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Your favorite 90mm Mak?

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115 replies to this topic

#26 Joe1950

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Posted 11 March 2021 - 01:20 PM

That is an excellent image, Jaimo! As is the moon image.


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#27 barbie

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Posted 11 March 2021 - 09:13 PM

I had similar results with the moon back in January.
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#28 Dwight J

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Posted 11 March 2021 - 09:26 PM

I have an ETX 90 RA.  Great optics, mount so-so but adequate for what I ask of it.  In addition to solar system targets it is very good for double stars.  I bought the ScopeStuff 11/4” rear cell eyepiece adapter and I use a regular diagonal.  


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#29 sportsmed

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Posted 12 March 2021 - 05:10 PM

My first mak was a C90 it came with a backpack and a few other accessories for around $160 and I loved that little scope. I ended up selling it to a friend that wanted one and I upgraded to the Celestron 127 SLT. But yea from the views I got, nothing wrong with the C90 only limitation is its aperture, most DSO were of course very dim. But overall a great grab n go scope also used a bunch for solar and as a spotting scope.


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#30 Mitrovarr

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Posted 12 March 2021 - 08:32 PM

And to be transparent, the Jupiter image is (and I'm not bragging) exceptional.  The seeing that evening was very favorable, a majority of my planetary images are a little softer.  But part of the luck in "Lucky Imaging" is just getting out there.  The Lunar photos are typical, it is a much easier target, especially when you are stacking images.

 

Jaimo!

I'm definitely still impressed at what you managed to pull out of a 90mm telescope.


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#31 barbie

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Posted 12 March 2021 - 09:30 PM

Yes, quite impressive!! These 90mm Synta Maks are excellent considering their price!!  I enjoy tack sharp images of the moon and planets when viewing conditions are favorable!!



#32 Mitrovarr

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Posted 12 March 2021 - 09:44 PM

Anyways, I think my favorite is the C90. I think the C90 is about the same optically as the other modern Chinese 90mms but the modern C90 has really good well thought out mechanics and is cheap, which puts it ahead.


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#33 Gregrox

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Posted 12 March 2021 - 11:16 PM

Please remember, you can pick up a good used Questar Standard for ~$2,250-$2,750, or a good used Field model for $1500 or so. If this is a scope you're going to keep for years and years and years (I've had my Standard for over 35 years now), you're really talking about under $100/year.

 

But I know... indeed... they're expensive.

 

Ron

You'd have to buy something like one replacement C90 every other year or one replacement ETX90 every leap year to keep up with the price per year of a Questar. Not saying Questars aren't worth it, but no one buys a Questar for economical reasons.


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#34 Kevin Barker

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Posted 13 March 2021 - 02:28 AM

IMG_0332.jpg
P1060894.JPG

 

 

89 mm. A second hand 1980's Questar Duplex, ota on a GEM in first shot.

Shows lovely star images.

 

I have viewed through sharp ETX 90's. I found them hard to use. Lots of mirror shift, dodgy finder etc


Edited by Kevin Barker, 13 March 2021 - 02:30 AM.

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#35 Jon Isaacs

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Posted 13 March 2021 - 02:45 AM

As a general rule most 90mm Maksutovs give very nice images for their size.  The only ones I would try and avoid is the old C90 with the center focus ring and as already mentioned the new Vixen.  A

 

That and the Meade Clone, I think it was called the Meade 97.  I had one many years ago. Not good at all.

 

Jon


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#36 Jaimo!

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Posted 13 March 2021 - 09:41 AM

That and the Meade Clone, I think it was called the Meade 97.  I had one many years ago. Not good at all.

 

Jon

Forgot about that... 

 

At least Meade didn't name the ETX the 97.   I've seen so much confusion about the two different C90.  


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#37 SandyHouTex

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Posted 13 March 2021 - 09:50 AM

Thanks for the feedback fellas. I like Ed’s videos........very matter of fact. I’ll check this one out. Looks like a photo finish between Celestron and Meade!

Actually Ed much preferred the Celestron over Meade.



#38 LU1AR

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Posted 13 March 2021 - 10:26 AM

I have enjoyed an ETX-90 RA for almost a quarter of a century. During my andropause I sold it and bought a model with Autostar, which turned out to be crap.
So I bought back an ETX-90 RA and made several improvements to its battery, finder and movement power; which I reflected in these forums:  https://www.cloudyni...etx-90-upgrade/

I have a 6 "F / 8 Newtonian and an ETX-125, but my ETX-90 accompanies me in the trunk of my car and I still enjoy it.
Regards.
Edgardo


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#39 Adun

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Posted 13 March 2021 - 05:53 PM

Quite a few options out there from every mfgr in this class but I’m looking for the best optics for Lunar AP. I think it’s safe to say we can cross Questar off the the list as it’s just waaaaay to expensive. Was thinking Vixen might be a quality scope but user reviews report very soft images and focus.....what’s your experience and thoughts on these gems!

 

My very first telescope was a C90 Mak, influenced by this big thread as I recall. I don't use it as much anymore, but I'm rather fond of that little scope.

 

Other scopes showed me how great the optics of the C90 really are: lack of aberrations (spherical, chromatic, coma, etc), nice tight stars, great star test, quick cooldown. It really is a little gem:
 

Jupiter image with C90 and IMX224

 

Saturn image with C90 and IMX224

 

Mars image with C90 and IMX224
 
The problem with 90mm maks is the small aperture. For visual observing of the moon my 10" dob (same focal length as the Mak!) provides hugely more impressive views, and that's because of the much higher resolution wich reveals smaller lunar details.
 
Sure, AP is not the same and you can compensate by choosing a camera with very tiny pixels, and lucky imaging~processing helps a lot, but if high resolution imaging of the moon is what you're after, a little more aperture (102mm?) won't hurt if you can afford it.

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#40 barbie

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Posted 13 March 2021 - 08:22 PM

That's not my experience!! I had a 102mm Mak and the improvement in resolution was negligible. The overall optical quality of my former C90 and my current C90 clone is much better and much sharper...tack sharp whereas the 102mm Mak was lacking, severely!! I've gotten far better photos of the moon and planets with my 90mm Mak than with a 102mm Mak!! The 90mm Mak is just plain sharper and is the sweet spot aperture for these small Synta-made Maks. My photos of the moon are far sharper and just plain better through my 90mm Mak than they were through my 102mm Mak. Same for visual performance. As for a 10" Newtonian showing more, naturally the resolving power of the 10" will win out but I don't have any intentions of going that route again! Been there, done that and I prefer to not break my back when setting up my scopes!!


Edited by barbie, 13 March 2021 - 08:34 PM.


#41 mayhem13

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Posted 13 March 2021 - 09:49 PM

The 12” Dob is great for observing for sure.....the moon looks soooooo detailed but I can’t do prime focus  AP without a coma corrector and AP through a Barlow of the moon is just too much. Just came in from some time with M42 and the Pleiades with Mars in the same view until it began to cloud up. Will test out the C5 later tonight if it clears up.



#42 Joe1950

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Posted 13 March 2021 - 10:14 PM

I’m leaning toward purchasing another C-90 (having foolishly sold the one I had). I would also consider another brand such as SkyWatcher, Orion (is that Synta?), or other. And I would consider a 102mm scope, though Barbie (post #40) doesn’t find the extra 12mm to be an advantage and found the quality of that size inconsistent. I’ve never had a 102mm Mak.

 

Right now there aren’t any scopes of 90mm or 102mm available anywhere. Most domestic dealers have more not in stock items than in stock of all products. Any idea on how long this situation will last? Plus any further thoughts or experiences with the 102mm size?

 

And, any thoughts on brand differences if say a SkyWatcher or other were to show up being available.

 

The C-90 I had was a solid scope and had very good optics. I don’t know if other names are the same or different.

 

Thanks.



#43 Adun

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Posted 13 March 2021 - 11:53 PM

That's not my experience!! I had a 102mm Mak and the improvement in resolution was negligible. The overall optical quality of my former C90 and my current C90 clone is much better and much sharper...tack sharp whereas the 102mm Mak was lacking, severely!! I've gotten far better photos of the moon and planets with my 90mm Mak than with a 102mm Mak!! The 90mm Mak is just plain sharper and is the sweet spot aperture for these small Synta-made Maks. My photos of the moon are far sharper and just plain better through my 90mm Mak than they were through my 102mm Mak. Same for visual performance.

 
Well, perhaps 12mm is not enough to make a tangible difference.
 
I mentioned it because I got more planetary detail from my 150mm C6 SCT, even despite it having more aberrations and being more finicky to keep collimated and "thermally isolated". However, 150mm is a larger leap.
 
Indeed the build quality of the newer C90 is kind of famous, and I've read lesser reviews of "Explore First light", ETX and other maks. It's a good point whether 1#mm extra aperture are worth risking quality.
 
Makes me wonder: ¿What kind of camera is the OP planning to use? A mono ASI183 (2.4um)? Aphocal with DSLR? What's the plan?
 

I’m leaning toward purchasing another C-90 (having foolishly sold the one I had). I would also consider another brand such as SkyWatcher, Orion (is that Synta?), or other. And I would consider a 102mm scope, though Barbie (post #40) doesn’t find the extra 12mm to be an advantage and found the quality of that size inconsistent. I’ve never had a 102mm Mak.
 
Right now there aren’t any scopes of 90mm or 102mm available anywhere. Most domestic dealers have more not in stock items than in stock of all products. Any idea on how long this situation will last? Plus any further thoughts or experiences with the 102mm size?

 
Considering you have an AT102ED, what exactly makes you long for a 90mm Mak? Is it the size/weight?

Edited by Adun, 13 March 2021 - 11:56 PM.


#44 Joe1950

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Posted 14 March 2021 - 12:43 AM

 

Considering you have an AT102ED...?

Good question, Adun.  Perhaps the very compact size and ease to use on a lightweight mount.  Perhaps just a whim that will pass by.  shrug.gif

 

Why duplicate 102mm, spending over $200? The refractor likely has a slight edge in observing the planets.

 

Ok. You talked me out of it!  lol.gif


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#45 Jaimo!

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Posted 14 March 2021 - 01:42 AM

 
Well, perhaps 12mm is not enough to make a tangible difference.
 
I mentioned it because I got more planetary detail from my 150mm C6 SCT, even despite it having more aberrations and being more finicky to keep collimated and "thermally isolated". However, 150mm is a larger leap.
 
Indeed the build quality of the newer C90 is kind of famous, and I've read lesser reviews of "Explore First light", ETX and other maks. It's a good point whether 1#mm extra aperture are worth risking quality.
 
Makes me wonder: ¿What kind of camera is the OP planning to use? A mono ASI183 (2.4um)? Aphocal with DSLR? What's the plan?
 
 
Considering you have an AT102ED, what exactly makes you long for a 90mm Mak? Is it the size/weight?

I completely agree adun, for solar system imaging my 6" Mak gets the lions share of the work, small OTA small mount.  The activation energy invovolved is as low as the C90.  My C9.25 takes a bit most effort and a larger mount, therefore only comes out on special occasions...  I need an observatory.  I do enjoy imaging with the C90, I like the challenge of the small aperture.  I have also been considering the ASI183, which would compliment my Maks nicely.

 

Your images above are lovely.


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#46 mayhem13

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Posted 14 March 2021 - 03:24 AM

 
Well, perhaps 12mm is not enough to make a tangible difference.
 
I mentioned it because I got more planetary detail from my 150mm C6 SCT, even despite it having more aberrations and being more finicky to keep collimated and "thermally isolated". However, 150mm is a larger leap.
 
Indeed the build quality of the newer C90 is kind of famous, and I've read lesser reviews of "Explore First light", ETX and other maks. It's a good point whether 1#mm extra aperture are worth risking quality.
 
Makes me wonder: ¿What kind of camera is the OP planning to use? A mono ASI183 (2.4um)? Aphocal with DSLR? What's the plan?
 
 
Considering you have an AT102ED, what exactly makes you long for a 90mm Mak? Is it the size/weight?

It’s a tough call......while the 102 grabs .38 more light, the 90 see 3x deeper and in a light polluted environment, the aperture advantage might not be as significant. The 90 is half the weight and size so there’s that. Probably only a side by side would tell the whole story.


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#47 Jon Isaacs

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Posted 14 March 2021 - 04:03 AM

Good question, Adun.  Perhaps the very compact size and ease to use on a lightweight mount.  Perhaps just a whim that will pass by.  shrug.gif

 

Why duplicate 102mm, spending over $200? The refractor likely has a slight edge in observing the planets.

 

Ok. You talked me out of it!  lol.gif

 

Joe:

 

Optically, I think you'd find the refractor had more than a slight edge on the planets.  That was the case comparing a 127mm Starmax to a 120mm Eon. You also have a CO80ED.

 

The Mak is more compact if you have a more compact mount for it..

 

Jon


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#48 Joe1950

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Posted 14 March 2021 - 05:13 AM

I guess that is one of the pluses that I was considering for having a Mak. You know my situation with the trees and neighbors, so something ultra and portable is appealing. But, you’re correct, I have the C-80 to fit that need and the 102 which is just a little bigger and heavier. But not enough to really matter.

 

But they are a great option that works very well, as seen by their popularity.

 

I’m pretty much set for now, though. I’ve been off grid for too long!

 

Thanks Jon.


Edited by Joe1950, 14 March 2021 - 05:23 AM.

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#49 Jaimo!

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Posted 14 March 2021 - 12:58 PM

Jon, Joe and Adun, 

I completely agree, if I were going to visually observe, a 100mm refractor would be nice.  But for lunar imaging, as per the OP, the 90mm Mak with 2x the focal ratio ~f/13.8 is probably better suited for capturing the subtle details.  The central obstruction is also a consideration for visual, when imaging it is not as the contrast can be enhanced in processing.  But as a caveat, I have seen some "wide field" lunar images are VERY nice.


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#50 Mitrovarr

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Posted 14 March 2021 - 02:25 PM

Does it really makes sense to get a slower telescope for planetary imaging? I mean, can't you just use a barlow lens to slow down any fast telescope?




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