Barnard's Star The Movie, The Sequel

[RickJ]

After a summer of clouds and lousy seeing I was finally able to add this year to the video which now covers 2007 to a couple weeks ago. Image scale is my normal 1" per pixel. This star really moves.

http://www.prairieastronomyclub.org/...son/BS2012.GIF

Rick

[Rhaedas]

That's a better picture than in the wiki article on the star. Is it something that needs to be updated in catalogs, or is it just one of the variables that everyone knows about?

[mapguy]

That's pretty cool. So each frame is spaced, what... about one year apart?

[RickJ]

That's a better picture than in the wiki article on the star. Is it something that needs to be updated in catalogs, or is it just one of the variables that everyone knows about?

Catalogs give positions at given dates. Most are J2000 right now so are 12 years behind in its correct position. They also give a star's proper motion so the user can then calculate its current position. Unfortunately, most go-to telescopes aren't smart enough to make this calculation so will point to the 2000 position. Normally this isn't an issue but it is with this one. For instance if you go to a POSS server (http://stdatu.stsci.edu/cgi-bin/dss_form/ for example) and enter Barnard's Star it will center the image on its J2000 position. If you used the default for the red POSS 2 plate it will be in the frame but low because the image was taken in the 1960's. It isn't smart enough to use catalog proper motion data to center it. If you select a POSS 1 image it won't even be in the frame at the default 15 minute frame size. You will have to enlarge the frame to 20 minutes to pick it up at the very bottom. If using a telescope to locate the star expect it to be north of the predicted position by about 2 minutes of arc as its motion is about 10" of arc per year to the north. It will be a bit west of the predicted location as well but that is pretty insignificant. Since it is the brightest star in the area it will be easy to spot.

Rick

[RickJ]

That's pretty cool. So each frame is spaced, what... about one year apart?

The period between frames was approximately 31,536,000 seconds, give or take a million or two. So yes about a year apart, weather, the moon and my schedule prevented a highly accurate spacing. Also when I started this I wasn't planning an animation. I was just wondering how accurately I could calculate its proper motion from my images and how that would improve with time. Turned out in just one year I was within 0.01" of the catalog value and that has improved to about 0.002" after 7 years. Since the software only claims 0.001" I've about reached my limit. I didn't expect it would be that easy when I started this. Considering my image resolution is only 1.01" per pixel and my seeing runs well over 2" I expected far lower accuracy.

Rick

[Galactic2000]

Awesome Animation Rick! I have always wanted to do that....just kept forgetting to go shoot it again! Great Job!!