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CGEM polar alignment scope

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#1 AlienRatDog

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Posted 22 July 2009 - 12:52 PM

IS there a CGEM polar alignment scope? I know there is a routine, but I am curious about a polar alignment scope...Also, does the pier extension for the Atlas mount work on this mount?

#2 Scott Beith

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Posted 22 July 2009 - 12:55 PM

here you go. link

#3 AlienRatDog

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Posted 22 July 2009 - 01:01 PM

Sweet...I used the Orion version, how is Celestrons? Anyway to have it illuminated? Or any alternatives? Also, how quiet does it slew? The specs for it say it has optical encoders...can I move it manually and keep track of its position?

#4 Scott Beith

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Posted 22 July 2009 - 01:16 PM

I haven't used my CGEM yet and I don't have the polar alignment scope.
I am still in the process of moving into my new place and haven't had time for scopes lately...

#5 Lane

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Posted 22 July 2009 - 04:17 PM

You cannot move the CGEM manually. You can however bypass the alignment process and just move it around using the 4 arrow buttons.

If you put 5 Atlas mounts all together and did a GOTO with all of them at the same time, that would be about the noise level of a single CGEM when it is doing a GOTO.

Part of the reason for the noise though is speed, its GOTO is twice as fast as the Atlas.

I started to buy the polar scope but decided against it after using the CGEM. The hand controller software is much more sophisticated than the Atlas and that polar routine is really sweet. But if you just want to do visual observations you really don't need to get that close to polaris anyway. The CGEMs alignment process is extremely good and results in much more accurate gotos than the Atlas. So if you plan to run the scope from the hand controller I would definitely stay away from the Atlas. But many people buy the Atlas without the hand controller which saves you 300 dollars, then they use a computer and eqmod software to run it. That is apparently the only way to go. I plan to the do the same thing with my Sirius very soon since it has the same cheesey hand controller as the Atlas.

#6 waassaabee

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Posted 22 July 2009 - 04:28 PM

I echo Lane's statements above.

If I take my time and use the reticule eyepiece to polar align the mount via the hand control routine, all targets are dead center in the camera regardless what part of the sky. At the end of the night I put the mount in Hibernate, power down, remove the scopes and cover the mount. The next night power on and GoTo whatever target and it's still dead nuts on target. I've left it in place for seven nights without touching the alignment and been spot on every night.

#7 Blixx

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Posted 22 July 2009 - 05:25 PM

I think that the cgem is a very quit mount. I also have a cg5 and I have a few friends that have the atlas and I think the cgem is quiter than both. Even when it is slewing.
Dan

#8 Lane

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Posted 22 July 2009 - 05:56 PM

We are only talking about GOTO or slewing noise. All the mounts sound about the same otherwise.

Quiet is a relative thing. Mounts that have a quiet GOTO in my backyard sound loud out in the country at the dark site. So it all depends on the background noise at the time you hear the mount. Side by side at our site the GOTO noise levels for the mounts I am familiar with goes like this:
LX200 - very loud
CG5
CGEM
ATLAS
SIRIUS
SHPINX - real quiet
We use to have some CGE's at the site but have not seen anyone with one in many years so can't really determine where it goes in the list.

Of course GOTO noise level also increases with the load. A heavier OTA, an unbalanced OTA, or just an overloaded mount is much noiser. I know that CGEM is much quieter during GOTO operations with the ED80 on top than with the C11 even when it is balanced properly.

#9 waassaabee

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Posted 22 July 2009 - 07:41 PM

Now about the pier extension.... I think that fits the CG5, so I don't think the CGEM would work. They made sure there was enough difference so folks wouldn't want to buy just the head, and put it on a CG5 tripod... :whistle:

#10 mclewis1

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Posted 22 July 2009 - 08:27 PM

There are two popular pier extensions from Orion, one is a 16" model for the SVP that also fits all the CG-5s and it's variants. The other is an 8" model that fits the Atlas/EQ-6 and CGEM tripods.






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