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SSAG and 6SE autoguide issues?

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#1 jeffpkamp

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Posted 17 February 2013 - 11:08 PM

I got the Orion magnificent mini autoguider this december to help with my long exposure photos using my celestron 6se. I noticed that it wasn't seeming to guide in the north south direction when my PA was slightly off.
I hooked it up to PHD and used the manual guide direction buttons to see if there were issues there. The east/west buttons make it move about 6 arc seconds (This seems right to me). However, the north button doesn't do anything and the south button makes it jump 2-3 degrees. I am only using components that came with the camera, and my hand controller works fine. I was hoping someone had had experience with this and could give me some guidance on getting this working.

#2 Midnight Dan

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Posted 18 February 2013 - 06:53 AM

Hi Jeff:

Unfortunately I think you'll find few, if any, who have any experience autoguiding with an SE mount. While it does come with an autoguider port, the mount has far too much backlash for guiding to work very well.

Here's a link to a lengthy thread regarding one person who did get it to work ... to a degree:
http://tinyurl.com/yffuk2y

Be sure and read towards the end. He did eventually abandon the quest and ended up buying a GEM mount which is much better suited for long exposure AP.

Just some questions regarding your attempt - do you have the scope mounted on a wedge and is the mount set to EQ mode?

-Dan

#3 jeffpkamp

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Posted 19 February 2013 - 04:58 PM

That was a nice long post you suggested. A nice equatorial mounts is on my wish list, but way out of my budget at the moment.
I have my 6se mounted on a wedge I built for $30 (much cheaper than the celestron one) and guiding in EQ mode. The wedge works very well. As for guiding the East/West (RA) works great. I had it guide on a star for over an hour without problems in the RA, but all the while the Dec was wandering off. I know having my PA just right would solve all my problems (and the backlash issue for the future), but I just wanted to know if this was a simple fix common to this guider setup. I found a Troubleshooting guide for PHD that described a similar problem due to using a crossover st4 instead of a straight through, but mine was the correct orientation (straight through).

#4 jeffpkamp

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Posted 20 February 2013 - 10:32 AM

I found a work around that gives me an idea of where the problem is coming form. When I use a serial-RJ11 converter to connect to the telescope via the hand controller (a 4 pin connection rather than the st4 autoguide slot) I can get the commands to go through fine, and PHD autoguides without too much effort.

This means the problem is either the out port on the camera, the cabel (Not likely) or the autoguide port.

I was wondering if anyone with some technical know-how could give me an idea of of how to test these. Could I use a multi-meter to test the out put on the pins on the cable to see if they are the correct signals?

As for the backlash issue in the 6se, I did run into it a little bit when using the Autosetting on PHD, but it was pretty easy to over come by adjusting the scope so it only had to guide one direction (This should be the case normally) and clearing the backlash in that direction post calibration before I started guiding. I didn't get any time to test it out on a long exposure picture due to work this morning and freezing cold last night, but it appears to have held the star in position for over 30 minutes straight, which is good I think.

#5 Midnight Dan

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Posted 20 February 2013 - 01:32 PM

Hi Jeff:

Sounds promising. I'll be interested to hear how things work out for you!

As for testing the guide camera output pins, you might be better off asking that question in the Beginning Imaging forum, or the Mounts forum. I think you'll find more people with in-depth technical knowledge of the electronics.

The problem with backlash is when you're guiding in the Dec direction. There is no "natural" movement direction as there is with RA, so guiding corrections can occur in both directions so backlash becomes a big issue. In fact, it's possible that Dec guiding is working (or trying to work) but you may be seeing Dec wander around due to this issue.

-Dan

#6 jeffpkamp

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Posted 24 February 2013 - 11:44 AM

so a quick update. I checked the pins on the ST4 camera while using the manual commands on PHD. The camera seems to be putting out the right commands, so I ordered a RJ12 crossover cable (ie ST4 crossover cable). I'll let you know it works...






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