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Guiding issues that have just appeared


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For some reason my guiding has turned into a nightmare. When calibrating in PHD2, the star never gets anywhere near back to the crosshair and the backlash seems excessive. It will guide al lnight but each sub looks like it a pixel off every time - see below where i have attached a L frame from last night. I haven't changed anything, i spent a while making sure the mount was balanced. My PA routine isnt the greatest but i find the online guides a bit confusing and ive never had probems before using the method i have been. Any ideas?

M51 L 29 July.jpg

Edited by steviemac500
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Hi

I'd start by checking your balance and also monitor performance unguided with the aid of the guiding assistant. Obviously PA needs to be reasonable... Poor calibration needs to be sorted before trying to guide.

Louise

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You appear to be trailing in RA, I would suggest weighting the mount to ensure the gears stay meshed while tracking your target rather than being perfectly balanced.

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1 hour ago, D4N said:

You appear to be trailing in RA, I would suggest weighting the mount to ensure the gears stay meshed while tracking your target rather than being perfectly balanced.

Could you explain what this means? Do you mean moving my weights so that its heavier in one direction?

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As said trailing appears to be in RA, how long is the exposure ?

If you centre a star in a high magnification eyepiece and use the hand set to move in RA you can see how long it takes to respond to the buttons to check for excessive backlash.

You can fiddle with the RA aggression settings in PHD, the assistant makes recommendations.

Small PA errors should show as field rotation not eggy stars.

Are you imaging in the same area as previously ? as changing from one part of the sky to another can aggravate balance / backlash / guiding issues.

Dave

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4 hours ago, steviemac500 said:

Could you explain what this means? Do you mean moving my weights so that its heavier in one direction?

Yes, you want the mount to have to work a little bit to track as this keeps the gears meshed stopping it being sloppy with backlash when guiding.  The problem you can get is that the guiding software issues a command and nothing happens so it issues more commands, eventually the gears will mesh and it will move, however the gears are no longer meshed for tracking so it will have to start issuing guide commands the other way.  The end result is eggs for stars.

If the scope is on the East side of the mount you would move the counterweight in slightly, if the scope is on the West side of the mount you would move the counterweight out slightly.

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now having eqmod I tried out everything last night inbetween the clouds I wanted to polar align using eqmod I failed but completly understand why I failed and pretty sure a clear night will do it, 2nd I wanted to drift align and couldnt before as I was using "camera on mount" method. I thought occured to me while connecting the guide camera on PHD2, do i still connect it "on camera" as well as eqmod?

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You shouldn't have to connect to the mount to drift align, only to the camera as you don't issue any guiding commands whilst drift aligning.

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7 hours ago, brrttpaul said:

I was lost on the co ordinates, when its connected to ascom its done for you 

True, you only need to enter these if you want the prediction thingy.  If you just don't put them in you simply point east and correct the drift then point South and correct the drift, repeat until no drift :)

2 hours ago, steviemac500 said:

Sorted thanks guys, it was a weight issue.

Great that you have it working, guiding issues can be so frustrating.

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