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Alt/AZ vs EQ

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#1 sonny.barile


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Posted 27 January 2013 - 08:18 PM

What is the procedural difference in how you set up the CG-5GT eq mount versus the 8se alt/az?

#2 Tel



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Posted 28 January 2013 - 05:39 AM

Hi Sonny,

Well obviously you are familiar with your 8SE's set up but of course the setting up of the CG-5 GT is an entirely different "ball game" !

To demonstrate this, I've been trying to download the CG-5/CG-5 GT manual for you but it seems as if Celestron have blocked this: reason unknown but I could access an "Our Bad" from them and a "404" error.

However, if you think it would be of use to you in demonstating the differences you presumably seek, then just "Google" CG-5 GT mount manual and your search should produce the following link which I find WILL open by this search route but NOT directly as written down here.


There may well be another way of going about this, but the above instruction should get you to the original manual for comparison with that of your 8SE.

Hoping this helps,
Best regards,

EDIT : It seems that the link to the CG-5 GT manual has self corrected and thus WILL now open !

#3 Midnight Dan

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Posted 28 January 2013 - 06:54 AM

Hi Sonny:

Tel's link will give you all the details. But in general, the main differences I see in a GEM vs the SE mount is in assembly, balancing and polar alignment.

The SE is light enough that I leave it fully assembled and carry the whole thing out. With most GEM mounts, they weigh more, and the counterweights add a lot to the overall package weight, so it is carried out in pieces and assembled in the field - tripod first, then mount head, then counterweights, then scope.

Once the scope is on the mount, you have to balance the setup along the DEC and RA axes. This is done by moving the mount so the scope is horizontal, releasing the clutches and seeing which way things want to spin. You then have to adjust the position of the scope fore and aft for Dec balancing, and the position of the counterweights for RA balancing.

The final additional procedure is polar alignment. This is started by placing the mount in the home position and aiming the tripod roughly north. You then use adjusters to change the altitude and azimuth angles of the base of the mount so that it points towards the north celestial pole. This is not exactly at Polaris so the mount may have a polar scope in the mount with a reticule that allows you to set it up for the time/date and offset Polaris to the proper location.

If you're doing AP, then you may need to go further than a normal polar alignment with the polar scope, and do a drift alignment. This involves aiming the mount at a star and seeing which way it drifts over time, and then correcting your mount's polar alignment with the alt/az knobs on the base.

At this point, you move on to a procedure similar to the 8SE alignment involving aiming at stars in the sky and aligning on them.


#4 sonny.barile


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Posted 29 January 2013 - 09:29 PM

Thanks gents. I also was unable to get the link to work on Celestron's site hence the question. I am currently battling a case of refractoritus and wrestling with picking up a Celestron Advanced Series C6-RGT. It is equipped with this eq mount and Nexstar. However, after searching through some on-line images today and getting a look at it with an actual human standing next to it, I have quickly changed my mind.


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