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Which 11" SCT, ASGT, Nexstar, Or CGE ????

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#1 braindontstop31

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Posted 16 March 2005 - 07:11 PM

I have sold all my scopes and I am ready to make my first scope purchase over $2000 I have around $3000 to spend and don't mind spending more. I have had a 8" celestron newt on a asgt cg5 mount and a meade ar-5. I am ready to buy a bigger scope. I am in good health and can handle a large scope. My interest are high in planets and secondary to DSO's. For some reason the c11-s Ota is catching my eye as a good comprimise scope. I am kind of confused as to with mount to go with. The cg5 ASgt is decent and gives you the ability to mount other OTA's on it. The nexstar is probally a more sturdy and precise mount, but you loose the ability to mount another OTA. The CGE is very expensive, is it worth it over these other two options? Or would a 9.25 Celestron a better choice on planets? For some reason the Celestron website says the 9.25 is better on planets? Why?

Man why is so hard to make a new scope purchase?

#2 celestial_search

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Posted 16 March 2005 - 07:24 PM

Well, I, and others, have gone through the same tribulations that you are. It is tough to know in advance!

The CGE-mounted C-11 is much more expensive. The CG-5 GOTO handles the C-11 OTA fine. If you want aperture then you should go with the C-11 over the C-9.25. The C-11 OTA weights just under 30 pounds and is not too hard to handle.

If you are not going to do astrophotography, then the CG-5 mount should be fine. I'm only responding to that part of your inquiry related to the C-9.25 and C-11 (as I made a similar decision back in November).

The C-11 will do well on DSOs and planets. The SCT is a good compromise scope. If you want tracking (and GOTO) then the SCT is the best compromise when it comes to aperture (which is why I bought mine). I have not been disappointed.

Keep in mind that you will spend money on accessories (Telrad, eyepieces, 2" diagonal, etc.). If you start with a C-11 CG-5 GOTO (should be able to find a new set-up for $2100 or so) you will have some money for accessories.

You are already familiar with the AS CG-5 GOTO mount. You are correct that you can use other scopes on it (I use it for three scopes!). They all work fine on the mount.

If you get the C-9.25 you may wish that you went for more aperture to begin with (especially when you start viewing DSOs).

Good luck on your choice (and I'm sure others will give you other suggestions to consider).

P.S. The CGE would mainly be for astrophotography and mounting a guidescope, etc. The CGE can handle more weight than the CG-5. You can always buy the CG-5 GOTO version and sell the mount and get a Losmandy G11, etc. You probably get a better deal getting the GOTO mount with the scope than purchasing the OTA separtely (unless you can get a good used one).

#3 jrcrilly

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Posted 16 March 2005 - 07:29 PM

The cg5 ASgt is decent and gives you the ability to mount other OTA's on it. The nexstar is probally a more sturdy and precise mount, but you loose the ability to mount another OTA. The CGE is very expensive, is it worth it over these other two options? Or would a 9.25 Celestron a better choice on planets? For some reason the Celestron website says the 9.25 is better on planets? Why?


There's no question that the forkmount is more stable and precise than the CG5-GT; for the price difference it had better be. For planetary magnifications that might be very important to you.

Near as I can tell what's magical about the C9.25 is that it's SLIGHTLY slower primary permits it to come very near the performance of the C11 with a lower price and less weight.

#4 Rusty

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Posted 16 March 2005 - 09:51 PM

I have the NexStar 11 GPS; one of my astro-buddies has the C11 AS-GT. Obviously, the N11 is the more robust (and considerably more expensive and at 67 lbs for the mount/OTA, not grab-and-go), but his ASGT works just fine, and he does some very good short-exosure imaging (Canon 10D) with it. I think it's a heckuva bargain.

Courtesy of jcrilly, I have an AS-GT which I use for three different OTAs, and it's a versatile and excellent mount for the money.

#5 southmike

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Posted 17 March 2005 - 12:40 AM

cge is by far the best if you have the cash , and you are looking to do ccd or photo work. ..though i have been waiting to here if the new eq6 goto is photo worthy..
that is around 1200 ish and an 11" ota you would be good to go.

#6 Rushwind

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Posted 17 March 2005 - 12:41 AM

My understanding of the "magic" of the off-sized C9.25 is that it was designed with a flatter focal plane, useful for film astrophotography.

I have a CG-5GT that I use specifically for photography, but I don't mount anything nearly as big or heavy as a C9.25 or C11 on it for photography. The CGE would be beefy enough to do photography even with those bigger OTAs, I imagine.

But, back to the visual user who wants to look at planets and some DSOs, ... I think that the NS is more stable, but the CG-5 is more versatile, and the CGE is wonderful but not worth it for you unless you're doing photography, in which case I'd have a whole raft of different suggestions anyway. :)

Jimbo

#7 jrcrilly

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Posted 17 March 2005 - 09:05 AM

My understanding of the "magic" of the off-sized C9.25 is that it was designed with a flatter focal plane, useful for film astrophotography.


Hi, Jimbo.

That, of course, was Celestron's stated reason for the modified design. I never seem to hear folks speaking of using film on a C9.25, so I figure there's something else driving its popularity.

#8 Guest_**DONOTDELETE**_*

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Posted 17 March 2005 - 09:26 AM

Hmmm, some tough choices here.

If you're heavily into the planets (imaging & observing) the C9.25 or C11 AS-GT are a hard value to pass up.
The mount is quite portable if you'll be travelling.

I absolutely love my C11, and the AS mount tracks pretty darned good.

If you have a permanent setup, the CGE could offer more stability for DSO imaging.

You could also get just the C11 OTA and then by a Losmandy G11 mount, I guess that would still be in your range or a little bit over.
Sorry if I've confused you even more :)

#9 LittleDob

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Posted 17 March 2005 - 09:54 AM

If your primary interest is in planets, with a secondary interst in DSOs, the 9.25 may be the way to go. Check out the CN telescope report that pits a 9.25 against a 7" Mak and IIRC 4" Apo. Long story short - 9.25. The Nexstar group has often compared the 9.25 to the 11 with many concluding that the differences are minimal (perhaps a little better contrast and flatter field with the 9.25 and a little brighter with the 11). Either optical tube should satisfy. As for mounts, well, as others have stated, it depends on your objective and budget. If you want to do photography, or plan to get that 6" Apo someday, the CGE would be the way to go. If however, you want simplicty (and I mean it can't get easier) then the NexStar is the way to go. Not to pull you away from the 11, but one option to seriously consider is the 9.25 ASGT. The 11" tube on that mount is stable enought for visual but only marginal for photography. The lighter weight of the 9.25 should make it very stable for visual and stable enough for photography. Plus, it is the cheapest of all options, leaving extra cash for all those accessories you will need. (IMO leave 20% of your total budget for accessories - more, much more, if you have ambitions of imaging.).

Jason (NS11)

#10 Guest_**DONOTDELETE**_*

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Posted 17 March 2005 - 01:01 PM

For some reason the Celestron website says the 9.25 is better on planets?



Does this answer your question?

#11 jrcrilly

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Posted 17 March 2005 - 01:57 PM

Does this answer your question?


It's a nicely-written article, and the writer takes nice pictures. He doesn't really address the differences between the different SCT's, though - except to state that the C9.25 holds collimation better, which I've not heard before (and don't quite get). He focuses on the ideal MTF calculations but fails to mention that this is based only on central obstruction and thus any other common SCT would do better with the same calculations under such ideal conditions.

#12 Donnie

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Posted 17 March 2005 - 05:58 PM

Actually the 9.25 I had "seemed" to hold collimation better than the normal SCT's I have owned. I say "seemed" because I think that the 9.25 with its longer primary is less suceptible to collimation errors. More specifically, collimation errors that are minor for the 9.25 would be more detrimental to image if they are present in a "regular" SCT.

I think this to be true because of the longer focal length primary of the 9.25. Of course both optical systems end up at F10, but it seems the 9.25 with its less "amplifying" or "magnifying" secondary can handle small collimation errors that affected the 8" that I had.

It is my theory that this is part of the reason that many 9.25's are so highly thought of. I understand that it is easier--relatively speaking--to produce the slower primary more consistently. However, I have seen so many SCT's in use that are out of collimation over the years, I think that is part of the perception as well.

Meaning, a lot of SCT's are not at the "optimal" collimation. The 9.25 I had seemed to suffer less from these minor errors. Perhaps the 9.25's most people encounter are collimated as well as the normal SCT's, but since they seem to me to be less succeptible to these errors they are assumed to be superior somehow?

I really dont know for sure, my "theory" is just that. My experience with the 9.25 I had and several other SCT's. Whether it is even remotely relevant is another story. :)

I do know that if I took the time to collimate the SCT's I owned at almost ridiculous high powers, they performed much better. Of course that stands to reason. But, if I stopped a step or two before reaching that level of collimation, they were a tiny bit soft. But not the 9.25, that is why I "think " it is less succeptible to collimation errors.

But who knows, since they both do end up at F10, perhaps it doesnt matter. I dont know for sure, but the above was my experience over the years that I owned SCT's regularly.

#13 Chris G

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Posted 17 March 2005 - 10:23 PM

Well I haven't used the 11" but do love my 9.25". The ASGT mount handles it nicely as I would expect it does the 11", either way you'll have a great instrument.

#14 DaveMess

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Posted 19 March 2005 - 01:31 PM

I was very unhappy with my C11 AS-GT and returned it. I might go with the Nexstar or will probably by a Meade because of it's better accuracy in pointing and tracking. Good luck on your new purchase!

#15 LittleDob

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Posted 19 March 2005 - 04:09 PM

Dave,

Why do you think that Meade has better accuracy in pointing and tracking? Would you be able to provide more information? I know that PEC does not work with the NexStar, but Celestron is supposed to have a fix "soon". Or at least that is the buzz in the NexStar group. Other than PEC, I've never heard that the NexStars are less accurate in tracking. Do you mean specifically the NexStarGPS vs LX200s, or the ASGT vs LX-75, or Celestron vs Meade in general? Very interested in your response.

Jason

#16 Strgazr27

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Posted 19 March 2005 - 04:20 PM

I was very unhappy with my C11 AS-GT and returned it. I might go with the Nexstar or will probably by a Meade because of it's better accuracy in pointing and tracking. Good luck on your new purchase!


I found just the opposite with the C11 AS-GT that I owned. With a good level and decent Polar align, the mount would put it dead center of a 12mm Plossl time and again. I would only start to see misalignment in GoTo's after about 3-4 hours of time expired. I attributed this to not being able to Sync (Or not knowing how at the time) on each object like you can with some of the Meades.

YMMV :crazy:

#17 Jure

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Posted 19 March 2005 - 04:27 PM

I like NexStar, but the tripod is really bad.
CS!Jure

#18 jrcrilly

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Posted 19 March 2005 - 04:37 PM

I like NexStar, but the tripod is really bad.
CS!Jure


Is that the original tripod or the current, heavier one? I liked the original one myself but folks are saying nice things about the newer one.

#19 LittleDob

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Posted 19 March 2005 - 04:45 PM

My NexStar came with the new tripod and it is very robust. It would take the force of a whole offensive line trying to sack a quaterback to budge it. Well, you know.. Plus it is very attrative - at least moreso than the older version.

Jason

#20 Jure

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Posted 19 March 2005 - 05:11 PM

Must be the old one (scope bought in spring 2004) - it LOOKS robust and sturdy, but the rubber tips on the legs make it shake and wiggle a lot. I was very disappointed with it - the OTA is nice, so is the fork mount, but the tripod should've been something like Losmandy's G-11 tripod. What's the new one like?
CS!Jure

#21 celestial_search

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Posted 19 March 2005 - 05:33 PM

I also would like to hear some details. My C-11 and CG-5 GOTO work well, especially given what I paid for them.

#22 Guest_**DONOTDELETE**_*

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Posted 19 March 2005 - 06:06 PM

For some reason the Celestron website says the 9.25 is better on planets?



Does this answer your question?

I don't know if it does, but please allow me to muddy the waters a little. :D See my signature line. :tonofbricks: Just messing with ya. I'd keep the APO forever, but keep thinking of selling the Celestrons and go to a truss dob. Thing is the NS8 is almost a grab and go and the NS11 can be as I keep them in the garage setup and ready to go. The NS11 is on a plywood platform deal to use a handtruck to manuever it around. Both are very easy to setup and go. I use all of them togehter sometimes and look through one while the other slews, or just to compare views. I have an FRC on the NS8 and use bino's almost exclusivley on the NS11. The APO has manual slo-mos right now. I say try them all and keep them :roflmao:

#23 jrcrilly

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Posted 19 March 2005 - 07:08 PM

Must be the old one (scope bought in spring 2004) - it LOOKS robust and sturdy, but the rubber tips on the legs make it shake and wiggle a lot. I was very disappointed with it


Those are apparently carpet protectors. I never tried using the tripod with them, but would expect poor performance. Removing them reveals nice pointed feet as a telescope tripod should have.

#24 Guest_**DONOTDELETE**_*

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Posted 19 March 2005 - 10:45 PM

I was very unhappy with my C11 AS-GT and returned it. I might go with the Nexstar or will probably by a Meade because of it's better accuracy in pointing and tracking. Good luck on your new purchase!


I found just the opposite with the C11 AS-GT that I owned. With a good level and decent Polar align, the mount would put it dead center of a 12mm Plossl time and again. I would only start to see misalignment in GoTo's after about 3-4 hours of time expired. I attributed this to not being able to Sync (Or not knowing how at the time) on each object like you can with some of the Meades.

YMMV :crazy:


I think Dave Mess just got a lemon out of the bunch, this mount tracks as good as you'd ever want to expect for something in this price range.
Mine tracks dead-on for hours and hours.

#25 Jure

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Posted 20 March 2005 - 03:28 AM

Feeling really stupid now...
CS!Jure


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