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Equipment Discussions >> Refractors

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Raldo
member


Reged: 03/24/11

Loc: PR
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Starhawk]
      #5483451 - 10/22/12 11:21 AM

Thanks, starhawk.

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Zamboni
scholastic sledgehammer
*****

Reged: 01/03/05

Loc: Colorado Springs
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Starhawk]
      #5483585 - 10/22/12 12:37 PM

Quote:

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.


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core
Pooh-Bah
*****

Reged: 02/23/08

Loc: Mostly in Norman, OK
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: watcher]
      #5483589 - 10/22/12 12:42 PM

Quote:

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.


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KWB
Postmaster
*****

Reged: 09/30/06

Loc: Westminster,Co Elev.5400 feet
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Zamboni]
      #5483603 - 10/22/12 12:47 PM

Quote:

Quote:

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.


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watcher
Carpal Tunnel
*****

Reged: 11/21/07

Loc: St. Louis, MO
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: core]
      #5484771 - 10/23/12 04:26 AM

Quote:

Quote:

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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BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Zamboni]
      #5484958 - 10/23/12 09:53 AM

Quote:

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.



Looks like some people don't want to recognize a good deal This scope has been reviewed elsewhere,including one of the websites in England and rated well.This would be a good starter scope ..


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Meadeball
sage


Reged: 10/22/12

Loc: Midlothian, Virginia
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: BigC]
      #5485048 - 10/23/12 10:56 AM

GM everyone -- I'm new here; I read this thread after doing a Google search and had to join to make a couple of comments. I'm 47 and have been into amateur astronomy since I was 11. I started with a $19 2-1/2-inch reflector from Sears and at one time owned an 8-inch Celestron SCT, and in the interim have owned about 10 other scopes of various design including Maks, SCTs and newts. Right now I'm divorced and just casually into the hobby. The last scope I had was an Orion Starmax 127 that replaced a Meade ETX-90, but I got rid of the Starmax about five years ago.

Last fall I was in Costco and came across the same deal you guys are talking about this fall. I picked up the 102GT and have been enjoying it casually ever since. Yes, the mount and tripod is its Achilles Heel; the tripod needs to be taller and beefier. I've been looking for a way to modify it because it could stand being about a foot taller. Anything near overhead and I'm on my knees in the dewy grass.

Tell you what, though, this "little" scope has one heck of a set of optics for the price. I'm splitting close doubles all the time, and the Orion nebula surprised the heck out of me. I guess a little chromatic aberration can be a good thing when it comes to celestial beauty, lol! Truth be told, the aberration is low considering some other refractors I've used. The focuser is actually metal and well-lubricated -- it shines compared with the plastic one Meade put on the 8-inch Starfinder reflector I once purchased for more than twice the price of this little refractor. The rubber inlays in the focuser knobs are helpful on cold nights too. I've considered buying something like a CG-4 mount and putting the OTA on it, but I'd be doubling the price of the scope and then some, and I'd lose the GOTO capability. I'm still undecided on what I'll do to modify that mount.

One thing I think Celestron took the cheesy approach on is the battery setup. Most of their Nexstars have a battery compartment inside the base. For some reason this one has a cheap little battery holder that you have to plug in to the base and set (or hang) on the tripod. It doesn't bespeak high-quality. If you buy one of these scopes, go ahead and spring the ~$20 for the AC and/or DC power adapters, because (a) they're a much more elegant solution, and, more importantly, (b) the 8 AA batteries will only last a few hours at best. The mount EATS batteries. One other quibble; there's no "on-off" switch on the mount. Plug in the power from whatever source and it's running until you pull the plug.

Bottom line? This scope isn't perfect, but it's worth every bit of $199. It belongs in the $300-$400 category. It's a great scope you can one-hand-carry out at a moment's notice, or if you prefer to pack it up, here's a great accessory I purchased:

http://www.telescopes.com/telescope-accessories/cases/zhumellmediumtelescopecase.cfm

The best telescope is the one you're going to use most, right? Well, by that standard, this may be the best telescope I've owned!

Like last year, this scope was a bit of an enigma at Costco. It never appeared on their website, and the store even had a hard time locating it in their inventory list when I called asking how many they had left.

But if you're considering one, keep a close eye on the stock and WAIT. Last year, when they started to run low in early November, they enacted a $50 instant rebate which brought the scope down to $149. I didn't hear about it until January and successfully went back and had the rebate applied retroactively, but it took two visits and some phone calling. Do yourself a favor and watch what happens over the next few weeks. It's a great deal at $199, but a steal at $149!


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Zamboni
scholastic sledgehammer
*****

Reged: 01/03/05

Loc: Colorado Springs
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Meadeball]
      #5485156 - 10/23/12 12:09 PM

I'll definitely keep an eye out for the rebate deal!

What you said about the battery pack indicates that it isn't the SLT mount after all. It looks like they took the older Nexstar GT mount (which is still sold under the Skywatcher brand in Canada) and added the SLT tripod and dovetail rail setup and supplied it with the current Altaz hand controller. Will still make a great mount for my PST.

I'm thinking when ai build the L bracket for the PST I'll make a YouTube instructional video for it. I already have the parts list and blueprint written up. I have an iPhone with a tripod adapter and iMovie app. Might as well spread the joy.


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Meadeball
sage


Reged: 10/22/12

Loc: Midlothian, Virginia
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Zamboni]
      #5485245 - 10/23/12 01:02 PM

Thanks for the kind reply. Yep, I'm out there for a deal too -- money's tight these days. How's this for a deal -- you guys should keep your eyes open for stuff like this too -- back in 2008, KMart offered a Meade RB60 -- your basic, 60mm "department store" refractor -- for Christmas for $79.99. I was browsing the store sometime in January and found the store's "clearance" aisle, and there were two of these scopes, still in the box -- they had been picked over because their boxes were a little dinged up -- but they'd been reduced twice since Christmas, and they were currently asking only $28.99 for each of them! I couldn't pass up such a deal, even for a cheap little throwback to my first days in the hobby.

I've played with the scope a few times; as expected, it's not much -- but it came with two Meade MA eyepieces (25 & 9 mm) -- Meade has redesigned the MA's into Plossl lookalikes, complete with fold-down rubber eyecups, and even though they have "China" stamped on them, they don't look (or see) bad. The eye relief is OK on the 25 (I wear glasses), but sucks on the 9. Here's a pic:



They have a 40mm FOV, which, like somebody said over on the eyepiece forum, was state-of-the-art when I was getting into the hobby. I figure, hey, two OK eyepieces and a toy telescope for $28. Whadda bah-gain!!! Motto of story: Watch those closeout and clearance sections!


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Meadeball
sage


Reged: 10/22/12

Loc: Midlothian, Virginia
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Meadeball]
      #5485641 - 10/23/12 04:51 PM

BTW, I skimmed the posts in this thread and didn't see anyone provide the link to Celestron's page on this telescope. Believe it or not, it's on Celestron's site ... it's just not easy to find. Here's the page ...

http://www.celestron.com/astronomy/telescopes/nexstar-102-gt-computerized-telescope.html?opentab=support

Scroll down the page and you'll see an instructional video, a .pdf of the manual you can download, and an accessories sheet. (You can read my review -- the author is "M" -- too!) Hope this helps someone.

Meade

Edited by Meadeball (10/23/12 05:00 PM)


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tnakazon
sage


Reged: 06/26/10

Loc: Los Angeles
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Meadeball]
      #5486272 - 10/23/12 11:39 PM Attachment (33 downloads)

Thanks for the link! I also saw that this scope was on the Celestron website, but that it can't be purchased online (only through Costco). I'll need to register this scope online.

Still having some problems with the GOTO - I can only get the two-star alignment to work in a light-polluted setting. But the SkyAlign (3-star) worked in a dark-sky site.

Also sometimes the hand controller power goes off (a faulty cord?) and I have to play with the connection to get it back on again and reset the alignment.


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BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: tnakazon]
      #5486384 - 10/24/12 01:47 AM

Poor power connection is a weakness of Celestron scopes;they use a slightly non-standard power connector but if your cord is Celestron it should be correct.

It is best for reliable operation to have good batteries in the mount as well as the external power tank.The internal batteries will get you through the cord being pulled out,etc. Be careful about leaving batteries internally too long,after some time (months)they may leak and corrode.


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Meadeball
sage


Reged: 10/22/12

Loc: Midlothian, Virginia
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: BigC]
      #5486758 - 10/24/12 10:34 AM

Quote:

It is best for reliable operation to have good batteries in the mount as well as the external power tank. The internal batteries will get you through the cord being pulled out, etc.




Not possible. This telescope doesn't provide internal battery storage -- the batteries are inserted into an external 8-AA pack that plugs into the same connector on the side of the fork that you would also plug external power into. It's either/or, not both.

The arrangement is just visible in the photo below, which I found using Google. Celestron provides a little "leatherette" snap-case with a loop hanger on it for the pack -- the user here has elected to hang it on one of the tripod leg adjustment screws. I place mine on the accessory shelf. I've been thinking about going to Radio Shack and "upping" the battery pack to an 8-D cell pack, or retrofitting the cord to a small 12-volt SLA battery I have for a piece of camping equipment. Either way will provide lots more observing time than the 3-4 hours a set of fresh AAs will provide. (And as a bonus, the heftier weight of a heavier battery pack, placed on the accessory shelf, will help a bit in stabilizing the mount and tripod. ...)



Meade

Edited by Meadeball (10/24/12 10:51 AM)


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mclewis1
Thread Killer
*****

Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: BigC]
      #5488689 - 10/25/12 02:00 PM

Quote:

Poor power connection is a weakness of Celestron scopes;they use a slightly non-standard power connector but if your cord is Celestron it should be correct.



The connector is hardly "non standard" ... it's a 2.1mm x 5.5mm DC power connector which is very popular and used in a whole variety of products including the whole Celestron scope/mount family. The other popular connector is 2.5mm x 5.5mm (used my Meade and others) and this is where the problems sometimes occur ... the two look identical but the 2.5mm connector fits too loosely and causes intermittent power problems.

The first number in the specifications is the diameter of the center pin, the second is the diameter of the barrel of the connector. Seen side by side the two different connectors are obviously different but on their own it's almost impossible to differentiate a 2.5mm opening from a 2.1mm one.


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*skyguy*
Carpal Tunnel
*****

Reged: 12/31/08

Loc: Western New York
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: tnakazon]
      #5489296 - 10/25/12 09:27 PM

Quote:


Also sometimes the hand controller power goes off (a faulty cord?) and I have to play with the connection to get it back on again and reset the alignment.




I used to have the same problem with my SLT mount. The center pin on the SLT connector is split. Take a very small screwdriver or knife and carefully widen the pin. It will now hold the plug tighter and you won't loose the connection anymore.


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BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: Meadeball]
      #5489457 - 10/25/12 11:16 PM

OOOPS!

So many battery powered scopes have internal battery compartments I just assumed the scope under discussion also had that compartment.

I have enough computer and other stuff that all use different size connectors ,it would be nice if all scopes used the same one!


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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: ASTROLAWYER]
      #5489464 - 10/25/12 11:20 PM Attachment (42 downloads)

I was at my local Costco today, and all they had was this 90mm Meade.
I don't think I have ever seen so much plastic.
Even the silver focuser draw tube was plastic, and when I turned the focuser the draw tube would flex up and down not just in and out.
The mount fork arm was also plastic.
Don't you love it when they set up scopes the wrong way...


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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: stevew]
      #5489471 - 10/25/12 11:21 PM Attachment (33 downloads)

I'd love to see this scope pull in 30,000 objects....

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Jim7728
Postmaster
*****

Reged: 04/10/05

Loc: Stoop Landing Observatory, NYC
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: stevew]
      #5489534 - 10/26/12 12:01 AM

LOL I also went to Costco and the Celestron was set up the same way.

However, I did put the ota in it's correct position...then security swarmed around me. Not!

Still tempted to pick one up, but have too much astro clutter.


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tnakazon
sage


Reged: 06/26/10

Loc: Los Angeles
Re: Celestron 100 mm f 9.8 achro with goto at Costco new [Re: *skyguy*]
      #5489576 - 10/26/12 12:38 AM

Quote:

Quote:


Also sometimes the hand controller power goes off (a faulty cord?) and I have to play with the connection to get it back on again and reset the alignment.




I used to have the same problem with my SLT mount. The center pin on the SLT connector is split. Take a very small screwdriver or knife and carefully widen the pin. It will now hold the plug tighter and you won't loose the connection anymore.



Thanks for the tip! I'll try it out.


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