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The Grandson C90 Project

cassegrain Celestron Maksutov
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#1 rg55

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Posted 15 August 2014 - 03:40 PM

I have a couple of grandsons who are late elementary age and interested in astronomy. I've decided to get them each a C90 for Christmas, and wanted to include the best useful simple accessories. The C90s come with a finder, daytime diagonal and a 32mm Plossl. I'd like to add items that could fit into the Celestron bag and be carried by a 8-12 year old. While I don't have a Questar budget, I want the items to be good enough to last them until they get jobs and can start their own astro obsessions.  :)

 

Do any of you have suggestions for items to include? This is a fun project. Thanks for reading. 


Edited by rg55, 15 August 2014 - 03:42 PM.


#2 rg55

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Posted 15 August 2014 - 03:43 PM

I'm also testing out a couple of tripods made by Celestron. 



#3 jrbarnett

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Posted 15 August 2014 - 04:52 PM

I have a couple of grandsons who are late elementary age and interested in astronomy. I've decided to get them each a C90 for Christmas, and wanted to include the best useful simple accessories. The C90s come with a finder, daytime diagonal and a 32mm Plossl. I'd like to add items that could fit into the Celestron bag and be carried by a 8-12 year old. While I don't have a Questar budget, I want the items to be good enough to last them until they get jobs and can start their own astro obsessions.  :)

 

Do any of you have suggestions for items to include? This is a fun project. Thanks for reading. 

A 90-degree star diagonal would be a good addition.  They might also enjoy a second eyepiece with shorter focal length for extra magnification, but for alt-az use and young folks, I wouldn't overdo it on magnification.  The 32mm produces ~40x with the C90, so I'd look at adding an eyepiece that would double that - something in the 14mm to 16mm range.  A 15mm Celestron Omni Plossl isn't bad and would be less than $30.

 

Regards,

 

Jim



#4 DocFinance

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Posted 15 August 2014 - 06:21 PM

The mount is critical - it has to be simple enough for them to use yet stable enough that they will want to use it.  A fluid head is almost a necessity, but those scopes are light enough that you should be able to use a light duty head.  Another thing that has worked for me is using the handle slot to attach a counterweight of some kind.



#5 rg55

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Posted 15 August 2014 - 06:34 PM

Good suggestions on the eyepiece and the tripod, Jim and Doc. I'll probably be giving them a couple of my old eyepieces as well. The tripod really is a challenge. I just checked out a Celestron 'heavy duty alt-azimuth' mount that turned out to have been broken, although ordered new. Not sure it's going to work out, I found a couple of problems but didn't get to take it through a field test. Also ordered a Celestron Astromaster alt-az but not received yet. I might not end up with either of them. May end up looking at photo/video tripod set ups in the $100 range. 



#6 DocFinance

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Posted 15 August 2014 - 08:05 PM

The tough part with the standard alt-az will be observing near the zenith.  That's where a rigged counterweight comes in handy.  I've always struggled with my orange C5, but the new C90 should be much lighter.

 

see here

 

http://www.spacegaze...sp?pageid=97490

 

and here

 

http://freescruz.com...reviewblues.htm

 

(note: I can't be held responsible for anything on the 2nd site; that guy seems to HATE Cloudy Nights)


Edited by DocFinance, 15 August 2014 - 08:13 PM.


#7 KarlL

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Posted 15 August 2014 - 08:17 PM

Richard -

 

You are a very generous grandfather.

 

 

I love my C90 very much. I would recommend the Orion RA 6X30 finder; it makes an enormous difference. For a mount, I use a Celestron Heavy-Duty Alt-Az mount (it has slow-motion controls). Very stable. I am using this setup solely now due to convenience and a bad back, and I am very satisfied with it. I'm a lunar, solar, and planetary observer, anyway. (I might try doubles with it.)

 

 

I would recommend flocking each one; the glare is annoying otherwise.

 

 

Regards,

 

 

Karl


Edited by KarlL, 16 August 2014 - 08:57 AM.

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#8 hardwarezone

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Posted 15 August 2014 - 09:02 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.


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#9 rg55

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Posted 16 August 2014 - 08:13 AM

Attached File  SmallCelestronShootOut3.jpg   88.54KB   0 downloadsOriginally I had considered the Celestron C70 as a grandson scope. It's still probably a reasonable less expensive choice. Here's a comparison shot of the Moon that I did recently: 

 

 


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#10 elwaine

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Posted 16 August 2014 - 08:36 AM

Hi Richard. What great gifts!

 

Just a personal preference of mine would be to add red dot finder. As I'm sure you know, it can be frustrating to target an object (like Jupiter or Saturn) using an Alt/Az mount the small finder scope that come on the C90. The easier it is to use, the more fun your grandchildren will have with the C90.



#11 rg55

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Posted 16 August 2014 - 08:52 AM

Good point, Larry. I think I would go for the RDF if it were the right one. I've personally had problems with the cheap plastic ones breaking and wonder if a child would remember to turn off the LED light. I think there's a unit out there that turns itself off after a while but don't recall the brand.


Edited by rg55, 16 August 2014 - 08:52 AM.


#12 Geo.

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Posted 16 August 2014 - 09:19 AM

The Mak is a good choice. Young people will want to explore the Moon and planets and this is a good compact package with enough power for that. I use a Celestron 127 Mak quite a bit. By adding a f/5 focal reducer it can do wide field well, too.

 

This is a German Giro III, my favorite mount. The ES Twinstar is a poor imitation. The Giro isn't cheap, I paid $250 for it used with a cracked knob (now replaced with Meade LXD75 knobs) and no tripod . But I think this is what you want to shoot for, Something that permits free movment in both axis. The Orion VersaGo comes to mind and sells used about $125 I don't think a mount with fine geared controls like the Vixen Mini Porta is what you want.



#13 rg55

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Posted 16 August 2014 - 09:35 AM

George, this is the other tripod/mount I'll be testing with the C90:

 

http://www.amazon.co...tromaster mount

 

This doesn't allow for fine movements, but certainly simpler. I'll be field testing this and the alt-az 'heavy-duty- mount. If neither work out, I'll be looking elsewhere for sure. Maybe even small video tripods...  



#14 Geo.

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Posted 16 August 2014 - 09:51 AM

Yes, I have experience with it and it's a good place to start. As long as the legs aren't fully extended, it's pretty sturdy. And given it's cost, ease of setup and portability you can forgive some lack of steadiness when focusing and traversing with it at full height. Meade and Celestron use this design for a lot of their mounts, Some of which really overload it, but as an Alt/Az for a 90 Mak it will work well. It may take some fiddling with the tension on the axle bolts as it wears in to keep movements smooth, otherwise no complaints and that's not a bad price.



#15 rg55

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Posted 16 August 2014 - 10:13 AM

Although I plan to use mine as a guide scope, the Celestron Travel Scope C70 can do surprisingly well when barlowed up 5x or so. One problem however is that the OTA becomes extremely unbalanced with the focuser extended and barlow and camera added. With some other mounting set up it could probably work better. I purchased the C70 OTA new on Amazon for about $50, without the usual finder, case and tripod, which as a package usually runs about $80.

 

Here's how the C70 did with the Moon, 5x barlow and Canon XSi this morning:

 

 

Attached Files


Edited by rg55, 16 August 2014 - 10:20 AM.


#16 Starhawk

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Posted 16 August 2014 - 11:40 AM

With my own kids, I have observed smaller telescopes are far more attractive to them- they are on their scale and easier for them to operate.  The current version of the C90 definitely needs a star diagonal to use for astronomy.  The small size means they can take it out, but anything like a photo tripod is woefully inadequate to mount it.

 

I did mount one successfully on a Universal Astronomics UniStar Deluxe, but that's probably a bit of a cost stressor for this.

 

At the end of the year, Costco has been offering variants of NexStar SLT telescopes starting around October each year.  That is about $200 and has some OTA on it- last year it was a 90mm refractor, the year before it was a C102, which really was too large for the mount.

 

-Rich



#17 rg55

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Posted 16 August 2014 - 12:14 PM

Good comments, Rich. I own a SLT mount with my Orion 127mm mak on it. While it's not that difficult, I don't think they're quite ready for a motorized mount with hand control. I do like the idea of transferring the C90 to one once they're ready. I had to replace my SLT mount's tripod with a more robust Orion one. I come up with some weird cross brand combos but they work. :D



#18 rg55

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Posted 16 August 2014 - 12:18 PM

Richard -

 

You are a very generous grandfather.

 

 

I love my C90 very much. I would recommend the Orion RA 6X30 finder; it makes an enormous difference. For a mount, I use a Celestron Heavy-Duty Alt-Az mount (it has slow-motion controls). Very stable. I am using this setup solely now due to convenience and a bad back, and I am very satisfied with it. I'm a lunar, solar, and planetary observer, anyway. (I might try doubles with it.)

 

 

I would recommend flocking each one; the glare is annoying otherwise.

 

 

Regards,

 

 

Karl

Thanks, Karl. I do my best. I really like the finder idea. I know I prefer RA.



#19 Starhawk

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Posted 16 August 2014 - 08:33 PM

I'm not sure what the ideal push mount is, but I definitely see the kids resonate with the idea of "I want to look at that" and there is no voyage of discovery needed to get a look at it.

 

The C90 is big enough to be able to get basic features on planets. I would alternatively suggest the C80ED offered by astronomers without borders- yes, it is more, but wow does it have a big magnification range, and it's built like a tank. 

 

I'm going to poke at mounts, some.  I built one once from wood as a tabletop on a tripod.  It worked really well, but the dry weather of the desert destroyed the wood over time.  That made me sad- so I am pretty well attached to something metallic for a mount.

 

-Rich



#20 stevenf

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Posted 17 August 2014 - 03:15 AM

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. 


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#21 Brent Campbell

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Posted 17 August 2014 - 08:21 AM

Been watching this thread with interest. and I don't even have grandchildren yet!   You might want to consider one of the Nexstar Goto mounts to pair with the C90.   Younger generation and technology...they embrace it.  You can get Nexstar mounts used for around $70.00 each. 


Edited by Brent Campbell, 17 August 2014 - 08:24 AM.


#22 esldude

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Posted 17 August 2014 - 11:51 AM

I agree about the mount needing to be good.  Don't have good suggestions.  I use an older EQ mount I scored off craigslist.  Not a super expensive one, but was meant for a much larger scope.   I think starting out an Alt-AZ is better anyway.  The suggestion for goto is probably good as well.

 

I also concur on the red dot finder scope, and a good star diagnonal.  The prism that comes with the C90 hampers performance noticeably.  Need not be an expensive diagonal, even a basic mirrored unit is an improvement.

 

Finally if the money is available I would suggest one of the zoom eyepieces.  Some current ones aren't that much behind separates and make it such a joy to use for someone new to the hobby.



#23 PowellAstro

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Posted 17 August 2014 - 12:59 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...


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#24 jrbarnett

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Posted 17 August 2014 - 01:44 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...

That's a pretty good suggestion.  The only counterpoint I'd offer is that the spotter version works a little better than the NexStar version for terrestrial use.  While Richard's long term goal is to engender a love of astronomy in his grandkids, I remember finding my way as a similarly aged child.  I used my 60mm long focus achromat on its alt-az mount almost as much for terrestrial viewing as astronomical.  Of course the NexStar version does not preclude terrestrial and adding a 45-degree correct image diagonal would be pretty cool.  Adding a dependency on batteries may be a negative, too, though kids today manage lots of electronics, so maybe not a big deal either.

 

Here's a pretty sweet little eyepiece set for a 90mm (125x, 83x and 31x):

 

http://www.optcorp.c...ce-package.html

 

Regards,

 

Jim



#25 rg55

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Posted 17 August 2014 - 07:35 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...

That's a pretty good suggestion.  The only counterpoint I'd offer is that the spotter version works a little better than the NexStar version for terrestrial use.  While Richard's long term goal is to engender a love of astronomy in his grandkids, I remember finding my way as a similarly aged child.  I used my 60mm long focus achromat on its alt-az mount almost as much for terrestrial viewing as astronomical.  Of course the NexStar version does not preclude terrestrial and adding a 45-degree correct image diagonal would be pretty cool.  Adding a dependency on batteries may be a negative, too, though kids today manage lots of electronics, so maybe not a big deal either.

 

Here's a pretty sweet little eyepiece set for a 90mm (125x, 83x and 31x):

 

http://www.optcorp.c...ce-package.html

 

Regards,

 

Jim

 

The nice thing about a OTA like the C90 is that, if they show continued interest in the astronomy side, I (or another) could pick them up a motorized mount and transfer the OTA to it. If they don't, it could still serve a purpose as a spotting or wildlife scope or telephoto. You never know. ;)







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