Re: [ap-ug] Multi-star guiding

Dale Ghent

It's a bit serendipitous that you've brought up this topic! Just yesterday, the PHD2 developers released a development preview build of PHD2 2.6.9 that has multi-star guiding implemented. It has been in testing for the past 2 or so months, and this is the first public release where it's available.

I used it for the first time last night during a 10 hour long dusk to dawn session, imaging StDr 56 and then M81/82 in Ha. Using APCC Pro with a fresh model and a recent PEC, my Mach1 guided in the mid-.40's arcsec RMS on average, and down into the mid-.30's whenever the wind that was present decided to completely die down. My pixel scale is 0.888 arcsec/px. I got fantastic stars and the only throw-aways were due to some cirrus clouds that blew through in the early morning.

I guide using a Baader Vario-Finder with ZWO ASI290MM-mini camera.

On Dec 3, 2020, at 12:06, Roland Christen via <> wrote:

Hello fellow Astronuts,

I've been meaning to try something new (for me) in my guided imaging. My setup consists of a 160EDF refractor on a mach2 encoder mount, a QSI-683WSG camera with off-axis pickup, and a Lodestar guide camera. I do all of my imaging with MaximDL Pro6 which has a multi star guiding function. Up to now I have used single star guiding and so i have to pick a guide star and let the guider do its thing. That's an extra step, and since I'm lazy I decided to let the program guide on the whole enchilada using the multi star guide method. So, how did that work out for a 20 minute exposure? Well see below:

The guiding was effortless, extremely accurate (partly thanks to the precision movements of the Mach2 mount), and required no thinking on my part. The Lodestar guide camera is really tops in my book. It picks up stars in every part of the sky, even in star-poor regions. My guide exposures are 5 seconds with 1 second delay between exposures. My Min Move for both axes was set to 0.02 seconds (which is 0.3 arc sec), and the aggressiveness was set to 8 out of 10 since the seeing was quite good. Outside temperature last night was 25 degrees F. The peak values reflect the dither moves between exposures in case you're wondering.

The California Nebula did not fit into my camera's field of view, oh well. Thus I'm in the market for a larger chip camera for Christmas


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