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Celestron 100 mm f 9.8 achro with goto at Costco

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#1 ASTROLAWYER

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Posted 17 October 2012 - 03:53 PM

I've been around long enough to know to stay away from department store refractors or anything which says 450x on the box, BUT Costco has this thing for $200. I figure the tripos has to be lousy, but if the optics are even decent then this thing seems like it would be a good buy. Anyone want me to pick ne up and test it? :confused:

#2 Zamboni

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Posted 17 October 2012 - 04:12 PM

The optics are the same as the Omni 102. I plan on getting one so I can remount the OTA down the road and use the mount for my PST.

#3 tomchris

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Posted 17 October 2012 - 05:26 PM

I don't think I could buy a scope from Costco unless I wanted to use it's parts for something, as it appears Tristan is doing. I can't believe that the optics would be decent at all. I'd use the $200 toward some worthwhile eyepiece....only my opinion.

#4 Zamboni

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Posted 17 October 2012 - 06:16 PM

As I said, the optics are exactly the same stock Synta f/9.8 as the Omni 102 and the old C-102 HD. The Skywatcher 102 f/9.8 in Canada is also from the same optics. These scopes have VERY respectable optics, but are undermounted in this circumstance. Still, the OTA is worth the asking price in my opinion.

#5 Jim7728

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Posted 17 October 2012 - 06:56 PM

What goto mount could a Celestron 100mm f/9.8 ota be on other than a puny LCM for $199? Or is this a 100mm f/6 ota on a SLT mount?

I should just renew my Costco membership, could use some bulk supplies of kitty litter. :grin:

#6 Zamboni

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Posted 17 October 2012 - 08:22 PM

This thing is WAY undermounted in this case, but I have been wanting a Synta 4" f/10 OTA for a really long time, and I've been seriously eyeing the little nexstar mounts for my PST (just need a dovetail rail and an L bracket and I'll be golden!

I would pay the asking price for the OTA alone. Gettin a decent small mount for the PST as a freebie is a great bonus. I should have the funds to snag this next month and I hope they still have them in stock.

#7 KWB

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Posted 17 October 2012 - 08:27 PM

What goto mount could a Celestron 100mm f/9.8 ota be on other than a puny LCM for $199? Or is this a 100mm f/6 ota on a SLT mount?

I should just renew my Costco membership, could use some bulk supplies of kitty litter. :grin:

It's the 102mm F/9.8. There is an every growing thread about it here. Nexstar 102GT

#8 Jim7728

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Posted 17 October 2012 - 09:38 PM

Thanks!

Looks like one person was having fun with it.

#9 Zamboni

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Posted 17 October 2012 - 11:46 PM

Looking over the specs, it looks pretty certain that the mount itself is the Nexstar SLT. Same tripod, vixen style dovetail rail, skyalign, etc. Considering the mount itself typically costs 300 when purchased individually, and the OTA costs around 230 when purchased individually (from Skywatcher Canada, since it's typically not available individually in the US), this is possibly the single most insanely good bargain I've ever seen as long as you intend to use the mount and scope separately.

I'll be picking mine up in about a month. I'll provide a comprehensive test report.

#10 watcher

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Posted 18 October 2012 - 12:49 AM

Saw one a few weeks ago. Considering the short 4" on the SLT has been more than double the price..... Well, if I had 200 in my pocket at the time, I would have bought one just because!

#11 tomharri

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Posted 18 October 2012 - 07:00 AM

AND IT'S GOOD!!! For an achromat. Max power on Jupiter is 250x, 4mm, before the scattered colors smear out the image. Couldn't see the E & F stars in Trapezium, had light high cirrus clouds. But at high power the stars are little airey discs with 1 diffraction ring.
For a Chinese mass-mass produced scope, this is as good as the Jaegers leftover scopes I've been building. And their lenses cost $200. Gotta use the mount for something else however, hang flower pots or something.

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#12 Zamboni

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Posted 18 October 2012 - 07:46 AM

Not at all surprised. Every time i've looked through a C102HD/CR-4/Omni 102/Skywatcher 102 etc. the views have always been pretty top notch. I've been wanting one of these OTAs for about ten years but didn't want a CG4 mount. I wanted to get the OTA and mount it on a CG5. Well, I'm getting a CG5 next year so this is beyond perfect.

Also, since I picked up a PST two months ago I had been taking some long looks at the Nexstar SLT mount to use as a dedicated PST tripod. I do a lot of outreach so tracking is important, but the $300 price turned me off. Now I see this and I'm pleased as punch.

Maybe I'm a bit overexcited...

#13 watcher

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Posted 18 October 2012 - 09:18 PM

The SLT mount is actually a very nice little G&G goto mount for a shorter scope, especially if you replace the legs with wooden ones. Use mine with my TMB 80SS. It's a perfect match.

#14 Raldo

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Posted 21 October 2012 - 10:16 PM

Hi, I want to change the dovetail of my scope to tube rings. Which size and what extras do I need. I have a cg5 gt. Where can I buy the rings. I don't want to spend to much money. Thanks.

#15 Zebra24601

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Posted 21 October 2012 - 10:45 PM

scopestuff.com has all sorts of rings and stuff.

Why do you want to replace your dovetail with rings? You'd probably still need to buy a dovetail to attach your rings to a mount.

#16 Raldo

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Posted 21 October 2012 - 11:16 PM

Hi and thanks for your reply. I added a 2in diagonal. With the diagonal and my 2in eyepieces I am having balance problems on the mount. The dovetail is to short, and I am afraid that eventually will hurt the gears of the mount. Maybe my concern does not justify the change, I don't now.

#17 Zamboni

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Posted 21 October 2012 - 11:38 PM

Your concern does justify the change. When I get mine I'll be adding a 9x50 finder, a 2" diagonal and replacing the focuser with a dual speed crayford. That wil definitely throw the balance off and that short little dovetail just doesn't give you any room to rebalance.

#18 Raldo

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Posted 22 October 2012 - 05:03 AM

So, going back to my original question, what size of rings I need for this OTA and any extras?.

#19 Starhawk

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Posted 22 October 2012 - 09:38 AM

Put a tape measure around the barrel, measure the circumference, then divide the result by 3.14159. That's the size of rings you need.

From eyeballing and handling, I'd guess maybe 4.5" in diameter. But measuring is a much better idea.

-Rich

#20 Starhawk

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Posted 22 October 2012 - 09:40 AM

Indeed- a great deal on two pieces of equipment, but ones which are unusually poorly suited to each other.

-Rich

Looking over the specs, it looks pretty certain that the mount itself is the Nexstar SLT. Same tripod, vixen style dovetail rail, skyalign, etc. Considering the mount itself typically costs 300 when purchased individually, and the OTA costs around 230 when purchased individually (from Skywatcher Canada, since it's typically not available individually in the US), this is possibly the single most insanely good bargain I've ever seen as long as you intend to use the mount and scope separately.

I'll be picking mine up in about a month. I'll provide a comprehensive test report.



#21 Raldo

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Posted 22 October 2012 - 10:21 AM

Thanks, starhawk. :)

#22 Zamboni

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Posted 22 October 2012 - 11:37 AM

Put a tape measure around the barrel, measure the circumference, then divide the result by 3.14159. That's the size of rings you need.

From eyeballing and handling, I'd guess maybe 4.5" in diameter. But measuring is a much better idea.

-Rich


This is too complicated of a step for this particular scope. Orion, scopestuff, Astrotech, Agena and more all sell tube rings explicitly sized for this OTA. Since the tube is the same diameter as all Orion, Celestron, Skywatcher and Synta 4" Achros, just look for tube rings rated for those tubes. You'll find them easily.

#23 core

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Posted 22 October 2012 - 11:42 AM

if you replace the legs with wooden ones. Use mine with my TMB 80SS. It's a perfect match.


Wondering if you replaced the entire tripod (pics?), or just the legs? I'd thot the legs on the SLT were riveted in. Looks like I may pick one up as well, mainly for the mount to use on smaller OTA's.

#24 KWB

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Posted 22 October 2012 - 11:47 AM

Put a tape measure around the barrel, measure the circumference, then divide the result by 3.14159. That's the size of rings you need.

From eyeballing and handling, I'd guess maybe 4.5" in diameter. But measuring is a much better idea.

-Rich


This is too complicated of a step for this particular scope. Orion, scopestuff, Astrotech, Agena and more all sell tube rings explicitly sized for this OTA. Since the tube is the same diameter as all Orion, Celestron, Skywatcher and Synta 4" Achros, just look for tube rings rated for those tubes. You'll find them easily.

There is more than one way to tree a coon,as in however one finds a needed tube ring size is all that matters. Using a caliper is a 3rd way of helping to resolve the problem.

#25 watcher

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Posted 23 October 2012 - 03:26 AM

if you replace the legs with wooden ones. Use mine with my TMB 80SS. It's a perfect match.


Wondering if you replaced the entire tripod (pics?), or just the legs? I'd thot the legs on the SLT were riveted in. Looks like I may pick one up as well, mainly for the mount to use on smaller OTA's.


Mine's a little buried in the garage right now. Moved here in February and haven't even used that one since I got here. The legs are swappable. no need to change the whole tripod. Here's a pic of someone else's with additional mods in a different thread






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