Mu Cygni -what a beauty

Good evening, double star observers.

Last Thursday night 27th and again on Saturday 29th August, I had great times with the 158 mm apo scope splitting Mu Cygni at a mere 167X. In fact even at 140X, the secondary was visible touching the primary. However, my reliable 6.7 mm Meade eyepiece split it tightly but cleanly at 167X. I did see slight yellow hues. Astronomers from the pages of history give different colours such as white, yellow, blue and lilac. The primary has a magnitude of 4.7 and B is 6.1. The current separation is 1.5". It is my first time to split Mu Cygni. It appears I need to look at him one more time to check out its true colours. I must push the apo to higher magnifications -say 225X and 280X. But I have to say -this little fellow is a true beauty at medium powers! Perhaps more of us could give it a try. There is something quaint about seeing a bright star sitting on top of an even brighter star nearly in the 12 o'clock position. The PA is 321 degrees.
My thanks to Pat (Plough C) for informing me about this stunner!

Clear Skies,
Aubrey.

Aubrey, congratulations on splitting mu cygni it is a lovely double. I had trouble splitting it
last week with my 6 inch reflector, i found I had to go to 275x to get a proper split you were doing
well to split it at 167x thats a good scope you have there. I found last August with the same scope
the primary looked yellow whereas last week it looked white its difficult getting the colours right.
maybe something to do with the moon or maybe not.
Have a look at 78 Ursa Major Its giving me lots of trouble trying to split it.

Pat.

Thank you, Pat, for congratulating me.
We must meet face to face some time.
And I will try to study Mu Cygni again in the near future to check out its colours.

Now about 78 Ursa Majoris. This double star will be extremely difficult to split for the next number of years. I have been checking it out on the famous website stelledoppie.goaction.it . Back in 2000, its separation was 1.4". It is now exactly 0.8". So only telescope owners with an aperture of at least 10 inches may have a go at it. I would say about 400X might be sufficient to see A and B. It will be getting even tighter in 2016.

Aubrey.

Aubrey, you are right about 78 ursa Majors I was looking it up in Burnhams where the sep.
is 1.0" I forget to check stelledoppie. still you never know on a night of wonderful seeing maybe.
No observing tonight here wall to wall clouds.

Pat.

Mu Cygni was featured in Jim Kaler's "Stars" website in July of this year ( stars.astro.illinois.edu/sow/mucyg.html ). It's a great site, giving detailed data about the 881 stars included to date, spiced with all sorts of interesting snippets of star lore.

Mike

Hello, Mike, Pat and everyone else.
I observed Mu Cygni once again on Thursday 24th September.
Again I was just about splitting A and B at 167X. But to check its colours, I went to higher magnifications -namely 225X and 280X. There was a bright Moon in the sky, but my final judgement is that A is yellow white and B is a slightly stronger but an intense yellow. This double sure is a beauty!
Burnham's Celestial Handbook and Jim Kaler both state that A is class F and B is class G. Therefore F is yellow white and G is yellow like our Sun. It is nice to know that my 158mm apochromatic refractor completely agrees with the double star astronomers.
One more thing I should mention at this point is that Sissy Haas' book seems to give incorrect colours. Although she seems to be quoting from historical astronomers from the past.

Clear skies,
Aubrey.