Monday, January 09, 2017

NGC 2539 and 19 Pup (Halifax)

Back on 15 Dec, I tried to image the Finest NGC 2539 with the Burke-Gaffney system. The result was satisfactory but the open cluster was not quite centred or framed the way I wanted. So I aimed a bit to the east, centering on TYC 05434-2972 1. It worked. And this time I also caught the multi-star system 19 Pup.

NGC 2539 and 19 Pup in luminance

Luminance only, 30 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; east is left.

19 Pup aka BU 1064 is to the south-east, near the bottom-left corner of the image. The D and E components, to the west of the primary, are obvious. D is the dimmer star to the north; E is brighter below. Curiously, SkyTools 3 Pro, according to the chart display, says D shines at magnitude 8.9 while E is 9.4. But E is clearly brighter. The Object Information box says E is mag 7.8. That's better.

Now things get really interesting. There's a pair of stars (GSC 05434-3319 and GSC 05434-2503) with similar spacing to D and E to the south of D and E and fainter than D. They are not part of this system. There's J081115.6-125648 to the south of A, about the same separation as E, brighter than D, but again is not considered an element.

There's something up with the C star. ST3P shows C to the north-west of A at mag 13.2. The photograph shows a star at this position but extraordinarily dim. Is that it? Or did C move?

ST3P shows the A and B stars as very tight (and very different) so I'm not surprised that I cannot isolate them in this image. Too bad there are optical problems in this corner. Doesn't help.

There seems to be a glow around this multi-star system. I'll look in that, check and see if there's something really there.


Did a deeper analysis of 19 Pup.

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