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First Attempt at Autoguiding


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I bought a small WO guide scope, inserted my Altair GPCAM3 178C planetary/lunar camera and attached it to my Redcat 51 with ASI 533 MCP. This was mounted on my SW AZ-EQ5. I used PHD2, Sharpcap and EQMOD on my laptop with 3x USB cables running to the cameras and mount.

It all went pretty smoothly apart from trying to calibrate PHD2 using a star too near the North celestial pole. I heeded the error messages and all seemed OK when I pointed further south and recalibrated.

The video below shows an unguided run using the same set-up, followed by a guided run from a few days later. Each run was 120 x 30s exposures. The video is at 10 fps so each approx 1 hour run lasts 12 seconds. The images are 1000px X 1000px crops of the original 3000px X 3000px exposures. So each frame is about 52 arcminutes high and wide.

The guiding has clearly improved the mount's tracking. Should I be happy with this result or should I expect be better? I have posted PHD2 log analysis below.

 2022-04-26_130032.thumb.jpg.415e2eaa38809db4c39464558b2d7780.jpg

 

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Looks good to me, though I’m not an expert. You can try with longer exposures and check the stars’ shape. 
Next step should be dithering, to prevent walking noise. 

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4 hours ago, barbulo said:

Next step should be dithering

Thank you. Dithering is on my list of things to try. Can I do dithering with my Sharpcap, EQMOD and PHD2 software or would I need to use NINA or similar?

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I think you are supposed to calibrate on a star close to the intersection of the meridian and celestial equator as there is where the Earths rotation is most noticeable.  Calibrating near the NCP is practically the opposite.

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16 minutes ago, malc-c said:

I think you are supposed to calibrate on a star close to the intersection of the meridian and celestial equator as there is where the Earths rotation is most noticeable.  Calibrating near the NCP is practically the opposite.

Yes, calibrating near the NCP failed...even though I tried it several times!

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1 hour ago, Jim Smith said:

Thank you. Dithering is on my list of things to try. Can I do dithering with my Sharpcap, EQMOD and PHD2 software or would I need to use NINA or similar?

I did a bit more research and I now see that I can dither with Sharpcap Pro and PHD2.

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Results look good.

I would only point out the guide rates    RA guide speed = 1.5a-s/s  , Dec guide rate = 1.5a-s/s.

Theses are very low, should be at least 7.5a-s/s, and points to using the default ASCOM  PulseGuide Setting in EQMOD:

 

EQMOD.jpg.66e2eac50335ba85fdd1995159eec7bd.jpg

 

The fact that you tried to Calibrate at Dec=90 suggests you haven't read the PHD2 instructions ?

Michael

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2 hours ago, michael8554 said:

The fact that you tried to Calibrate at Dec=90 suggests you haven't read the PHD2 instructions ?

Well...I read some of them! Thanks for the suggestion regarding guide rates.

Jim

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