Nu Draconis is my fourth double star observation from the night of the 1st May (see my previous post for a discussion of this). Here is my image:-
This was a 5s exposure at ISO 1600 on a Nikon D90 at the prime focus of a 140mm Maksutov Cassegrain (an Orion OMC-140). The picture can be better seen by 'clicking' on it. The image is being viewed at full scale (in other words it has not been binned up). Nu 1 and 2 Dra are marked and these two stars are equal in brightness both being visual magnitude 4.88. The image scale is 0.5859 arcseconds per pixel and this is a 1600x1067 pixel crop of the original.
My method for orientating the image has been described in a previous post. Using this I have made some measurements of the separation and position angle (PA) of Nu Draconis (for a discussion of PA and how it is measured please again refer to my previous post). A couple of measurements of the separation gave me 106.65 and 107.71 pixels. This averages to 107.18 pixels and, at 0.5859 arcseconds per pixel, this is 62.8 arcseconds. Again a couple of measurements of PA gave 311.2 and 310.8 degrees which averages to 311.0 degrees. The published separation and PA for this double star is 62.3 arcseconds and 311 degrees, so in very good agreement.
All text and images © Duncan Hale-Sutton 2024
No comments:
Post a Comment