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The Grandson C90 Project

cassegrain Celestron Maksutov
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#26 PowellAstro

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Posted 17 August 2014 - 08:47 PM

Yes I see. I just wanted to mention it incase you were thinking you would provide the whole unit and I wasn't sure.



#27 rg55

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Posted 17 August 2014 - 09:05 PM

Here's a shot of the last quarter Moon through the C90 with a Canon XSi. 

 

 

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#28 rg55

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Posted 17 August 2014 - 09:22 PM

I used a 90mm mak on one of those Celestron heavy duty alt-az (AZ3) mounts for years with no problems. The slow motion controls were very handy to keep planets aligned and the short length of tube works well with the mount, doesn't unbalance it the way a larger refractor can. 

I'll get to finally try this combination out when the new AZ3 arrives this coming week. I can see where the slo-mos would really help on the higher powers.



#29 rg55

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Posted 17 August 2014 - 09:25 PM

You may consider the Celestron Nexstar 90SLT scopes instead of the C90. It has the same optics as the C90 but comes with a computer goto mount, a star diagonal, two nice eyepieces, the star pointer finder scope and a nice tripod. It is a complete system and you would not need to purchase any extras. B&H has them for 341 shipped. I dont believe you could by the C90, star diagonal, extra eyepiece and a computer goto mount for less or even the same price. Just a thought...

I have a SLT mount that I took off the flimsy tripod and put on a beefier Orion tripod. Works great with my C80ED and 5" Mak. I could see them getting something like that in their teen years but it might be a bit much for now. They might be inheriting my stuff someday too.

 

I've also seen these little GT mounts like listed in our Classifieds here: http://www.cloudynig...t-mount-bundle/

 

I don't know what these mounts could handle. I suspect that the C90 with a camera might be a bit much. Am I right?


Edited by rg55, 17 August 2014 - 09:30 PM.


#30 Hesiod

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Posted 18 August 2014 - 03:31 AM

Have you give a look at "Skywatcher Virtuoso 90"?

It comes with 2 eyepieces (20 and 10mm), a stardiagonal, a red dot finder and an autotracking altazimuthal mount (well, a shorty one, but really steady) wich can be upgraded to full GoTo.



#31 rg55

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Posted 18 August 2014 - 06:45 AM

Have you give a look at "Skywatcher Virtuoso 90"?

It comes with 2 eyepieces (20 and 10mm), a stardiagonal, a red dot finder and an autotracking altazimuthal mount (well, a shorty one, but really steady) wich can be upgraded to full GoTo.

Yes, I did. There was even one that just sold on ebay. The models that I've seen are for tabletop...I think that might be too limiting, but perhaps that depends on the child and their circumstances.



#32 Starhawk

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Posted 18 August 2014 - 09:36 AM

Tabletop mounts are all but completely useless.  Even ifmyounhave a concrete picnic table to put one on, the table is between you and the eyepiece.

 

if you had the right top to put on a surveyor's tripod, that would work, and be cost competitive with any other option.  How handy are you with aluminum?  Sheet Teflon is readily available to make nice bearings. 

 

-Rich


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#33 rg55

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Posted 20 August 2014 - 09:33 PM

Update:

 

I've ordered 6x30 right angle finders, mirror diagonals and zoom eyepieces. Also tucked into their C90 cases will be headlamps.

 

Still waiting to receive the AZ3 tripod back for testing. The Astromaster was good in every respect except panning...the panning seemed very stiff to me. When I contacted Celestron support about it, they said that some people put teflon pads in to make it smoother. I resisted the urge to ask why they weren't included in manufacturing. :p

 

More later as I receive and test the items.  



#34 rg55

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Posted 22 August 2014 - 07:14 AM

Tabletop mounts are all but completely useless.  Even ifmyounhave a concrete picnic table to put one on, the table is between you and the eyepiece.

 

if you had the right top to put on a surveyor's tripod, that would work, and be cost competitive with any other option.  How handy are you with aluminum?  Sheet Teflon is readily available to make nice bearings. 

 

-Rich

Rich, I'm not very confident about pulling the mount apart yet for that purpose, but Celestron support said something similar. I may need to study further.



#35 rg55

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Posted 22 August 2014 - 04:07 PM

Here is a picture of the field kit. What I will be adding are a headlamp, basic star chart and Moon map. I had thought about including lens cleaning supplies but I need to think carefully about instructing children on the subject. all of this fits into the Celestron backpack.

 

 

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#36 5RNS

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Posted 22 August 2014 - 10:23 PM

Looks great, I bet they are going to love them. nice work!



#37 rg55

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Posted 23 August 2014 - 08:38 AM

Looks great, I bet they are going to love them. nice work!

Thanks. I'm getting lens pouch bags for the smaller items so they don't get damaged in the backpack. In the next few days I'll set up one on its tripod and take a picture to post.

:)



#38 Starhawk

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Posted 23 August 2014 - 03:26 PM

That looks really good.  Have you seen one of these in person?:

 

http://universalastr...arOverview.html

 

The mount has 1/8" thick teflon (PTFE) pads between flats between the moving parts. Adding compression adds drag to make it controllable.

 

-Rich



#39 rg55

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Posted 23 August 2014 - 05:22 PM

That looks really good.  Have you seen one of these in person?:

 

http://universalastr...arOverview.html

 

The mount has 1/8" thick teflon (PTFE) pads between flats between the moving parts. Adding compression adds drag to make it controllable.

 

-Rich

I haven't. The Unistar Light looks like a great match for the C90. At about $270 it's $200 more than the mount I bought. I'm the generous grandpa but not the wealthy grandpa.  ;)



#40 rg55

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Posted 25 August 2014 - 10:19 PM

Flocking the primary baffle helps very much with the contrast and light pollution.

Cheap and easily done within 2 hours. Can be done without any risky disassemble.

I've never done this...always been cowardly about taking apart telescopes...   :lol:



#41 hardwarezone

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Posted 25 August 2014 - 11:11 PM

I've never done this...always been cowardly about taking apart telescopes...   :lol:

 

 

I took a few photos of the process when I did that half a year ago. Just a simple tube insert through the rear visual back.

 

mw6A8Rxl.jpg

 

4mWCulgl.jpg

 

An43UUxl.jpg







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