Collimation Nightmare - The Rosette Nebula with a fast reflector [Talk]
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- เผยแพร่เมื่อ 13 ก.ย. 2024
- Is it better to try out new telescopes or keep using a good, cheap trusty one? Starting to think it is better to master an old friend than chase better gear. Going to be using our first telescope for Spring season. The one and only.. the Orion 8" Astrograph! But before that, here is a video of the Takahashi Epsilon 180 aiming at the Rosette Nebula.
The Rosette Nebula full post: www.galactic-h...
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Galactic Hunter takes you on mysterious adventures to other worlds. Whether we are visiting planets, galaxies, nebulae, comets, or star clusters, the goal of Galactic Hunter is to teach you astronomy through one of the most rewarding hobbies: Astrophotography. Join my wife and I in our galactic adventures, and question everything you know about what lays outside of our little world.
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The Basics:
CMOS Camera: ASI 1600MM Pro - bit.ly/2pbF7c0
DSLR Camera: Canon 7D Mark II - amzn.to/2RDeDcq
Telescope: Orion 8” f/3.9 Newtonian Astrograph Reflector - bit.ly/2NgKcYm
Mount: Orion Atlas Q-G Computerized GoTo Mount - bit.ly/2Jr3ZD9
Guiding: ZWO ASI 290MM MINI - bit.ly/2MRTmvt
Coma: Baader MPCC Mark III Coma Corrector - bit.ly/2WlEV5M
Read my lips TAKAHASHI EPSILON130ED... The collimation has been greatly improved on this scope and the collimation tools come with it. I absolutely love mine. Trust me, this is the scope you should be going for. The older 180's at F2.8 are notoriously difficult to collimate. The Epsilon130ED is F3.3 which is fast enough for me. The faster these telescope get the more tricky they are to use.
CHECK the back focal length!!!!!and the tilted issues may happens on your cmos plane, fast system just makes every thing sensitive
Wow, I was expecting a happy ending! Bummer Dude.
It's ok! Our trusty Orion 8" never failed us so we'll be using that now!
The faster the scope, the more critical collimation and tilt become. But once adjustments are achieved, this should be an awesome instrument!
Oh no...... Frustrating.
I spent 8 nights (about 2 months) at least on my RASA 8 before I figured out where the problem is. Don't give up so quickly epsilon is a great scope.
What was the problem? About to buy a RASA 8, so this may be useful for me. lol
@@XShadowAngel 1) original t2 adapter is poorly designed it shifts from the optical axis and could be not exactly at right angle to it, one of collimation screws is sticking out a fraction of mm over top of the flange. 2) filter glass adds to backspacing. I didn't account for it first time.
I got precise parts adapter, stripped a thin layer from inside so it clears the screw (yes i decided to not touch the collimation as it was good enough originally). I like the scope very much totally worth the money. I'd like to buy 11"v2 in future for an observatory as it has longer FL and more backspacing to make tilt control possible. www.flickr.com/photos/nkondrashov/
I just wanted to thank you and your wife for such a good show. Keep up the good work and I hope you and your loved ones are healthy and safe. Clear skies.
You can't collimate a newton horizontally !!
You have to pre-collimate it on a mount at your place (verify tilt and global mirror positionning)
Then you have to collimate it on the field with the cats eye as vertically as possible.
Why: The primary mirror always have to be free in its cell to avoid bracket compression which would result in mirror constrains and astigmatism.
So when the scope is horizontal, the primary mirror slightly move in its cell and therefore is not aligned anymore.
it is the price to pay for highly openned reflector telescope
I know the struggle! I Image with a 150 mm f2.8 hypergraph and it was not easy to get the collimation right. Interestingly enough the central obstruction of a fast Newtonian astrograph is not central, it slightly offset to one side, if properly collimation. Collimation for me works just fine, if I first center the secondary on the primary and then the primary on the focuser. Also, with this design, if the stars are ever so slightly out of focus, they seem elongated.
you guys rock, stay with what works, if it ant broke don't fix it....... i have modified 8" Orion great scope
Yes we completely agree, less headaches that way!
If you decide to try another Epsilon, you need to get the Takahshi Tube and Eyepiece kit for collimating Epsilons. The scope needs to be set vertically (not horizontally) while collimating it as well. Catseye (the first tools you were using) and generic lasers will not work correctly. The manual has good information on how to do this all. Done this way, the scope is not bad to collimate. At F2.8 its pretty fast, so maybe try the F3.3 E-160ED which is pretty amazing.
Thanks a lot for the tips!
Just watched your collab with Dylan, Trevor and Chuck. Keep up the awesome work!
Thank you Helena!
Hi! I'm sorry You gave up on that... I own a bigger brother of the 180, the 210 f3 even if it is quite older since it comes from the 80's. It is a completely different beast in terms of mechanics and is built like a tank. Anyway the 210 is even more difficult to collimate since it has no spot on the primary mirror 'cos it is with a hole in the center. These scopes are, in fact, true RC scopes used at prime focus using a Rohss ED corrector. The primary mirror is Hyperbolic and, coupled with the corrector, they generate a flat field illuminated circle. These "fast" scopes that I prefer to call them wide field since the word "fast" is related to old emulsion (with today's sensors which are linear, the velocity in filling up the pits it is irrelevant 'cos we speed up also the noise acquisition from the skyglow but we can't speed up the number of photons related to a subject in a considered angle of the sky wich is, in fact, the photometry), all have a very narrow CFZ (Critical Focus Zone). An f2.8 system has a CFZ (which in the end is the distance for having all the stars and the wavefront in correct focus) of less than 20 microns. If the sensor is not perfectly within this tollerance, You will experiment field curvature and odd shaped stars due to the hyperbolic shape of the primary that means is "aplanatic" and without coma. This is not related to collimation but to mechanics and placement of the sensors. Most "commercial" CMOS cameras and also some CCDs, are not guaranteed to be mounted perfectly squared respect to the body of the camera, I've experimented this since if You change different cameras of the same type and brand, any has different results... In the end, with these kind of astrograph with flat field, the crucial thing is more on the machanical side that has to be super perfect! You have to have almost half of the resolution of the adjustment to be sure to fall in the correct spot in terms of co-planarity which means they have to resolve a minor adjustment of about 8 microns for an f2.8 system! It is a time consuming process to set up such systems in a way they performs at best but, once You manage to did it, they're exceptional and very able to mantain the perfection for a very long time! I'm always using my scope for travels out in the field in the back of my car and, with camera attatched, I've never had the necessity to make any adjustment! Even the focus it is always very near perfection every time. Next time, spend Your efforts in putting the camera at the perfect distance from the corrector first then adjust the tip/tilt of the camera itself prior to think about collimation issues... Sorry for the long comment but I just wanted to share my experience on that. Keep going!
Might be on the focuser tilt? I’m looking at a similar Newt HNT to add. I have my Hyperstar and absolutely like it. The faster these scope go collimation is pain to deal with on starting sessions. They bend and suck in a lot of light. Keep it up I’ve seen some Epsilon users have absolutely dialed the collimation down.
as an Epsilon 180ED user for more than 8 years I will say you Yess! this is difficult to colimate this scope but the quality of image that produced with this scope is superior. this is an ultra sharp scope with star size only 10 micron.Sharper than most of class A astrographs and i can say you this scope does not make any tilt.I think the tilt should be caused by camera adapters.and one more thing: Takahashi tool is very usefull to colimate this scope.
I feel your pain Antione , I brought a Explore Scientific refractor a few years back and it was big money, had it for a few weeks and could not get sharp images at all, turned out to be an issue with the glass cell, had to send it back to the USA for replacement. but since I got the replacement it all been good. I like how we can always relie on you for honest product reviews... clear skies man.
And THIS is why I shoot with a top notch Apo refractor!
Is it fast? What is brand? And reducer? Thx
nkondrashov Stellarvue SV102T Triple Apo. f/7 with ASI1600MM Pro. Fast enough! And no collimation!
Rick Paul not every one has money like u
Ahah me too
alpha tango ah, excuse me. But I was comparing a refractor that costs half the price of the scope he was trying collimate. So don’t be rude.
Collimation is a pain in general. Try getting a collimation ring. This is a ring, that attaches on the focuser to the OTA to "collimate" your focuser alignment to the mirror. I found that no matter how perfect I got my astrograph collimated with a laser collimator as soon as I removed the laser, and put it back in to test the collimation it was still off. I was collimating the slight tilt in the focuser which threw off collimation even more. Once you have your focuser collimated the rest of the collimation goes a lot smoother.
Probably a camera tilt problem that scope has a tilt adjustment i think
I really feel for you, I am in the same position as you, trying to get my astrograph correct.
I am soon uploading yet another video on how i am trying to collimate, and i think i have found my issue... And it looks like it is not collimation but a corrector / thumb screw issue.
Hang in there :)
Clear skies!
Looking forward to your video. I have the same TAK 180 and are also struggeling with the collimation :)
I can understand exactly what you guys went through as I've had a very similar experience with my Skywatcher 200 PDS Newtonian. Basically I decided to wash the mirror and when I put it back together the fun started. Try as I might to collimate including using star collimation and artificial star collimation nothing worked. Basically I was getting distorted triangular stars. Even though the collimation looked good. Then I saw a TH-cam video about "pinched optics" and hey presto problem solved. Basically when I put the cleaned mirror back in it's cell I over tightened the 3 x mirror retaining clips. And that was enough to distort the mirror. Like a mirror in a house of terrors giving distorted reflections. The solution. Back off the screws holding the mirror until then were just gently cradling the mirror but not putting any pressure on it. And there were round stars and all was well again in the universe.
We actually just cleaned our 8" Newt's mirrors as well and had the exact same issue! We actually have a video about it ready for next week :)
That's for a Losmandy style dovetail, not a vixen. It might not be collimation, it might be field rotation from polar-alignment or focuser sag/alignment. If it were collimation I would assume to see all stars misshapen.
I really enjoyed this video because it shows what what real problems exist with this hobby or lively hood in some cases. It is good to have a technical friend nearby who was spend a lot of time to help. It is frustrating to have the really expensive Tak that is supposed to be great (and it probably is). However, most of all, this is also about enjoyment and your experience certainly does not sound like enjoyment. You were correct to send it back (besides Chuck got his ADODs with $ 1300 refractor). - Cheers Kurt
Yes we plan on using our $500 Astrograph now (or the Meade, depending on the target).
Oh and you need to check if the focuser is perpendicular to the tube. That is a common source of tilt.
I've just bought the f.4.8 Explore Scientific 150 mm Comet hunter, not as fast as the Tak, but stars look so good and no spikes. Fairly easy to collimate..
I know the struggle, but it looks like either a backfocus or tilt problem. Usually, for Tak the backfocus is about 56.2 mm, definitely not 55 mm. And focus needs to be exact also using autofocuser. they are amazing scopes, the 130d is wonderful, comes with an extender to image at 650 mm at f/5. And the color......
F2.8 is critically fast and super sensitive to collimation or tilt issues. I would also explore potential issues with the corrector lens and distance from corrector to sensor. Dont rule out optical problems with the primary or secondary either, even despite its high cost and reputation. Each of these need to be addressed seperately if you have the time and patience
I’d like to see an Orion Newtonian or say an Astro Tech RC go head to head with A Takahashi Mulon. The build quality is obviously better with a Tak or an ASA but optically there probably isn’t much difference in images, provided the proper coma corrector is used and all other parameters are equal. Apparently people just like the beauty and build quality and I get that. I’d love to have an ASA Newtonian astrograph if I could afford it but as far as mirrors go it seems the only difference between high dollar ones and cheaper ones is reflectivity and thermal expansion properties of different types of glass. Maybe the coatings are better and the mirrors are designed to be lighter but it doesn’t seem to make that much difference in image quality to me. I may be wrong but it would be an interesting contest.
Pinched mirror. Did you discuss it with the person who loaned it to you?
That's a good point!
Excellent Rosette nevertheless ! Yes, fast optics are very critical to collimation, tilt and centering.
I feel your pain. I had some issues too with a fast 2.8 reflector and even with good filters I was still not happy with my imaging. I got back to a refractor for the wide field and I'll get a RC for the deeper shots. They are booth slower but they'll work
Love your videos
Thank you :)
Sorry to hear all this about a Tak. Well, at least you didn’t pay for it. By the way, APOD is not about equipment, it is about opportunity and “good eye”. And also it’s not a contest, it’s a recognition,
Yes we agree, which is why we decided to now use our first telescope, the Orion Astrograph 8" which we've been using for years.
Galactic Hunter I’m crossing my fingers so you get that APOD more sooner than later!
sorry to hear your troubles but I have heard that to collimate tak newts they have to go back to the factory .
I believe these scopes have lenses and mirrors and like the Vixen Visac can be a complete bear to collimate. That being said your image still looked pretty darn good. At least you gave it your best.
Thanks, just couldn't keep using that scope knowing one of the corners would always have elongated stars
I use my super fast LND75 SN8 and no problems collimating
VixenVSD100 user here, I had a lot of collimation issues with my refractor (yeah, refractors can have collimation issues with them as well). The faster the scope is, the more problems come from just slight collimation issues.
Yes, with our f/3.9 astrograph we are used to quickly collimate it before each session and never ran into any major issue, but here... it was probably at a point of no return
Other option would be to remove the corrector... collimate the scope... re center the corrector , remove tilting and test again...
Hi.... I had the same issue... a friend of mine too
I think we fix it not perfect but the E-180 is doing a great job now
If you need any help or advice please let me know
it looks like your sensor is to far from the coma corrector,so the stars looks like it goes in circles..when the stars are pointing to the center the sensor is to close to the coma corrector.
it should be some like this www.astrobin.com/uueoty/B/?nc=user greetings John .. ps good channel
Have you tried without filters? I had something similar where one side was completely out on the edges and the other side was okay. Turned out to be the filter and filter adapter that I hooked on my camera was causing this.
Might I suggest the Tak FSQ106 Refractor? My friend uses this scope for his imaging on the same mount.
Compare images from different telescopes on cs.astronomy.com. You’ll notice some cheaper scopes do as well as high dollar Officina Stellare astrographs. The main difference I see is in what type of camera you use, CCD brand and post processing or DSLR, which has a hard time coming close to CCD. Tony Hallas had the best advice I’ve seen for making DSLR come close to CCD results but in the end you just can’t beat a monochrome CCD and we’ll calibrated filters.
This makes me slightly nervous about my f3.9 newt. I bought Hutech laser collimator after my first session (with 10Micron mount of all) was ruined by super out of collimation scope. And I've read that for reflectors with f
Unfortunately, you might have camera tilt. The sensor plane on your camera is not parallel to the image. Rotate your camera 90 degrees and see if you out of focus stars are not 90 degrees rotated. If they are... its camera tilt.
Yes that's what we thought as well, and the adapter that came with it was pretty wonky which didn't help.
@@GalacticHunter Not that you need more to complicate your life but... since you are a native French speaker you might want to try an acquisition software called PRISM. With PRISM you can measure the tilt of your images. You can download a free 80-day trial at Hyperion Astronomy. PRISM will help you in identifying if you have any tilt issues and how much you have. The biggest stumbling block with using PRISM is the English translation of the users manual ... it is very very poorly translated. There is a French forum but as a non-French speaker, I really can't use it. Google translate does not do a very good job and no one can understand me :-) If you load an image into PRISM they have a one-click "measure tilt" function and it will show you where you have tilt. Just a suggestion. Your posts are great I wish you luck.
@@M31glow Oh wow, I have heard of PRISM before but never knew they had this tilt feature, that's good to know! We'll not be using this telescope anymore so we shouldn't have any tilt problem with our current Astrograph but we're glad we now know about this, thanks!
Best friend as I can see this is an ordinary Newton telescope and these always have distorted stars in the corners themselves the best collimating doesn't help the only thing that helps is applying a coma corrector had this at my skywatcher 150/750 also before I applied the coma corrector so there's nothing wrong with your Takahashi; however, it surprised me that you haven't applied this.
the tak newtonians do not need a coma corrector because of their offset optics to provide a flat field , I think this is one of the things that makes them hard to collimate
@@SoRealsEntropiaUniverse In other words, if you do this yourself and you don't know about it and you apply the collimation like an ordinary Newton, you'll kill him.
Perhaps it’s more of a coma problem or perhaps the mirror is pinched. My god is collimating really that difficult? I’ve only collimated three different scopes but never had many problems except with longer focal lengths.
On this particular scope, yes, collimation is a pain, but i wouldn't be surprised if there was also tilt issues.
We're you're test shots at the end of the video done at home?
No, from the same location (Bortle 2)
Looks like (focuser) tilt to me.
Did you check the corrector ?... maybe the corrector has some screws to fix tilting... once you correct tilting.... again collimate and all is done..
We checked pretty much everything, but we did assume that the corrector was fine, maybe that was the issue.
These scopes are well known to be extremely difficult to collimate, and it's easy to complete ruin it's collimation up to the point you've got to send it back. I hope this isn't the case for you, but I'm afraid it might be.
Yes that's what we're afraid about. Oh well.
I’m not experienced with this sort or thing, but can you not take off the mounting plate on that difficult to collimate telescope and attach it to a different scope?
Yes we did that and are now using our first telescope instead (Orion 8" Astrograph)
@@GalacticHunter Ah ok
Hey guys! I am very new to astrophotography.. I wanted to take this as a hobby so I am confused between purchasing a Celestron 130SLT or a Startracker (I already own 2 DSLR’s ) for a decent astrophotography ..which would you suggest ? If I purchase the telescope with mount will I be able to attach my canon DSLR with a t-ring?
Or should I wait and get a good telescope with eq mount
We would suggest going with the star tracker first. It will teach you how mounts work, how to polar align and how to find deep sky objects on your own without a GoTo. You can several DSO's with a 50mm or telephoto lens. When you are ready to upgrade to a telescope and mount, make sure to get something you will enjoy for years to come without having to upgrade again (I would personally not go with the Celestron 130SLT). You can read more about beginner equipment here: www.galactic-hunter.com/post/dslr-astrophotography-equipment and feel free to email us if you have more questions!
Thank you soo much! You guys are a huge inspiration 😊.
Keep it, don't give up. You will do it, if not go to a specialized shop or find someone who cal help you, this is the tool for your 2020 APOD! :)
We have wasted too many nights trying to fix it :( We decided to go back to our regular telescope.
get a c rasa 11. brighter and no collimation ncessary ever. newtons are always prone to collimation issues
Not necessarily true.
When I first received my RASA 11, the collimation was very off. It is quite easy to collimate, despite what you may hear.
I found this at Astropixels with a solution on how to properly collimate the Epsilon 180 ED: astropixels.com/bifrost/tak_e180-collimate.html
Several image results can be found here: astropixels.com/messier/messiergallery.html
Where’d that cgx come from??
We don't have a CGX
Galactic Hunter what is that mount in the yard then? Or am I just not paying attention😂
@@seanspoerhase3878 The MyT Paramount (it's new, made a video about it last week hehe)
Galactic Hunter oh my goodness😂 I feel dumb now that’s not a cgx at all. My bad haha
4,000$ worth of headache and the images with my sky watcher reflector are just as good if not better.🤪
“With a coma corrector.”
No. its has a hyperbolic main with a corrector, a true "Astrograph".
Plus collimation really isn't the same thing as coma, coma creates elongated stars going away from the center, while collimation creates elongated stars perpendicular to coma. Please correct me if i'm wrong :)
@@humwhatever185 Coma = Optical defect of a Newtonian telescope system. Stars become "Comet" shaped toward the edge of the field(Off Axis). Controlled by a coma corrector.
I know what coma is and when collimation is out you get more. When it’s really out you get aberrations. I was merely asking what coma corrector you might recommend for a fast Newtonian but never mind.
money doen't help experience ...
Apo Refractors forever
I'm starting to lean that way too... haha
Too much drama for the collimation :)
Just get the RASA!! You’ll love it!
We really, really want to!
Galactic Hunter too bad you guys can’t drive down to LA right now. I’d let you guys borrow my RASA 11 for a month since I can’t leave the house.