Astrophotography: Refractor VS SCT!!

In this video I compare a refracting telescope to a Schmidt Cassegrain Telescope (SCT). I discuss the strengths and weaknesses of both and show images of the same targets taken with each telescope.
Slide Deck start: • Astrophotography: Refr...
Image comparison start: • Astrophotography: Refr...
Crescent nebula comparison: • Astrophotography: Refr...
M101 comparison: • Astrophotography: Refr...
Orion Nebula comparison: • Astrophotography: Refr...
Field of view/dissimilar targets: • Astrophotography: Refr...
Summary: • Astrophotography: Refr...
Gear used:
Telescope: AT115EDT
Camera: ZWO ASI1600MM
Mount: SkyWatcher EQ6R Pro
Filters: Astrodon 5nm, Ha & Oiii
Telescope: Celestron Edge HD 8
Camera: ZWO ASI294MM
Mount: Skywatcher EQ6R Pro
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Clear Skies!
#astrophotography
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[@legacysearches4481]

Great vid. I have never done this type of comparison with my scopes.

[@DSOImager]

Thanks! One night you should point them at the same target and see how they do. :)

[@aw7425]

Very helpful and a super comparison. Clear skies

[@DSOImager]

Thanks, CS!

[@ttp_007]

Superb video comparison, thanks for the video!

[@DSOImager]

Thanks!

[@MrMrduke1975]

Awesome video sir! Exactly what I was looking for! I think you have helped make my decision on my upgrade from WO GT71 to the Askar 120

[@DSOImager]

Thanks! Have fun with the new 120 askar!

[@mif1118]

Excellent comparison and video, James! I am only imaging with refractors to date (80mm and 110mm aperture) and I am still shying away from going to mirror telescopes. This video gave me a lot of insight of pros and cons! Thank you!

[@DSOImager]

Thanks! I understand. Refractors above all other telescopes are the easiest/most forgiving scopes for astrophotography. They just work :)

[@AndreH3d]

What a fantastic and thorough comparison! Thank you so much for this... I was between exactly those two scopes and I went with a vintage C8 just because I found a great deal, so the Edge will come in a future time... planing on having a hyperstar whne the time is right... So the first time I used the C8 reduced to 6.3 I had a blast on resolution and light gathering, I was amazed to have capture so much detail on the Iris Nebula just undr 45 minutes on the tail end of the night under Bortle 8-9 skyes, I was just very curious to understand how the F ration woudl compare with the extra aperture and there you got the perfect example on how much aperture actually means in a pratical standpoint... awesome job

[@DSOImager]

Thank you Andre! I'm glad you liked this video. CS!

[@ppoinha]

+1 for SCT and then just get a hyperstar for shorter focal lengths. You can have 2000mm, 1400mm and 400mm all in one scope.

[@johnrobertson1953]

Totally agree. In fact, that’s what I have, Edge HD 8(2 tripods- w/ wedge & alt/az), .7x reducer, & Hyperstar. I’ve added the asi183 for greater detailed shots, and asi2600mc for wider shots. I wanted to have as many options as possible, including planetary and solar. No question seeing can be challenging at times. But good or better, I’m totally satisfied with results.

[@DSOImager]

It is a super versatile scope for sure. One day i may try hyperstar.

[@johnrobertson1953]

@@DSOImager Once u try it, u won’t come back. I promise. 25 times faster than F10; 12 times faster than F7. Worth every penny!

[@Phenolisothiocyanate]

​@@johnrobertson1953How much time does it take to swap between configurations? I'm torn between a 10" carbon fiber newt and a C11 Edge.

[@johnrobertson1953]

@@Phenolisothiocyanate I’ve actually drawn up pictorials of various configurations, ie. spacers, adapters, etc to help speed up the process. Maybe 5-10 minutes in total to change over.

[@steppen57]

Great video. I have a C8 Edge which I use for DSO at f/7. I have experienced pretty much everything you described in your video. Just recently I got the OAG to work with the C8 for guiding and it's a game changer. I also have a small refractor for wide field (500 mm), and have considered getting a 700 - 800 mm for galaxies, but your video is changing my mind. The details will not compare with what I can get with the C8. And it's such a short time when I can image Galaxies anyway. This is a very useful comparison. Thank you!

[@DSOImager]

Thanks! I'm glad you found this video helpful. CS!

[@ateiviz]

Very informative video, I'm the perfect target audience for this subject. Been working with a DSLR and a 73mm refractor and considering what my options are going forward into mono and later greater focal length.

[@DSOImager]

Thanks! What ever scope you decide on next.. it's going to be amazing with the mono camera. Thanks for watching, clear skies!

[@NoxusGr01]

Great video and great comparison, loved the technicalities and the accurate way of describing your process. I own an Evolux 82ED and I absolutely love the possibility of framing multiple targets in my image but man... I have to admit that those details in the SCT are juicy! Sure you can expect that because of the higher resolving power but still makes me want to order an edge HD right now!

[@DSOImager]

Thanks! I think something like the edge compliments a ~80mm refractor well. :)

[@dh2970]

Very informative, thanks!

[@DSOImager]

You're welcome! :)

[@jlecomte0719]

Great video, as always! To deal with filter offsets and an OAG, I created an OAG focuser and corresponding software that solves that problem once and for all. CS!

[@DSOImager]

That's right! I remember seeing your video on that a few months. I need to get a 3d printer one of these days. :)

[@mycarolinaskies]

For SCTs the cooling isn't an issue when you start using an insulating blanket to stop the thin wall tube from quickly equalizing temperature. This means you can get to imaging much quicker. Mirror shift of an SCT and external guiding have no special relationship, an OAG will be affected as well as the star being tracked will move suddenly. If the mirror moves it's only in one frame of exposure and a very fractional amount less than actually bumping the tripod leg. In fact you are more likely to have issues from wind pushing(and stop pushing) on an OTA (regardless of style of telescope). The external guider supplies a much wider field of view for more stars especially in relatively starless fields. If the guider is properly mounted, where issues arise is whether the sampling rate and the pixel scale are too far off and mismatched between the guiding system and the imaging system. If the pixel scale of the guider is too dissimilar then guiding corrections will move the mount in the corresponding corrective direction at a rate too fast or too slow and result in star trailing. For SCTs this is more critical because the much longer focal length has little fudge-factor for guiding error. Whether the guide scope is 30mm or 80mm, if the pixel scale figured by the focal length and guide camera pixel size is poorly matched there will be problems especially as focal lengths >800mm. At one time there wasn't as much of an issue when the pixel sizes of the CCD cameras were ~6-9um and using an 80mm ASI120mm 2x barlow was close enough guiding. However, as pixel sizes dropped in cameras, pixel scales did too and guiding for those with the newest equipment began to believe long focal length imaging was impossible for DSOs. Currently a good SCT external guide camera package would be guidescopes around 200-250mm with either ASI678mc or QHY5-III-715c and 2x or 3x depending on focal length of the SCT. Yes an ST80 could be used, but the key isn't the aperture of the guidescope as much as the focal length guide camera pixel scale.

[@DSOImager]

Thanks for the tip on the thermal blanket. I've seen others use that, have not tried it myself yet. Good points on using a guide scope, especially in regards to matching the pixel scale.

[@SimonsAstro]

Hey James, super comparison video mate! Interesting stuff indeed! Being a refractor guy! I love my 120, so sounding a bit bias, I thought your 115 stood it’s ground against the reflector, the crescent images were excellent from both! That being said, I have thought I wouldn’t mind a little more reach for those distant galaxies! And I thought the SCT 8 would be nice! We’ll see how the funds go🤣 Great job mate and clear skies!

[@DSOImager]

Thanks Simon! Love the work you do with the esprit 120. Let me know if you want to play with some edge data. I believe i have a link for my pacman data on my channel update video.

[@Luftbubblan]

Nice comparison!

[@DSOImager]

Thanks!

[@avt_astro206]

Great Video James! As a Reflector owner, Im used to High Magnfication shooting Deep Sky Objects to, lol. But Then There are Big Wide field Targets like Clusters and Some Nebula! Though, My Dream Setup is To own a Larger scope (for Visual/Photography ) along with a DSLR for Widefield and a Tracker. Clear skies!

[@DSOImager]

Thanks Avanteesh! Having both a larger scope and the dslr/tracker will cover all the bases :) CS!

[@petesastrophotography]

That's a fantastic comparison James. I love my small refractors for taking widefield images, but I do sometimes crave something with a longer focal length for galaxy work. My concern has always been that the weather/seeing here in north east Scotland is rarely that good, so while something like an 8" EdgeHD would provide higher resolution, it's debatable if that could be fully exploited. Lovely images btw, I've always believed that stars on SCT's weren't as good as refractors due to the central obstruction etc, but your images prove otherwise.

[@DSOImager]

Thanks Pete! BTW, I checked out your astrobin, good stuff.. especially that M13 shot. CS!

[@petesastrophotography]

@@DSOImager Thank you, much appreciated🙂

[@emuhead]

Really helpful video comparison. Your SCT images are among the best I've seen. How about an SCT image showcase?

[@DSOImager]

Thanks Andy! That's a good idea.

[@williammauney1129]

I started with a 6”SCT and went to a 72mm refractor. I’ll keep the SCT and one day even invest in a hyperstar. As it is I’ve decided for now to buy two refractors (80,115) and change the FOV by camera (294,533,2600). Yes more expensive but I find using the refractors more fun and less hassle to use

[@DSOImager]

Ive been watching cuiv's videos on the hyperstar with the 6 sct, a potent setup. :)

[@AmatureAstronomer]

I do electronic assisted astronomy (EEA) with Sharp Cap, so I do not use or need guiding. I do not do any post possessing. Being elderly and feeble, I use a Star Adventurer GTi go to mount which can handle 11 pounds. I have been using a Celestron short tube 80/400, a Skyoptikst short tube 90/500 with a x0.80 reducer/ corrector and an SvBony sv305 80mm ed with a x0.80 reducer/ corrector. I use a SvBony cls filter and a ZWO asi294mc camera. I have found, oddly enough, that the 90/500 takes the best photos. I also have an Orion 130/650 Newtonian reflector, which takes good photos and has a smaller field of view. I just bought a Celstron 6" Schmidt Cassesgrain and a x0.63 reducer/corrector, the largest my mount can handle. I am going to see how it works and may buy a HyperStar 6 v4.

[@DSOImager]

Good to hear that you've been getting good results. Good luck with the 6" SCT.

[@IcemanAstro]

Your video has alot of information James. Personally, since i have started using refractors, that has been my goto, aside from the Rokinon that is 😂. Clear skies !

[@DSOImager]

Thanks Isaac! I think the Rokinon counts as a refractor.. doesn't it? Sort of.. maybe? :) CS!

[@IcemanAstro]

@@DSOImager As far as glass, yeah. I didn't want to say I considered it that way 😅

[@DSOImager]

@@IcemanAstro lol

[@aneyesky]

Side note-the Crescent neb has always reminded me of a horseshoe crab, not a “Euro sign or Crescent. Especially in your fine images. Excellent video btw.

[@DSOImager]

Thanks! I think a lot of these deep sky objects were made by visual observations. Our imaging rigs reveal so much more :)

[@gregerianne3880]

This was a really great comparison, James. I see the Celestron 8" EdgeHD offered as a package with an AVX mount (30 lb capacity). Would you consider the AVX mount to be suitable with use for the 8" EdgeHD after all the accessories (OAG, astro cam, filter wheel, etc) are added? I have an Askar 107PHQ (750mm fl) right now and I'm using a ZWO AM5 mount which works great with the 107PHQ. As you mentioned in the video, though, galaxy season was a bit of a letdown using the 107PHQ and I'd like to have something bigger for the next go-around, and also for some planetary imaging and observation. However, I'm sure I'd need a different mount to accommodate the 2032mm focal length of the SCT. I've heard so many different opinions about the AVX mount I was unsure if it's worth getting the EdgeHD/mount package. Thanks again for a great video!

[@DSOImager]

Thanks Greg! I've had my AVX since 2017. I'm still using it today with my 65PHQ. The AVX is fine with the Edge 8" when it comes to visual and planets. I do not recommend it for DSOs @ long focal lengths. While you can make it work, you'd be tossing out too many subs due to inconsistent tracking.

[@gregerianne3880]

@@DSOImager Okay, thanks so much, James. Exactly what I wanted to know. Although the AVX seems like a great mount, it might be better to get the OTA separately and look for an all-arounder mount I can use for DSOs as well. Thank you for the great input and advice!

[@DSOImager]

@@gregerianne3880 You're welcome :)

[@EthanJohnston-eg9si]

AM5 Works pretty darn good on my C11 and FLT 132 btw.. easy peasy 300s subs.

[@DSOImager]

That's impressive with a c11.

[@johnposavatz]

One more thing to add (under the umbrella of "consider your targets"), I presume that an SCT is really the best (only?) option for planetary imaging.

[@DSOImager]

Most of the best planet shots Ive seen have been taken with SCTs, especially the C14.. that thing is a planet killer :)

[@Si-fp2ij]

Great comparison video James, I have the Askar 65 PHQ currently and I’m now wondering if I should think about mounting my 8” Dobsonian for galaxy’s 🤔

[@DSOImager]

Thanks! If you have a mount that can handle that dob, it might be worth a shot :)

[@Si-fp2ij]

@@DSOImager I only have a skywatcher gti for the Askar currently but I’m thinking of getting a larger mount to handle the extra weight of the Dob and possibly an additional SCT in the future as I’m new to the hobby (1 year now)

[@DSOImager]

@@Si-fp2ij Nice! Definitely get a mount that will give you some room to grow.

[@Si-fp2ij]

@@DSOImager yeah I was thinking either the EQ6R pro or maybe one of the ZWO AM5 harmonic drive mounts? Any thoughts?

[@DSOImager]

@@Si-fp2ij EQ6 should probably handle it. I have no experience with the AM5. Seems like it should be okay.. unless it's a really long scope.

[@luboinchina3013]

I have 8HD, ASI2600MC Pro on EQ6R Pro, used Canon 5D M3 before. Stars are definitely bigger IF YOU DON'T USE FILTERS. I did few nights with L-Ultimate dual narrowband filter on Crescent nebula and it blew my mind compared to my old unfiltered photo using my old Canon. However with filters you may expect halo around bright stars due to internal reflection between the filter and secondary/corrector plate? If too windy, but dark, remove the dew shield from SCT and you will be fine. Also with SCT you have smaller chance of your camera hitting the tripod legs while slewing. The point of balance is much lower which makes your setup ending up higher and you will be able to keep tracking even well past meridian without worrying about it hitting something. The main question should be: DO YOU PLAN TO SEE AND IMAGE PLANETS OR NOT? If you want to image planets, get SCT.

[@DSOImager]

Yes! SCTs do great on planets. Ive considered removing the dew shield but haven't due to some stray lights in my backyard. I may give it a try anyway. CS!

[@luboinchina3013]

@@DSOImager I forgot to mention, I used skywatcher 60/700 scope for guiding at 700mm and asi290mm mini on top of the scope. Glued the tubes to prevent any movement and only relied on a helical focuser to focus. Always easy to find guiding star and guiding was good. I went recently with OAG and thought myself, can't be that bad. How wrong I was. I can only find one or two reasonable stars if I am lucky. Also, cannot use full frame anymore due to small image circle. If I can find the star, it has better guiding results. But if you want to guide on comet, you need a separate guiding scope option.

[@DSOImager]

@@luboinchina3013 Yep, the OAG can be tricky to set up. I find comets to be challenging. I've only shot a couple recently. Tricky to process.

[@luboinchina3013]

@@DSOImager ASTAP works the best if you want to process comet that had been tracked on.

[@Jcastleinfo]

very informative. I've been debating getting an Edge HD8 for months. Anyway, I love the background image for this video. Which part of space? I really like some good visible small galaxies in a wide field image.

[@DSOImager]

Thanks! That background shot is a small part of the Witch head nebula. HaLRGB with my at115edt. I'm thinking about revisiting that area when it's back up in the sky with my Edge.. to get a closer look at those galaxies. Full res of that shot is on my astrobin page.

[@denodan]

Get the standard 9.25, the field on it is better than the standard 8" as its mirror is F4.2 rather than F4, so is a better mirror than even the 8" Edge is cheaper, so gaining more aperture for less money. The Edge 8" feild while flatter than the 9,25, its not by much, so not worth the extra costs. The accessories as so muich more expesive for the edge also. The reducer is no only heavy, but very expensive. Also for planets bigger is better, and since you have your objected centred, no point buying the edge for planets when you can get the 9,25 cheaper

[@Jcastleinfo]

@@DSOImager Thanks for sharing. Stunning work.

[@Jcastleinfo]

@@denodan very interesting. you've given me a lot to think about now. The price difference is negligible and lots of great reviews for the 9.25.

[@denodan]

@@Jcastleinfo remember also if you want to do astrophotograhy you will need the reducer, and for the HD is very heavy and very expensive. Can get the Starizona F6.3 reducer and flattener and works as well as the Edge, but cheaper

[@julesarcher8073]

What about dew challenges on the corrector plate? I see you are using a dew shield. Do you need to use a dew heater? If so, does that affect star size/shape as others have noted?

[@DSOImager]

Yes, I am using a due heater strip with the dew shield. I have the heater strip on top on the dew shield, right at the corrector plate. I had my doubts that this would actually work... but the only time in the past 4 years I had due on the corrector plate was on a very damp night and I had forgotten to turn the dew heater on. In regards to star shapes.. no I have not noticed anything. In fact, if the wind is over 7mph I'll remove the dew shield. All the data gets stacked, with the same flats even. What I do notice with star shapes.. is that my Edge takes longer to cool or equalize than my 115edt and it's noticeable on the star shapes.. usually after an hour the star shapes are back to normal.

[@julesarcher8073]

Thanks! I've been fretting for the past few months on this very same 'next longer FL scope' choice. Your thoughtful and informative comparisons are very helpful in making a decision---hopefully soon before Galaxy season is over!

[@DSOImager]

@@julesarcher8073 You're welcome :)

[@anata5127]

During presentation on TAIC, Garry Imm mentioned that 9.25 Edge is sightly better in resolution than TOA 130mm (finest refractor there is). Then, I asked him to send examples showing it. He did. But margin was absolutely tiny, which could be seen after massive magnification. However, his TOA was old version. New version has incredible flattener producing 1um star test. In my opinion, top end 130-180mm refractors are equal to SCT. However, their price and their weight are not justified. Thus, I have TEC 140mm on order. I am not sure that purchase will be justified, when I have 9.25 Edge.

[@DSOImager]

I would be very interested in hearing your thoughts on the tec 140 vs 9.25 edge after you've had some time with it.

[@anata5127]

@@DSOImager I will get TEC 140mm in January-March 2025. Such a waiting time for this scope! I have sold all my original scopes: Stellarvue 70 triplet; C8; vixen 103 and skywatcher 150p Newtonian. Now I have 9.25 Edge and Epsilon 130. Refractor is remained. I just cannot make mind about it. Candidates TEC 140; TOA 130 and Esprit 120. What will be purpose of refractor? It will not beat 9.25 Edge. No way. Refractor will not beat Epsilon 130 in wide field, either. Refractor could be used for second rig. But … I forgot how to guide, and AVX will handle only Epsilon anyway. Bottom line, I don’t know what I will get. So far I more inclined for Esprit 120.

[@DSOImager]

@@anata5127 Esprit 120 is what I was planning to pick up. I was like a month or two away from pulling the trigger when the prices surged.. pushing beyond what I was willing to spend. The AT115EDT is what I ended up with instead. I've seen a lot of great work done with the Esprit 120. I had a chance to play with a TOA 130 for one week last December. Was a great scope.. worked just fine on the EQ6... and with the stock focuser + zwo EAF. I had heard that the Tak stock focusers on the refractors were not good.. but this one worked perfectly fine for the short time I had it. It's a hard choice. I was asked recently, of the three scopes I currently use, if I could only keep one which would it be. My answer is the Edge. With that said, I really do like the fov I get with the 115 (or that toa 130).. enough that I think I will always have a scope in my arsenal to cover that range.

[@anata5127]

@@DSOImager Yeh. Edge is unbeatable versatility, resolution and price wise. Therefore, 8”, 9.25” and 11” Edge are top three most used scopes in astrophotography. Epsilon has whooping 6 degree FOV. It will handle massive 35-44mm sensors. Now, where does it leave refractors? I will do any type of target without it. However, Esprit 120 could be better for few targets. TOA130 and TEC140? I am not sure. Maybe TEC180, but then it is not for backyard anymore. Then it is better PlaneWave 14-17” or similar. So, all in all, I will wait. 9.25 Edge with Epsilon will be enough for now.

[@oishisakana]

so your saying I should buy more telescopes....

[@DSOImager]

Well, that depends on your personal situation.. but assuming you have the financial means, the time & the interest, yes :)

[@denodan]

Have seen tests between the edge 8 and standard 9.25. While the edge 8 has a slightly flatter field, its not that much flatter then the 9,25. Certianly the edge 8 is costs more, but price and performance wise better off with the 9,25. The 9,25 has the better mirror, as it F4.2 rather then an F4

[@DSOImager]

I have heard that the 9.25 were the best optically.. both edge and non edge. My friend @AstroSoundscape has done some really nice shots with his standard C9.25. There's a few improvements that the Edge has over the standard, they are all minor but collectively.. they might be worth it to some.

[@denodan]

@DSOImager Not worth the price difference, fittings are not stand, so far more expensive. Sure minor differences but also smaller aperture. The 9.25 has the better mirror also. And the 9.25 has a sharper image, less glass also, as the edge has the built In flatter. It's the accessories your paying far more than the standard, and even on cloudy nights said the bigger aperture for less money was the way to go. It's just a no brained and if I want the same benefits as the edge would just buy the staraziona coma abs reducer and still cheaper than the edge, cannot beat aperture, your getting 1 25" more for less money. I also wad going go get the edge, but when I added I the reducer which you need, the cost outweighs the benefits, when the starzonia reduce dies tye exact same job as the edge and still cheaper. Have seen reports were its stated the 9.25 has thr best optics, even clearer than the 11"

[@DSOImager]

@@denodan I just checked the prices of these scopes since I've been out of the market for some time... the 9.25 standard sct is $300 more than the Edge HD8. The 9.25 will need a flattener/reducer. The reducer is optional on the Edge HD8. Many people do use their Edge's at F10, especially during galaxy season. Also the Starizona SCT corrector IV is the same price as the Edge HD8 reducer. So there is no cost advantage here for the 9.25 standard vs hd8. Yes.. the 9.25 gives you more aperture but IMHO your a bit dismissive of the Edges flat field. For some people it may not be an issue. I know many imagers that don't worry about corner stars. I also know other imagers that can't stand bad stars in the corners and will sacrifice much for good stars at the corners. Natively the Edge line's spot diagram is superior to the non Edge. It does look like the starizona reducer tightens it up a bit for the standard sct's. For visual and planets, yes.. the 9.25 standard sct is the better choice compared to the HD8. I disagree that it's a no brainer when it comes to DSO imaging. Both have their merits. I've done my research prior to purchasing my HD8 4 years ago.. including looking closely at many images on astrobin (after all its the finished images that matter in the end.. right?). If I had to do it again today.. I'd still go with the HD8. If I wanted to go with a 9.25, I'd pony up for the Edge version.

[@denodan]

Thats a massive change. Got my 9.25 cheaper then the edge. Yes galaxies at F10 is fine other DSO will need the reducer. The staraziona reducer is looking at prices $100 cheaper then the edge one. Wow the price of the 9.25 has gone up then, or edge dropped in price. When I got mine was 200 cheaper then the Edge 8

[@denodan]

@@DSOImager If galaexies your interested in, then the bigger aperture will give beter resoultion and detail

[@Robb-jf7vg]

Q. You actually started with a "Baby Sized" 70mm scope? W O W ! I know plenty of folks that began with an ancient or even homemade 6 inch Newtonian. But a 70mm ? I'm speechless!

[@DSOImager]

Starting astrophotography with a small refractor is pretty common. What is so surprising?

[@wesleyjohnson597]

Why do so many people use reducers with sct's i mean isn't the focal length the reason you bought it.

[@DSOImager]

There's a few different reasons. For me it's mostly about the speed, F7 vs F10. F7 will produce a brighter and more detailed image for the same total integration time. Also the shorter FL and larger image scale makes the whole rig more forgiving, suitable for a non premium mount like an EQ6 with average seeing conditions. And 1440mm FL is decently long anyway. You're not going to find too many other scopes out there with 1400mm+ FL at F7 for this price.

[@--Adrian--]

Should compare same aperture, same image scale, same mount.

[@DSOImager]

Did you watch the whole video? I explain the difference in aperture. I did register one to the other on the crescent shot, thus same image scale. They both run on the same mounts. Same sky, same location.

[@--Adrian--]

@@DSOImager It doesn't have any meaningful end-point. You can find the same comparison on countless threads on CN. What you don't see is a 8 inch apo vs 8 inch SCT, 10 inch apo vs 10 SCT etc. Mostly because people can't afford a quality instrument like a big frac, and second, the comparison will be pointless because, of course, the unobstructed scope will perform better in every way.

[@DSOImager]

@@--Adrian-- What makes this comparison work is that the two scopes are very similar in price. The reason you see countless threads on CN is because people are planning their next scope purchase. I go over all these points in the video :) That said, if I ever end up with an 8" APO, I will do a direct comparison. CS!

[@skywatcherca]

Ok, let me start by saying that I make this comment with the greatest of respect to DSO Imager and any other subscribers: this is my opinion. Respectfully, I had a 7" Astro Physics Starfire refractor (I sold it) - and I presently have an F10 and an F8 Meade SCT. (Yes, I have both and they are pristine, and yes I'm an idiot for having both - there is a reason, but that's not part of my rambling now.) I found that the 7" AP was NOT nearly as good as what the reviews had stated. (It was greatly wanting! Oh yes, I like AP, but perhaps Roland rushed the last production of 7" Starfire refractors - I don't know.) I truly believe that many, not all, but many of these reviews are PAID by the supplier/manufacturer - which is a shame. It (some of these paid-for reviews are not real) it misleads the new astronomer. The Meades - they work, and let me be clear, I am not a Meade paid stooge, and quite honestly I have had many BAD experiences with Meade - I do NOT love Meade! Obviously, I can't compare the 7" to the 16" OTA's, (its not an apple to apple comparison) but I'm old: I've been observing for over 60 years, and I've used/observed through a 74", a 24" and I have seen the ccd images from a 100" (2.5 m), and through a 1 m. So, let me return to the 7" refractor and the 16" Meade(s). I also have and use a 100mm Skywatcher Esprit - the 100mm Esprite gave better images than the 7" AP - really. The visual images from the 16" Meade ACF (f10 or f8) far exceed the images from the 7" AP or from the 4" Esprit. There is no substitute for aperture; really, on reasonable nights where there is reasonable (NOT perfect, but reasonable) sky stability, there is no substitute for a large OTA. Respectfully, I hear all of these reviews on various scopes - you get what you pay for: really - the larger the aperture (when reasonable viewing allows) the views from a large OTA are best. I hope that I have not offended anyone: please - this is just my comment. Perhaps I am wrong! Good review though: and thank you.

[@DSOImager]

Hi Jonathan, No offense at all. I value your opinion and I agree with all your points, there is no substitute for aperture. I think that showed up pretty well on the comparison I showed with the M42 shots. It is interesting that there currently isn't to my knowledge a premium SCT out there. I think Meade and Celestron are the only options. Seems all the premium manufacturers are using different designs. Your comments in regards to the 7" AP vs the Espirt 100 was interesting. The most premium optic I have used was a tak 130 toa for one week, I shot the Jellyfish nebula with that one. Thank you for your comments. Clear Skies!

[@skywatcherca]

@@DSOImager Mr. DSO Imager - due to the simple fact that you appear to be honest and say it as it is, I have subscribed to your channel. With respect, all that I ask from anyone making reviews is, to be honest - and, as you must know, there ARE paid by the manufacturer stooges who truly misrepresent the product. To keep it respectful, I won't mention the channel name, but you may know who I refer to: he's a paid stooge to Skywatcher - he's a scam, and I have contacted KZbin to advise them of this, but they do nothing. It's really a shame, as many new folks, (some folks) new to astronomy science/field depend upon these reviews. In any case, thank you - you are a gentleman. Clear skies as some tend to say!! :0))

[@refetastro]

Great video How Meade etx 90 or 125 is on galaxies.

[@DSOImager]

Thanks! I have no personal experience with them but I do not think either one of those would be good for imaging galaxies. They have two factors working against them. 1) They are using alt/az mounts. This would limit you to short exposures and reduce your field of view due to image rotation. 2) The F ratios are very high. Imaging at F 13.8 or higher yields dim images. You'd need to much higher integration time compared to faster optics. These would not be good choices for deep sky astrophotography.

[@refetastro]

@@DSOImager ohh I missed to inform you that I can de fork than put them in eq6 pro R I’ll give a try just for experimenting.

[@DSOImager]

@@refetastro Ah, got it. That's good. I do still think the F ratio is too slow on those.. but if you already have the scope you might as well give it a try. I'm sure you'll get something :)