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Object of the Week – July 23, 2017 – Abell 72 (& Friend)
Object of the Week – July 23, 2017 – Abell 72 (& Friend)
Object of the Week – July 23, 2017 – Abell 72, PN G059.7-18.7, PK 059-18.1, ARO 173 (& Friend), in Delphinus
R.A.: R.A.: 20h50m02.1s Dec.: Dec.: +13°33'30" (2000)
Size: 2.0'
Mag; V = 14.60
I had the best time last week, spending 5 nights under the stars observing from about 8500’ in the White Mountains, in California, the location of the Ancient Bristlecone Pine Forest, just a little east of Bishop. I was in the company of several fellow observers, including my wife Debbie Searle Alsing, Kemer Thomson, John Hoey, Carter Scholz, Rick Linden, Jimi Lowrey and Steve Gottlieb. Also in attendance was Jimi’s amazing wife Connie.
All 5 nights were pretty nice, but both transparency and seeing were somewhat variable… but mostly really conducive to pleasant viewing. My SQL meter recorded a high of 21.80 and a low of 21.30, but I only measured this about 4 or 5 times over the entire 5 nights, so it could have been both higher and lower.
Steve & Jimi tracked down many difficult objects during the week, and these 2 guys don’t just take a quick peek and then move on to the next object, they fight tooth and nail to drag out as much detail as possible. Of course, I let them do all the hard work and then wander over to Steve's telescope and mooch eyepiece time! It is always a special treat to observe with either Steve -or- Jimi, but together they are a tenacious pair. Steve has a 24” f/3.7 StarStructure dobsonian, a very capable instrument.
One of the many objects observed last week was Abell 72, a planetary nebula in Delphinus… a very faint planetary. It was easy enough to see with averted vision and (to my eye) barely detectable with direct vision.
a 72.jpg
After taking a nice long look and seeing a ghostly filtered image floating on a black background, Steve wants to know how many stars in the interior of the planetary I can see. What? OK, I’ll take another look, Steve, without the filter… and… with a lot of averted vision (relax, Paul, relax), I can eventually see several stellarings popping in and out, here and there across the surface of the nebula, perhaps 3, perhaps 4, but never more than 1 or 2 at a time.
Then Jimi says… “so, do you see the galaxy nearby?” OK, for this I need to go to Jimi’s computer and look at the DSS image that he has overlaid on Megastar, which shows the galaxy MCG 2-53-5 (mag 16.2) about 2’ SSE from the center of A 72. After making a mental note of the star field in question and now back at the eyepiece knowing exactly where to look, the galaxy grudgingly yielded to my scrutiny, appearing as a very slightly elongated smudge at just the right location. Here is the DSS overlaid on SkyTools…
abell 72 dss.jpg
All in all, it was a terrific experience, made even better because it was shared with remarkable astro-buddies!
As always, give it a go and let us know
