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Your favorite 90mm Mak?

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115 replies to this topic

#101 barbie

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Posted 13 April 2021 - 09:04 PM

To be completely honest, when comparing views through an ETX90, a C90, and a Questar, I saw virtually no differences in optical performance on the moon and planets. Mechanically, the Questar is tons more refined and finely crafted but optically, all three were pretty much identical. All three scopes were properly cooled to outdoor ambient temperature and all three were used to view the moon and brightest planets. That's what my experienced eyes showed me.


Edited by barbie, 13 April 2021 - 09:10 PM.

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#102 Blacksmith

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Posted 13 April 2021 - 10:50 PM

I unpacked the scope just now. Really good packing job. The scope box is packed well also.

  • It’s a later model than the one pictured. The logo says “Sky-Watcher Skymax 102” It has a nice looking green anodized dovetail with 2-1/4” mounting holes and 2-3/16” mounting holes on the bottom.
  • Comes with a 90° right angle mirror diagonal and a nice red-dot finder with the standard Celestron dovetail mount. Also has a nice fitting front lens cover.
  • It also comes with 2 TeleVue DeLite eye...Just Kidding. 2 Keller eyepieces, a 25mm and a 10mm. They look to be about 55°. Nice comfortable FOV.
  • And it comes with a really nice soft-case for the scope. It has extra pockets for accessories and is well made. Instruction, manual and 2 year warranty.
I’m pleasantly surprised with the package! And I’ll tell you, it is almost indistinguishable from a 90mm scope, in size and weight. I will use it on a Celestron alt-az mount with slo-motion controls on both axes. It’s literally a one hand pick-up and go. But sturdy with the small scope on it.

I’ll take some pix.
I really appreciate it. I want it for the same reasons as you and no joke I was going to use the same kind of mount.
Sometimes when you get a break in the clouds you just want something to grab that’s fast and light.
Thanks again
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#103 Stevencbradley

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Posted 18 April 2021 - 11:02 PM

Here is what I did last night with the C90.  HERE is a link to the full size image, it is WAY is too big to upload, it is my first mosaic.
 
Celestron C90, SvbonySV305, AS!3, GIMP
 
attachicon.gifMoon Moasic 20-Mar-2021 FINAL2 - small.jpg


GREAT image! Thank you!

#104 Joe1950

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Posted 17 May 2021 - 10:12 PM

I finally got to use my favorite 90mm (actually 102mm) Mak, a Sky-Watcher 102. I’ve had it for a few weeks, bit the weather and moon position would not cooperate.

 

I took a couple quick iPhone pix, just handheld, single image. Not great photos but I didn’t set up the phone on the bracket as it should be.

 

3C0FA4C6-9F11-4AB3-A6BF-0B220FB6F989.jpeg

 

C7B188EA-562A-4846-9EA1-E2D5F8AC26DD.jpeg

 

But visually, the moon was very good! I had a Meade 8 to 24mm zoom and at 8mm, 162.5x, the image remained very sharp. Seeing was average 5-6/10.

 

Next time, if seeing is good, I’ll try higher power.

 

I did notice that the focus position is very precise. There is not a range of ‘in focus’ movement of the knob. So I’ll probably do something to make the focusing knob larger to have a little more fine control. It’s good that it snaps into focus at one point only, though, and doesn’t mush through a focus range. And I didn’t have any image shifting at all when focusing.

 

I haven’t even checked collimation yet. I will do that on Polaris. But judging from the visual images, it’s got to be very close.

 

So it looks good. The set-up with a Celestron Alt-Az mount is ultra light to take outside and move among the trees.

 

Thanks.


Edited by Joe1950, 17 May 2021 - 10:42 PM.

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#105 erin

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Posted 18 May 2021 - 06:51 AM

Hey Joe! That’s great! I am glad you got a chance to bring it out and it performs well. Nice pics! Interesting about the snap to focus. I wonder if that’s an indication of good collimation? I find that with my ACF.

 

It turns out that Orion did ship me a mak and I got it yesterday, but it was a 90mm and not the 102. mad.gif So the wait continues another month or so.


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#106 Joe1950

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Posted 18 May 2021 - 07:54 AM

Oh my. That’s a shame, Erin! I hope it gets to you soon.

 

The snap to focus means a scope is well corrected and has one best focus position. If it were over or under corrected to any degree, the light rays would not all converge at one point. In that case, the best focus would spread out over a range of positions and not be as sharp at any one position.

 

I’ll check the collimation with Polaris or an artificial star just to make sure it’s right on. 

 

These MAKs are very well made. The corrector and mirrors are all spherical in shape which are easier to make, especially since they are made on a machine. 

 

Hope yours arrives soon, Erin!



#107 erin

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Posted 18 May 2021 - 09:15 AM

Thanks Joe! The 90mm is really cute and all, but I could use that extra light grasp.

 

Oh, that makes sense! So snap to is more about over/under-correction than collimation. Good to know! 


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#108 rmollise

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Posted 18 May 2021 - 03:21 PM

My sweet little Orange Tube, natch... ;)

 

https://uncle-rods.b...mighty-c90.html

 

 

c90 lar small.jpg

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#109 25585

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Posted 18 May 2021 - 03:26 PM

Orange tube C9 


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#110 Joe1950

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Posted 18 May 2021 - 04:00 PM

Nice article on the Orange C-90, Uncle Rod! 



#111 rmollise

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Posted 19 May 2021 - 04:16 PM

Nice article on the Orange C-90, Uncle Rod! 

Thanks. And I'm glad I happened upon this thread. It's reminded me I need to get that C90 out of her case a little more frequently! "The refractors get lots of starlight, Uncle Rod. What can't I have any?"  lol.gif


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#112 Joe1950

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Posted 19 May 2021 - 09:44 PM

waytogo.gif



#113 paulsky

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Posted 24 July 2021 - 09:18 AM

Hi, 

And for terrestrial observations one C90 for Example with a erector prism... How is? 

How Much magnification for objects very far?



#114 barbie

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Posted 24 July 2021 - 09:39 AM

My recently acquired ETX90 Mak has splendid optics and can be pushed to well above 200x on a steady night. In fact, I can push it even higher with the appropriate eyepiece/Barlow combination and the image stays sharp. These USA made ETX90's have "Questar Like" optics which really perform beyond their aperture class!! It's also a testament that a well made Maksutov scope can perform every bit

as good as a comparable unobstructed scope of similar aperture and focal length, at least visually!!


Edited by barbie, 24 July 2021 - 09:58 AM.

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#115 Drew56

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Posted 25 July 2021 - 04:55 PM

LOMO Astelle 95 if you can find one on the used market. They don't get resold often.



#116 Drew56

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Posted 25 July 2021 - 04:56 PM

I saw an ad for Lomo Astele 95 with original tripod for $300. Thoughts?

Edited by Drew56, 25 July 2021 - 04:57 PM.



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