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jake47
sage
Reged: 03/03/04
Posts: 460
Loc: North Texas
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Okay. So Celestron didn't come through with my dream mount. You know -- the alt-az go-to that would take a number of different scopes like the CG-5GT does. They have the technology. Look at the baby nexstars with a Baader bracket or the big double fork ones. But they didn't. I think I might have to give up on a sturdy, tracking alt-az. Push to with dsc is okay, but I wanted tracking. A GEM seems to be what I must get.
I'm a visual observer with a small refractor. The SV85S is around 9.5 pounds. I'm thinking CG-5GT. I have only used my Unistar Light and the NS11 alt az mounts. What will I have to give up for what I will get? Viewing with alt-az is so easy for visual use, but I expect that the GEM will have some idiosyncrasies of its own. What should I look for as a change in my viewing evening? How much does the CG-5GT weigh? Can it be considered easy to go from den to driveway? Will it hold the scope steady for focusing at high power? Would a smaller mount do? Lots of questions, but CN has never let me down.
Help me guys. I want to use the limit of my scope without things moving out of view before I can sketch any details.
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Jim in Texas
NS11GPS (Celeste)
C6S-GT (Celia)
SV 85S (Stella)
SV66 (Red)
Pentax Binoculars (the Twins)
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markf
Carpal Tunnel
Reged: 10/13/04
Posts: 1935
Loc: Houston, TX
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When aligned to the Celestial north pole, the EQ mount tracks very very nicly. Heck, just getting close works pretty good for visual. I've got good enough tracking without even seeing Polaris to where an object will stay in FOV for 3-5 minutes. (Of course knowing your lattitude and about where Polaris should be is required)
I've just gotten my CG5 mount, and it does take some getting used to how it moves. I'm still working it out. But for me it's not too big a deal.
As to the weight, it's hefty, especially fully assembled with weights and OTA. I have a 6" newtonian. Fully assembled I'd say it ways 60+ pounds. For a small refractor, probably not too bad. I make 3 trips, tripod, weights, OTA. The mount without weights or OTA is probably 30lbs...just guessing, but mount/tripod alone isn't too heavy.
Very stable! Focusing at high powers only wiggles the image a little, and it settles as soon as I move my hand from the knob. And since it tracks so well, I can take my time focusing...
I'm just answering a little bit, I'm sure the others have more detailed answer to provide! 
Mark
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Celestron C6N on a CG5-GT
Orion 80mm Refractor (guidescope)
ToUCam Pro II
Canon Digital Rebel
http://www.carsandfish.com/astroweb
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Rushwind
Carpal Tunnel
Reged: 03/11/04
Posts: 2133
Loc: Newark, CA
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I'm betting that you don't need that big of a mount to carry your OTA, but I think that the CG-5GT is probably the smallest GEM with GOTO (you could retrofit a NexStar or ETX mount maybe, but tube length, ...). So, yes, a smaller mount would do for weight concerns, but not for the GOTO feature you desire. I've mounted my ED80 on an EQ-2 mount with 2.5# counterweight. Works great. But no RA drives, and no GOTO. Up to you.
The CG-5GT is of decent heft. When I am going to view with my 8" Newt, I carry the mount+CW out first, then the OTA on the second trip. When I'm viewing with my ED80, I often just carry the whole thing in one trip (one less CW to deal with, much lighter OTA, etc). The SV85S is probably about ED80-sized (80mm f/7.5 = 600mm focal length; haven't weighed it). The mount will carry this OTA brilliantly. Under my light refractor, it is rock solid for focusing. I like this OTA/mount combination. Great for visual, even great for photography (it's my main imaging OTA and mount).
If you have an opportunity to go to a store and see the thing, it would be good; it's no "photo tripod". 2" (or 1.75") tubular steel legs, mount head probably weighs 20# or so (haven't weighed that either  ).
In your viewing evening, I noticed that the EP isn't always pointing in the same direction, but that's why diagonals rotate, right? Also, it's interesting learning how to make the OTA point at various parts of the sky; to get from East to West you have to flip the counterweights to the other side of the mount (instead of just rotating in Az), but you get used to that pretty quick, and it's not "worse", just "different". Once you're on target, it'll track for a long, long time. The CG-5GT has builtin slew limits, so a little past zenith, it will stop tracking automatically. Flip the CW to the other side, and it'll keep tracking down to the horizon.
GOTO *is* nice, although I don't use it all that much. Do you *require* GOTO? Because if not, then a regular ole RA tracking motor will keep your target in sight all night, too, and those are available on all GEMs from EQ-1 on up.
Hope all that makes sense. If not, I'll come back and clarify
Jimbo
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Order of the Unblinking Eye
G-11 D70 ST4 8"f/5 AT66ED (Rig)
I used to shoot film.
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Anonymous
Unregistered
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Jake,
I agree with everything that Mark and Jimbo say - I have the C6-RGT. The CG5 mount is very capable - it handles the large C6R (26# w/mods) quite well and any vibration introduced from focusing settles in 1-2 seconds. I carry the scope, weights and mount/tripod out on separate trips.
The tracking is excellent - with a quick polar alignment and the "quick align" routine, I can be out the door and up and running in less than 10 minutes - and the mount has kept objects in a wide EP for an hour or more (IF you use the right and up arrows to center the object - otherwise the object will drift out in a minute or less).
It only takes a short time to get used to moving the scope with the motors - it is frustrating though to try to center an object by moving the scope manually by loosening the clutches. It may be more mount than you need for the SV85S but is works quite well and the tracking is a real convenience.
Regards,
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chazcheese
professor emeritus
Reged: 11/21/04
Posts: 545
Loc: Phoenix, Az
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While I don't have the goto I do have the CG5-AS. This mount easily handles my AT1010 or my C4R, the only problem is the dec balance for the AT due to its shorter tube length. Wants to tip towards the objective, I got around this by using my 50mm finder and 2" WO digonal. I can carry the mount out in two trips but prefer 3 as the counter weight makes it a little awkward. But tell you what, ths mount s solid and tracks great. Had Saturn at 280X (using the C4R) in the eyepece last week for at least 30 mins without having to recenter it and only did a minimal polar alignment.
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chuck
10" Orion xt
8" Meade LX200 mount/2080 OTA
C4R on CG5
Vixen ED80Sf on Porta Mount
AT-1010
PST
12X63 mini giants
15x70 Skymasters
Virgo Bino mount on Sanford/Davis tripod
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Rushwind
Carpal Tunnel
Reged: 03/11/04
Posts: 2133
Loc: Newark, CA
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Chuck,
Not that I'm going to argue with a big finder and WO diagonal , but you might be able to get some balance help by mounting on a longer dovetail, which might allow you to push the rig farther forward.
Just a thought.
Jimbo
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Order of the Unblinking Eye
G-11 D70 ST4 8"f/5 AT66ED (Rig)
I used to shoot film.
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chazcheese
professor emeritus
Reged: 11/21/04
Posts: 545
Loc: Phoenix, Az
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Good idea, but got it to balance with the supplied dovetail. But I did order the longer dovetail for the CR4 with the thought that I might have to use it on the AT. Might still have to use it as the AT won't focus with a 2" diagonal and a barlow. Don't have a 2" barlow to place in front of the digonal. Love the wide field views anyway.
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chuck
10" Orion xt
8" Meade LX200 mount/2080 OTA
C4R on CG5
Vixen ED80Sf on Porta Mount
AT-1010
PST
12X63 mini giants
15x70 Skymasters
Virgo Bino mount on Sanford/Davis tripod
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LesB
Carpal Tunnel
Reged: 12/20/04
Posts: 1687
Loc: Z-Hills, FL
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possibly a CG-4, or its equivalent with RA drive may do. I have an 80mm, f/11 refractor and it handles well. It should be quite steady for what you want. Of course, the CG-5 will work fine but I leave my CG-4, (no drives) set up all the time and carry it outside when I need it. With a TV85 it's probably a light combo less than 40lbs.
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"The genius of humanity is to establish an identity which lies at an ever-increasing distance from our organic nature." Ray Tallis
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