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LXD75 Autoguiding Problem

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#1 Clumpybug

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Posted 20 March 2013 - 10:31 PM

Howdy folks,

I have a 8-inch Newtonian that I use with my Meade LXD75 mount. I try to autoguide using an Orion Starshoot autoguiding camera. About half the time it works great, but lots of times, it won't track in the declination direction. It almost always tracks in RA, but a lot of times, it simply won't even calibrate in the Dec direction. Sometimes even in the same session it will work for a while, then I'll go to a different part of the sky, try to re-calibrate, and the Dec direction is useless. My computer is communicating with the mount, it can move the mount in the Dec direction, and the weights are slightly unbalanced. I don't even know where to begin troubleshooting. Does anyone have any thoughts about why it wouldn't work?

Thanks

#2 Gray

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Posted 21 March 2013 - 12:46 AM

You might wanna make sure you tube is balanced. Really, my 8" newt is wayyy to much weight for my lxd75. Also, you may wanna check the meshes and see also if your gears are slipping like mine were. I put broke off tacks in between the gears and the shaft. It stopped the slipping. Also, guiding in one direction (North or South) seems to work better than auto on the LXD75.

#3 Cliff Hipsher

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Posted 21 March 2013 - 12:34 PM

Like Gray said, check you DEC drive for gear slippage. If you find the gears are slipping, make sure the set screws are gripping a flat. If the drive shafts to do not have flats, take a jeweler's file and make flats. The used BLUE thread locker to keep the set screws from backing out.

With that being said, doing a drift alignment will negate the necessity of having to guide the DEC axis.

#4 Clumpybug

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Posted 21 March 2013 - 01:21 PM

This might seem stupid, but. . . what is a drift align?

#5 Clumpybug

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Posted 21 March 2013 - 01:46 PM

I don't think my gears are slipping. . . I don't know exactly what happens when your gears ARE slipping, but i know that even with my whole set up, with whatever misbalance I have, I can push the DEC buttons on my hand controller and the scope will move in the correct direction. I just doesn't seem to do anything when PhD tries to move in the DEC direction. Does this sound like something that could happen with gear slippage? (Again, not trying to sound sarcastic. . . I really don't know if this could still move back and fourth in the DEC direction if you have gear slippage!)

#6 OzAndrewJ

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Posted 21 March 2013 - 04:21 PM

Gday Clumpy

What firmware are you running?
Some versions of later firmwares send the DEC pulseguide commands to the RA motors.

Andrew Johansen Melbourne Australia

#7 Cliff Hipsher

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Posted 21 March 2013 - 09:01 PM

This might seem stupid, but. . . what is a drift align?


Actualy it is called a Declination Drift Alignment. Performing a Drift Alignment eliminates all tracking error in Declination. This is accomplished by observing stars in the south and west and then adjusting the mount in Altitude/Latitude and Azmuth.

Once all DEC drift is eliminated, your only tracking errors will be in RA, and those errors should be taken care of by your autoguide setup.

These links should get you started.

http://starizona.com...sing_polar.aspx

http://www.petesastr...www.petesast...

http://astropixels.c...ralignment.html

#8 Geo.

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Posted 22 March 2013 - 03:17 PM

Don't confuse stupidity with ignorance. The latter is usually cleared up by admitting it and asking a question. Nature keeps the former in the gene pool for our amusement.

#9 Mkofski

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Posted 22 March 2013 - 03:23 PM

Don't confuse stupidity with ignorance. The latter is usually cleared up by admitting it and asking a question. Nature keeps the former in the gene pool for our amusement.


:lol: :lol:

#10 Clumpybug

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Posted 22 March 2013 - 05:33 PM

Hmmm. . . ok great! I'll give the Dec drift alignment a try. Any ideas on where to start troubleshooting, though? Ideally, my autoguiding would work in the first place. What would my mount behave like if the gears were slipping? In other words, what kind of symptoms would I see?

#11 JoseBorrero

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Posted 23 March 2013 - 10:59 AM

there's a few users of LXD-75 on the beginers astroimaging forum. you might want to post there too.






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