Next entry: My 20 favorite double and multiple stars, part 5: winter

Previous entry: My 20 favorite double and multiple stars, part 3: summer

My 20 favorite double and multiple stars, part 4: autumn
13. Eta Cassiopeia (S)truve 60, double star)
Constellation Cassiopeia, magnitude 3.4 / 7.5, separation 12.9”, position angle 317°. RA 00h49m DEC +57°49’. This beautiful double was discovered first by William Herschel in 1779. At the moment, both components of Eta Cassiopeiae are separated 12.9”. Calculations based on observations show that the separation varies from 5” (in 1890) to approximately 16” in 2150. The period of the apparent orbit is somewhere between 480 and 520 years. In different observing reports the colors of both components are reported as gold or yellow for the primary and orange or red for the secondary. I only observed it once, under mediocre circumstances, with the 8-inch Klevtzov-Cassegrain. To me they both looked “golden”.

14. Gamma Arietis (Struve 180, Mesarthim, double star)
Constellation Aries (Ram), magnitude 4.8 / 4.7, separation 7.8”, position angle 0°. RA 01h53m DEC +19°18’. Gamma Arietis was probably one of the earliest discovered double stars. Robert Hooke stumbled into it by accident, while following a comet in 1664. Last year, I observed quite a few interesting doubles in Aries myself, but the two white, almost equally bright stars of Gamma Arietis are my favorite. With my 8-inch telescope at 166x both the primary and the secondary look like sparkling white diamonds set against a jet-black sky.

15. Almach (Gamma Andromedae, multiple star)
Constellation Andromeda, magnitude 2.3 / 5.5, separation 9.8”, position angle 63°, RA 02h03m DEC +42°19’. Almach is in fact a multiple star with three components, but the C component can only be detected with larger telescopes. The primary star of Almach is a golden or yellow K2 or K3 type of star, the secondary looks bluish in my 8-inch, but there are many observers that detect a definite green color in the secondary.

16. Iota Cassiopeia (triple star)
Constellation Cassiopeia, magnitude ABC 4.6 / 6.9 / 8.4, separation AB 2.5” / AC 7.2”, position angle AB 230° / AC 114°, RA 02h29m DEC +67°24’. This is one of the finest triple stars that I have observed until now, and it is certainly the most beautiful in the Cassiopeia area. With the 8-inch Tal 200K at 222x I split Iota Cassiopeiae into a bright white primary with a slight hint of yellow, and two white companions showing a hint of blue.

image

Image from SkyTools 2 by CapellaSoft, click to enlarge!

Posted by Math on 05/29 at 07:42 PM
Deepsky observing • (0) Comments • (0) TrackbacksPermalink

Name:

Email:

Location:

URL:

Smileys

Remember my personal information

Notify me of follow-up comments?