A Few Pairs of Bear Pairs

Hi there

A beautiful night beckoned last evening, it was a late start, well after 11, but Ursa Major was at the zenith and begged to be observed.

M81 & M82 were good jumping off points for the first four doubles observed.

STF 1415: A nice wide pair of white stars that were easily split at X59, at 6.5 & 7, they are a bright pair sitting in a triangle of fainter stars.

STF 1350: Both stars are of equal magnitude 7, the primary is a beautiful pale yellow with a pure white companion. Wide with a separation of 10.4". I managed to split them at X29, the best view was at x59 with x100 showing the yellow colour at its best.

STF 1349: Just a short slide down a trio of 8th magnitude stars this pair consists of a brilliant blue-white primary with a white companion. A very wide pair at 19.2" a split was achieved at all magnifications. Magnitudes 7 & 8 make them obvious as they are surrounded by fainter stars.

23 Ursae Majoris: 4th magnitude 23 is a yellow star, the companion is 9th magnitude, but due to the wide separation of 23" this was not an issue as I could split them at X59. If they were separated by about 10" I believe that I could not split them.

Megrez provided the anchor point for the next three pairs.

STF 1630: This is a tight pair, an orange primary of 8.5 is accompanied by a white 9th magnitude associate, with a separation of just 2.5" this required the highest magnification I possess, X135, to see a hairline of darkness between them, it needed a moment of perfect seeing to split.

STF 1603: Yellow-orange and white are the colours of this pair, wide at 22" making the 8 & 8.5 pair an easy split.

STF 1608: The highlight of the night, this is a pair of deep orange stars of 7.5 & 8th magnitudes, wide at 12.7", the best view achieved at x59. The colours of the pair at so attractive that this is a pair worth returning to.

Alioth was the best guide for the last two.

STF 1695: A tight pair of stars, white and blue-white, magnitudes of 6 & 8, the separation of 3.7" required at magnification of X100 to split. The 2 magnitude difference in brightness was not a deterrent, as they were wide enough.

STF: 1691: A deep orange 8th magnitude primary is accompanied by a 9th magnitude white companion, a wide separation of 18" makes it an easy split. I saw it best at X100, though it was split as low at X29.

Time was short, work in the morning, and all that, the sky was very transparent and the seeing excellent, even from my light polluted back garden. To the south Virgo was very prominent with the shape of the constellation standing out wonderfully. There is so much to explore in Ursa Major that there is much to bring me back another night.

Thanks for your time.

Paul

Excellent work and great report- I was just too lazy to drag myself outside that late on a school night, was filled with regret this morning though! .... gotta take those chances when they're here, so rare lately

Great report Paul. I was working last night and your account really makes me wish that I had been able to get out.

I did have a quick trawl through some doubles in Ursa Major a couple of weeks ago and happened to observe two of the same targets as you. Here are my notes for comparison:

STF1349: Slightly unequal pair of white stars well separated at 70x. A much fainter pair, with a similar separation and mirror image orientation is close by, like a ghostly reflection of the main pair.

STF1350: Very pretty pair of matched bright white stars, with a hint of yellow, nicely close at 70x. The C component is slightly fainter, and is widely separated.

There are many attractive doubles in the Great Bear and I particularly liked STF1358 (7.9, 9.2, 23.7") an orange bluish, unequal pair, with a bright white star in close attendance and adding to the colour contrast. I took a quick image of that system and hope to get into a routine of capturing images of the prettier binaries to accompany the visual observations.




Thanks again Paul.

Mike

Great list of 9 doubles, Paul. If there is a clear night of the weekend, I'll be out observing. Wednesday night was a beautiful clear night, but Valerie and I were out doing music in Greystones. And I am enjoying the brilliant snooker in Sheffield.

Aubrey.

Hi Paul, I was out the same night having a crack at splitting Porrima
with my Telementor. I found that at 140x which was the highest power I
have for the Telementor I got a well defined figue eight and for brief
moments almost two seperate discs. What a beautiful double Porrima is
and its getting easier at the moment.

Pat.

Hi Pat. Could you please educate us as to what is a Telementor? I personally haven't a clue. In 2012, I could split Porrima at 140X in my 6.2" apo.

Aubrey.