Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

I'm Going To Take The Plunge - Advice On First SCT

This topic has been archived. This means that you cannot reply to this topic.
37 replies to this topic

#26 Stelios

Stelios

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 6552
  • Joined: 04 Oct 2003

Posted 25 March 2004 - 01:41 PM

OK, here's where the bidding stands after receiving all of your advice:

Celestron Nexstar GPS 8" SCT XLT with 2" diagonal - $2,325
Celestron Power Tank (or similar auto store version with longer battery life) - $70
Astrozap Flexible Dew Cap - $40 (Astronomics.com #1958G)
TV Panoptic 24mm / 1 1/4" - $295
TV Nagler Type 6 13mm / 1 1/4" - $280
TV Nagler Type 6 9mm / 1 1/4" - $280

Total (w/o tax): $3,290.00

I've slightly gone over my budget, but my wife did not have a grabber when I told her the total (w/out tax), so I guess I'm ok. Now I have to go to a star party, try to check out some alternatives (such as the orthos mentioned in prior posts), and dust off that credit card. Thanks to all of you for your advice.

I didn't see why you have opted for the GPS rather than the AS-GT. The AS-GT is the same scope, the GoTo is the same, you CAN do long exposure astrophotography without investing in a wedge if you are so inclined, and it is CHEAPER. For over $400 *less* money you can get a 9.25" scope, and believe me, when all is said and done, THAT is the part that counts, the scope. Your eyepieces, diagonals, etc. will NOT compensate for the scope being smaller.

Some more comments:
1) I have the flexible dew shield. It's easy to transport, but otherwise I ***hate*** it. I would get the rigid one next time.
2) You need a lower power eyepiece. Remember the scope comes with a 26mm. I would dump the 24mm Panoptic and opt instead for something like a 40 or 50mm (I assume you will be getting the 2" diagonal).
3) Consider an observing chair. My best investment. For an SCT, a Televue stool works great (the chairs that offer wider range of adjustment are useless as the SCT doesn't force you into weird positions).
4) Consider a narrow band filter (you will need a color filter set too). It will hugely improve your pleasure in observing nebulae. Broadband filters are a waste of time.

#27 conus

conus

    Gemini

  • *****
  • Posts: 3053
  • Joined: 12 Oct 2003

Posted 25 March 2004 - 02:23 PM

For over $400 *less* money you can get a 9.25" scope, and believe me, when all is said and done, THAT is the part that counts, the scope.


Ditto.

#28 bierbelly

bierbelly

    Voyager 1

  • *****
  • Posts: 11544
  • Joined: 23 Jan 2004

Posted 25 March 2004 - 02:36 PM

For over $400 *less* money you can get a 9.25" scope, and believe me, when all is said and done, THAT is the part that counts, the scope.


Ditto.


Yeah, I was wondering why nobody had suggested this. Seems to me that the C9.25 with the AS/GT mount is about the best deal going out there right now.

#29 Guest_**DONOTDELETE**_*

Guest_**DONOTDELETE**_*
  • -----
  • topic starter

Posted 25 March 2004 - 03:04 PM

I didn't see why you have opted for the GPS rather than the AS-GT. The AS-GT is the same scope, the GoTo is the same, you CAN do long exposure astrophotography without investing in a wedge if you are so inclined, and it is CHEAPER. For over $400 *less* money you can get a 9.25" scope, and believe me, when all is said and done, THAT is the part that counts, the scope. Your eyepieces, diagonals, etc. will NOT compensate for the scope being smaller.

Some more comments:
1) I have the flexible dew shield. It's easy to transport, but otherwise I ***hate*** it. I would get the rigid one next time.
2) You need a lower power eyepiece. Remember the scope comes with a 26mm. I would dump the 24mm Panoptic and opt instead for something like a 40 or 50mm (I assume you will be getting the 2" diagonal).
3) Consider an observing chair. My best investment. For an SCT, a Televue stool works great (the chairs that offer wider range of adjustment are useless as the SCT doesn't force you into weird positions).
4) Consider a narrow band filter (you will need a color filter set too). It will hugely improve your pleasure in observing nebulae. Broadband filters are a waste of time.


Just when I thought I had reached consensus, the debate begins again. :foreheadslap: A few thoughts:

1. I was concerned about portability. In addition to my backyard viewing, I will haul the rig to star parties, remote dark sky locations, and to our cabin in the mountains outside Taos, NM, which may involve strapping the whole shebang to an ATV to get it up to a mountain valley at about 10,000 feet (talk about clear dark skies!). So that's why I was thinking 8" with XLT. I am tempted by the 9.25", but will that scope be as portable? Will the 9.25" significantly improve my viewing (I understand that aperture rules). I'll also lose Fastar capability, but that's not a significant issue for me now since I won't be pursuing astrophotography for a while.

2. Should I really give up the GPS (with the built in compass, altimeter and levelling)? Others have commented that its really helpful. I know that I can just do a two star alignment instead and can figure out where the north star is, but is the GPS worth the price difference?

3. The 8" Nexstar GPS XLT comes with a 40mm Plossl. Obviously if the 9.25" (if I go that route) comes with a 25mm eyepiece, I'll need to adjust my eyepiece selection. I was going for the 2" back and diagonal.

4. Another poster recommended a flexible dew shield for the 8" GPS. I'll look at the fixed dew shield if I go the 9.25" route.

5. I appreciate the advice on the Televue stool and the filters as well.

So now I'm really confused. :confused: But research is part of the fun so keep the suggestions coming. Thanks.

#30 jrcrilly

jrcrilly

    Refractor wienie no more

  • *****
  • Administrators
  • Posts: 35401
  • Joined: 30 Apr 2003

Posted 25 March 2004 - 03:34 PM

Hi, Chris.

I suppose it doesn't help that we are offered a greater array of great-performing systems these days than ever before!

For portable use there is NOTHING easier to set up than an SCT on an alt/az goto fork mount. I've owned the NX8GPS and also a GEM comparable in size and weight to the ASC. The GEM breaks down into smaller parts, but there are lots of 'em! With the alt/az, you plunk the tripod down, stick the scope on it, and align.

Not that the ASC9 wouldn't also be a cool setup, of course. The differences between the ASC and the NX8GPS go deeper than GEM v. forks, though. The NX8GPS is a true Celestron product; terrific quality and precision throught. It's inherently more difficult and expensive to make a good GEM than a good forkmount; a GEM for the same or less money won't be in the same class. The GEM that would compare to the NX8GPS would be the CGE800, which is much more expensive.

Folks will point out that the GPS function is unimportant - they are, of course, correct - but it's the least of the differences in the control systems. I really wish that both Meade and Celestron hadn't made the mistake of sticking "GPS" into the model names - it gives the impression that it's the major functional attribute of the model.

#31 conus

conus

    Gemini

  • *****
  • Posts: 3053
  • Joined: 12 Oct 2003

Posted 25 March 2004 - 03:42 PM

The 9.25 is very portable. OTA only weighs 21 pounds. Before I got my wheely bars, I just picked the whole thing up--OTA, mount and tripod-- and carried it from the garage to the back yard.

#32 Norvin

Norvin

    Surveyor 1

  • -----
  • Posts: 1540
  • Joined: 10 Oct 2003

Posted 25 March 2004 - 04:23 PM

I do not own a SCT. I would eventually like to get one around 10" - 12" with GPS. My understanding of GPS is that the GPS on the telescope will know exactly where it is on the Earth which would make it easier to find and track objects and to be polar aligned, etc. Correct?

Norvin
Post #429

#33 conus

conus

    Gemini

  • *****
  • Posts: 3053
  • Joined: 12 Oct 2003

Posted 25 March 2004 - 04:36 PM

Yeah, but I opted not to go with it. Maybe I'm wrong, but it seemed to me that it would only save me 3 to 5 minutes set-up time, not to mention the weight and cost differences.

#34 Don W

Don W

    demi-god

  • *****
  • Administrators
  • Posts: 22411
  • Joined: 19 May 2003

Posted 25 March 2004 - 04:38 PM

The GPS will only give the scope the time and location. That's it. It will not do anything to help with GOTO's or polar alignment. If you have a handheld GPS, it will give you the same information except that you have to enter it into the handcontroller.

#35 Guest_**DONOTDELETE**_*

Guest_**DONOTDELETE**_*
  • -----
  • topic starter

Posted 25 March 2004 - 05:33 PM

I’ve done a bit more research following the last few posts and (remembering my budget, portability, and ease of use) here are the results (as compared to a Celestron 8” Nexstar GPS XLT - $2,124 and 61 pounds total net weight) - for comparison, all prices are from Astronomics:

• If I go for a Celestron 9.25” CGE XLT, I’m looking at $3,975 and 129 pounds total net weight. This goes way over our budget (I can see the rolling pin coming out) and breaks my wife’s back if she wants to use it alone.
• If I go for a Celestron 8” CGE XLT, I’m looking at $3,625 and 95 pounds total net weight. This still breaks the budget (by a lot) and does nothing for my wife’s disposition.
• If I go for a Celestron 9.25” Nexstar GPS XLT, I’m looking at $2,874 and 77 pounds total weight. This still breaks the budget (when you include eyepieces and accessories) but my wife could do some more push ups to get ready.
• If I go for a Celestron 9.25” C91/4 SGT XLT, I’m looking at $1,874 and 62 pounds total net weight. This doesn’t break the budget and my wife will be no worse for the wear. However, if I change out the 24mm Panoptic for a 41mm Panoptic (since the 9.25” comes with a 25 mm Plossl instead of a 40mm Plossl), the cost of that lens is $200 more than the 24mm Panoptic (a 55mm TV Plossl would be about $65 less than the 24mm Panoptic). So far so good, I’m still below my total budget for the Celestron 8” Nexstar GPS XLT and accessories. But if you add a polar alignment tool, you’re pretty much back at the same price as the Celestron 8” Nexstar GPS XLT and accessories.
• Celestron 9.25” C91/4 SGT XLT vs. Celestron 8” Nexstar GPS XLT: From what I can tell, even though I’d be gaining 1.25” in aperture, I’d be giving up the following (based on the Celestron and Astronomics product descriptions, and ignoring the advantages of a german equatorial mount (the 9.25” SGT) vs. the cost of a wedge (8” Nexstar GPS) vs. Fastar capability (8” Nexstar GPS) since Astrophotography is not a major issue for me at this point):
o The GEM mount of the SGT XLT doesn’t appear to be of equal quality to the Nexstar GPS Alt/Az fork mount or the CGE mount - taking into account jrcrilly’s points.
o GPS (but could be added at extra cost), compass (which provides, I believe, auto north, so no need for polar alignment), altimeter, auto leveling, Permanent Periodic Error Compensation, adjustable backlash compensation, serial ports, separate CCD autoguider port, separate 12 Volt DC accessory power outlet.
o Aluminum Tube vs. Carbon Fiber Tube (in Nexstar GPS)
o Does the SGT XLT cause cable wind around the mount when slewing (it looks like it would)? The Nexstar GPS doesn’t.
o Ease of setup / breakdown compared to the Nexstar GPS fork mount.
o Slightly greater portability (in terms of the size of the tube) with the Nexstar 8” GPS (although this may be a draw since the Nexstar GPS fork mount is so large and is not easily removable).
o Nexremote Telescope Control Software (not included in SGT XLT accessories list).
o AC adapter (included in Nexstar GPS accessories list) vs. car battery adapter (included in SGT XLT accessories list) is a wash.

So, I think I’m probably sticking to the 8” Nexstar GPS system I described in my previous post - absent a compelling argument to the contrary or everyone ganging up on me. As for filters and a stool, a Lumicon narrow band filter for Schmidt-Cassegrain visual backs runs about $200, a Vixen 1.25” eyepiece color filter set will run about $80, and a TeleVue Air-Chair will run about $210. So the filters will probably be a delayed but inevitable purchase and I’ll just use our old card table chair for the foreseeable future.

#36 Stelios

Stelios

    Fly Me to the Moon

  • *****
  • Moderators
  • Posts: 6552
  • Joined: 04 Oct 2003

Posted 25 March 2004 - 07:29 PM


If I go for a Celestron 9.25” C91/4 SGT XLT, I’m looking at $1,874 and 62 pounds total net weight. This doesn’t break the budget and my wife will be no worse for the wear. However, if I change out the 24mm Panoptic for a 41mm Panoptic (since the 9.25” comes with a 25 mm Plossl instead of a 40mm Plossl), the cost of that lens is $200 more than the 24mm Panoptic (a 55mm TV Plossl would be about $65 less than the 24mm Panoptic). So far so good, I’m still below my total budget for the Celestron 8” Nexstar GPS XLT and accessories. But if you add a polar alignment tool, you’re pretty much back at the same price as the Celestron 8” Nexstar GPS XLT and accessories.


You do not need a polar alignment tool. Sighting Polaris through the mount hole works just fine.

Celestron 9.25” C91/4 SGT XLT vs. Celestron 8” Nexstar GPS XLT: From what I can tell, even though I’d be gaining 1.25” in aperture, I’d be giving up the following (based on the Celestron and Astronomics product descriptions, and ignoring the advantages of a german equatorial mount (the 9.25” SGT) vs. the cost of a wedge (8” Nexstar GPS) vs. Fastar capability (8” Nexstar GPS) since Astrophotography is not a major issue for me at this point):
o The GEM mount of the SGT XLT doesn’t appear to be of equal quality to the Nexstar GPS Alt/Az fork mount or the CGE mount - taking into account jrcrilly’s points.

Perhaps it's not of the same quality. But the quality is more than adequate.

o GPS (but could be added at extra cost), compass (which provides, I believe, auto north, so no need for polar alignment), altimeter, auto leveling, Permanent Periodic Error Compensation, adjustable backlash compensation, serial ports, separate CCD autoguider port, separate 12 Volt DC accessory power outlet.

And the net value of this in practice is... skipping the polar alignment. Which takes about 30 seconds (make sure mount is level, then sight Polaris through mount hole).

o Aluminum Tube vs. Carbon Fiber Tube (in Nexstar GPS)
o Does the SGT XLT cause cable wind around the mount when slewing (it looks like it would)? The Nexstar GPS doesn’t.

I doubt you would ever be able to tell if your Carbon Fiber tube was replaced by an Aluminum one. And no, the AS-GT does NOT cause cable wind, the mount is smart enough to go the long way to avoid that.

o Ease of setup / breakdown compared to the Nexstar GPS fork mount.
o Slightly greater portability (in terms of the size of the tube) with the Nexstar 8” GPS (although this may be a draw since the Nexstar GPS fork mount is so large and is not easily removable).
o Nexremote Telescope Control Software (not included in SGT XLT accessories list).
o AC adapter (included in Nexstar GPS accessories list) vs. car battery adapter (included in SGT XLT accessories list) is a wash.

Ease of setup if you are strong goes to the Nextstar GPS. But the difference is minor. (I say if you are strong, because the 45lb weight is a bit much for some of us with bad backs). The SGT breaks down in the OTA, the mount+tripod (one piece in practice) and the counterweights.
NexRemote I am unfamiliar with. What exactly does it do? Make sure it is something that you would miss before you assign it a value.

I am not trying to put down the Nextstar series, which is a great series. But if you get a Nexstar, the scope to get is the Nextstar 11! The other scopes in the series are simply way overpriced. Make no mistake, the difference between an 8" and a 9.25" is quite real.

And I AM trying to score a few points for the AS-GT series, which I think is an incredible bargain. I have one and two friends have one, and we all love the mounts (although there IS a learning curve). The truth is that after the feature comparison excitement, the following things matter most:
1) Quality of OTA
2) Stability of the mount
3) Accuracy of the GoTo system

Then the two concerns below are important *IF* they are outside acceptable limits:
4) Ease of setup
5) Ease of transport

The AS-GT is at a happy point where 4) and 5) are not real factors. I rejected the Nextstar (I only considered the 11) because I could not lift it due to a bad back, so for me 5) *was* a factor.

Anyway, good luck with whatever you decide!

#37 Victor Kennedy

Victor Kennedy

    Pooh-Bear

  • *****
  • Posts: 12359
  • Joined: 22 May 2003

Posted 27 March 2004 - 07:38 AM

Chris, it sounds to me like you have chosen an excellent setup. I have a C8 on a Vixen eq mount and I think the best accessory I bought for it was a 2" diagonal and a 34 mm 2" eyepiece. The wider field of view made it much easier to find things, and gave a better view of some of the larger, more spectacular DSOs.

I would also suggest that you put the biggest finder on your scope that you can get. I currently have an 8 x 50 finder on mine, which is ok, but I fondly remember a Lumicon 80mm superfinder I once had (Crocodile Dundee voice: "You call that a finder? Now THIS is a finder").

p.s. pushups are ok, but for getting the tube up on the mount she'd do better to practice the snatch, clean, and jerk.

#38 John P

John P

    Messenger

  • *****
  • Posts: 443
  • Joined: 27 Jan 2004

Posted 27 March 2004 - 07:39 PM

I'd go for the 9.25 gps, forget the powertank for now, and consider less expensive eyepieces. The Celestron runs just fine off your car, the 9.25" is an exceptional telescope with great optics, and you don't need the Naglers for a system with this focal ratio, or can always move up...add the powertank (I love mine)or anything else you need. Get the optical system and GPS before anything else. You will not regret the GPS go-to.


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics