Double Star Observations
Posted 12 July 2009 - 05:06 PM
When I was cooled down and was ready to observe it was around 10:30p.m. and Lyra was really sticking out. I went up to M57 to see a quick look and it was fun to take a look. I then proceeded to organize my double observations for that night and will share the following four sketches. All are based on sketches done at the scope and these were reproduced using GIMP. All observations were done with a XT10 and a 5mm Hyperion EP.
This is a sketch of Graffius or Beta Scorpii, or also known as Acrab, Akrab or Elacrab. The separation is 14 arc seconds and the distance between the two stars is 2200 AU. The primary was white and the secondary or companion was faint blue in color. Both are very hot B class stars 10x more massive than our own sun. Both should end their existence as supernova.
This is Al Niyat Sigma in Scorpius. It is a variable star and both the primary and the secondary are blue-white super giants. In my view the primary was white with the companion being white to hints of whitish blue. When I first observed the brightness of the main star almost hid the companion which is smaller and to the west, slightly south-west of the primary star.
The first of the two stars is a class O (O9) hydrogen fusing star while the other star is a mid-class B (B2) super giant. The orbit each other in 33 days and the distance apart is roughly the distance from the Sun to Venus. The stars are 735LY + or - 134 LY from Earth.
One possible reason for the blur/brightness I saw is that Al Niyat Sigma is involved with a large mass of interstellar gas which it ionizes and makes it glow in photographs. Both stars are very young, only a few million years old. The B2 star should become a supernova first while the O9 star should end up as a similar star to Sirius B, a white dwarf companion to a larger star.
Delta Serpentis or Qin or Chin as it is known is made up of a primary yellow/white F subgiant and it companion is also a F subgiant and they are 210 LY from Earth. Their separation is 4 arcseconds and they orbit each other every 3200 years. There are actually 4 stars in this mix but only two were observed. This was a very close double and 200x barely split it this night. I had to use a 2x barlow and take it up to 400x to improve my view of the split.
The last image I'll post is of Delta Herculis (also known as Sarin?). I saw that in the Sky Pocket Atlas (but I could have misread) that Delta Herculis is not listed as a double in there. The primary was white in color and the companion was grayish white in color. I also have in my observation notes that I saw the companion as being bluish gray also at times. Easily identified at 57x, 92x and at 200x.
Delta A appears to be a white class A star (A3 subgiant) but its not. It is really two vibrant, fairly youthful hydrogen fusing dwarf stars which cannot be split in an amateur scope. You can see more information here on this multiple star system. I thought it was rather cool to learn that the main star is actually two very bright dwarfs.
It was nice to be out and I am hoping for some good skies this week at home and then next weekend up at a dark site east of where I live in that is up in the mountains.
Posted 12 July 2009 - 05:34 PM
Stunning sketches with subtle star colors and light diffraction. You really handle GIMP to its max.
It is nice to see you back and you bring with you a new look to your sketching techniques and format. Great stuff.
Posted 14 July 2009 - 02:32 PM
These are indeed interesting targets during moonlit night.
Great sketches, but that's a matter of taste. I like them alot.
Posted 14 July 2009 - 11:34 PM
Posted 17 July 2009 - 12:18 AM
Just seeing the words "Double Star" was a sure way to pique my interest as these are among my favorites to observe as well as sketch.
Well, I am glad I took a peeksie at your post because I was more than pleasantly pleased with what I saw...which were some wonderfully rendered sketches of great doubles/star systems that everyone needs to observe at least once!
Posted 17 July 2009 - 11:14 PM
Excellent observations of various double stars. You have captured their appearances very nicely. Thank you for sharing it with us all.
Posted 18 July 2009 - 06:20 PM
Very nice digital renderings. I particularly like to see Graffias as I used this double as a jumping off place to make my first observations of Comet Lulin and also to catch MP 4 Vesta when I was tracking it back in 2007. It can be a busy neighborhood.