A few issues from this evening

[JamesF]

This evening's shakedown session has thrown up a few little niggles that I could do with some advice on...

Firstly, it appears that my 314L+ shows a few hot pixels with 600s exposures.  What's the best way to deal with that?  Dither guide and let sigma stacking take care of it?  Would I be likely to be better off dropping the set point temperature?  (Currently it's set to 0C.)

And also related to guiding, after a meridian flip my guiding seems to completely go to pieces.  Normally I get an RMS figure for the error of < 1" reported, but after the meridian flip it goes completely bananas, the guide star keeps being lost and so on.  If I clear the calibration data and recalibrate then everything seems to sort itself out.  Having done that I'm seeing an error figure of around 0.8" RMS being reported.  Can anyone suggest what might be possible reasons for this?  If it wouldn't resettle at all after the flip I'd assume poor balance, but as it does, I'm really not sure.

The final question I think I'll post over in the software section as it probably makes more sense there...

James

[michael8554]

This is usually down to the "Reverse Dec Output after Meridian Flip" tick box in PHD2.

Michael

 

 

 

[geordie85]

I always recalibrate phd2 if I ever do a meridian flip

[don4l]

My old camera seems to have more hot pixels than normal ones, so I have several methods to deal with them.

The first is dark frames.  These really should be all you need with the 314L.  That 285 CCD chip really is very good in this respect.

My stacking software has a "remove hot pixels" option which sometimes cleans things up, but sometimes doesn't do much.

For really bad cases I use Picture Window Pro V7.  This has a very good "speck removal" tool hidden away under "Advanced Sharpen".  This will work on a final colour tiff file.

I cannot help with the autoguiding issue.  I haven't even recalibrated since April or May.

[JamesF]

Good point about the darks.  I've never taken anywhere near 600s images with this camera before, so I've never previously bothered with them.  I'll come out tomorrow morning and kick some off.

James

[don4l]

40 minutes ago, JamesF said:

Good point about the darks.  I've never taken anywhere near 600s images with this camera before, so I've never previously bothered with them.  I'll come out tomorrow morning and kick some off.

James

That sounds good.  I was wondering if you had a dodgy ccd in your camera.