tjswood
Carpal Tunnel
Reged: 05/18/05
Posts: 1748
Loc: Tempe, AZ
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Which would you pick:
1) C-14 OTA w/ XLT & Fastar, on a CGE or G-11 (w/ DSC) ($6600 for CGE package, and about same for c-14 OTA and G-11 w/ DSC).
*OR*
2) 18" Obsession with Argo Navis DSC. ($6200 w/ DSC and w/out Servocat, ~ $8500 w/ Servocat and DSC)
I will be using it for visual work primarily, but will also tinker with Webcam images of planets, and maybe some DLSR work... (but no CCD long exposure work).
The ServoCat is $2900, so its a big investment to make the Dob track... so it comes down to how good are dobs for planetary / deepsky imaging? I like the idea of not having another EQ mount with the DOb choice... and could always upgrade the "push to" to track later on... (but it costs more than 50% the price of the scope - $2900 - to make a Dob track... that is high)
Which would you buy? And how important is Dob tracking in your decision.
Tim
PS - I thought about getting a 5-6" refractor *instead* of the above, but need to give the larger aperture option some serious thought for when I do get to star parties....
Edited by tjswood (08/21/06 10:37 AM)
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conus
Carpal Tunnel
Reged: 10/12/03
Posts: 2978
Loc: OC, Calif
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Quote:
so it comes down to how good are dobs for planetary / deepsky imaging?
Have you seen Wes Higgins work? His first stuff was with a 14.5" dob. Last year he got an 18" dob.
Here's an image of Saturn.
Here's a link to some of his other stuff. Higgins and Sons
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Steve R.
12" Orion XTi
Fujinon 10x42
Oberwerk 12x60
My toUcam Images
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JerryWise
Postmaster
Reged: 12/26/03
Posts: 7006
Loc: Lexington, SC
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Tim, I'm a C-14 fanatic. Fantastic scope with great optics. Weight is right and on the CGE tracks like a champ.
And I won't look through an 18 inch Obsession. I don't know of anyone that has looked through one that didn't start craving it and raving about the views. The views would surely be better, much better. And the views in the 14 Celestron XLT are fantastic. I don't envy your decision process.
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Jerry
LX200ACF 14", Tak FS 152 & TOA 150
AP-1200 & Mach1
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tjswood
Carpal Tunnel
Reged: 05/18/05
Posts: 1748
Loc: Tempe, AZ
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Jerry,
I thought about it further, and realized I am not comparing apples to apples - to make the 18" on par with the C-14, it would need to track also, and have some aspect of GOTO instead of push to. Problem is to get the Obsession that capability you are up in the $9K range, where the C-14 on a CGE is $5800 with std coatings all the way up to $6600 with Fastar.
I think a better comparison here would be "Do I get a 15" Obsession with tracking / goto *or* a CGE1400 with Fastar. The 15" Obsession is $4295, plus $2900 for ServoCat / Argo Navis. So even the 15" Obsession weighs in at over $7200 by the time it ships to you...
I keep hearing folks make the case that the DObs are pound for pound the best value, but once you configure them with comparable capabilities they are more than SCTs of similar size...
Tim
Edited: corrected cost for servocat, argo.
Edited by tjswood (08/21/06 10:35 AM)
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conus
Carpal Tunnel
Reged: 10/12/03
Posts: 2978
Loc: OC, Calif
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Quote:
I think a better comparison here would be "Do I get a 15" Obsession with tracking / goto *or* a CGE1400 with Fastar. The 15" Obsession is $4295, plus $2900 for ServoCat, plus $800 for Argo Navis. So even the 15" Obsession weighs in at over $8000 by the time it ships to you...
Another thing you might consider would be seeing. How much more seeing dependant would the 18" be over the 15"? Perhaps you would have more opportunities for imaging during the year with the 15" than with the larger mirror.
Also, why is the Fastar necessary? Isn't this just for planetary imaging?
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Steve R.
12" Orion XTi
Fujinon 10x42
Oberwerk 12x60
My toUcam Images
Edited by conus (08/21/06 09:57 AM)
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tjswood
Carpal Tunnel
Reged: 05/18/05
Posts: 1748
Loc: Tempe, AZ
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Conus,
Good point... the extra aperture does lessen the chances to use it seeing-wise... but understand whether I get 15" or 18", it will be relegated to star parties and dark skies when I get to them... it won't go out in the yard much (that is until I get into planetary imaging :-) )
since I already own a N11, everytime I think of bumping up to 14-15" of aperture, I ask myself is it worth the huge outlay for only 3 more inches?? WHich is why I started along the path of 18" in the first place.
Tim
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conus
Carpal Tunnel
Reged: 10/12/03
Posts: 2978
Loc: OC, Calif
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Yeah, that seems to be one of the toughest decisions in amateur astronomy-- the 15" or 18" Obsessions w/Servocat. It's one I'll eventually have to make. In fact, for a lot of people that decision is an inevitability.
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Steve R.
12" Orion XTi
Fujinon 10x42
Oberwerk 12x60
My toUcam Images
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tjswood
Carpal Tunnel
Reged: 05/18/05
Posts: 1748
Loc: Tempe, AZ
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When it comes to a Dob, like an Obsession, you can tell yourself that DSC's are enough, but tracking is a necessity long term IMHO.... especially when observing planets.
And to your question before, yes, Fastar is primarily included for planetary imaging... not convinced I need it, as it costs a few hundred extra. And I think it increases the CO a tad also.
Tim
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Steve Chamberlin
sage
Reged: 08/04/05
Posts: 218
Loc: New York City, NY
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Quote:
When it comes to a Dob, like an Obsession, you can tell yourself that DSC's are enough, but tracking is a necessity long term IMHO.... especially when observing planets.
When I daydream about our next house and the scope I'd like to get at that time, this is the biggest reason why I jump back and forth between something like a C14 and a 15-18" Obsession.
I'd sure love the wider potential FOV with the Dob, but I'm not sure how happy I'd be without a GEM and tracking.
steve c.
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C8-XLT, NP-101, TV-76, Starblast 4.5, XT6
Sphinx, EQ5, Microstar/3046, EQ1
TVue 8, 11, 20, 32; Nag 13T6, 16T5, 20T5, 31T5, 3-6Z; Pan35; UWAN 4; TMB/P's
Orion Ultraview 10x50
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RogeZ
professor emeritus
Reged: 11/21/04
Posts: 575
Loc: Miami, Florida
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Quote:
And to your question before, yes, Fastar is primarily included for planetary imaging... not convinced I need it, as it costs a few hundred extra. And I think it increases the CO a tad also.
I dont know about the CO issue but the fastar system is used for widefield DSO imaging since it shortens the focal lenght to 716mm in a 14" SCT, it would be really wasteful to do any planetary imaging at 700mm.
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RogeZ 
6" C6-RGT "Yard Cannon"
12" Deep Space Observer
Working on a BS Mechanical Engineering
www.rogeastronomy.com
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conus
Carpal Tunnel
Reged: 10/12/03
Posts: 2978
Loc: OC, Calif
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Quote:
And to your question before, yes, Fastar is primarily included for planetary imaging... not convinced I need it
If planetary and lunar is all you're doing, then you don't need it. Not at all. In fact, it would defeat your purposes. For planetary imaging all you will need is a laptop, a couple of barlows, a Phillips toUcam or the newer version of the Phillips webcam and a copy of Registax for stacking images. Some people are now going over to monchrome Firewire type cameras, such as the DMK 21AF04, then getting their color images via multiple shots taken through rgb filters and then stacked in Registax, but frankly I don't seen enough of a difference to justify the effort or cost. Most of the best images ever taken have been through the Phillips webcams.
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Steve R.
12" Orion XTi
Fujinon 10x42
Oberwerk 12x60
My toUcam Images
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tjswood
Carpal Tunnel
Reged: 05/18/05
Posts: 1748
Loc: Tempe, AZ
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RogeZ - I stand corrected.... and makes me realize even more that I don't need it.
Do you have any thoughts on the topic at hand??
Tim
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tjswood
Carpal Tunnel
Reged: 05/18/05
Posts: 1748
Loc: Tempe, AZ
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Conus -
I have been learning about Webcam imaging on the side - I am going to start with my N11 this fall / winter on Saturn. (not the best year with 15 degree ring incline, but hey, gotta start somewhere.)
I have already decided on the Philips SPC 900NC PC, which is the successor to the TuoCam. (I don't think you can buy a new TuoCam anymore, only the SPC.)
I thought that Fastar would help with that (my N11 does not have it) but to now understand it makes the scope "faster" (duh!) for deep sky I won't get it. I actually thought it would assist in planetary imaging as well... but just did not think it through.
Tim
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LivingNDixie
Lord of Ferrets
Reged: 04/23/03
Posts: 15913
Loc: Hoover, AL
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I would go with the 18in Obsession, as long as you have something to transport it (if applicable).
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Preston
Celestron 11" Nexstar GPS XLT
Tak FS 78
Lunt LS60T/Ha 60mm f/8.33 (on order)
Vixen Porta Mount
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conus
Carpal Tunnel
Reged: 10/12/03
Posts: 2978
Loc: OC, Calif
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Quote:
(not the best year with 15 degree ring incline, but hey, gotta start somewhere.)
Right, but at least it will be pretty much straight overhead. And there's always the moon. You could spend a lifetime on that. As far as Jupiter goes, in the northern hemisphere I don't think we will have another good shot at it until around 2010. You'll have plenty of time to practice until then, and that N11 will give you some great images.
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Steve R.
12" Orion XTi
Fujinon 10x42
Oberwerk 12x60
My toUcam Images
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Scott Beith
SRF
Reged: 11/26/03
Posts: 34350
Loc: Gulfport, MS
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C14
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  Scott (Kilt Boy)
"The only thing necessary for the triumph of evil is for good men to do nothing." -- Edmund Burke.
"People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf." -- George Orwell
"The measure of a man’s greatness is not determined by what he accomplishes for himself, but by what he accomplishes for others.” -- Some Bald Guy
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RogeZ
professor emeritus
Reged: 11/21/04
Posts: 575
Loc: Miami, Florida
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Hi Tim
I have used an 11" SCT and a 18" Starmaster Dob. Never used a C14 before but if I had the chance I would always go for the largest scope.Why? It will show you more, always, those individuals that say that the largest optics is usually more seeing dependant may be right, but I have never seen that effect myself. My experience has been, the bigger the scope and the better the optics, the better the image. I would suggest you Tim to buy certain kind of tracking plataform for the dob, so you can push the powers up.I'll go for the dob.
Another point is that the dob with a EQ Platform is a very good planetary imaging rig, that is what Wes Higgins uses.
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RogeZ
6" C6-RGT "Yard Cannon"
12" Deep Space Observer
Working on a BS Mechanical Engineering
www.rogeastronomy.com
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oldsalt
Astro Philosopher
Reged: 02/12/05
Posts: 8010
Loc: Pa - between starparties
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I'd go with the 18" obsession, seeing as you have a C11, the extra apperture is going to reveal a great deal more detail. You can always add the Servo-Cat later.
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There are no winners in war, only bigger loosers.
Jim
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tjswood
Carpal Tunnel
Reged: 05/18/05
Posts: 1748
Loc: Tempe, AZ
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RogeZ,
Great points. And many of the root points as to why I posted!!  Its hard to beat aperture, you are right - and why everytime I want to get a 14-15" I say "but I already have the 11" and lean toward the 18" Dob again.
Maybe I need to find a pristine used one locally... the almost $9k to get a new Obsession made with tracking / GOTO is the main hitch... I would like to keep that closer to $5K if possible.
You owned the Starmaster 18", bet that was sweet! Did yours track??
Tim
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tjswood
Carpal Tunnel
Reged: 05/18/05
Posts: 1748
Loc: Tempe, AZ
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Jim, I think I was posting your same conclusion the same time you were telling me!!
The 18" is a whole different level than the C11 as far as light gathering.... you are so correct... a C14 may not be enough extra oomph to justify $6K.... but a used Obsession 18" might.
Tim
Edited by tjswood (08/21/06 01:16 PM)
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