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Best choice for a used sct ?

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33 replies to this topic

#26 SeattleScott

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Posted 22 May 2019 - 07:19 PM

No protective overcoat on Coulter mirrors? Well that explains a lot! Good to know. Even so my 8” comparison does show that high reflectivity coatings have their merits, even if it isn’t a dramatic difference

#27 Cajundaddy

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Posted 22 May 2019 - 07:39 PM

OP,

 

For peace of mind and the ability to separate the eagles from the turkeys quickly, learn how to star test a scope.  This way you can shop a much wider range of builds and find a really nice example, often for not much $$.  If you find a scope you like, have the seller set it on the porch for 1 hour at sunset to get acclimated.  Then go have a look and run a quick star test at high mag.  A nice scope is pretty easy to see compared to a dud.

 

This is not as thorough or precise as a full bench test but it quickly separates the wheat from the chaff.


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#28 rugby

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Posted 23 May 2019 - 11:09 AM

I started this thread more than a month ago and can update saying that I opted for an 8 Meade lx 10. At the time there were several to choose from. I think for what I paid I got a good scope. Everything on it works having used it a dozen times under the stars. Granted it is a tad heavy compared to other grab and go scopes and I am still looking for a solution to a missing battery compartment door.  

 

I wouldnt hesitate to recommend this sct to others. Things I would add or change are as follows: 

1. electric focusing. Not many options here but I did receive a kind offer by Rigel Systems to build one to fit the model. I sent the dimensions but have heard nothing back for weeks.

2. Find a battery compartment door so the battery doesnt fall out. Apparently this problem is not uncommon.

3.Learn how to collimate the optics. I think I am ready to tweak the screws on the secondary. This scope needs collimating.

4. Stop buying accessories to improve the view. I changed the finder to an RACI which really helped my neck but the new diagonals were a waste of money.  I wonder if that focal reducer will take me to observing nirvana?

5. At f10 I found I dont need high end eyepieces. Cheaper , smaller, lighter oculars of somewhat dubious quality still form a sharp image. 

6. Get your eyes checked yearly. The combination of poor collimation and my astigmatism doesnt make double star resolution easier. Think I will check out those diopters soon


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#29 laixiaolue

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Posted 23 May 2019 - 01:07 PM

Actually you are right for the Evolution mount. You can adjust the clutch tension on Evolution mount, but the tension won't stay there when you rotate the mount, it will be too tight, or too loose, depending on your rotation direction. I think Celestron has a design problem here, they save one or two components, so the tension won't hold. I have 2 Evolution mounts now, and I find them useless if I want to use them manually. LX200 classic is a much better choice if you want to run it in manual mode - it has slow motion knobs on both axis.

 

 

Thanks for the clarification on the Evo clutches. I must have misunderstood that from my prior research. Good to know! I did at least say “as I understand” since I haven’t personally seen an Evo mount, but good to have an experienced user chime in. So Evo sounds like it might be a good option, other than requiring a one star alignment for tracking each time it is moved around.

As for the Celestron SCTs fogging up, this has been well documented in long threads on CN, in addition to my personal experience (even if it isn’t my personal scope). Again it is more the newer models. Not sure what the year cutoff is. Eddgy I think was the first to report it so he would know more.

Scott


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#30 JohnnyBGood

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Posted 24 May 2019 - 07:50 AM

 

2. Find a battery compartment door so the battery doesnt fall out. Apparently this problem is not uncommon.

4. Stop buying accessories to improve the view. I changed the finder to an RACI which really helped my neck but the new diagonals were a waste of money.  I wonder if that focal reducer will take me to observing nirvana?

5. At f10 I found I dont need high end eyepieces. Cheaper , smaller, lighter oculars of somewhat dubious quality still form a sharp image. 

 

 

Congrats on the scope! I love my LX-10.

 

Battery door: I use rechargeable 9v batteries and they're ever so slightly too big for the door to close on them. So I leave the door off and they haven't fallen out yet. Aesthetics aside, that's been way less of a problem than I thought it would be.

 

Diagonals: The Meade prism it probably came with is, to me at least, a perfectly fine diagonal. I like prisms.

 

Focal reducer and eyepieces: Yep, I love my f/6.3 focal reducer. Once I put it on there it hasn't come off. With it, my field of view is more or less the same as what I was already used to with my ETX-90 (i.e. about 39x magnification with a 32mm Ploessl) making it easier to find things with the scope. I also use the same eyepiece/Barlow combinations I use with the ETX-90 since the effective focal length is more or less the same. I use 32mm, 26mm, 20mm, and 15mm Ploessl eyepieces and a 3x Barlow and they work fine. I sometimes also use a set of "red line" Expanse clones that work great without the focal reducer and "okay" with it (edges are out of focus). Without the focal reducer I found it too hard to find targets with a 32mm eyepiece. With more practice I'd probably get used to it, though.



#31 KevH

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Posted 24 May 2019 - 08:35 AM

"The issue with Celestron is the newer models have a tendency to fog up inside, requiring taking the corrector out to clean it every couple years. Not saying this is the case with all of them, but it happened to a buddy who bought a used one."....??????

 

You have given an example of ONE model that fogged up, and you got this info second hand.  Please..... Give us another verified example of the new ones "fogging up".

 

 

https://www.cloudyni...rror-on-edgehd/

 

https://www.cloudyni...sing-corrected/

 

https://www.cloudyni...ehd-outgassing/

 

https://www.cloudyni...-the-corrector/

 

https://www.cloudyni...erved-realtime/

 

There are more threads if you search.  I don't think it would stop me from potentially buying one but the issue has been discussed quite a bit.


Edited by KevH, 24 May 2019 - 08:40 AM.


#32 Reid W

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Posted 24 May 2019 - 10:01 AM

"The issue with Celestron is the newer models have a tendency to fog up inside, requiring taking the corrector out to clean it every couple years. Not saying this is the case with all of them, but it happened to a buddy who bought a used one."....??????

 

You have given an example of ONE model that fogged up, and you got this info second hand.  Please..... Give us another verified example of the new ones "fogging up".

 

I'll verify (right hand raised) that my Evolution C8 tube had the grease film on the corrector.  


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#33 Stargazer3236

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Posted 24 May 2019 - 05:04 PM

My Nexstar 6SE and 8SE never fogged up on the inside. In all my years of owning a Nexstar C8 (about 7 years), I never had a problem with fogging.



#34 SeattleScott

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Posted 25 May 2019 - 12:27 PM

The Nexstar 8 should be fine. I would be more nervous about the newer SE models. Certainly doesn’t seem like all the newer models fog up so if you get past a couple years without issue you should be good.

Scott


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