Barlow lenses & Powermates - Do you need either?
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- เผยแพร่เมื่อ 28 ส.ค. 2024
- What are they? How do you use them? What is the difference? and do you need either?
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*Barlows & Powermates*
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StellaLyra ED Deluxe 2x 2" Barlow Lens:
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ED Deluxe 2x two-inch Barlow Lens
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Smashed it as always Chris, all you need to know in a nutshell.... I keep trying, shouting, pleading with the clouds but THEY NEVER SODDING LISTEN!
Cheers Jay, same here for the last couple of weeks, we may need to find a new tactic!
Thanks for the shout out, and you're welcome for the coffee.
The least I could do in return, and thank you :)
Liked this video? Watch my video on eyepieces here: th-cam.com/video/na3NmOSMIX0/w-d-xo.html
A little known function is and you kinda touched upon it addressing pushing the exit pupil but BOOSTING an eyepiece by sliding it slightly out of the Barlow, dramatically raises the power/magnification of the systen while having an easy pupil to aquire compared to a very short focal length eyepiece.
Great videos !!
Nailed It Chris!! Nice Video Editing As Well!😎. I use a simple Celestron 2x Barlow for My planetary Imaging And Visual. Im Really Tempted To Get a Telvue Powermate! Great Informative Video Man! So Will The Next One Be About focal Reducers and Correctors? That's Would Be Cool! Nicely done!😀
Hi Avanteesh. Thanks my friend :) Snap, I've been pondering a Powermate also! Video wise, I'm hoping to get clear skies so I can make a video of me attempting to get a decent image with the Star Adventurer lol, but a reducer corrector video is a very good idea also. I'll add that one to my short list cheers!
Great video Chris, lovely editing..
Thanks Vineeth, It's pretty cool what you can do with a green screen.
Thanks Chris - I’d just always assumed that Powermate was a brand name for TV’s Barlow lenses. How wrong I was!
No worries Paul, easily done. I'm glad to be able to shed some light on the subject :)
Thanks Chris! I finally found a televue 2.5x powermate on the used market and it's really good. I can really pump up the power on planets now 🙂
Congrats ziggy! that's an excellent purchase, I should really do the same :D
Straight to the point video - appreciate the detail behind them, as opposed to 'just drop it in' to the eye piece holder. - Thanks
Glad you liked it, cheers for the supportive comment :)
I use my Tele Vue 2x Barlow for splitting stars and for planetary viewing mostly with my 18mm Takahashi Ortho. Super clear and sharp.
Nicely put together Chris I actually didn't really know what a Powermate was so thanks for this. Very useful information as always.
Hey Ollie, cheers mate, it makes me happy to give useful info :) p.s. Just noticed the keyboard added to your thumbnail, looks really good!
@@Astrolavista Ha thanks Chris I thought it would represent my content a bit better.👍
@@AstroSoundscape You nailed it :)
Hey Chris! - I had absolutely NO idea of the difference between barlows and powermates! - however.. now, I do, thanks to you! - It's one of those kits I keep telling myself I should get, to enable serious attempts at planetary imaging (and maybe some certain deep-sky planetary nebulae lucky imaging, looking at you, m57..) - I will do eventually!
I'm actually off now to watch your 462mc video again, i'm giving it consideration in case I could use it as a dual-purpose planetary & guide cam at some point, I'm just wondering though if it can work with ASIair as a guide cam!
Thank you for all that you do for this community mate, you deserve every success!
Luke
What a heart warming sign off, thank you so much Luke! I learn so much from your channel it makes me happy to be able to give something back :) I think the 462 is best planetary cam I've used so far, and I've owned several 120's in mono and OSC, and a 385mc to compare it to. The 462mc is blimming sensitive so it would make for a fantastic guide cam and it's IR sensitivity makes it very versatile. It's also very good for lucky imaging small bright DSO's. I can't believe how well the 462 did on M57 with just 4 second exposures for example. I'm not sure if it's ok with the ASI air, but I'm sure a quick question on their FB page will get to the bottom of that, and if not it might prompt them to add it. Take care mate and likewise! :)
@@Astrolavista Well Chris, I did visit the other video again... and now I've ordered a 462mc and the 0.77x reducer for the Esprit 120 again (I really want one to work, I could cry haha) using your affiliate link mate - I hope I didn't bugger anything up while checking out!
Best wishes,
Luke
@@lukomatico Awesome! I can't wait to hear how you get on with both the cam and the reducer, and thanks so much for using my links! Nothing is showing yet, but I think there is a lag so I'm sure it's all fine :) What back spacing did you try with the 0.77x last time Luke? I've noticed there's a bit of confusion with regards spacing, and I was reading an SGL thread the other day which pointed towards it being 95mm from the shoulder just past the thread, when on the box it says >75mm. I'm really looking forward to hearing how you get on. Here's the SGL thread regarding the 0.77x RF. Near the bottom of page 2: stargazerslounge.com/topic/366049-new-sky-watcher-077x-reducers-for-esprit-120-150/page/2/
@@Astrolavista Hey Chris! - Thank you very much for that mate, I see what you mean about the 95mm from the collar - I tried it with the 'on the box' info, so 55mm with the included spacer + m48 ring.
It seems highly likely that the box could well be wrong! - I'll do my best anyway, I love the idea of the esprit 120 reduced to f5.4!
Thank you so much for digging up that info for me my friend!
Clear skies :-)
Informative video, thanks. My 2x Barlow's lens can be screwed off and can be attached to a planetary camera or eyepiece - it gives a 1.5x magnification.
Great video Chris! really helpful, I use the Televue x3 barlow and I find it fantastic on planets for eyepiece and photography! keep it up :)
Thanks! I'll try :)
A 2X Powermate is a must for both planetary visual and imaging.
Great to the point video, It sounds like a powermate is the same as a focal extender?
Yes, it is :)
Hey Chris. Thanks for the info in this interesting video. Hoping we get clear skies alot this autumn and winter so I'll test these out. Which do you prefer? I've looked through a Barlow lens at Saturn with friends telescope when we took our scopes and got night for seeing the persied meteor shower and we looked at Saturn. His scope was reflector and gave lovely views of Saturn's rings.
Planetary viewing with my Bnise 70mm scope I'm going to use Barlow lens. Last night was clear and I was camping and saw Jupiter and then the moon. At last clear skies. Bortle 3 skies here and tonight I think it's going to be clear.
Hey Chris tell mother nature to be kind to me this autumn and winter so I'll have plenty of clear nights for my astrophotography setup as here in scotland we do get alot of nights that are clear!
Looking forward to your next video and stay safe buddy!
Thanks John, I'll beg mother nature to be kinder to you this autumn and winter. You've had terrible luck so far. Take it easy :)
Can you please add Siebert Optics to your list of recommended barlows? They make custom barlows that other manufacturers simply don't - for example my 1.5x telecentric elite series barlow. Very high quality, easily on par with TeleVue from an optical point of view (and also build quality). I needed a 1.5x barlow for optimal setup for my C9.25/ZWO 290mm setup (to take the imaging train from f10 to f15 and best match the scope/pixel size). None of the other manufacturers were really an option in my example, although I could have went with a 2x powermate I guess for some undersampling.
Hi Chris Nice video, I have tested also barlow lenses until now but i am curious to see the difference with a power-mate. By the way i recently bought also whith whireless go II mic, with a rodelink lavaliere and a few more accessories
Hey loan, I feel the same way. My research suggests that Powermates are more 'neutral' and act as if nothing has been added to the light patch, only the effective focal length is multiplied. That's great to hear about the Rode Go II, I use the original and have no complaints. Do you know what has been improved with the Go II version? Thanks for watching!
@@Astrolavista I watch also a video comparison a few weeks back but i am not sure what are all the differences. you can search rode go vs rode go ii. I heard the distance of signal is improved, the rode ii does record also internal, and can record up to 40 hrs, battery life around 7 hr, not sure about the old one
What happened? Love your original work with that Skywatcher
Hi Ray, do you mean the 200p in the observatory? Nothing has really changed, only lots of clouds here in the UK. Weeks of it, so I end up making tutorials or information videos. Just bought a Skywatcher Star adventurer for wide field so when it is clear I'm using that for summer nebula. I'll be back in the obsy over the Autumn and Winter though because the 200p has the focal length for galaxy season :)
@@Astrolavista nice!
Great video! I've recently picked up a used Celestron C90 (no eye pieces included) for lunar imaging which has been great with my Micro Four Third camera. I'd love to get much higher magnification though and feeling a little lost. Was thinking I'd get myself the Skywatcher AZ-GTI and the Tele Vue 5x Powermate. Really no idea what would be best here. Appreciate any advise.
Thanks Dominic :) The AZ-GTI has good reviews so I'll be picking one of those up myself at some point. Unfortunately the 5x Powermate will be way too much for a C90 though. The general rule of thumb for planetary imaging is to aim for a focal ratio 3-5x your pixel size. Say you have 4um pixels (I'm not sure which M4/3 camera you have?) if you multiply 4um pixels by the top limit which is 5 you get f/20. The C90 is f/13.9 natively so even a 2x Barlow would be pushing things a little too far at f/28. The 5x Powermate would give you f/70 at 6,250mm focal length. There would be virtually no light getting through at f/70 with 90mm aperture. You might get away with 2x though.
@@Astrolavista thanks so much!
Is a 3x Focal Extender really a lot better visual quality than a 3x Barlow?
Tell us more about the new job. Very interested. Hope you’re well. Clear skies.
Hey Garnett, good to hear from you :) Yeah sure no problem, I get to work from home now, so I'm all setup with a desk and Macbook in the corner of the dining room. I work on the FLO help desk answering technical astronomy questions, problem solving, and checking, chasing, or changing peoples orders, helping to improve the site etc. I'm working up to being able to answer around 50 emails a day and I'm about up to speed now. It can be challenging, but it's a really good challenge and I love being involved in the astronomy community. Everyone at FLO is really nice too, I'm very lucky!
How have you been? I've not had a notifications for your channel recently. Are you still posting vids at the moment?
@@Astrolavista great to hear. Yeah I’m alive lol. Just posted a short today. Still waiting on a mount I ordered a year ago. That kinda slowed me down. Glad you found a job you love. Sounds fun.
I use an Astro-physics 2" photo-visual barlow and Televue 2.5X powermate.
But only for imaging. I much prefer the views and convenience of a dedicated focal length eyepiece. Nice simple video.
So, which one is more suitable for planetary imaging???
Hi Biswajeet. There wasn't a clear winner from my research - The Powermate shows a more neutral image as it only changes the effective focal length of the telescope and nothing else. The Barlow changes the effective focal length and diverges the light path, hence I think the Powermate will give a more uniform field of view. This wont matter so much for planetary imaging though because you tend to capture footage with the planet in the centre of the frame. The Powermate might show more of an advantage on larger objects such as the Moon which fill the frame more but this is just my speculation. They are both suitable so you wont go wrong with either for planetary imaging. Other factors like matching your pixel size to your f-ratio are probably going to be more important considerations.
Visual astronomy was a different story as Barlows can cause vignetting with longer focal length eyepieces.
@@Astrolavista Pls make a video explaining the physics behind image scale and sampling (like over and undersampling). I couldn't find a single video in TH-cam that actually explains them.
@@biswa145 I've certainly talked about this in other videos, but in a nutshell if the combination of pixel size to focal length results in a pixel scale of say 1 arcsecond per pixel, you would unlikely be able to resolve 1 arcsecond because the seeing conditions are typically around 2 arcseconds. This would be oversampling because you can't resolve the resolution your system is capable off and such fine resolution reduces sensitivity because small pixels can't hold as many photons. Under sampling would be where you have a focal length / pixel size combination that gives you 4 arcseconds per pixel, but the seeing allows for 2 arcseconds, so you lose resolution. The sweet spot is a focal length and pixel size combination that gives you around 2 arcseconds per pixel as it's the best compromise between resolution and sensitivity. I guess I could make another short video specifically explaining this one concept. I've been asked to make a few videos recently so I'm not sure when I'll get round to it.
@@Astrolavista Thanks for your reply. BTW does that matter for planetary imaging?
@@biswa145 Over and under sampling is often talked about in relation to longer exposures for deep sky imaging because over and under sampling is often considered in relation to the average seeing conditions. I don't think over and under sampling applies in the same way to planetary imaging because you're filming the planet and only using the sharp frames from when the atmosphere is still for fleeting moments. Therefore the 2 arcsecond rule doesn't apply and you can get much finer resolution, probably in the region of 0.4 arcseconds per pixel. I should imagine planetary imaging relates more to the Dawes limit (resolving power of your telescope) The more aperture you have the more resolving power you have. Also, your focal length will scale with aperture for a given f-ratio, so the more aperture you have the more resolving power you have and the finer the resolution given by the pixel size of your camera in relation to focal length. This makes sense because the best planetary images are taken with telescopes like C11's and C14's with lots of aperture and focal length. I went to a talk by Damien Peach years ago and I think that was the general gist of things :) Dawes limit is determined by splitting double stars, but that's just a convenient way of quantifying resolving power, so you could think it doesn't relate to planetary imaging but it kind of does. Another point to note is that because planets are bright there is less of a down side to oversampling. In other words losing a bit of sensitivity is less important with planetary imaging compared to deep sky imaging where you're trying to capture faint objects.
Useful video, thanks. What happened at 1:38 though ?
lol sorry, even when I'm trying to make a formal information video I can't resist adding something odd :D I nearly had it upside down but sideways looked more quirky.
BTW I liked it when you went sideways for a bit. 😅
lol I'm glad you liked my weird sense of humour.