Author Topic: Lake Sonoma OR from Saturday May 20th  (Read 205 times)


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Lake Sonoma OR from Saturday May 20th
« on: May 21, 2017, 01:52:49 PM »
I decided to go to head to Lake Sonoma yesterday afternoon (Saturday) as the predicted conditions were excellent.   Only two others showed up -- Matt Marcus and Shneor Sherman, which was surprising as this was the best weather in terms of temperature/humidity/wind, etc. that we've had in awhile.  It turned out to be a dark night with pretty good seeing.  I made a SQM reading of 21.45, which beats most locations close to the bay area, though the Milky Way wasn't that impressive, so the transparency wasn't ideal.

Unfortunately, we were interrupted for at least an hour and a half by a parade of cars/pick-up trucks that drove into the large Lone Rock lot every few minutes, apparently looking for the rowdy party that took place in the equestrian area just below Lone Rock.  There was also an unusually high amount of road traffic on Rockpile Road, so not a very relaxing evening.  Around 12:30 it finally quieted down and fortunately stayed that way.

One highlight was the type IIP supernova SN 2017eaw in NGC 6946 -- the appropriately named Fireworks Galaxy, which was discovered a week ago on May 14th.  It was easily visible (close to mag 12.5) in the halo of the galaxy, 1.0' west and 2.4' north of the center, and formed a wide pair with a fainter star.  This is the 10th supernova in the past century in the NGC 6946 (I believe I've viewed 4 of these) and it holds the record for the most prolific SN producer: SN 1917A, SN 1939C, SN 1948B, SN 1968D, SN 1969P, SN 1980K, SN 2002hh, SN 2004et, SN 2008S, and now SN 2017eaw.  It may still be on the rise -- in any case it was easy to see in Matt's C-8 and certainly a 6" (or smaller) will do the trick.  Check it out if you view in the next week!!

I also viewed Comet C/2015 V2 (Johnson) in Bootes, which was a bright 7th magnitude (visible in binoculars) and displayed a faint but obvious tail that extended through much of the 13mm Ethos eypeiece field.  It displayed a large coma and an intensely bright nucleus.  This is easy to find and well placed mid-evening, so another one not to miss.

As far as deep-sky objects, I took notes on about 3 dozen galaxies -- mostly working on two projects.  One is to pick up very faint companions to NGC galaxies.  The companions are sometimes in the IC, but often just carry a PGC designation.  The other project is galaxy mergers -- where two nuclei can be resolved within a single common halo.  A good example is NGC 5259, a faint galaxy in Canes Venatici, which I viewed around 1:30.  The second nuclei, labeled in this image as Holmberg 533B (Eric Holmberg studied double galaxies as part of his doctoral thesis in Sweden in the 1930's), was tough at 375x but definitely visible most of the time.