August 10, 2009: Two object OR from Lake Sonoma on 7/25/09

Steve Gottlieb

After returning late Friday from two hectic weeks in China capped by five and half minutes of standing in the shadow of the moon, I was planning on spending the weekend recouping and adjusting to the jet lag. But when I checked my e-mail Saturday afternoon, I received an e-mail from Greg Laflamme that he was meeting Carter Scholz, Dana Patchick and Dave Staples at Lake Sonoma that evening. Tired or not, I couldn't resist the offer, so threw my Starmaster into my Sienna and headed over to Lake Sonoma.

As Greg mentioned in his OR conditions were pretty sweet for that site -- fairly warm, dry, calm and SQM-L readings of 21.39-21.45. Early on in the evening Dana Patchick came over and asked if I had heard about a planetary in Sagittarius that had recently been discovered (though not announced) by Austrian amateur Matthias Kronberger by a visual search of the DSS. You'd think the DSS has been completely mined, but sometimes new objects are still found. In the case of this object, it is catalogued as PGC 932285 though misclassified as a galaxy. You won't find it though in any other online or printed catalogue.

With Dana's help, we quickly located the field though initially I though an very close unresolved double star that was just a couple of arc minutes away was the intended object. After a little more careful observing we picked up the faint glow of the planetary -- most likely among the first couple of observers to nab this object!

In my 18-inch at 275x (unfiltered) it appeared as a small, hazy spot with a mag 14.5-15 star at or just off the SE end. The main glow was only 15" in diameter and had a very low surface brightness. The shape seemed slightly irregular or elongated, though it was really too faint to pin down a distinct outline. Occasionally an extremely faint superimposed star was seen. This new discovery can be found 6.3' NNW of mag 6.9 HD 185044 and forms a small triangle with two 14.5- magnitude stars 1.6' WNW and 2' N.

We also spent close to an hour observing the object in Greg's 22-inch at various magnitudes using a UHC and OIII filters. At 462x, the star off the SE end was cleanly resolved and the planetary displayed a moderate contrast gain using a UHC filter (easy to hold continuously). I felt the UHC filter gave a better contrast boost over the OIII, though perhaps at a lower magnification the OIII would have been more helpful. The overall size seemed roughly 20"x15". The total magnitude is perhaps 15 and I'm guessing a 12-inch should pull in this object (or perhaps smaller in exceptional conditions).

A couple of days later Matthias "announced" this object on AMASTRO, so the secret is out. Still if you'd like to be among the first few to observe this object, take a look later this month.

For the past several months I've been chasing down variable galaxies for an article in S&T. In fact some of these objects were discovered or originally thought to be galactic variable stars as they appear virtually stellar even on deep plates. Examples are BW Tauri = 3C 120, BL Lacertae = VRO 42.22.01, AP Librae = PKS 1514-24 and W Comae = ON 2. But later investigations revealed these "variable stars" were the compact cores of galaxies with active galactic nuclei (AGN), that can visually vary by up to 5 magnitudes over a long period and short-term outbursts of a couple of magnitudes in just a few days. All of these objects fall in the class of active galaxies knows as blazars and are powered by supermassive black hole with a high-speed plasma jet ejected head-on in our line of sight.

At Lake Sonoma I took a look at the blazar 3C 371, located in Draco at 18 06 50.7 +69 49 28. This object has been found to visually vary from mag 13.5-15.0. At 275x it appeared as a faint, extremely compact object containing a mag 14.5 or fainter stellar nucleus surrounded by a 10" halo. A sharp, stellar nucleus was visible during moments of better seeing. Otherwise this blazar appeared as an easily visible "soft" star that wouldn't focus. I thought it appeared comparable in magnitude to the nearby mag 15.2 star GSC 4433:1796.

Steve