Barnard's Star
Barnard's star has the highest proper motion of any known star and moves against the starry background at just over 10 arc-sec per annum. This motion is easily detected using moderate focal length telescopes and CCD cameras. I became interested in Barnard's star in the late 1960's when I bought a copy of the 'Larrouse Encyclopedia Of Astronomy' and read about this amazing star. A few years later the then Junior Astronomical Society suggested in a newsletter that members could make observations of Barnard's star to try and detect its motion, however it wasn't until I had a reasonable setup for photography through my 14" reflector that I took my first image of Barnard's star on home-hypered Technical Pan 2415 film in 1991. I returned to the star in 1996 when I acquired my first CCD camera. The motion was very easy to see over the 5 year period and so I started a semi-regular imaging campaign which has resulted in these images and the astrometric measurements below.
I have recently taken the 2007 image and went back over the old data to make a higher quality result. This was very time consuming as I had to deal with several old file formats from my old CCD camera and different apparent image scales. The images were layered using Photoshop using lighten mode which left most of the background stars from the 2007 image. A larger version of the animation can be seen here.
The oldest images were of poor quality for astrometric measurement so I
used the positions from 1998 and 2007 to determine the proper motion using
Astrometrica Software.
| 26 May 1998 | 17h 57m 48.61s | +04 41' 19.6" |
| 30 May 2007 | 17h 57m 48.15s | +04 42 52.9 |
| Difference | -6.9" | +93.3" |
| Annually | -0.7658 | 10.3549 |
| Simbad Data | -0.7987 | 10.3378 |
The largest errors are most likely due to measurement of saturated star images, the original images were not taken with the purpose of astrometric measurement in mind. Nevertheless I am quite pleased with the results. You can read the fascinating original 1916 paper by Barnard on his discovery titled "A small star with large proper-motion" in the Smithsonian/NASA Astrophysics Data System Archives.
See also my other images and measurements of high proper motion stars.