Calibration

[Richard Brown]

I'm set up on an apartment deck facing north to west and can't get optimal star to calibrate. The star that I selected was Murphrid, at 16-degree dec about 28 degrees from meridian. I'm using a scope with2350mm focal length, and set the ASI178 camera to bin 3. Attached is the most recent log and a screenshot of the review of calibration data. Also the star profile image appears to out of focus. 

Richard

[Brian Valente]

Hi Richard

Can you clarify your equipment setup? I assume this is an oag on some style of reflector scope, maybe a slower one ilke f/8+?

I also see a number of events about setting lock position - are you manually selecting stars and/or using a slit?

 

The logs you sent did not include the calibration run, so I can't comment on that.From the few guided runs it's clear the calibration is not valid, so until you sort that out you aren't going to get good guiding results. It looks like you ended up at a reasonable exposure time of 4 seconds, using sub-second exposure is not going yield good results as it looks like you discovered. 

You should use the calibration assistant to calibrate your mount, including sky position and guidestar selection. Leave the exposure around 3-5 seconds for now. 

When you guide, let PHD select the best guidestar automatically. If it's picking stars that are too dim you can adjust your settings, but the improtant thing is PHD will do a better job of star selection based on data, not just on looking at the screen.

I also recommend you enable diagnostic image logging: for lost stars and autoselect stars - the ones you are choosing are quite dim. If its out of focus, that would compound the issue. 

Sending us some logs once you do that will help clarify what's going on (Also please make sure to use the built-in log uploader function)

Brian

On Sun, Jun 28, 2026 at 12:00 PM Richard Brown <lacien...@gmail.com> wrote:

I'm set up on an apartment deck facing north to west and can't get optimal star to calibrate. The star that I selected was Murphrid, at 16-degree dec about 28 degrees from meridian. I'm using a scope with2350mm focal length, and set the ASI178 camera to bin 3. Attached is the most recent log and a screenshot of the review of calibration data. Also the star profile image appears to out of focus. 

Richard

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Brian Valente

astronomy portfolio https://www.astrobin.com/users/bvalente/