screw it on. If anyone is watching me do this, 9 times out of 10, they will say "the other direction," like I don't know what I'm doing. But I know that I am ensuring the threads are properly seated and consequently the parts are less likely to fuse from having mashed threads.
Nice video ouido. I have the same scope and focal reducer. I did not have the extension tube to attach my dedicated astronomy camera to it. I have used several extensions that are not rigid. Your one piece extension is definitely the solution for my problem. I hope to get it soon and start imaging from my deck. Cloudy skies here in Toronto. Thank you for posting. Clear skies
Thanks AstroDeck! I used several extension rings, the one connecting the filterwheel to the rest of the imaging train came with my zwo asi1600mm camera. the rest of the extension rings I bought separately, including the sct to 2" adapter. Hope you'll have some clear skies soon!
Amazingly helpful, Wido! Just got a surprise early birthday present of an Edge 8 HD and was researching the best way to sort out my imaging train! Your videos and tutorials are marvellous and extremely helpful, so keep up the great work! Best wishes from Scotland! :)
Hi. I’m using the C8 Edge HD with this reducer but with my camera and filter wheel behind, the focal lens is exactly 1443mm after a plate solve. Not 1422mm. Anyway it’s wider and I’m happy with it. Clear skies and enjoy your C8. It’s a nice telescope. JM
In theory the image quality improves too. The reason is you will crop less in the optics light circle provided by the telescope. In most cases the quality stays the same because of the glas quality of the reducer. I use a RC6" with an 0.67 Reducer. Thanks for sharing this. Regards Andreas
Good video. I also have the EdgeHD 800 and 0.7x Reducer. For your viewers, you may want to explain that back focus is a critical measurement, measured from the back surface of the 0.7x Reducer (not including the threads). The EdgeHD 800 has a focal length closer to 2125mm (not what it says on the front of the scope). Celestron offers EdgeHD, 0.7x Reducers, and an Off-Axis Guider (OAG). From this list, you can sometimes only use any two of the three. The image circle of the EdgeHD 800 is about 42mm and the 0.7x Reducer reduces this to 26mm which limits the size of the sensor you can ultimately use. You can't easily use a DSLR with the OAG and 0.7x Reducer. Celestron OAG offers a clear aperture of 60mm on the larger 0.7x Reducers but only 35mm on the EdgeHD 800 (2" vs 3.25" form factor) and the OAG has a minimum prism center height that is 15mm. Compare 35mm to 26mm to 30mm and you will see why (when looking into their OAG) that half the image circle is cut-off. Fortunately, there are other "thin" OAG e.g. from QHY, ZWO, and others which will work with your existing kit (and refractors with a Reducer BF of perhaps only 60-65mm), which greatly widens the choice of what you can use. Without an OAG you may find EdgeHD 800 astrophotography difficult/frustrating. The 0.7x Reducer will initially make the task a lot easier. Simon
Hi Simon, thanks for all the info. I would not recommend the Edge HD for someone who just starts out in astrophotography - a smaller refractor is much better as it affords more inaccuracies in guiding without ruining your pictures. I did some initial tests this weekend with the .7 reducer with the filterwheel and camera and a "traditional" guidescope on the telescope, actually I used my small 50mm orion guidescope which is a bit on the short side in terms of focal length, with my zwo120mc. I was still happy with the results I got with 3 to 5 minute exposures, stars were not perfect, but pretty round in sub-optimal weather conditions. Thanks again and clear skies!
@@AstroForumSpace The two "locks" on the EdgeHD 800 are more like "clutches" so they help up to a point. If you have a focuser then small adjustments can be made whilst "locked". OAGs are not that difficult - I never tried guiding without one. 290 (I have a 178) has a small sensor that would pair well with a ZWO OAG or similar (not Celestron). I use OAG for a refractor, SCT, a wastepaper bin, etc. and stars are perfectly round. You could compare unguided with guided times to gauge the effectiveness of guiding and even with polar alignment off. Where you point the scope determines the movement of the mirror - probably when you least want it, too! No "wastepaper bins" btw. Simon
Hi Simon. I am having a senior moment here and wondering if you could clarify something you said above. You mention the 800 having an image circle of 42mm and only 26mm with the 0.7X FR. For some reason I keep wanting to think that the image circle would become larger with the FR since the FOV is greater. Can you clarify that for me? The reason for my interest is because I have a new to me EdgeHD 800 and want to use it with a FF Canon DSLR. I am trying to figure out the optimum couplers to minimize vignetting. I realize with a FF sensor I will have plenty but this is the camera I already have. Thanks
@@w8bya There are two issues with FF and 0.7x Reducer: BF is 105mm but an attached SLR is more e.g. 111mm. The image circle reduces to 26mm. For FF the EdgeHD 800 is OK without the 0.7x Reducer. Celestron could explain this (better) in their manual/product description? From their website (the issue): “The EdgeHD optics are designed to optimize an image circle 21mm in radius from the center of the field of view. Doubling this figure gives an image circle 42mm in diameter. This is big enough to illuminate a 35mm sensor. The OTA's image circle extends well beyond the formats of popular APS-C sensors found on many DSLR cameras and many smaller chips used in specialized astrophotography CCD cameras. If you are using one of the .7 reducer lenses for either the 1400 or 1100 Edge HD optical tubes, the diameter of the image circle will remain at 42mm. If you are using the .7 reducer lens for the 800 Edge HD the image circle will will shrink to 26.7mm in diameter. The shrunken image circle will fully illuminate a cropped DSLRs (APS-C) senor or smaller CCD”. Hope that helps. Simon
@@foxglovemead TU kindly for your reply. When you said "BF is 105mm but an attached SLR is more e.g. 111mm. The image circle reduces to 26mm." Is this reduction in image circle due to the BF being increased from 105mm to 111mm alone or are there other reasons? Also you said if you use either the 1100 or 1400 Edge scopes with the 0.7X FR the IC will remain at 42mm, is this because those scope use M48 sized coupling whereas the 800 uses only M42? I accept your answers to be accurate but I still do not understand why the IC drops when the FR is used with the 800. Can you maybe point to a URL or maybe show a simple ray diagram illustrating the reason? I appreciate your time in explaining this but so far I still do not understand WHY this is happening. TU
Thank you for the video. I bought the edge hd 8 as a christmas present to myself. I also have the f7 reducer and the t adaptor but was told I didn't need any more spacers. Needless to say I have been extremely frustrated and between the holes in the clouds I have been using it visually only. I am going to be on the phone first thing tomorrow.
Hi Robert, that's unfortunate. I've read the instructions that came with the reducer and asked some experts, I'm pretty sure it needs a 105mm backfocus. Hope you'll be able to sort it out. Weather here is terrible ATM but I'm going to try this asap. Cheers, wido.
@@AstroForumSpace I too read that but I was assured that I would be ok. Maybe it is why the weather is still bad if we keep on buying new toys. I have just added your hoodie to my list as well. Stay safe.
Hi Robert, I have an Edge HD with 0.7X reducer, but the 105mm back focus is not negotiable. I experienced this the hard way with severe streaking for 60%+ of the imaging field. I have tried various combinations of T-adapters, but could never quite get closer the 3-5mm, the tolerance is 105mm +/- 1.5mm. I have partially solved the problem using a Baader variable focus adapter, but I realised after that I need a T2 adapter to connect this to the 0.7X reducer. Unfortunately, I live in Ireland and all the suppliers insist on supplying from the UK...with BREXIT, that's taking 4 months plus with huge added costs! I'm debating whether or not to bother this year. but that's another discussion! Basic advice is that this will not work if you do not carefully work out the backfocus of your imaging rig and get appropriate adapters to give you as close to 105mm as possible. Once you have that, it is an amazing setup and will give you years of happy imaging!! Clear skies :)
Thank you all. I have been on the phone most of the morning g and still haven't got it working as shown in the video. The stupid thing is that when I reconnect the diagonal and put the camera in where the eyepiece is supposed to go I get an image aaarrrghhh.
Great timing! My first night out last night with my EgdeHD 8 and 0.7 reducer. The moon frames perfectly with my APS-C camera. Took some images of M42 too, but not with filters fitted yet. Some issues with vignetting with 1.25" filters according to what I've seen on other reviews. I've fortunately a 2" filter drawer but need to get the right backspacing before I can test that. Great video, thanks and best regards from the UK
Hi Mark, great! I just used my .7 reducer with filterwheel and 1.25" this weekend. Was expecting vignetting to be an issue but that was not such a big issue. Weather conditions were bad unfortunately. Hope we'll have some clear skies soon!
Respectfully, I thing there’s something that needs to be clarified. The amount of light a telescope gathers depends on the aperture diameter, not on the f-ratio. F-ratio determines how much of that light is focused on a given part of the field of view. That’s why when the f-ratio is faster you have a brighter image. While imaging, if you’re above read noise of the camera (added to the thermal noise), faint details of the object will begin to show, no matter the f-ratio. Certainly will take longer if optics are slower and that’s the benefit of faster systems. I use a C9.25 EdgeHD with hyperstar at f2.3 and sometimes at f10. So, at f2.3 faint details come faster.
@ Alfredo: Good point. May I ask something? You say: The amount of light collected by the telescope is determined by the aperture. - Looking at point-like sources and/or areal light in front of the scope (parallel light) the statement is obviously true. Same aperture - same light - no matter how long the "tube" is. - But looking at a real patch of night sky: I guess you will find more photons (absolute) per time in a wide patch of sky than in a narrow patch (FOV). So if you spread both onto a given&fixed sensor the scope with a long focal length will produce an image with a brighter areal luminosity than the scope with the shorter focal length -- given a fixed sensor, aperture and exposure time. Or am I mistaken? - So to my curiosity: Stars should stay equally bright (point sources) when prolonging the focal length while fixing everything else - whereas the areal luminosity should drop?! Thanks for clarification! -Chris
@@catchingphotons : Hi Chris The amount of light captured depends only on the telescope aperture (think of an analogy in which a bucket gathers rain drops). This light will come from the region of the sky, or FOV, where it’s pointing at. At the same aperture with short focal length, and thus faster f-ratio, more of that light will be focused on the same pixel, increasing the signal to noise ratio - SNR per pixel. If focal length is longer, then that same amount of light will be spread over more pixels. This results in that with the same aperture, and same time exposure, a faster f-ratio will produce a higher SNR image per pixel. Let’s assume we’re imaging a wide nebula. In a wider FOV we will gather more light from it, but what matters for capturing faint detail is to have more SNR per pixel. I’ll leave a link to my gallery where you can see images I’ve taken both at f10 and f2.3 with the same telescope (C9.25 EdgeHD). See for example the faint halo of M51 captured at f10. It is possible because the signal was above the total noise produced by the camera. Instagram: instagram.com/p/CAoJlqUpy1m/?igshid=hrmdx14gtbqb Full resolution here at Flickr: flic.kr/p/2j5EZqu About stars will happen the same and, being point light sources, at faster f-ratio would potentially saturate pixels faster that at a lower f-ratio, precisely because at faster f-ratio will direct more of that light to a single pixel.
@@alfredobeltran611 Ok thanks!! Quote: "At the same aperture with short focal length, and thus faster f-ratio, more of that light will be focused on the same pixel" But my argument was: If you collect light over the time d_t from a larger patch of sky you are able to collect more photons than from a smaller patch of sky over the same time d_t. Just because (physically) there are fewer photons coming from that patch of sky (because there is less universe behind that patch). >> So if you spread this total amount of photons on the same sensor the areal luminosity (photons per area sensor per time) does actually decrease with increased focal length. The SNR is "just" a side effect of the quantity of photons hitting the sensor/area/time :-) See my video about the science behind stacking and please (!) leave your comments under the video!! th-cam.com/video/BL31BMg8fLg/w-d-xo.html Clear skies (and high SNR) to all of you! -Chris
Chris Of course the bigger the area of the FOV, the more photons of that area you'll get. But to capture faint details we need to look at the SNR per pixel. By the way, subscribed already to your channel!
Nice video. One point worth mentioning is that the actual native focal length of the edge had 800 is 2125mm (according to the white paper). This can be confirmed by platsolving, once you have nailed down the 105mm backfocus.
Hi again, do you mean 2125mm? I did notice that I got a bit more focal length then I was expecting when aiming at the moon. It didn't fit the whole moon into a single shot with my asi1600mm, so I think you're right in saying that the focal length is a bit longer than advertised. Clear skies!
Got the 8" SCT from celestron and the .7 reducer.... With the asi294 pro, you get sharper images with the reducer due to better tracking and sampling. Often after drizzle, the images are better then using the native 2032 focal length.... BTW I am also using an OAG, reduces weight and helps to guide much more accurate at 2000mm focal length....
Great video! I appreciate you taking the time to share your experience. I use a field flattener on my smaller scopes but a reducer on skywatcher 100ed. It reduces the focal length and fstop but also helps with those smeared edges. Again, thanks for the vid from Tacoma, Washington USA
Yes I’m considering getting the 0.7 reducer for my C8 EdgeHD. It’s a bit pricey, so I’m waiting a bit to save up for it. I’m also going to need a better imaging camera and a proper go to equatorial mount versus the single fork arm one that the EdgeHD came with. Perhaps the Celestron Wedge would work well enough?? Great clear video by the way and I do enjoy visiting the Netherlands (been to Amsterdam probably 25 times!).
Thank you Martyn! I live in Utrecht, about 30 km from Amsterdam:-). The wedge definitely will improve your tracking, but I've heard that it cannot beat a true equatorial mount. And yes, Astrophotography is a moneypit. I would first go for a good EQ mount. If your tracking is accurate, you can start taking long exposures and that really improves your pictures. Good luck, clear skies!
Look forward to seeing some images with your new toy. I am actually waiting on my 0.8 reducer/flattener for my 80mm refractor. I was actually sent the wrong one, very annoying as I can a currently only take small objects in the centre of my frame because of the way the stars look without a flattener.
@@AstroForumSpace Thanks Wido yes looking forward to it, it's a standard 55mm backfocus so should be good. Wido have you tried our Australian based space podcast th-cam.com/video/4h7dKgTMBsY/w-d-xo.html you may like it. 👍👍
Great video. Always impressed with how knowlegable the Dutch are regarding optics. Guess it make sense since the dutch invented the telescope and the microscope. Oh, and the CD, of course.
I just bought the .7 reducer today, after 2 attempts at imaging at F10 and meeting with failure due to not enough stars for stacking. I am hopeful that the reducer will correct my issues. Until now, I’ve only images with HyperStar, F2 and the images are too small for some targets.
I’m curious. So it zooms out objects, but halves the exposure time needed to gather light for an image. Let’s say that the object in focus is the distant *”Black Eye Galaxy M64”* Will the final product of it be smaller due to the Reducer?
The reducer helps for sure but still does not increase the field of view enough for larger targets with my 8" SCT. I am thinking about buying another scope with a wider field of view. I have been looking at the Explorer Scientific Comet hunter and the Orion ED80T ......It's only money, can always make more....
Thanks, nice summary. I've got my .7 reducer waiting for me at home, it was on back order for ages. One question I have never been able to find an answer to, why is f/10 to f/7 considered 1 full f stop? I still need to wrap my head around the math associated with light gathering equivalents etc...
I tried to find the equation for this video, but couldn't find it. I did find this reference chart: havecamerawilltravel-com.cdn.ampproject.org/v/s/havecamerawilltravel.com/photographer/f-stop-chart-lens-apertures/amp/?amp_js_v=a6&_gsa=1&usqp=mq331AQHKAFQArABIA%3D%3D#aoh=16112992853014&referrer=https%3A%2F%2Fwww.google.com&_tf=Van%20%251%24s&share=https%3A%2F%2Fhavecamerawilltravel.com%2Fphotographer%2Ff-stop-chart-lens-apertures%2F. Cheers, wido.
Have not looked at the link below but you can always see what the light difference will be by squaring each f-number and dividing one by the other. So in this case if you take f/10 (you square 10 to get 100) and then take f/7 (and square 7 to get 49) then divide 100/49 you get 2.04. This is close enough to 2 which means that you are letting in twice as much light at f/7 as you are at f/10. A full f-stop is defined as changing the light by a factor of 2 which is what we have here.
Hi Wido, im new to the channel and have a question at the end of the video you measure the length of the back focus, i see you dont measure from the end of the tread, were do you start measuring on the edge 8, from the end of the thread or at the beginning of the thread at de reducer side?
Hi Wido, the 1600mm has 6.5mm to the chip, you also need to measure from the front of the reducer not the neck. you're probably not too far out but not quite :-)
I think you measure it wrong - at 11:05 it looks like you start at the end of the thread. Correct measurement is from the very top of the reducer. E.g. you have not enough backfocus in that image
According to the instructions you are right there. And the 6.5 mm back focus of the camera must also be taken into account. @AstroForum: I recommend a caliper for back focus measurements. It really depends on the millimeter ;-)
@@AstroForumSpace backfocus is not correct with your setup vido. You have actually 111.5mm but as long as your stars are still round in the edges... how is guiding without an off axis guider so far?
I did a quick test last Saturday under terrible weather conditions. I'm hesitating to share the results of my M81 attempt at half moon under cloudy city skies, but...long story short, the imaging train worked and I got nice in focus stars across the FoV with the setup shown in the video. Clear skies!
great video. i just bought an Edge 8. and 2600MM with zwo 2 inch EWF and optolong 3nm 2inches SHO and LRGB filters. I also have 0.7x reducer. and 174mm mini guidecamera. need some help for guiding setup. i need clarifications for the following: 1) which OAG is better suited zwo OAG-L or Celestron OAG? 2) would the new camera 2600MC DUO work well for Edge 8? Pls advise.
Yes, the whole world wants to get into Astrophotography. One of the few hobbies you can perform at home in complete solitude. Hope your gear will be delivered asap, thanks and clear skies!
@@AstroForumSpace I randomly came across this hobby about 2 months before the chaos began. So, at least I got enough equipment to image before the real shortages began.lol
Historically, I've been using a Hyperstar with my Celestron 8" since I was imaging with a fork mount. I recently purchased an Edge 11" with an EQ mount and I'm wondering if there are any benefits to using a .7 focal reducer compared to the Hyperstar or vise versa. Great information and thank you!
Hi Steve. A .7 reducer would allow you to shoot at a longer focal length than your hyperstar setup, but you'd also need to increase your exposure time as you're shooting at f/7. You'll need a good equatorial mount and guiding for accurate tracking.
Im desperately looking for this .7x reducer but still nowhere to be found. That's why I heard TS CCD47 .67x reducer for RC scopes works on EdgeHD 800 scopes so I ordered. Will see if it's gonna work or not. Actually there is a website shows that is working already if u are not sure about it.
So more questions if you don’t mind. So this is what I will be working with. Zwo 2 inch filter wheel ( can’t tell the one you have in the video) zwoasi294 Mc pro, celestron .7 reducer. Ok so here’s my question. Will I need any of those 42 to 48 adapters. I got the T adaptor that’s for the c8 hd. It’s different then yours so not sure of the threads. I imagine they are the same. But who knows lol. I hope it goes together as clean as yours did.
Ah, I'll have to check as I made this video a while ago. I could send you the exact list of spacers and adapters ordered, but I have a 1.25" filterwheel. Might be similar size, don't know.
@@AstroForumSpace thanks that’s ok. Between the camera and filter wheel I should have what I need. We shall see. They still no idea when it will get back in stock anyways.
Purchased a .7 reducer for my 9.25”HD Celestron telescope. However, when I tried to remove it i found it could not be removed. The reducer was stuck on the back of the telescope. I purchased a strap wrench from Amazon to remove it without damaging it. When it came off it took the backplate adapter with it. Without this adapter the telescope was useless. The solution I found was to purchase some medium bond lock-tight and put a little on the threads of the back plate adapter stuck to the reducer then screw it on the back of the 9.25” back. I let it set overnight. And then tried to remove the reducer with the strap wrench. Modest pressure removed it from the backplate adapter. Problem solved!
Just use a rubber strap wrench and you can apply equal pressure around the unit without damaging the item. The idea with the use of lock-tight came from cloudy skies!
I have both 1.25" and 2" eyepieces, and I find the 2" eyepieces to be better, larger field of view, more comfortable viewing, whether the telescope is large or small.
2" widefield EPs will benefit the 8" SCT when their field-stop is wider than the same FL on a 1.25" EP. However, for smaller focal length EPs, the limiting factor is the field stop and not always within the EP e.g. with the baffles/tube assembly in the scope. For smaller focal length EP you won't see any benefit and there will be increased weight and cost considerations. Celestron supply a 40mm Plössl with the EdgeHD 800 with a relatively narrow AFOV. Using a widefield bigger/longer EP will not give any increase in FOV because of the baffle in the scope. For smaller focal lengths a 1.25" EP with a 1.25" adapter is cheaper/lighter anyway without any disadvantages of the 2" equivalent FL.
Problem im running into is im trying to switch from manual using my failing dslr and a lens, to a geq telescope with a zwo camera and have no idea all the pieces and parts i need, and how to set it up out of the box. Seems like noone sets up a kit from scratch and just does part reviews.
Hi there, yes, astrophotography can be quite overwhelming and it's difficult to capture everything in one movie. On my website, I have multiple blogs like this one: astroforumspace.com/seven-essential-steps-to-start-astrophotography/ where I attempt to give an overview of the things you need to think about and gear reviews. Hope this helps, don't hesitate to ask questions. Clear skies!
Just got my reducer from Amazon. 2 popped up for sale out of the blue and I was quick on the trigger. Now to choose a camera. I have 2000 to spend and those red ZWO's are pretty. What would you recommend?
Hi Astrocapetown, I just did a first test this weekend and the 105mm setup worked fine. I didn't take into account an extra 12mm for the potential distance between the thread of the .7 reducer and the actual reducer lens...Clear skies.
A stupid question since I am thinking about buying a Celestron 8" or 9.25". In direct viewing to observe planets, will the quality be really better compared to my Nikon P1000 camera chich cost less than a quarter of those telescope with a maximum focal lenght of 3000mm???
Yes, definitely. The p1000 is cheaper and easier to setup, but that camera is not optimized for night sky observations. It depends a bit on what you're looking for. If you just want to have a bit of fun, the p1000 will do. If you're looking for high quality images, you'll need a planetary scope with a large aperture and focal length. FYI: th-cam.com/video/wqGezdz-FBY/w-d-xo.html. Cheers!
@@AstroForumSpace You are great! Thanks for your valuable input! I am not in spending hours stacking images to be able to see something but wanted to look directly to things. My P1000 give me some pretty good results for the moon and barely acceptable photos of Saturn, but nothing sharp enough and I wanted to be sure that an 'expensive' telescope will aloow me to see more then just 'white spots' in the sky....
Great review! Where online (URL) do I get the field of view calculator? Currently I have a Canon SL1 (cropped sensor) camera and would like to know the field of view with this camera for my C11 f/10 SCT, Astro-Physics 155 mm f/7 EDF, Astro-Physics 130 mm f/6 EDF and 73 mm f/5.9 William Optic refractors.
Sorry to bug you again brother but could you link me to the spacers you used to achieve 105 mm of back focus? I'm unsure what ones I need. The ones I have are M42. They are too small.
Viewers should know that the website for the edge HD 0.7 reducer says the back focus is 146mm, not 105mm like you’re saying here. Of course you never demonstrated that 105mm actually works in this video, I guess you never checked to see.
Reason 1. check, very good explanation. Reason 2. check also nice explanation. Reason 3. this myth again :D ... I know you disagree but food for thought here: if that f/ration myth were true ... why do you think all of the highest end professional instruments meant to capture deep-sky objects are f/30 with humongous apertures? Maybe because ONLY aperture lets you gather more light and you cannot achieve this by just reducing your focal length? I would be too happy to talk to you about this because I think such a great astrophotography communicator as yourself shouldn't be propagating this misconception. We can talk on Cloudynights
Hi Christopher we are in 2021 imaging and observation are two different things Celestron make also an raza at f/2 to gather en en more light faster this kind of telescope is designed specially to gâter more light to cut down imaging time exactly like he explains
Celestron Edge has a field of curvature much less than the classical SCT Celestron . It is not a flat field telescope. Only a Slevogt Schmidt Cassegrain is nearly Flat field telescope. This is a confusion with an aplanatic telescope or coma and Spherical aberration, free telescope. The reducer for Celestron SCT Edge doesn't touch the Coma and the spherical aberration, but improve the chromatism , the field of curvature and the stigmatism.
Celestron does a horrible job documenting the backfocus of their scopes. I still have no idea what the backfocus of my C9.25 (Non-edge) without reducer would be, for the .63 and .4 reducer I luckily found enough stuff online :D. So I use it exclusively with reducer :'D. They should really fix that :'D.
@@AstroForumSpace the thing is, there *should* be a 'correct' backfocus for any scope, just reaching focus doenst really tell you whether you're right or not, as it might compromise the optical performance or mess with focal lenght and f-ratio n stuff. But I rarely see manufactures making those figures public, even tho they have them, which really sucks :D
True. You know your stuff Luna! Based on my own calculations, I was expecting a different FoV so I'm probably at a longer focal length...ah well, live and learn.
@@AstroForumSpace Hey, thanks :) Just hours upon hours of research during bad weather. Trial and error would probably be the best way to find out about the correct backfocus, but it takes forever and is very tedious work, so I just accept slight discrepancies.
Have you noted any red & blue color fringing from your EdgeHD with the Celestron 0.7 focal reducer when photographing the moon? I have as shown at: mstecker.com/pages/CelestronEdgeHD925-tests.htm Not sure what causes it, but Cloudy Nights reported it as a problem with the Celestron 0.7x EdgeHD focal reducer. www.cloudynights.com/topic/758116-whats-wrong-edgehd-925-with-7-focal-reducer/
Hi Michael, I'm always imaging the moon in monochrome, so I wouldn't know. And for deep-sky I also use a cooled monochrome camera with lrgb and narrowband filters.
Very informative and helpful. Thank you. I have an EdgeHD 8 and look forward to getting the .7 reducer as the next upgrade. Pointer - when threading on filters, adapters, etc. try doing a left-loosy (CCW) rotation first to seat the threads, then righty-tighty (CW) to screw it on. If anyone is watching me do this, 9 times out of 10, they will say "the other direction," like I don't know what I'm doing. But I know that I am ensuring the threads are properly seated and consequently the parts are less likely to fuse from having mashed threads.
Sounds like good advice. Cheers.
Nice video ouido. I have the same scope and focal reducer. I did not have the extension tube to attach my dedicated astronomy camera to it. I have used several extensions that are not rigid. Your one piece extension is definitely the solution for my problem. I hope to get it soon and start imaging from my deck. Cloudy skies here in Toronto. Thank you for posting. Clear skies
Thanks AstroDeck! I used several extension rings, the one connecting the filterwheel to the rest of the imaging train came with my zwo asi1600mm camera. the rest of the extension rings I bought separately, including the sct to 2" adapter. Hope you'll have some clear skies soon!
Amazingly helpful, Wido! Just got a surprise early birthday present of an Edge 8 HD and was researching the best way to sort out my imaging train! Your videos and tutorials are marvellous and extremely helpful, so keep up the great work! Best wishes from Scotland! :)
Thanks for the positive feedback! Hope you'll have some clear skies in Scotland!
I’ve got the 0.63 reducer and use it with both my Celestron 9.25” and my 5”. It’s must with SCTs for deep sky photography.
Thanks Fernando, clear skies!
Hi.
I’m using the C8 Edge HD with this reducer but with my camera and filter wheel behind, the focal lens is exactly 1443mm after a plate solve. Not 1422mm.
Anyway it’s wider and I’m happy with it.
Clear skies and enjoy your C8. It’s a nice telescope.
JM
Sound good Jean-Marc! Thanks for the info. Hope I'll get that little bit of extra field of view.
In theory the image quality improves too. The reason is you will crop less in the optics light circle provided by the telescope. In most cases the quality stays the same because of the glas quality of the reducer.
I use a RC6" with an 0.67 Reducer.
Thanks for sharing this.
Regards
Andreas
thanks for the additional info!
Good video. I also have the EdgeHD 800 and 0.7x Reducer. For your viewers, you may want to explain that back focus is a critical measurement, measured from the back surface of the 0.7x Reducer (not including the threads). The EdgeHD 800 has a focal length closer to 2125mm (not what it says on the front of the scope). Celestron offers EdgeHD, 0.7x Reducers, and an Off-Axis Guider (OAG). From this list, you can sometimes only use any two of the three. The image circle of the EdgeHD 800 is about 42mm and the 0.7x Reducer reduces this to 26mm which limits the size of the sensor you can ultimately use. You can't easily use a DSLR with the OAG and 0.7x Reducer. Celestron OAG offers a clear aperture of 60mm on the larger 0.7x Reducers but only 35mm on the EdgeHD 800 (2" vs 3.25" form factor) and the OAG has a minimum prism center height that is 15mm. Compare 35mm to 26mm to 30mm and you will see why (when looking into their OAG) that half the image circle is cut-off. Fortunately, there are other "thin" OAG e.g. from QHY, ZWO, and others which will work with your existing kit (and refractors with a Reducer BF of perhaps only 60-65mm), which greatly widens the choice of what you can use. Without an OAG you may find EdgeHD 800 astrophotography difficult/frustrating. The 0.7x Reducer will initially make the task a lot easier. Simon
Hi Simon, thanks for all the info. I would not recommend the Edge HD for someone who just starts out in astrophotography - a smaller refractor is much better as it affords more inaccuracies in guiding without ruining your pictures. I did some initial tests this weekend with the .7 reducer with the filterwheel and camera and a "traditional" guidescope on the telescope, actually I used my small 50mm orion guidescope which is a bit on the short side in terms of focal length, with my zwo120mc. I was still happy with the results I got with 3 to 5 minute exposures, stars were not perfect, but pretty round in sub-optimal weather conditions. Thanks again and clear skies!
@@AstroForumSpace The two "locks" on the EdgeHD 800 are more like "clutches" so they help up to a point. If you have a focuser then small adjustments can be made whilst "locked". OAGs are not that difficult - I never tried guiding without one. 290 (I have a 178) has a small sensor that would pair well with a ZWO OAG or similar (not Celestron). I use OAG for a refractor, SCT, a wastepaper bin, etc. and stars are perfectly round. You could compare unguided with guided times to gauge the effectiveness of guiding and even with polar alignment off. Where you point the scope determines the movement of the mirror - probably when you least want it, too! No "wastepaper bins" btw. Simon
Hi Simon. I am having a senior moment here and wondering if you could clarify something you said above. You mention the 800 having an image circle of 42mm and only 26mm with the 0.7X FR. For some reason I keep wanting to think that the image circle would become larger with the FR since the FOV is greater. Can you clarify that for me?
The reason for my interest is because I have a new to me EdgeHD 800 and want to use it with a FF Canon DSLR. I am trying to figure out the optimum couplers to minimize vignetting. I realize with a FF sensor I will have plenty but this is the camera I already have. Thanks
@@w8bya There are two issues with FF and 0.7x Reducer: BF is 105mm but an attached SLR is more e.g. 111mm. The image circle reduces to 26mm. For FF the EdgeHD 800 is OK without the 0.7x Reducer. Celestron could explain this (better) in their manual/product description? From their website (the issue): “The EdgeHD optics are designed to optimize an image circle 21mm in radius from the center of the field of view. Doubling this figure gives an image circle 42mm in diameter. This is big enough to illuminate a 35mm sensor. The OTA's image circle extends well beyond the formats of popular APS-C sensors found on many DSLR cameras and many smaller chips used in specialized astrophotography CCD cameras.
If you are using one of the .7 reducer lenses for either the 1400 or 1100 Edge HD optical tubes, the diameter of the image circle will remain at 42mm. If you are using the .7 reducer lens for the 800 Edge HD the image circle will will shrink to 26.7mm in diameter. The shrunken image circle will fully illuminate a cropped DSLRs (APS-C) senor or smaller CCD”. Hope that helps. Simon
@@foxglovemead TU kindly for your reply.
When you said "BF is 105mm but an attached SLR is more e.g. 111mm. The image circle reduces to 26mm." Is this reduction in image circle due to the BF being increased from 105mm to 111mm alone or are there other reasons?
Also you said if you use either the 1100 or 1400 Edge scopes with the 0.7X FR the IC will remain at 42mm, is this because those scope use M48 sized coupling whereas the 800 uses only M42?
I accept your answers to be accurate but I still do not understand why the IC drops when the FR is used with the 800. Can you maybe point to a URL or maybe show a simple ray diagram illustrating the reason?
I appreciate your time in explaining this but so far I still do not understand WHY this is happening. TU
Thank you for the video. I bought the edge hd 8 as a christmas present to myself. I also have the f7 reducer and the t adaptor but was told I didn't need any more spacers. Needless to say I have been extremely frustrated and between the holes in the clouds I have been using it visually only. I am going to be on the phone first thing tomorrow.
Hi Robert, that's unfortunate. I've read the instructions that came with the reducer and asked some experts, I'm pretty sure it needs a 105mm backfocus. Hope you'll be able to sort it out. Weather here is terrible ATM but I'm going to try this asap. Cheers, wido.
@@AstroForumSpace I too read that but I was assured that I would be ok. Maybe it is why the weather is still bad if we keep on buying new toys. I have just added your hoodie to my list as well. Stay safe.
@@robertchandler2218 LOL, thanks!
Hi Robert, I have an Edge HD with 0.7X reducer, but the 105mm back focus is not negotiable. I experienced this the hard way with severe streaking for 60%+ of the imaging field. I have tried various combinations of T-adapters, but could never quite get closer the 3-5mm, the tolerance is 105mm +/- 1.5mm.
I have partially solved the problem using a Baader variable focus adapter, but I realised after that I need a T2 adapter to connect this to the 0.7X reducer. Unfortunately, I live in Ireland and all the suppliers insist on supplying from the UK...with BREXIT, that's taking 4 months plus with huge added costs! I'm debating whether or not to bother this year. but that's another discussion!
Basic advice is that this will not work if you do not carefully work out the backfocus of your imaging rig and get appropriate adapters to give you as close to 105mm as possible. Once you have that, it is an amazing setup and will give you years of happy imaging!! Clear skies :)
Thank you all. I have been on the phone most of the morning g and still haven't got it working as shown in the video. The stupid thing is that when I reconnect the diagonal and put the camera in where the eyepiece is supposed to go I get an image aaarrrghhh.
Great timing! My first night out last night with my EgdeHD 8 and 0.7 reducer. The moon frames perfectly with my APS-C camera. Took some images of M42 too, but not with filters fitted yet. Some issues with vignetting with 1.25" filters according to what I've seen on other reviews. I've fortunately a 2" filter drawer but need to get the right backspacing before I can test that. Great video, thanks and best regards from the UK
Hi Mark, great! I just used my .7 reducer with filterwheel and 1.25" this weekend. Was expecting vignetting to be an issue but that was not such a big issue. Weather conditions were bad unfortunately. Hope we'll have some clear skies soon!
Respectfully, I thing there’s something that needs to be clarified. The amount of light a telescope gathers depends on the aperture diameter, not on the f-ratio. F-ratio determines how much of that light is focused on a given part of the field of view. That’s why when the f-ratio is faster you have a brighter image.
While imaging, if you’re above read noise of the camera (added to the thermal noise), faint details of the object will begin to show, no matter the f-ratio. Certainly will take longer if optics are slower and that’s the benefit of faster systems. I use a C9.25 EdgeHD with hyperstar at f2.3 and sometimes at f10. So, at f2.3 faint details come faster.
Yes, good point. Aperture determines how much light the scope is able to gather. I'll pin your post to clarify this, thanks. Clear skies.
@ Alfredo: Good point. May I ask something?
You say: The amount of light collected by the telescope is determined by the aperture.
- Looking at point-like sources and/or areal light in front of the scope (parallel light) the statement is obviously true. Same aperture - same light - no matter how long the "tube" is.
- But looking at a real patch of night sky: I guess you will find more photons (absolute) per time in a wide patch of sky than in a narrow patch (FOV). So if you spread both onto a given&fixed sensor the scope with a long focal length will produce an image with a brighter areal luminosity than the scope with the shorter focal length -- given a fixed sensor, aperture and exposure time. Or am I mistaken?
- So to my curiosity: Stars should stay equally bright (point sources) when prolonging the focal length while fixing everything else - whereas the areal luminosity should drop?!
Thanks for clarification!
-Chris
@@catchingphotons :
Hi Chris
The amount of light captured depends only on the telescope aperture (think of an analogy in which a bucket gathers rain drops). This light will come from the region of the sky, or FOV, where it’s pointing at.
At the same aperture with short focal length, and thus faster f-ratio, more of that light will be focused on the same pixel, increasing the signal to noise ratio - SNR per pixel. If focal length is longer, then that same amount of light will be spread over more pixels.
This results in that with the same aperture, and same time exposure, a faster f-ratio will produce a higher SNR image per pixel.
Let’s assume we’re imaging a wide nebula. In a wider FOV we will gather more light from it, but what matters for capturing faint detail is to have more SNR per pixel.
I’ll leave a link to my gallery where you can see images I’ve taken both at f10 and f2.3 with the same telescope (C9.25 EdgeHD). See for example the faint halo of M51 captured at f10. It is possible because the signal was above the total noise produced by the camera.
Instagram: instagram.com/p/CAoJlqUpy1m/?igshid=hrmdx14gtbqb
Full resolution here at Flickr: flic.kr/p/2j5EZqu
About stars will happen the same and, being point light sources, at faster f-ratio would potentially saturate pixels faster that at a lower f-ratio, precisely because at faster f-ratio will direct more of that light to a single pixel.
@@alfredobeltran611 Ok thanks!!
Quote: "At the same aperture with short focal length, and thus faster f-ratio, more of that light will be focused on the same pixel"
But my argument was: If you collect light over the time d_t from a larger patch of sky you are able to collect more photons than from a smaller patch of sky over the same time d_t. Just because (physically) there are fewer photons coming from that patch of sky (because there is less universe behind that patch).
>> So if you spread this total amount of photons on the same sensor the areal luminosity (photons per area sensor per time) does actually decrease with increased focal length. The SNR is "just" a side effect of the quantity of photons hitting the sensor/area/time :-)
See my video about the science behind stacking and please (!) leave your comments under the video!!
th-cam.com/video/BL31BMg8fLg/w-d-xo.html
Clear skies (and high SNR) to all of you!
-Chris
Chris
Of course the bigger the area of the FOV, the more photons of that area you'll get. But to capture faint details we need to look at the SNR per pixel.
By the way, subscribed already to your channel!
This has cleared a lot of issues! Thanks
Glad I could help!
@@AstroForumSpace Can you please link your t2 adapter with 3 parts. Im want to integrate an OAG as well. Thankss
Hi Wido I Ordered the Focal Reducer will be delivered on 07/21/22 can't wait to try it.
It worked out great for me. Hope you'll have a good time with that reducer, clear skies 😉!
Hi Wido, Which Auto focuser do you use with your Celestron Edge HD scope.I have 9.25 Edge HD
I love OPT.
Nice video. One point worth mentioning is that the actual native focal length of the edge had 800 is 2125mm (according to the white paper). This can be confirmed by platsolving, once you have nailed down the 105mm backfocus.
Hi again, do you mean 2125mm? I did notice that I got a bit more focal length then I was expecting when aiming at the moon. It didn't fit the whole moon into a single shot with my asi1600mm, so I think you're right in saying that the focal length is a bit longer than advertised. Clear skies!
@@AstroForumSpace it definitely is. When you plate solve at 105mm back focus you get 1488mm which is correct.
Got the 8" SCT from celestron and the .7 reducer.... With the asi294 pro, you get sharper images with the reducer due to better tracking and sampling. Often after drizzle, the images are better then using the native 2032 focal length.... BTW I am also using an OAG, reduces weight and helps to guide much more accurate at 2000mm focal length....
Great video! I appreciate you taking the time to share your experience. I use a field flattener on my smaller scopes but a reducer on skywatcher 100ed. It reduces the focal length and fstop but also helps with those smeared edges. Again, thanks for the vid from Tacoma, Washington USA
Thanks Chad, also for the tip on using a reducer with a refractor. Clear skies!
If I ever get my Celestron 9.25 VX, I definitely will. The lead time is 10 months right now after ordering.
I feel for you! Yes, most astrogear is delayed and more expensive due to limited production (covid) and more expensive transportation costs.
Yes I’m considering getting the 0.7 reducer for my C8 EdgeHD. It’s a bit pricey, so I’m waiting a bit to save up for it. I’m also going to need a better imaging camera and a proper go to equatorial mount versus the single fork arm one that the EdgeHD came with. Perhaps the Celestron Wedge would work well enough?? Great clear video by the way and I do enjoy visiting the Netherlands (been to Amsterdam probably 25 times!).
Thank you Martyn! I live in Utrecht, about 30 km from Amsterdam:-). The wedge definitely will improve your tracking, but I've heard that it cannot beat a true equatorial mount. And yes, Astrophotography is a moneypit. I would first go for a good EQ mount. If your tracking is accurate, you can start taking long exposures and that really improves your pictures. Good luck, clear skies!
Good luck finding one........Amazon has 1 now.......if you hurry
It is very pricey indeed one thing that is putting me off the Edge HD
@@AstroSoundscape that and you cant find one anywhere right now.......
Look forward to seeing some images with your new toy. I am actually waiting on my 0.8 reducer/flattener for my 80mm refractor. I was actually sent the wrong one, very annoying as I can a currently only take small objects in the centre of my frame because of the way the stars look without a flattener.
Thanks Ollie. Yes, a flattener definitely helps, you'll need to check out the correct back focus. Hope you'll get those round stars! Best, Wido.
@@AstroForumSpace Thanks Wido yes looking forward to it, it's a standard 55mm backfocus so should be good. Wido have you tried our Australian based space podcast th-cam.com/video/4h7dKgTMBsY/w-d-xo.html you may like it. 👍👍
You changed your wallpaper!
My wife did, lol.😉🌌
Great video. Always impressed with how knowlegable the Dutch are regarding optics. Guess it make sense since the dutch invented the telescope and the microscope. Oh, and the CD, of course.
I just bought the .7 reducer today, after 2 attempts at imaging at F10 and meeting with failure due to not enough stars for stacking. I am hopeful that the reducer will correct my issues. Until now, I’ve only images with HyperStar, F2 and the images are too small for some targets.
I’m curious. So it zooms out objects, but halves the exposure time needed to gather light for an image. Let’s say that the object in focus is the distant *”Black Eye Galaxy M64”* Will the final product of it be smaller due to the Reducer?
Yes, use astronomy.tools to calculate your exact fov.
The reducer helps for sure but still does not increase the field of view enough for larger targets with my 8" SCT. I am thinking about buying another scope with a wider field of view. I have been looking at the Explorer Scientific Comet hunter and the Orion ED80T ......It's only money, can always make more....
Hi, yes. I really like my 80/480mm telescope for widefield pictures (larger nebulas). Clear skies!
I WANT the .7 Reducer.
Can you add a link for the extender you are using? Just ordering an EdgeHS 8". Great video...thanks!
Thanks, nice summary. I've got my .7 reducer waiting for me at home, it was on back order for ages. One question I have never been able to find an answer to, why is f/10 to f/7 considered 1 full f stop? I still need to wrap my head around the math associated with light gathering equivalents etc...
I tried to find the equation for this video, but couldn't find it. I did find this reference chart: havecamerawilltravel-com.cdn.ampproject.org/v/s/havecamerawilltravel.com/photographer/f-stop-chart-lens-apertures/amp/?amp_js_v=a6&_gsa=1&usqp=mq331AQHKAFQArABIA%3D%3D#aoh=16112992853014&referrer=https%3A%2F%2Fwww.google.com&_tf=Van%20%251%24s&share=https%3A%2F%2Fhavecamerawilltravel.com%2Fphotographer%2Ff-stop-chart-lens-apertures%2F. Cheers, wido.
Have not looked at the link below but you can always see what the light difference will be by squaring each f-number and dividing one by the other. So in this case if you take f/10 (you square 10 to get 100) and then take f/7 (and square 7 to get 49) then divide 100/49 you get 2.04. This is close enough to 2 which means that you are letting in twice as much light at f/7 as you are at f/10. A full f-stop is defined as changing the light by a factor of 2 which is what we have here.
Hi Wido, im new to the channel and have a question at the end of the video you measure the length of the back focus, i see you dont measure from the end of the tread, were do you start measuring on the edge 8, from the end of the thread or at the beginning of the thread at de reducer side?
If i remember correctly...it was 105mm from the thread of the reducer to the camera sensor. Good luck!
I have the Celestron 8" SCT with a 0.63 reducer
Hi Wido, the 1600mm has 6.5mm to the chip, you also need to measure from the front of the reducer not the neck. you're probably not too far out but not quite :-)
Yes, thanks. I took that into account. 6.5mm to the chip + 20mm for the filterwheel = 26.5mm. clear skies!
@@AstroForumSpace ok just looked wrong when you had the measuring tape on the side
I think you measure it wrong - at 11:05 it looks like you start at the end of the thread. Correct measurement is from the very top of the reducer. E.g. you have not enough backfocus in that image
According to the instructions you are right there. And the 6.5 mm back focus of the camera must also be taken into account. @AstroForum: I recommend a caliper for back focus measurements. It really depends on the millimeter ;-)
Hi there, I've measured it from the end of the reducer. Clear skies!
@@thefirstandroiduser6956 thanks, yes. I've checked the zwo manuals and asked an astroshop, clear skies!
@@AstroForumSpace backfocus is not correct with your setup vido. You have actually 111.5mm but as long as your stars are still round in the edges... how is guiding without an off axis guider so far?
I love your helpful videos :-)
Thanks!
I have a Celestron C6 with a .63 reducer but always end up having to crop out a lot of the image because of the rounded stars on the edge of the FOV
The C8 edge reducer gives good stars to the edge if you get your spacing correct.
I did a quick test last Saturday under terrible weather conditions. I'm hesitating to share the results of my M81 attempt at half moon under cloudy city skies, but...long story short, the imaging train worked and I got nice in focus stars across the FoV with the setup shown in the video. Clear skies!
Edge HD 9, 25 focal lengths 2350
great video. i just bought an Edge 8. and 2600MM with zwo 2 inch EWF and optolong 3nm 2inches SHO and LRGB filters. I also have 0.7x reducer. and 174mm mini guidecamera.
need some help for guiding setup. i need clarifications for the following:
1) which OAG is better suited zwo OAG-L or Celestron OAG?
2) would the new camera 2600MC DUO work well for Edge 8?
Pls advise.
Just ordered this reducer last night. Won't be getting for 6 months of course. No big deal because my 925 wont be here for 6 months either lol.
Yes, the whole world wants to get into Astrophotography. One of the few hobbies you can perform at home in complete solitude. Hope your gear will be delivered asap, thanks and clear skies!
@@AstroForumSpace I randomly came across this hobby about 2 months before the chaos began. So, at least I got enough equipment to image before the real shortages began.lol
Can you also advise the bracket that you have used for your guidescope please.
I've bought this one for my Orion mini guidescope: www.teleskop-express.de/shop/product_info.php/info/p300
Thank you again. There are a few holes in the clouds at the moment.ent so I am hoping to get some images on the 120ed
Historically, I've been using a Hyperstar with my Celestron 8" since I was imaging with a fork mount. I recently purchased an Edge 11" with an EQ mount and I'm wondering if there are any benefits to using a .7 focal reducer compared to the Hyperstar or vise versa. Great information and thank you!
Hi Steve. A .7 reducer would allow you to shoot at a longer focal length than your hyperstar setup, but you'd also need to increase your exposure time as you're shooting at f/7. You'll need a good equatorial mount and guiding for accurate tracking.
I just ordered the Edge 800, and the Focal Reducer. going to try OAG wish me Luck LOL, 105 or 133mm for back focus now I see conflicting info
Good luck! It's 105mm for the 8 inch.
@@AstroForumSpace Yes I see that now with Reducer 103 with out 133 I believe I understand that now. Thank you so much for the reply.
Im desperately looking for this .7x reducer but still nowhere to be found. That's why I heard TS CCD47 .67x reducer for RC scopes works on EdgeHD 800 scopes so I ordered. Will see if it's gonna work or not. Actually there is a website shows that is working already if u are not sure about it.
Hi there, the .7 reducers are in stock in Europe: bit.ly/3pvopON
@@AstroForumSpace OMG thank you but its too late now. If mines work itll be cheaper anyway. Thanks again how I miss that site, cant believe :)) 👍
So more questions if you don’t mind. So this is what I will be working with. Zwo 2 inch filter wheel ( can’t tell the one you have in the video) zwoasi294 Mc pro, celestron .7 reducer. Ok so here’s my question. Will I need any of those 42 to 48 adapters. I got the T adaptor that’s for the c8 hd. It’s different then yours so not sure of the threads. I imagine they are the same. But who knows lol. I hope it goes together as clean as yours did.
Ah, I'll have to check as I made this video a while ago. I could send you the exact list of spacers and adapters ordered, but I have a 1.25" filterwheel. Might be similar size, don't know.
@@AstroForumSpace thanks that’s ok. Between the camera and filter wheel I should have what I need. We shall see. They still no idea when it will get back in stock anyways.
Purchased a .7 reducer for my 9.25”HD Celestron telescope. However, when I tried to remove it i found it could not be removed. The reducer was stuck on the back of the telescope. I purchased a strap wrench from Amazon to remove it without damaging it. When it came off it took the backplate adapter with it. Without this adapter the telescope was useless. The solution I found was to purchase some medium bond lock-tight and put a little on the threads of the back plate adapter stuck to the reducer then screw it on the back of the 9.25” back. I let it set overnight. And then tried to remove the reducer with the strap wrench. Modest pressure removed it from the backplate adapter. Problem solved!
I've the same issue with my filterwheel and extension ring, can't get it removed. Clear skies!
Just use a rubber strap wrench and you can apply equal pressure around the unit without damaging the item. The idea with the use of lock-tight came from cloudy skies!
for visual observing, would you recommend getting the 2“ eyepieces with a 8“ sct?
Yes, or connect a camera :-).
I have both 1.25" and 2" eyepieces, and I find the 2" eyepieces to be better, larger field of view, more comfortable viewing, whether the telescope is large or small.
2" widefield EPs will benefit the 8" SCT when their field-stop is wider than the same FL on a 1.25" EP. However, for smaller focal length EPs, the limiting factor is the field stop and not always within the EP e.g. with the baffles/tube assembly in the scope. For smaller focal length EP you won't see any benefit and there will be increased weight and cost considerations. Celestron supply a 40mm Plössl with the EdgeHD 800 with a relatively narrow AFOV. Using a widefield bigger/longer EP will not give any increase in FOV because of the baffle in the scope. For smaller focal lengths a 1.25" EP with a 1.25" adapter is cheaper/lighter anyway without any disadvantages of the 2" equivalent FL.
Problem im running into is im trying to switch from manual using my failing dslr and a lens, to a geq telescope with a zwo camera and have no idea all the pieces and parts i need, and how to set it up out of the box. Seems like noone sets up a kit from scratch and just does part reviews.
Hi there, yes, astrophotography can be quite overwhelming and it's difficult to capture everything in one movie. On my website, I have multiple blogs like this one: astroforumspace.com/seven-essential-steps-to-start-astrophotography/ where I attempt to give an overview of the things you need to think about and gear reviews. Hope this helps, don't hesitate to ask questions. Clear skies!
where did you buy that amazing hoodie???
Can I add the celestron 6.3 reducer together with this reducer or is that not going to work
No, you need either a .7 reducer or the hyperstar.
Just got my reducer from Amazon. 2 popped up for sale out of the blue and I was quick on the trigger. Now to choose a camera. I have 2000 to spend and those red ZWO's are pretty. What would you recommend?
Hi there, congrats. As for zwo, i made this video on zwo color cameras, perhaps useful: th-cam.com/video/kNL12mCbbm8/w-d-xo.html clear skies!
Did you take into account that the reducer lens screwed into the extender? If not, you need to add another 12mm to compensate.
Hi Astrocapetown, I just did a first test this weekend and the 105mm setup worked fine. I didn't take into account an extra 12mm for the potential distance between the thread of the .7 reducer and the actual reducer lens...Clear skies.
My 8" EdgeHD white paper has the backfocus at 133.35mm. Not 105mm. Thanks.
It has to be 105mm for the edge hd 8". Check: www.celestron.com/products/reducer-lens-7x-edgehd-800
@@AstroForumSpace ahh yes, with the reducer lens on the 8". The larger EdgeHD's have the same back focus with the reducer! Thanks for the correction !
Can you start posting some of your videos on Rumble. Many of us are moving to that platform because of censorship on TH-cam.
Never heard of it. I'll take a look.
What censorship? Rumor or lame conspiracy theory?
A stupid question since I am thinking about buying a Celestron 8" or 9.25". In direct viewing to observe planets, will the quality be really better compared to my Nikon P1000 camera chich cost less than a quarter of those telescope with a maximum focal lenght of 3000mm???
Yes, definitely. The p1000 is cheaper and easier to setup, but that camera is not optimized for night sky observations. It depends a bit on what you're looking for. If you just want to have a bit of fun, the p1000 will do. If you're looking for high quality images, you'll need a planetary scope with a large aperture and focal length. FYI: th-cam.com/video/wqGezdz-FBY/w-d-xo.html. Cheers!
@@AstroForumSpace You are great! Thanks for your valuable input! I am not in spending hours stacking images to be able to see something but wanted to look directly to things. My P1000 give me some pretty good results for the moon and barely acceptable photos of Saturn, but nothing sharp enough and I wanted to be sure that an 'expensive' telescope will aloow me to see more then just 'white spots' in the sky....
Glad to help! Perhaps this is useful, my video about planetary telescopes: th-cam.com/video/wqGezdz-FBY/w-d-xo.html
@@AstroForumSpace Top! Thank you very much!
Great review! Where online (URL) do I get the field of view calculator? Currently I have a Canon SL1 (cropped sensor) camera and would like to know the field of view with this camera for my C11 f/10 SCT, Astro-Physics 155 mm f/7 EDF, Astro-Physics 130 mm f/6 EDF and 73 mm f/5.9 William Optic refractors.
astronomy.tools/
Sorry to bug you again brother but could you link me to the spacers you used to achieve 105 mm of back focus? I'm unsure what ones I need. The ones I have are M42. They are too small.
How does one setup the EdgeHD telescope with .7x reducer for visual use without a camera?
Hi Michael, if you're going for visual then I would keep to the original focal length and first target an object with the finderscope.
Have you tried mosaic imaging?
Only once
Viewers should know that the website for the edge HD 0.7 reducer says the back focus is 146mm, not 105mm like you’re saying here. Of course you never demonstrated that 105mm actually works in this video, I guess you never checked to see.
I think the 6.3 work with C8 edge hd
The .7 is especially designed for edge hd telescopes. .63 reducers usually with with regular Schmidt-Cassegrain telescopes. Clear skies!
I just bought a C8 edge hd beacause the normal have coma but coma reducer cost the edge hd soooooo….
Is it good idea to buy 0.5x reducer for F6 ratio Newtonian?(8 inch)
Hey Wido, Great information ! where did you get the adapter sc thread to M48 ?
Are you in europe or USA Siegfriet? I ordered mine here: bit.ly/3DHbDpV
Great video, Too bad these things are backordered through the next century!
Celestron 8" SCT with a 0.63 reducer
Reason 1. check, very good explanation. Reason 2. check also nice explanation. Reason 3. this myth again :D ... I know you disagree but food for thought here: if that f/ration myth were true ... why do you think all of the highest end professional instruments meant to capture deep-sky objects are f/30 with humongous apertures? Maybe because ONLY aperture lets you gather more light and you cannot achieve this by just reducing your focal length? I would be too happy to talk to you about this because I think such a great astrophotography communicator as yourself shouldn't be propagating this misconception. We can talk on Cloudynights
Hi Christopher we are in 2021 imaging and observation are two different things Celestron make also an raza at f/2 to gather en en more light faster this kind of telescope is designed specially to gâter more light to cut down imaging time exactly like he explains
Celestron Edge has a field of curvature much less than the classical SCT Celestron . It is not a flat field telescope. Only a Slevogt Schmidt Cassegrain is nearly Flat field telescope. This is a confusion with an aplanatic telescope or coma and Spherical aberration, free telescope. The reducer for Celestron SCT Edge doesn't touch the Coma and the spherical aberration, but improve the chromatism , the field of curvature and the stigmatism.
Celestron does a horrible job documenting the backfocus of their scopes. I still have no idea what the backfocus of my C9.25 (Non-edge) without reducer would be, for the .63 and .4 reducer I luckily found enough stuff online :D. So I use it exclusively with reducer :'D. They should really fix that :'D.
Yep, I pointed my C8 to the moon and turned the focusser, took me a while to get it into focus with the reducer :-).
@@AstroForumSpace the thing is, there *should* be a 'correct' backfocus for any scope, just reaching focus doenst really tell you whether you're right or not, as it might compromise the optical performance or mess with focal lenght and f-ratio n stuff. But I rarely see manufactures making those figures public, even tho they have them, which really sucks :D
True. You know your stuff Luna! Based on my own calculations, I was expecting a different FoV so I'm probably at a longer focal length...ah well, live and learn.
@@AstroForumSpace Hey, thanks :) Just hours upon hours of research during bad weather. Trial and error would probably be the best way to find out about the correct backfocus, but it takes forever and is very tedious work, so I just accept slight discrepancies.
How many astronomers does it take to attach a reducer?
🌌🔭👀
uhhm...I hope only one, but I guess this is the start of a good joke, hehe.
That’s not a review, it’s an explanation.
Have you noted any red & blue color fringing from your EdgeHD with the Celestron 0.7 focal reducer when photographing the moon? I have as shown at: mstecker.com/pages/CelestronEdgeHD925-tests.htm Not sure what causes it, but Cloudy Nights reported it as a problem with the Celestron 0.7x EdgeHD focal reducer. www.cloudynights.com/topic/758116-whats-wrong-edgehd-925-with-7-focal-reducer/
Hi Michael, I'm always imaging the moon in monochrome, so I wouldn't know. And for deep-sky I also use a cooled monochrome camera with lrgb and narrowband filters.