Chris Schroeder
Postmaster
Reged: 12/11/04
Posts: 8515
Loc: N.E. WI Sky Glow
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I have a Scopestuff’s SCT balancing kit on my CPC. M y question is, with the altitude being a little stiff so getting good balance is tough. Which way do I want to error in, front heavy or tail heavy?
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Chris
Mallincam Color Hyper Plus
10" DSH with SC DSC, CPC 800 XLT
AT 111EDT, AT 102Achro, ZS80FD 10th Anniv, AT 72ED, ZS66SD, PST
CG5-AGT, EZ-Touch, Voyager
POD XL3
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Starman1
Vendor (EyepiecesEtc.com)
Reged: 06/24/03
Posts: 17639
Loc: Los Angeles
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An SCT with a sliding weight cannot be balanced when pointing to all altitudes without sliding the weight. If you don't want to slide the weight for each altitude, point the scope 60 degrees up from the horizon and balance it at that point. 30 degrees either way won't strain the motors much.
If you want to be more accurate, balance the scope for 80 degrees up, 50 degrees up, and 20 degrees up and put white marks on the sliding bar for each of these altitudes. Slide the weight to the appropriate setting before moving to an object near that altitude, and your motors will have very little load when driving the scope.
If your eyepieces vary a lot in weight, either balance with the middle weight one or make different marks on the bar for the heaviest and lightest eyepieces.
Frankly, when all is said and done, the first recommendation is just fine--balance at 60 degrees and forget it.
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Don Pensack
www.EyepiecesEtc.com
12.5" Teeter/Zambuto, 5" Maksutov
Sustaining Lifetime IDA member
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Chris Schroeder
Postmaster
Reged: 12/11/04
Posts: 8515
Loc: N.E. WI Sky Glow
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Thanks Don, yes I use a wide range in EP weight as well as a binoviewer. As for tracking purposes, imaging, which is it better, to be nose heavy or tail heavy.
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Chris
Mallincam Color Hyper Plus
10" DSH with SC DSC, CPC 800 XLT
AT 111EDT, AT 102Achro, ZS80FD 10th Anniv, AT 72ED, ZS66SD, PST
CG5-AGT, EZ-Touch, Voyager
POD XL3
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Starman1
Vendor (EyepiecesEtc.com)
Reged: 06/24/03
Posts: 17639
Loc: Los Angeles
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Quote:
Thanks Don, yes I use a wide range in EP weight as well as a binoviewer. As for tracking purposes, imaging, which is it better, to be nose heavy or tail heavy.
On GEMs, driving is smoother and less jittery when the scope is slightly misbalanced toward the side being driven from, i.e. if the gears are pressed tightly against the driving gear even without the motor turning.
So it depends where in the sky the scope is pointed. Given that you are probably not yet using a wedge (are they available for this scope, yet?), you'd want the scope slightly nose heavy if pointed to the east (scope is rising) and slightly tail heavy in the west (nose falling).
On a wedge, you also have to be aware of balance on the other axis (which goes from being azimuth to RA), and you'll want the same thing--nose heavy when pointed east, tail heavy when pointed west. It may require more weight movement to accomplish this, but the principle is the same.
However, this misbalance of which I speak is slight, not measured in pounds! The gears may be slightly rough for a few years until broken in, so if the weight misbalance is too intense, the gears may become jittery.
A good way to tell is to use high power visually. If you can see no jitter in the image of a planet, the drive is probably smooth enough and the balance is probably good.
Does the CPC have any form of built-in periodic error correction (PEC)? If not, be prepared to mount a guide scope on your scope for anything longer than a few second exposure.
An autoguider may be able to compensate if it's not too bad.
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Don Pensack
www.EyepiecesEtc.com
12.5" Teeter/Zambuto, 5" Maksutov
Sustaining Lifetime IDA member
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Chris Schroeder
Postmaster
Reged: 12/11/04
Posts: 8515
Loc: N.E. WI Sky Glow
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Thanks for the info, that makes since about which end to keep slightly heavier. Ands yes it does have PEC, the manual says to use it when on a wedge. I understand about keeping the weight close to balance, it's just a bit diffilcult now because of the stiffness in alitude, even with the clutch fully released. Hopefully with use, it will become smoother.
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Chris
Mallincam Color Hyper Plus
10" DSH with SC DSC, CPC 800 XLT
AT 111EDT, AT 102Achro, ZS80FD 10th Anniv, AT 72ED, ZS66SD, PST
CG5-AGT, EZ-Touch, Voyager
POD XL3
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