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Re: G11 Mount Not Tracking Correctly

 

?dougwheeler90@...
2:29am???

Hey everyone, first post here.

I have used the G11 mount before and had success with it, but this past weekend, it seems like no matter what I tried, I could not get the alignment correct. ?I purchased the GPS attachment thinking that would make things more accurate and simple, but that didn't seem to help. ?After setting up my mount, I aligned it due north with a compass and waited for sunset to align with Polaris using the polar scope. ?The app I have on my phone to match the reticle never seems to be in the same position when looking through the reticle of the polar scope, but I've never had difficulty aligning before. ?So after aligning Polaris between the correct lines in the reticle, I fired up the mount and used quick start. ?I verified the GPS data with another source and verified the time zone UTC -5, or Central Daylight Time, and ensured the time was also correct, and it was. ?However when using the two bright stars to perfect the alignment, (typically I use Vega and Deneb), the GoTo was way off. ?It would slew but point in totally different directions for either star. ?After using the buttons to slew to the correct position, it still would not go back to the correct spot and then trying to slew back to Polaris did not even work. ?I put everything back in the correct position with CWD and all that, all my cameras pointing at Polaris and tried again using Vega and Arcturus, and then Arcturus and Dubhe and never got good results. ?All my images ended up with trailing and I was using short focal lengths with relatively short shutter times of 3-4 minutes. ?I have previously done 8 minute exposures and had no trailing whatsoever at 24mm focal length on a 35mm full frame. ?For this past weekend I had three cameras mounted and balanced, with an 85mm lens, a 24mm lens, and a medium format camera with 23mm lens (18mm full frame equivalent).
I wanted to also do a series of Andromeda with my 600mm lens, but that would have been out of the question since I was getting trails at short focal lengths.
Any recommendations for how to fix this? ?Honestly, even if the GoTo doesn't take me to the exact position, I'm fine with using the buttons to slew to where I want to go, but I at least need it to track properly.?
Hi Doug,

Sorry to hear of your problems with the G11. First a GPS will only help the Gemini get its initial positional GOTO closer. Once polar aligned and even a single star model is built the Gemini knows where it is in that part of the sky.

A few questions, which Gemini are you using? Did you install a battery you tested @ 3.0V or higher? Do you know that Gemini GPS coordinates are entered using DMS format? If your GPS was a recent purchase do you know if it has the firmware fix for GPS rollover? If you are using well know navigational stars for Gemini alignment and your GOTOs are off and you cannot slew and return to a once centered location you have a few potential issues.

The troubleshooting checklist I use is: test battery, wipe battery clip contacts and install battery, do a full factory reset, verify GPS data you used is correct and entered using DSM format, enter UTC and only use UTC - no need for local offset, verify time format is entered using correct Gemini format is different, verify polar alignment. If you do this checklist 99.9% of all issues are resolved.?

--?

Chip Louie - Chief Daydreamer Imagination Hardware
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