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PHD calibration question


griz11
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When you start the calibration on PHD it puts up a cross centered on the guidestar. When it starts to make the moves is the star supposed to stay on top of those lines? Are you supposed to rotate the camera slightly so it all lines up or does the software deal with that?

Griz

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When you start the calibration on PHD it puts up a cross centered on the guidestar. When it starts to make the moves is the star supposed to stay on top of those lines? Are you supposed to rotate the camera slightly so it all lines up or does the software deal with that?

Griz

Hi,

No you do not touch the camera, the software will deal with it, the idea of the callibratition routine is for the software to work out the orientation of the camera, and to work out where N S E W is, so you leave it well alone at this point, infact don't touch it again till you have finishes your session, or you will have to re calibrate.

During the callibrate routine it will move a little,in all four directions, and then back to the middle.

When the routine has finished, the cross hairs will change colour and guiding begins.

Hope that helps

AB

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When you start the calibration on PHD it puts up a cross centered on the guidestar. When it starts to make the moves is the star supposed to stay on top of those lines? Are you supposed to rotate the camera slightly so it all lines up or does the software deal with that?

Griz

Orientation of the guide camera makes no difference. I remember Craig Stark (the creator of PHD) specifically addressing this point. The calibration routine has two functions- one is to work out how the mount reacts to guide commands; the other is to work out which way the camera is orientated to the RA/DEC axis of the mount.

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Cool thanks. Last time I tried this was 15 years ago and it made a lot of difference if that camera was twisted in any way. I figured that had been taken care of but I wanted to check. The guider worked fine until the dew hit the front of my guidescope. Then it was an hour or so of frenzy trying to figure out why it was running away and the low signal kept popping up even though the guidstar was the brightest in the field. Typical newbie stufff. Such a huge improvement from what I experienced before. Now if the weather will cooperate I'll be all set :)

Griz

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Use the star profile tool to check that the Guidecam exposure  isn't saturated... I used to use slightly dimmer stars and longer exposures  typically 2-4s to avoid chasing the seeing...  I would aim for a peak intensity at  the center of the star of 70-80%. of max

I haven't used PHD for years so cant tell you exactly which buttons you need to press...

Peter...

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I have it roughly aligned it was just slightly off as it moved. I always get confused about that. Anyways this is one 10 sec shot. The moon was about 10 deg off to the right the background is terrible so I raised the blackpoint a lot. Just checking the guider really and I wanted to see if it sharpened up the detail in the nebula. Looks like its overshooting a little bit EW easy enough to fix and to me the detail does look a little sharper. Can't wait to get back out and get a full sequence to stack.

Ori-guide.jpg

Griz

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The latest one. It was way overbalanced on the dec axis to one side. Didn't even think about having the dual saddle and how that would effect it. I did some longer ones but they were all previews and it will take some time to find them.  A buddy told me about 3-d balancing so I'm going to do that next time and support my cables better. Just found out I'm going to have to have some surgery for the 14th time so my motivation level has dropped to the floor. I'm afraid all this is going to have to be sidelined for a bit.

Griz

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