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Paul Alsing
July 26th, 2017, 03:37 PM
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

Howard B
July 26th, 2017, 11:59 PM
Hi Paul,

I've seen this Abell a couple times but didn't notice the galaxy - I'll give it a go tonight if conditions are good enough.

Paul Alsing
July 27th, 2017, 04:54 AM
Hi Paul,

I've seen this Abell a couple times but didn't notice the galaxy - I'll give it a go tonight if conditions are good enough.

Hi Howard,

Well, this happens to me all the time. If I'm not aware of such details, I probably won't see them unless they are conspicuous. Having Steve and Jimi asking me to look for these specific details made all the difference in seeing them, it wasn't all that difficult when employing the observing techniques that I have practised so many times over the years.

Imagine that, looking specifically for details. As long as I've been an amateur astronomer, we'll over 55 years, you would have thought I would have figured this out by now ;)

Jimi Lowrey
July 28th, 2017, 12:01 AM
I also had a great time with some incredible astronomers in the beautiful White mountains. Abell 72 and seeing the little MCG galaxy nearby was one of the highlights of the week.

Steve G and myself also tracked down many interesting Lews Swift galaxy's.

Uwe Glahn
July 28th, 2017, 08:40 AM
Hi Paul,

I also overlooked this galaxy companion over the years but finally got it with my 27-inch. Nice object indeed.

8", 80x, [OIII], fst 6m5+
nice triangle of stars at the position of the PN; with [OIII] and 47x a laminar glow can be seen with direct vision within the triangle; better view to see the exactly size and position with 80x; with that mag glow can be hold easily with averted vision as a 3:2 N-S elongated glow

16", 129x, [OIII], fst 6m0+
PN faint also without filter, 8 mag star in the west, with [OIII] large, round, structureless
2617

27", 244x, [OIII], fst 7m0+
PN could be seen even without filter; with 293x the galaxy PGC 65491 S of the PN could be seen as a small glow; with [OIII] the PN could be detected with direct vision as a bright, round glow with better defined E and W edges; bright CS is visible even through filter

Jimi Lowrey
August 5th, 2017, 03:25 PM
Tom Harrison sent me this link to a super deep image of Abell 72 by Capella Observatory. I was shocked to see that there are two galaxies almost overlapped near Abell72

http://www.capella-observatory.com/images/PNs/Abell72Big.jpg

Paul Alsing
August 6th, 2017, 03:39 PM
Tom Harrison sent me this link to a super deep image of Abell 72 by Capella Observatory. I was shocked to see that there are two galaxies almost overlapped near Abell72

http://www.capella-observatory.com/images/PNs/Abell72Big.jpg

Although we glimpsed the brighter of the 2 galaxies, we were apparently only seeing the bright bar... it looks to me like it is actually a miniature version of NGC 1365! Look and those arms!