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Some great doubles revisited

On the night of September 3rd I revisited some double stars in Lyra with the TAL 200K. I started about 22.00 hours UT With the famous Double Double, Epsilon 1 and Epsilon 2 Lyrae. With the 32mm plossl (62x) Epsilon 1 and 2 where clearly split as a double star, but

both components showed no hint of being doubles themselves. At 80x (25mm) they started to look like they both where doubles. At 133x they where both clearly split and at 200x they looked like two close couples of stars, aligned perpendicular to each other (see image below. North is up and west is to the left. At the top you see Eta Lyra 1 with the A (the brighter lower one of the two) and the B component. At the bottom of the image you see Eta Lyra 2 with the C (the brighter one to the left) component and the D component.


Image from Skytools2 by Capellasoft

The AB pair is separated by 2.6”, the A component has a (visual magnitude) vM 5.4, the B component is of vM 6.5. The position angle is 357 degrees. The CD pair is separated by 2.3”, the C component has a vM of 5.1, the D component 5.3. The position angle is 94 degrees. All four stars seem to have the same colour, white. They are all spectral types A.

Vega (Alpha Lyrae)
This beautiful white-bluish star is the fifth brightest star in the sky, and the third brightest to be seen in our mid-northern latitudes. The five brightest stars are:

1. Sirius -1.46
2. Canopus - 0,72
3. Rigel Kent - 0.27
4. Arcturus - 0.04
5. Vega 0.03

Vega is a multiple star system (3) but I could not detect one of the two faint companions.

Zeta Lyrae
Zeta Lyrae forms a triangle with Vega and the Double-Double. It is a beautiful double star with two bright yellow-white components (vM 4.3 and 5.9), separated by 44”. A great couple for any telescope or big binocular. According to James Kaler the A component is a hydrogen-fusing dwarf and it’s companion, the D component, is a class F “subgiant”.

Delta Lyrae
The next stop is Delta Lyrae and the open cluster Stephenson 1. Delta Lyrae is a very wide pair, which is already split in the finder scope. The magnitude 4.5 Delta Lyrae 2 is separated about 10’ from the 5.6 Delta Lyrae 1.  Delta Lyrae 2 looks orange while Delta Lyrae 1 has a white-bluish colour. Between and around these two stars I can detect a group of 10 stars that probably belong to the open cluster Stephenson 1.

Beta Lyrae
I end my short trip along some doubles in Lyrae with Beta Lyrae. This again is a stunning pair with a bright 3.4 A component and a 8.9 B component as its companion at a position angle of 149 degrees. This close couple is only separated by 46”. Lyrae has some really great doubles for telescopes and binoculars. Earlier this year I observed almost the same stars with the 15 x 80 binoculars, but these beautiful doubles are great for all instruments! The light polluted sky does not affect these beauties too much.

Posted by Math on 10/08 at 07:49 AM
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