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Strange Celestron AVX Problem Last Night

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#1 Gary Minder

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Posted 07 July 2013 - 11:05 AM

I got a new Celestron AVX mount last week. Friday night I set it up, did a 2-star alignment with one calibration star, and did a ASPA. I got really good tracking with my Orion SSAG. Last night (Saturday) I set up for another cloudless night. I set up in the same place and the mount simply would not point anywhere near any 2-star alignment star.

It was probably 45 degrees off pointing to Arcturus. Same or worse for other stars. This is my first EQ mount so I thought I must be doing something wrong. I double and triple checked that the RA axis was pointing north. I double checked axis balances. Double checked the location info in Utilities etc., and still pointing was way off. I even checked to see if there were alignment or calibration stars still in memory from the previous night.

Out of desperation I reset the mount to factory settings and started over. That did the trick and I had another night of a really good ASPA and guiding.

Has anyone else had this issue with the AVX or other go-to EQ mount? It's a head scratcher for this EQ mount noob.

#2 WadeH237

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Posted 07 July 2013 - 11:39 AM

I've never used an AVX, but I've heard of this symptom many times with other mounts that use NexStar.

In fact, when I was reading the first few sentences, I was thinking to myself, "sounds like it needs a factory reset".

-Wade

#3 Gary Minder

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Posted 07 July 2013 - 11:44 AM

I was happy that the factory reset took care of the problem and it's not a big deal to reenter my location coords but it seems odd that it was needed. I don't know what else a factory reset affects behind the scenes. I am positive the location info was correct before I reset.

#4 ahan.tm

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Posted 07 July 2013 - 11:46 AM

This exact issue happened to me. Same circumstances. I also fixed the issue with a factory reset.

#5 Brachiopod

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Posted 13 August 2013 - 01:40 PM

This exact thing happened to me too last night, also involving Arcturus. Initial seek during align was about 45 degrees off. I double and triple checked the time and position. Tried it about 8 times with the same crazy pointing. Finally did a factory reset and re-entered my data and it was perfect after that. At least now I know what to do.

#6 RTLR 12

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Posted 13 August 2013 - 01:56 PM

How are you powering the mount? This can be caused by low voltage. Voltages lower than 12.3 has caused problems on Celestron mounts in the past.

Stan

#7 Brachiopod

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Posted 13 August 2013 - 03:48 PM

How are you powering the mount? This can be caused by low voltage. Voltages lower than 12.3 has caused problems on Celestron mounts in the past.

Stan


Well, I was using a just charged car charger battery pack. I think that the voltage was good, I have not charged the pack since then, and I used it after the factory reset fixed the problem... let me look... 12.9 V under load from the scope (it has a built in meter), so I think that the voltage was OK, and obviously no line noise on a DC battery. Also the alignment failed (about) 8 times in the same way, then everything was OK once I reset using the same power source. One further strange clue, during one of the alignment attempts, I went through with the entire alignment with 2 stars, slewing all over to center them. Afterwards I checked the polar error, and it was off by almost nothing in altitude but 27 degrees in azimuth, even though I could see Polaris through the polar scope opening. After the reset, everything went perfectly, the initial slew was very close, and after alignment the gotos were at the center of my 12.5mm eyepiece as usual. I'm really impressed with this mount overall, just mentioning this weird one time problem.

#8 RTLR 12

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Posted 13 August 2013 - 03:56 PM

That sounds good. 12.9 volts is textbook perfect. Hope your troubles are over.

Stan






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