Wednesday, April 28, 2021

answered double star questions

Jumped into a Cloudy Nights thread in the Double Star Observing forum.

It actually started a ways back (May 2019) with the original poster (LasVegasMikey) remarking on the confusing information from SkySafari. A screen-snap showed Mizar A and Mizar B well separated but the on-screen information on the A star showed that it was a double with 0.7" separation at a position angle of 35.9°.

There was a link to another thread explaining issues in the popular app. It referred to the the spectroscopic binary partner, Aa-Ab, as opposed to the well-known, easily-split visual double. This is still an unresolved issue in SkySafari. Makes me appreciate all the vetting done by Greg C for SkyTools.

It seemed the thread was done and dusted.

But another person (WillR) posted on 24 Apr 2021, admittedly new, and was also struggling. They did some reading and got themselves sorted. But then on 26 April, said they discovered the coordinates were wrong...

I provided a bunch of information pulling from SkySafari, SkyTools, and Stelle Doppie. Relayed the current distances and angles for the visual stars in the Mizar-Alcor system.

Still another person (clastro8*) chimed in, with a suggested edit for me, and a query about position angles.

A frequent contributor (dhkaiser) tried to help.

And I provided a diagram, at last. Picture worth a thousand bytes.

And then I clarified another question about transiting and culminating. 

Hopefully I helped out people.

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