High Proper Motion Stars
As well as my interest in Barnard's star, I started to take reference images of other high proper motion stars in 1999. I revisited Groombridge 1830 and Lalande 21185 a year later and their small motions against the background stars showed up quite well in the astrometric measurements but only as small differences in the images. In 2008 I took further images and made astrometric measurements with the excellent 'Astrometrica' Software by Herbert Raab. The much longer time span gave much better results in overall agreement with published values for their proper motions. North is up in all images.
Groombridge 1830
This is an animation of the 1999, 2000 and 2008 images.
| 12th February 1999 | 11h 52m 58.610s | +37 43' 10.70" |
| 22nd January 2008 | 11h 53m 1.506s | +37 42' 22.07" |
| Difference | 43.44" | -50.67 |
| Annually | 4.8581 | -5.6667 |
| Simbad Data | 4.0037 | -5.8146 |
Lalande 21185
Also an animation of the 1999, 2000 and 2008 images.
| 12th February 1999 | 11h 03m 20.30s | +35 58' 13.70" |
| 22nd January 2008 | 11h 03m 19.90s | +35 57' 32.75" |
| Difference | -6.1950" | -40.95 |
| Annually | -0.6926 | -4.5782 |
| Simbad Data | -0.5805 | -4.7699 |
Both sets of measurements were compromised by saturated star images even at 1s exposure, filtered images may be a solution to this i.e. attenuate the bright star to be measured whilst still leaving enough field stars as positional reference stars.