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CGEM Not Tracking

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#1 astro-vert

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Posted 09 September 2012 - 01:53 AM

I have a spakin' new CGEM mount... Intermitten issue, but doesn't work more than it works. I get it all setup, do a 2 star w/ 4 cal star alignment, plus a good polar align. Stars are dead center...problem is, once an object is selected, (using NexRemote from my laptop) the mount will slew to it, but will not start tracking. I've checked the menu - tracking is on (EQ North) and rate is sidereal. I listen close and when it is tracking, I of course here the faint sound of the RA motor. When not working, all's quiet...crickets. I realize it isn't tracking when PHD starts shouting for loosing the guide star... Hit the 'enter' button on NexRemote and the mount slews to the new place where the object now would be.

Any advice? Thanks!

#2 rmollise

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Posted 09 September 2012 - 07:08 AM

What does it do with the hardware HC?

#3 astro-vert

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Posted 09 September 2012 - 11:37 PM

I've been using NexRemote pretty much exclusively when outside, so can't comment on consistency of using the HC... Will ditch NexRemote and do some testing at home w/ the HC. Next time out, I'll plan to only use HC and see where I'm at.

Thanks

#4 EFT

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Posted 10 September 2012 - 09:51 AM

Definitely try using the hand controller. Also, since the problem is intermitten, make sure that you have a good power source. These mounts will do all kinds of strange things is the power is not good.

#5 astro-vert

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Posted 10 September 2012 - 01:14 PM

Thanks Ed. I wired up a 12V marine deep cycle battery w/ a 3 port power adapter for the mount/camera/inverter for the laptop. My wiring has a switch and a fuse. Will double check the output voltage at the ports and see if that is messing things up.

Thanks

#6 astro-vert

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Posted 12 September 2012 - 11:26 AM

I measured my voltage again...17V!!! This is bad news... The battery is a deep cycle 85Amp-Hour that is supposed to be 12V! This seems to be way too much, so...battery came from Costco, probably can return.

Can anyone recommend a specific battery they've used? Or, is there some sort of voltage regulator I can buy to get back to 12V

Thanks!

#7 EFT

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Posted 12 September 2012 - 11:31 AM

Definitely do not use that. I would recommend a simple deep cycle marine battery when it comes down to it. Jump start batties have a highly variable record of success for this use.

#8 dickbill

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Posted 12 September 2012 - 01:16 PM

maybe your object, say M57, is at the end of what the mount can track without doing a meridian flip, and therefore the mount just stop tracking.

#9 Jwemes

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Posted 12 September 2012 - 02:55 PM

Wow! If you are using a lead acid, deep cycle, or 'marine battery', you cannot have an open circuit voltage of 17vdc! Your 12v nominal battery has 6 cells. Each cell is theoretically capable at full charge of delivering 2.2 vdc MAX with a 'rest state' battery. Either your meter is not calibrated well or (If your inverter is not isolated from the battery) you're getting something back from your inverter.

If your battery is new, and fully charged, but in a 'rest state', you should see 12.8vdc in an open circuit test.
The CGEM current draw while tracking is ~300 milliamps. The CGEM may draw as much as 1,100 milliamps (1.1 amps) while slewing both axes. You should be able to run the CGEM by itself on your 85 AH battery for several nights before the resting voltage of the battery drops to ~12.4 vdc. There are all kinds of battery tutorials on the web. Some are even understandable!

Check the accuracy of your meter first.
Clear, Dark, and Steady

#10 astro-vert

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Posted 12 September 2012 - 04:25 PM

Thanks guys! I will bring the battery by a local auto parts store to verify the voltage. My meter is pretty old, as are any basic EE skills I may have picked up along the way... Perhaps my battery is not what I actually think I have. Anyway, I'm not going spend too much time trying to figure it out, I'll just get a proper battery.

Thanks again for the input into my problem.

#11 astro-vert

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Posted 12 September 2012 - 09:37 PM

Relief for me...my multi meter is wonky...12.19V double confirmed...so I feel so much better about power. Will test the HC now sans NexRemote....

#12 JameeDon

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Posted 12 September 2013 - 07:50 AM

Found this thread doing a Google search a year later... What ever happened with your tracking issue? I'm experiencing a similar problem, I have a CGEM and I'll be tracking and guiding a DSO and suddenly the mount will just stop tracking, the weird thing is if I lightly knock on the mount's housing it will "wake up" and slew to where it was supposed to be. The mount is new and in pristine condition and carrying an 8" Edge HD scope with a 80mm Celestron guide scope and the cameras which is well within the mounts payload capacity. I've had this mount for 3 months and the first month this same problem happened so I ended up doing a restore to factory defaults and the problem went away for 2 months, but this time something new happened, after the tracking issue started to plague me again I looked at the hand controller and it said press enter to begin alignment. The mount was turned on and receiving power the entire time yet my alignment was reset, Stellarium Scope was still connected and talking to the mount after the hand controller wanted me to begin with a new alignment. I don't know if these 2 things are related (the tracking and alignment reset) because the tracking issue I've had before but the resetting has never happened, but they could be.

Could there be an issue with my laptop and all the software I use with the mount? I use ASCOM, Stellarium Scope, Stellarium, PHD, BYEOS and I've been messing around with Astrotortilla. The resetting of the alignment almost sounds like a power issue but could the tracking "falling asleep" issue be related to power even though the mount remains getting steady power from the battery? I use a good battery, a Die Hard 12vdc 950amp 40ah that I keep fully charged and only has the mount plugged in it.

#13 mich_al

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Posted 12 September 2013 - 08:32 AM

Sounds like a power/connection issue. I've had the same happen when my HC connection was poor. Also check the power connection. A weak point is the connection at the mount, use a small blade to gently spread the split cylinder on the mount side.

#14 JameeDon

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Posted 12 September 2013 - 11:49 AM

Thanks Al, someone else told me to do the same thing last night but haven't tested yet to see if its still acting up. But I'm confused about if this is a power connection issue then how is it that the scope remains powered but the tracking just completely stops until I light knock on the housing on the opposite side of the power connection? And when I say lightly I mean lightly, it doesn't take much to wake the mount up. So would the tracking quit suddenly after it was working fine because of a bad power connection yet the mount remains on and still has all the alignment data I entered? It seems like either the mount would be getting power or wouldn't be getting power with no in between. Let me add that the mounts motor sounded like it was at 100% while slewing the full range of motion with no shuttering or sounding overloaded.

When you say you had the same happen, are you talking about the tracking issue or the restring issue? And which ever issue you're talking about, you say the hand controller connection was poor, do you mean at the mount? And what happened?

#15 mich_al

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Posted 12 September 2013 - 11:32 PM

JameeDon
I was addessing

...but this time something new happened, after the tracking issue started to plague me again I looked at the hand controller and it said press enter to begin alignment. The mount was turned on and receiving power the entire time yet my alignment was reset,


This is what would happen if power flickered. You may have multiple problems or just one. I'd attack the power issue and then see what else is going on.






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