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Just one remark.
Stellarium is of course free and nice.
But not reliable.

I discovered this when I tried to see the recent event of Jupiter passing
the Moon. Stellarium gave a totally wrong picture.
I suppose because it had wrong Moon diameter, but did not investigate
this further.

So I would not rely on Stellarium, but read the coordinates from
some reliable almanac.

Alex.

P.S. Some distributions of Linux (Fedora) have free software similar to
Stellarium but much better. I used this 10 years ago when I had Linux on
my laptop. It was especially useful for star distances. You click
in a star and drug to another star. And it shows the distance.
(Not corrected for refraction). It also had bugs though.

A.

> Looks like the distance from Merak to Polaris is 34.0699 degrees or 34°
> 4' 12". This is the value for today without refraction. You can calculate
> this if you know the stars' coordinates in RA (or GHA or SHA) and Dec. Let
> me know if you're interested. You can read out coordinates from the free
> software Stellarium (available from stellarium.org). While Stellarium has
> some bugs, you can usually count on things like stellar coordinates. Just
> click on each star, and the exact coordinates are displayed in the upper
> left. There is also an angle-measuring tool available in Stellarium and
> with careful clicking and zooming in and out, you can measure angles
> between stars with an accuracy of at least 1' of arc.
>
> This star-to-star distance will vary slightly during the year due to
> aberration, and it will vary significantly with the stars' altitudes due
> to refraction. For example, if you're in latitude 41 N and the Dipper is
> low in the sky with Merak almost directly below the pole star, Polaris
> will be lifted by refraction by 1.1 minutes of arc while Merak (at an
> altitude of about 7 degrees) will be lifted by about 7.3 minutes of arc so
> the angular separation will be reduced by 6.2' to 33° 58.0'. If instead
> Merak is high above Polaris, then the distance will be 34° 3.4' reduced
> by refraction by only 0.8'. In the latter case, we're nearly in the
> situation where the change in distance due to refraction follows the
> simple rule "0.1' for every 5 degrees of distance" which applies with good
> accuracy for any orientation of the pair of stars and any altitude as long
> as both stars are above 45 degrees altitude.
>
> -FER
>
>
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