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Replacing CG-5

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#1 Madratter

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Posted 19 May 2013 - 05:33 PM

I am strongly considering replacing my CG-5. I am using it for astrophotography, and while I can make it work by polar aligning carefully, the declination axis in particular leaves a lot to be desired. I am not interested in the VX as a replacement. I want a bigger upgrade than that.

There are a couple of things I DO really like about my CG-5. Those include goto accuracy, Nex Remote, and I have replaced the standard head with ADM parts so I can use either Losmandy or Vixen style dovetails with it.

My current astrophotography rig is a deforked C8 with Losmandy dovetail, a 60mm Finder, a 50mm guider, an STF-8300m camera with 8 filter wheel. So I was really pushing the weight on the CG-5 anyway.

The mount I am considering the most is the Atlas. I like the idea of EQMod as a replacement for NexRemote. What I don't like is that it only takes Vixen style dovetails. Is there a mod so that it will take both Vixen and Losmandy?

Another mount that has come to my attention is the iOptron IEQ45. What I like is the fact it comes standard with the ability to take both style dovetails. What I don't like is I am unaware of a NexRemote, EQMOD style interface for controlling it. (I'm rather spoiled using my Wingman for doing polar alignments). I'm also rather dubious about the low weight.

I plan to use this mostly from an observatory. I will put it up and take it down occasionally, but only perhaps once a month if that.

Any other mounts I should consider in this price range?

I'll probably end up with the Atlas, but I want to do my due diligence, especially since it is rather long in the tooth.

#2 rmollise

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Posted 19 May 2013 - 05:40 PM

ADM and others make Losmandy saddle plates for the Atlas. Even Orion sells them, I believe. Fairly common item. I believe folks have had good luck with the iOptron, but I think the Atlas is a safer bet as a proven performer. EQMOD makes it a fairly easy choice, I think...

#3 Madratter

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Posted 19 May 2013 - 06:07 PM

Thanks Rod. I was just (re)-reading your blog post on GEMs earlier. I just looked over ADM's site and found the adaptor. He doesn't seem to sell a dual dovetail solution, but I think one could be pieced together from his parts. I think all you really need is the correct "hockey puck". I'll have to give him a call.

#4 Madratter

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Posted 19 May 2013 - 07:17 PM

Uncle Rod:

Another issue you mentioned is the lousy latitude and azimuth adjustments on the mount. Do you know of anyone who has made replacements that are better?

Thanks.

#5 rmollise

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Posted 19 May 2013 - 09:56 PM

Uncle Rod:

Another issue you mentioned is the lousy latitude and azimuth adjustments on the mount. Do you know of anyone who has made replacements that are better?

Thanks.


People have offered various replacements. What I've found works and costs nothing? Until you have finished your polar alignment, leave the tripod's central bolt a little loose. Altitude? If it feels hard and you have to move a long way up in altitude, and have counterweights and scope on mount, push up on the counterweight bar and give it a little help (usually you won't need to go up very far). By observing these simple things I've never had a problem. ;)

#6 coinboy1

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Posted 19 May 2013 - 10:39 PM

I have the same issue with the CG-5. Mine had some serious DEC axis guiding issues and couldnt do exposures past 5 minutes @1350mm FL. I think the Atlas is a good mount with a good reputation. Ioptron mounts seem to be getting good reviews and seem to have good PEC control.

#7 orlyandico

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Posted 19 May 2013 - 10:49 PM

imho asking for more than 5 minutes guided at 1350mm on a CG-5 is... unmanaged and unrealistic expectations. :)

#8 rmollise

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Posted 20 May 2013 - 08:16 AM

imho asking for more than 5 minutes guided at 1350mm on a CG-5 is... unmanaged and unrealistic expectations. :)


Not really.

I was able to easily go at least 10-minutes--as long as I ever wanted/needed--at this f/l when I was shooting with the ST2000 on the CG5. The secret, if there was one? Very careful balancing. Underline that. Always east heavy just slightly. This is the critical thing with this mount.

#9 dragonslayer1

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Posted 20 May 2013 - 08:45 AM

Hey Rod, now I have a question on that balancing, if I remember correctly manual says OTA on west side, counterweight heavy and if OTA on east side OTA heavy? or visa versa... but if OTA straight up on the mount is "center" between two halves, how can OAT one side or the other not balance the same???? Or are you supposed to add or remove weight depending on which side of meridian your viewing?? :question: :question: :question: Thank you Kasey

#10 rmollise

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Posted 20 May 2013 - 10:46 AM

Whichever side the scope is on, you should balance so that the mount tends to move to the east when released. What does that mean? If you cross the Meridian, or even image something low on the horizon on the same side, you may need to rebalance. That's the price for getting longer exposures out of this mount. What I tended to do was image objects in the same general area on one night's run. ;)

#11 dragonslayer1

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Posted 20 May 2013 - 11:41 AM

thank you much, the weight difference is minimal, so will test both ways and config some type of tape-on weight or something and just keep it handy, if don't change things up will be real easy to switch, :bow: thank you again Kasey






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