OR: M22, some PNs and Pal 11

On this year's trip to Colorado I had a bunch of targets in Aquila queued up for my first night, but the only clear patch was near the south horizon. I only had the roughest of polar alignments (Polaris was clouded out as well), so I went for something bright:

M22 7/26/2011 00:40 MT; NELM 7, SQM 21.7
250mm Dall-Kirkham @ 180X

Very large with stars resolved into the core, but still a milky background to the center sections. Bright triangle of stars off the ENE edge of the core, and a dark patch biting into the WSW edge.

By the time I was done even the horizon was clouding out, so I gave up.

I got a reprieve several nights later. Well-pleased with my polar alignment this time, I decided to start with a bit of a challenge:

Pal 11 7/29/2011 00:15 MT; Pickering 4, NELM 7, SQM 21.7
250mm Dall-Kirkham @ 180X

At 260X a very faint star at the right location sometimes looks like a very dim PN in averted, but the glow around the star doesn’t seem big enough to be the globular.

340X fuzzier but gives more predictable field stars (down to about 14.5).

Backing off to 180X moves the averted-vision glow somewhat NNW from the faint field star, leaving the star at the edge of the glow, but the glow is still only 50% or so at best.

[The 180X observation, which offsets the glow to the NNW of the field star, indicates the exact position of Pal 11. I'd label this one "tenuous" if it weren't for that.]

B86 7/29/2011 00:45 MT; Pickering 4, NELM 7, SQM 21.7
250mm Dall-Kirkham @ 100X

Readily apparent at 100X, with a large triangular dark spot next to the staw-coloured field star and a second, smaller and less dark circular spot right next to NGC6520 (which appears “captured” against the open cluster by 4 or 5 field stars on the other side of it).

[Didn’t notice the elongated dark area to the SSW of the cluster.]

I had planned on sketching this, but to be honest, the idea was a bit daunting. Seeing as it was about to set behind the ridge line anyway, I felt that was a good enough excuse to move on.

So I switched to my Aquila target list I had abandoned earlier in the week:

NGC6781 7/29/2011 07:15 UT; Pickering 4, NELM 7, SQM 21.7
250mm Dall-Kirkham @ 100X, UHC

Looks cometary at 180X, but gives up an averted-vision minima to centre upon further study. UHC certainly makes it "pop" from the background, but leaves the field too dark and fails to reveal any more structure (or allow more accurate location of the direction of the "tail").

260X (unfiltered) brings out more background stars, but is of no help on the PN.

Minima more noticeable at 100X, and even more-so at 100X with the UHC. This is about as good as it gets, but the direction of the "tail" is still indistinct (somewhere between NNW and N).

NGC6804 7/29/2011 01:41 MT; Pickering 4, NELM 7, SQM 21.7
250mm Dall-Kirkham @ 350X

Small and cometary at 180X.

Dims a bit at 260X, but no longer cometary (this magnification reveals a close field star on the NE edge which was giving the cometary shape). 260X also shows hints (perhaps 30%) of an averted-vision central star.

340X confirms central star (100% in averted), but PN shell more difficult. Shell appears slightly more flared to W and WSW. [Flaring turns out to be more dim field stars at the edge which I couldn’t quite resolve under these conditions.]

It gets rather cold at 10,500' (even in August), so I decided to pack up while I could still feel my fingers.

Cheers,
Jeff.

Really nice sketches Jeyjey. Almost photographic in quality, especially M22.

I second that. Great sketches, lovely detail and brilliant quality. Well done.

Brendan
www.DonegalSkies.com

Thanks, John and Brendan!

Jeff.