Quote:
Originally Posted by Tinderboxsky
Observing this triple double has eluded me for a long time. I have tried a few times but weather and/or other interruptions have defeated me. Last night the seeing was perfect but the transparency a little variable with a lot of moisture in the air.
The triangular asterism stands out nicely against the rich star field and is easily seen near NGC 6193.
At 100X, HD149901 was a very close resolved pair of equal pin point white spots. HD150040 was more difficult but I was just able to resolve the fainter companion. I could not resolve HD150083 at 100X
At 160X, all three doubles were resolved, although HD150083 was still very difficult. Perhaps a night with less moisture in the atmosphere would resolve this more easily. 160X was through my LVW5, giving a 0.41 degree FOV. This easily framed the triangular asterism.
As you say, John, it is certainly a fine sight to have all three resolved doubles in the same FOV.
Interestingly, given your musings re possible other triple doubles, late at night I tripped over another possible candidate in ARA only 1.5 degrees from your triple double. I say "tripped over” as I was exploring the rich star fields and open clusters in the area when I noticed a small knot of stars that stood out against the background star field and had a closer look. The three primaries span only 2.5 arc minutes and the more remote star in the triangle was a distinct orange/red.
SkySafari Pro lists these as:
HD 151082 (red giant) mag 7.21/8.14 @ 106”
HD 151115 mag 8.13/9.5 @ 3.8”
HD 151116 mag 8.15/8.21 @ 45.3
For this triple double candidate, the primary stars cover a much smaller area, but the companions are more widely spaced. Observing and resolving these double stars was problematic. The transparency was staring to fluctuate and deteriorate. Dew was now streaming off everything. It was time to pack up.
Still, very pleased to have all last resolved the triple double. So no chance to have a close look.
Edit: having had another look at SkySafari Pro, there is some confusion in relation to the data for these companions. I’ll need to research a bit deeper to ascertain whether this a triple double candidate. The jury is now out in my mind. It all looked like a good candidate at the time in the cold and wet of the late evening!
Incidentally, there is yet another possible triple double very very close by. These are three of the stars in the small open cluster Hogg 22. The three stars are listed as double stars in SkySafari Pro but there is an anomaly in the listings for the companions. All three companions are listed as mag 11.5 sep 21.1” and at 232 degrees. Some more research needed! I did not try to resolve these as the conditions were not favourable given the stated mag 11 for the companions. The field view was very attractive with Hogg 22 and the very close open cluster NGC 6204 standing out against the rich star field.
Scope: Vixen NA140SS with LVW 5, 8 & 22 eyepieces.
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Thanks Steve, et. al. I had a crack at HD149901/HD150040/HD150083 last night, it what I thought were pretty OK conditions. I could split 149901 and 150083 at 150x, but couldn't split 150040 despite it having a slightly larger separation, even at 200x and 300x.
I also gave HD151115/HD151082/HD 151116 a crack. I'm still coming to grips with determining position angles in my dob, but it seemed like Skysafari has HD 151115 and HD151116 mixed up - 151116 seems to have a pretty easily split double at about 3.8",which is what Skysafari said 151115 should have been. The others were very widely spaced.