Observing notes from Pacheco 10/30/99

by Steve Gottlieb


Here's a summary of some of the highlights from Pacheco State Park -

The first object I headed for was NGC 6951. This is not a particularly exciting galaxy but it contained supernova 1999el which was discovered just 11 days previously (Oct. 20th). Using an image downloaded over the internet it was easy to confirm the mag 14.5-15 star just following the core (22" E and 8" S) at 220x-280x. The galaxy itself is moderately bright and large, and sharply concentrated with a small bright core surrounded by a diffuse halo elongated 3:2 E-W. A mag 12 star is 1.5' following the center and a mag 15 star is just visible a similar distance WNW. My first observation of this galaxy was in the early '80's with a C-8 and the bright core was even noted in this aperture.

After I had set-up before sunset I noticed how unobstructed the view was to the south, so decided to tackle some deep southern objects which are not accessible from my usual haunts.

IC 5148 is a 11th magnitude perfect ring nearly 2' in diameter but not well known to northern observers due to its declination -39.4 degrees in the constellation Grus. Even at a low elevation, this moderately large planetary is a beautiful annular ring at 100x with an OIII filter. Appears round, ~100" diameter, with an irregular surface brightness to the annulus. The central "hole" is perhaps 25" in diameter and fairly dark. A mag 10.5 star is close off the SSW edge.

I spent some time in Grus picking off galaxies down to -41 degrees dec (NGC 7087) and could have probed lower at this site but my struts were hitting the front board of my rocker box.

Heading well to the north I took a look at the planetary Minkowski 2-51 (PK 103+0.1) located at 22 16 03.3 +57 28 41. This object is bright enough (V = 13.5) that it's surprising it was missed by the Herschels in the surveys. It was easily picked up at 100x using an OIII filter and appeared fairly bright, round, ~30" diameter. At 220x it was faintly visible unfiltered and two stars are superimposed oriented SW-NE with the brighter star eastern star just following the center of the PN. It responded very well to filtration (OIII and UHC) and easily held 280x with a UHC filter. A slight elongation N-S was evident at this power. You can find this object 16' N of mag 5.9 SAO 34256.

Another interesting object in Cepheus is the emission nebula IC 1470 (Sharpless 2-156) located at 23 05 10.3 +60 14 37. A previous observation from the mid-80's with a 13-inch compared this object to Hubble's Variable Nebula. This time I picked up the object at 100x using an OIII filter as a small, bright glow surrounding a mag 12 star. The best view, though, was at 280x unfiltered. The involved star is attached at the north edge and the 1' oval nebula appears to hang off the south side of the star. Close west is a very close, evenly matched faint double star!

About 3 degrees SW of IC 1470 is the large emission complex NGC 7380 (Sharpless 2-142). It was a snap to identify at 100x with both OIII and UHC filters as a bright triangular-shaped nebulosity, 8'-10' diameter which is superimposed on a rich grouping of stars within a striking milky way field. The brightest mag 8.5 star (very unequal double) is at the west vertex. Also fascinating was a wide strip of nebulosity attached near the SE vertex and extends to the SW. A dark band appears to separate this strip from the triangular patch. The surrounding region appears weakly nebulous and the "edge" can be traced with some certainty a ways to the north.

A couple of weeks back I posted a list of the brightest globulars in M31 as well as my own observations of over a dozen extragalactic globulars. Before the moon rose I decided to search out a few new ones. M31-G73 appears as a mag 15 star just 6' east of the center of M110. It was visible without much difficulty 1.0' NE of a mag 12.5 star and 2.5' S of mag 9.3 SAO 36570. This globular may actually be physically associated with M110.

M31-G72 is another mag 15 "star" situated 1.5' WSW of mag 12.5 star. There is a 1' pair of mag 12.5 stars situated 5' S which are nearly collinear with the globular. Just 5' SSE is M31-G78, one of the brightest globulars in M31 (I had previously observed this one). It was easily identified as a mag 14.5 star 2' following a mag 12.5 star which forms a 1' pair with a similar star due south. It appeared slightly "soft" compared to nearby stars though not I couldn't log it as resolved with certainty. I also attempted several additional mag 15 globulars which I had previously listed on TAC (including M31-G148 and M31-G165) to the east, but I discovered these were impossibly buried in the glare of the high surface brightness core. By this point, the glare from the soon to rise moon was starting to illuminate the eastern horizon and it was time to call it quits for an enjoyable evening.