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CGE w/o RA limit switches?

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#1 idahoman

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Posted 12 July 2009 - 05:46 AM

I am thinking about making the switch from fork mount to equatorial. I see that AP mounts can track significantly past the meridian, depending upon the scope that is mounted. Since I like to image at long focal length, I am nervous about not regaining a guide star after meridian flip. And, APs are expensive. Could someone remove the RA limit switches from a CGE, for instance, and delay the meridian flip? Or, does hand controller software interfere? Has anyone tried this?

#2 Eddgie

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Posted 12 July 2009 - 11:03 AM

Even it it would work, it would not buy you much. Just a few degrees past the electronic limit, the mount reaches the physical limt where the Dec motor housing will contact the RA Motor Housing. Defeating the switch migth get you an extra 10 minutes past the meridian.

Would it work though? Sounds reasonable. It appears that the switch that monitors this is dedicated to that function. There is a second switch that monitors the "Home" function.

#3 idahoman

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Posted 12 July 2009 - 11:54 AM

Thanks for the clarification. So, the CGE has physical dimensions that prevent going much past the meridian? Are there any reasonable good german equatorials that do not have "geometric" limitations regarding the meridian besides APs?

#4 DaveJ

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Posted 12 July 2009 - 01:26 PM

Thanks for the clarification. So, the CGE has physical dimensions that prevent going much past the meridian? Are there any reasonable good german equatorials that do not have "geometric" limitations regarding the meridian besides APs?


Yup...the CGE Pro. Substantially more than the standard CGE ($5000 vs. $3000), but significantly less than the APs.

#5 jrcrilly

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Posted 12 July 2009 - 01:45 PM

Yup...the CGE Pro. Substantially more than the standard CGE ($5000 vs. $3000), but significantly less than the APs.


The limit switch on the Pro model isn't much farther along than the stop on the CGE, but I don't remember whether there's a physical stop or not. As someone who normally operates remotely, I'll comment that the only thing about the NJP that doesn't completely please me is the lack of such a safety feature. I miss the built-in tracking limits of the CGE (hardware) and the LXD750 (firmware). It's easy to say that I'll be careful to avoid collisions (and, of course, I WILL be careful) but falling asleep is always a possibility. I don't like the idea of expensive hardware slamming into the pier, or cables and connectors being pulled apart, or stalled motors burning up.

#6 LLEEGE

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Posted 12 July 2009 - 03:51 PM

G11.

#7 LLEEGE

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Posted 12 July 2009 - 03:53 PM

You can't remove the limit switches either. They are needed to find the home position.

#8 CounterWeight

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Posted 12 July 2009 - 10:07 PM

Thats what I thought/think too, maybe not needed for operation but both switches are 'looked for' in the mount initialization outine... if a switch is not found will keep going in direction looking for it until potential disaster or scope pointing at ground or something weird...

#9 freestar8n

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Posted 13 July 2009 - 06:42 AM

The limit switch on the Pro model isn't much farther along than the stop on the CGE, but I don't remember whether there's a physical stop or not.



According to the cge pro product description there is at least an extra 20 degrees past the meridian, which would be great. Much more than that would require care that camera equipment doesn't collide with the mount, and it would let you do a meridian flip either early or late - in a spread of over two hours - which would be much easier to coordinate with a sleep schedule.

As for the cge - the physical stop where the mount hits itself is just past the limit switches, so I agree there is not much win in circumventing the limit switch.

Frank

#10 Chris Rowland

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Posted 13 July 2009 - 06:48 AM

Yup...the CGE Pro. Substantially more than the standard CGE ($5000 vs. $3000), but significantly less than the APs.

The limit switch on the Pro model isn't much farther along than the stop on the CGE, but I don't remember whether there's a physical stop or not.

The CGEM is a less expensive alternative to the CGE but lighter; it might be suitable.
The CGEM and CGE Pro are supposed to move 20 degrees past the meridian, in both directions. This means that you can keep tracking for 80 minutes after the object has passed the meridian or slew to it and start tracking it 80 minutes before it gets there.

Chris






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