Click here if you are having trouble logging into the forums
Privacy Policy |
Please read our Terms
of Service | Signup and
Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User
MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 917
Loc: Columbia Gorge, WA
|
|
Hi folks,
I may be in the market for a 14" SCT in the next few months. I have been struggling to find a mount capable of using my Z12 for photos, and the price tag for something capable of handling an OTA of this size in a newtonian is simply staggering me.
Then I realized that perhaps my pursuit wasn't making all that much sense, and that with a focal reducer I could get similar performance out of a big SCT, which already includes a fork mount capable of handling it. And all for a lower price for a bigger scope than the mounts I was looking at.
In reading all the details it seems that Meade and Celestron are more or less neck and neck on optical quality,( given that you don't unluck out and get the rare lemon. )
With that in mind, and given my continual struggle with periodic error on my much lower end scopes, my question is this...which brand tends to have the more accurate RA drive?
I'll probably be looking for a GOTO model, used, in either brand, (unless it turns out I can pick up a bigger older one. ) I haven't done much pricing, but I expect I'll have about $2500 to spend and I'm hoping a used 14" can be found in this price range. Seems like I might be hoping for too much, but you never know...I see fully loaded 8's and 10's going for 800-1500 used. I've seen some 12" meades going for this. It may be I have to give up on GOTO to hit my price range...not sure what to do about that. The two scopes in parallel with GLP pointing trick is working fine, but it eats up time (ETX with laser, SN6 on old fork mount). I don't care about the GPS units because I'm not above entering some numbers myself every evening.
Anyhow, if you have any comments on optical quality, my price expectations, and especially periodic error on the stock fork system, chime in I'd love to read it.
--------------------
"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
Edited by MtnGoat (08/06/08 12:12 PM)
|
yg1968
Carpal Tunnel
Reged: 01/26/04
Posts: 1714
|
|
If it's for imaging, you are better off with a GEM mount. Perhaps the CGE.
|
sang33ta
professor emeritus
Reged: 07/08/08
Posts: 539
Loc: UK
|
|
I think a 14" will not only be rare but also hard to move on your own. As is often said on this forum the best scope is the one you can be bothered carrying outside.
If you want a fork I think you'll also need to budget for wedge or de-rotator, Meade do one, not sure about Celestron?
--------------------
Hioptic 152mm f12.5 Maksutov
Celestron Advanced CG5-GT Mount (Mr Noisy!)
Meade 4000 Super Plossl Set
Casio QV-2900UX
Got fed up of waiting for Meade ETX-150 so put this together for £500/$1000 
Edited by sang33ta (08/06/08 02:19 PM)
|
MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 917
Loc: Columbia Gorge, WA
|
|
Gol dangit, I was afraid someone would tell me that. But everything I've read suggests that for the mass of 12" and larger OTA's, one is firmly in $5k+ mount territory if you want it *solid*.
It's odd that the GEMs would be better, I'd think the fork systems offer inherently better rigidity and the opportunity for much larger RA gears.
I've had a bellyfull of dealing with not quite there mounting in terms of rigidity and resistance to gusty nights.
--------------------
"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
|
MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 917
Loc: Columbia Gorge, WA
|
|
Quote:
I think a 14" will not only be rare but also hard to move on your own. As is often said on this forum the best scope is the one you can be bothered carrying outside.
If you want PEC on a fork I think your need to buy a de-rotator, Meade do one, not sure about Celestron?
I was planning on wedging up whatever I get, so unless I"m not understanding something real basic, I don't think I'd need a derotator.
Also, I have a pier for the Cave GEM I am currenly using that would be used for any CAT I wind up with, so I'm thinking moving it isn't going to be a big deal..especially in summer. I haven't put a scope back inside for going on three months now, they're covered but thats it.
--------------------
"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
|
MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 917
Loc: Columbia Gorge, WA
|
|
Been doing still more reading...looks like Meade 14's are not around much..are they new? lots of 12s though.
I sure would like that extra couple inches if I'm going to spend the money, I've already got a 12". this pushes me into Celestron territory. Now I have to read up on how far back their GOTO goes on the C14, model wise.
--------------------
"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
Edited by MtnGoat (08/06/08 12:47 PM)
|
Kolenka
professor emeritus
Reged: 06/01/08
Posts: 593
Loc: Seattle Area, WA, USA
|
|
The Meade 14 is out of production for the time being. You won't find them new. I personally echo the comment of a GEM if you want solid. The LX200 fork isn't bad, and sure beats my ETX fork by a huge margin, but it wouldn't call it rock solid. Sturdy, capable, sure.
The fork has advantages, but I still say that for AP, a GEM will win by some margin in terms of vibration. A large gear in a fork will win in other areas. It comes down to what is least desirable in the photos and it is usually tracking vibrations.
--------------------
Meade 10" LX200R
Orion 80ED
Nagler 7T6, 9T6, 13T6, 17T4, 26T5
Canon XSi, TIS DMK 31AF03
Northwest Astro Photoblog
|
core
super member
Reged: 02/23/08
Posts: 116
Loc: Mostly in Norman, OK
|
|
Quote:
I've already got a 12". this pushes me into Celestron territory. Now I have to read up on how far back their GOTO goes on the C14, model wise.
Compustar 14? 
iirc the only other GOTO C14's are all on GEMs 
But at any rate, depending on what astro imaging you're intending to persue, 12" can already do quite a fair bit.
--------------------
~Peter~
|
MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 917
Loc: Columbia Gorge, WA
|
|
Yes, aperture wise, I've been happy with the results from the poorly mounted Z12. I just figured if I was going to all this effort, I may as well pick up a couple inches.
What I'm starting to take home from this is that there is little way to do photography at this aperture scale without $$x$$. The GEM's are preferred so far, and one for the Z12 is hyper expensive, and a comparable CAT OTA is not going to be any lighter that I can see, so I wind up on the same $$$ mount anyway.
--------------------
"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
Edited by MtnGoat (08/06/08 01:44 PM)
|
core
super member
Reged: 02/23/08
Posts: 116
Loc: Mostly in Norman, OK
|
|
Quote:
I just figured if I was going to all this effort, I may as well pick up a couple inches.
I keep tellin' myself that
Quote:
there is little way to do photography at this aperture scale without $$x$$. The GEM's are preferred so far, and one for the Z12 is hyper expensive, and a comparable CAT OTA is not going to be any lighter that I can see
One thing to keep in mind is SCT's shorter tube and moment of inertia would make a (slight?) difference. fwiw for my recent re-introduction into astro imaging (from film days years back), I'm leaning heavily towards beefy mount and small scope combo.
--------------------
~Peter~
|
mclewis1
Thread Killer
Reged: 02/25/06
Posts: 2436
Loc: Colorado
|
|
First there's no Celestron fork mounted 14" so any comparison is apples to oranges.
Celestron's CGE1400 is a popular configuration but that 14" tube is at the limit for the CGE mount. For imaging you're likely better off with a CGE1100 package (so you can add a guide scope and other accessories without over taxing the mount).
The Meade 14" fork scopes on a wedge have been a bit questionable (some folks report good results, others have vibration issues). Most who are serious about imaging with their 14" scopes put them on big gems ... big expensive ($10k+) gems.
--------------------
Mark
C11, C6, APM/TMB115, and AT80ED
Tandem mount CGE and CG-5A, WO EZ-Touch and AT Voyager
25x100s, 8x56s, T-Mount Light, and Mark 1 eyeballs
Modded 350D, SPC900, Mallincam
|
Rick Woods
Post Laureate
Reged: 01/27/05
Posts: 4262
Loc: Inner Solar System
|
|
My 14" is on the heaviest fork mount Meade ever made (short of the 16" LX200 fork), and I have it on a wedge. If you want to go this way, vibrations are going to be a big problem. It's just the nature of the commercial fork mount. It's OK for me because I'm pretty much a visual guy; but if you want to image, you'll have to be concerned with any little breeze, etc. It can be done, but it's a factor. The big forks are very stable in alt-az mode, so a de-rotator might be the ticket. They're about the same price as a good wedge, IIRC.
And you're right - a GEM that will carry the load is a ton of money. Even the 14" CGE is right at the limits.
If/when my fork finally poops out and if I can't get it fixed, I'm gonna be in trouble!
--------------------
- Rick
14" LX200GPS
8" Meade 826C
|
tim53
sage
Reged: 12/17/04
Posts: 317
|
|
There's a used Mathis fork mount on "the 'mart" right now. It's been upgraded 2 goto, and it was designed for the C-14. All you'd need would be an OTA (and a pier, I suppose).
I'm not the seller, but I remember seeing those mounts at RTMC many moons ago.
-Tim.
--------------------
"We`re just waiting looking skyward as the days come down.
Someone promised there`d be answers, if we stayed around."
-Orchestral Maneuvers in the Dark, "The Romance of the Telescope"
|
rmollise
Carpal Tunnel
Reged: 07/06/07
Posts: 1564
|
|
Quote:
Hi folks,
I may be in the market for a 14" SCT in the next few months. I have been struggling to find a mount capable of using my Z12 for photos, and the price tag for something capable of handling an OTA of this size in a newtonian is simply staggering me.
If you don't like struggling with periodic error, I'd advise against either. The C14 is a fine OTA, but if you are dead serious about imaging at long focal lengths, especially in a portable setup, you'll want a Titan, minimum. The CGE mount is workable, but may not meet your standards for steadiness. Especially on less than calm nights.
The Meade (if it were available) is worse. Last one I've used needed Pempro before it could reliably be _autoguided_ even with a focal reducer.
I'd suggest thinking good mount + C11 or Meade 10 or even a C8. Unless you really want to go after smaller objects, all 14-inches gets is smaller fields and more problems with guiding. Visually, of course, they are great.
--------------------
Uncle Rod
Watch for Rod's New Book:
Choosing and Using the New CATs--coming soon!
|
David Pavlich
Postmaster
Reged: 05/18/05
Posts: 6502
Loc: Mandeville, LA USA 30.38 X 90....
|
|
If you can find a Meade 14"R, it makes a good imager because of its flat field. BUT, it's 69lbs without anything attached. As Rod said, your well into the Titan or the AP1200's capacity.
The C14 is 45lbs and a proven imager. However, you're still looking at a Titan or better. And again, as Rod said, there's that long focal length.
Getiing to that size OTA, I wouldn't even think about fooling with a fork mount unless you get something exotic.
For portability, maximum would be the C11 on a CGE. Or you could do like me and get a Vixen VMC260L. Only 22 lbs, but it comes in at a very slow f11.5. Confused?
David
--------------------
A few scopes and mounts.
Proud Member; PAS NOLA,
Life expectancies would go WAY up if green vegetables smelled like bacon...
|
Wmacky
professor emeritus
Reged: 11/24/07
Posts: 547
Loc: Middleburg Fl US
|
|
I have a C11 CGE and with the 80mm scope on top it's at the imaging limit. Just adding the 80mm, vibration settling went from 0 sec to several.
--------------------
William
C-11 SCT
EON 80ED
CGE
Canon 40D
Phillips SPC900
SS Autoguider
Scopebuggy
|
Hal Pollner
Reged: 08/30/05
Posts: 6189
Loc: Southern California Desert
|
|
HEY DAVID:
The 12" Meade is 75 pounds, OTA & fork only.
If your 14"R is only 69 lbs, then the mirror must be missing. The weight of the OTA/Fork is 116 pounds.
HAL
--------------------
|
MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 917
Loc: Columbia Gorge, WA
|
|
This is fascinating stuff.
It seems to me a fork mount ought to be fairly simple to make very solid. And yet everyone here seems to agree that their factory forks for the various scopes are less than optimal. I don't get it, the forks on the LX's look pretty danged beefy for example. The pix of the massive LX16 forks look like they would be bombproof.
Is it the lack of a balanced RA moment as you get with a GEM and counterweight? The side load with a big OTA on forks that are fine with a 10" or smaller OTA?
In my reading, there are comments on the web here and there on PE for factory fork assemblies, some seem to get great shots, others don't like them. But the bulk of the complaints in all arenas does seem to center on vibration issues more than PE. It may be that due to the vibration issues, folks don't get to the point of worrying about PE as much.
My take home so far is...oddly enough, the fork systems sold with the large CATS are more a sales device to move a ready to go, compact mount system for their OTA's.. than sell a very solid, technically capable mount.
So far, wether I stay with my Z12 or go with a CAT, it looks like the single constant is a fairly expensive GEM. If that's the case, all moving to a CAT does is add $2-3K to my spending in order to get one, on top of the same mount I'd need either way. This leaves me thinking that my idea of going around the need for a new mount by picking up a forked CAT doesn't get me anywhere because I'd still need the beefy expensive new GEM.
--------------------
"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
Edited by MtnGoat (08/07/08 12:14 PM)
|
tim53
sage
Reged: 12/17/04
Posts: 317
|
|
I've got a NS925GPS that I use for planetary and DSO imaging from my home in NE Los Angeles. It's got two Losmandy dovetail plates, a Megrez 80, two firewire cameras (weigh almost nothing), an ST2000, a tube counterweight, and a few other stuffs hanging on it.
I find that the assembly wobbles for several seconds after a slew or even a manual centering correction (in dec, doesn't seem to be a problem in RA. Wind will also set it to oscillating, which messes with autoguiding.
Did you check out the Mathis mount on 'mart? Not portable, but designed for a C-14 tube and as stable as you can get commercially in a fork. I remember seeing these at RTMC 25-30 years ago, and being quite impressed. Mathis makes a modern version of the mount, and has a good article about the pluses and minuses of fork mounts on his website.
Probably the cheapest way to get into a goto fork-mounted 14" would be one of the old Compustars. But I don't know how stable the old fork mount is compared to other options.
-Tim.
--------------------
"We`re just waiting looking skyward as the days come down.
Someone promised there`d be answers, if we stayed around."
-Orchestral Maneuvers in the Dark, "The Romance of the Telescope"
|
MtnGoat
scholastic sledgehammer
Reged: 02/18/07
Posts: 917
Loc: Columbia Gorge, WA
|
|
I checked out the mount but couldn't get the price..I'm not paying them 12 bucks just to look at ads. For now.
that does look like a monster of a mount and very capable. However, it still entails my basic problem...I spend mucho dollars only to still need the OTA to use it with. Leaning ever more to just figuring out how to mount the Z12 since then I only need the mount.
--------------------
"Ignorant people think it's the noise which fighting cats make that is so aggravating, but it ain't so; it's the sickening grammar they use." Mark Twain
|
|
6 registered and 10 anonymous users are browsing this forum.
Moderator: Jason B
Print Thread
|
Forum Permissions
You cannot start new topics
You cannot reply to topics
HTML is disabled
UBBCode is enabled
|
Thread views: 705
|
|
|
|
|
|
|
Previous
Index
Next
Threaded
Edit
Reply
Quote
[Re: 