April 7, 2010: Springtime Observing At Dinosaur Point, CA

Peter Natscher

Nighttime weather conditions during April 7th-8th at Dinosaur Point on the large San Luis Reservoir was remarkable. I, along with Albert, Scott, Jim, George, and Alex, had the opportunity to observe with our telescopes in better than average transparency, humidity, and seeing, with no dew or wind. The temperature didn't go below 48°F. and our paper charts outside on our tables stayed fairly dry. We observed from twilight with our views of Mercury and Venus not far apart from each other, until an hour past midnight. The very good seeing and transparency allowed us to enjoy detailed views of objects located beyond -40° Dec to the south. I took advantage of the evening's fine conditions to get detailed views of a new deep sky objects for me in southern Hydra and Antlia, and in making sketches of them. My 24" f/3.7 Starmaster was pulling out nice detail in planetary nebulae and galaxies located at this low declination - only 12° above the S. horizon!

Highlights of my observing were planetary nebulae from the Jay McNeil 450+ planetary nebula list, downloaded from Doug Snyder's www.blackskies.org home page (a planetary nebula site); and a few interesting looking galaxies.

NGC 2610 Hya PN 13.0 50"x47" 08 33 53 -16 11 19 PN G239.6+13.9
24" 8mm 324X An average-sized planetary nebula appearing as a round ring with soft edges and slightly less luminous interior. Gray in color and a magnitude 15.5 central star was seen with averted vision. NE side looks brighter possibly due to glare from the 13th magnitude field star hugging its NE edge. Using a OIII filter darkened the center and added0 contrast. It is 5,500 light years distant.

Abell 33 Hya PN 13.4 270" 09 39 42 -02 51 32 PN G238.0+34.8
24" 21mm 123X A very large and faint planetary nebula in the shape of a disk with uneven illumination and with brighter parts along all the edges. Object was seen only with a OIII or UHC filter. Interior looks mottled, fainter to non-existing. A 'bright' 7th magnitude field star located on its SW edge hampers seeing this low surface brightness (25.3) planetary.

NGC 3132 Vel PN 8.2 62"x43" 10 07 29 -40 29 31 "Eight-burst" Nebula, Southern Ring Nebula
24" 13mm 200X A medium-sized planetary nebula with a distinct oval shape and outstanding blue color. This is a classic planetary nebula being very close to the size and brightness of the famous Ring Nebula in Lyra. Good detailed structure was seen: a bright outer shell divided by a darker ring and a brighter interior hosting a fairly bright 10th magnitude central star. Burnham points out that this visual star isn't the star that is illuminating the planetary. This light comes from a 16th magnitude dwarf companion (separation 1.65") which has a very hot surface, about 100,000 kelvin. An OIII filter added contrast and brightened the outer ring.

NGC 2997 Ant GX 10.1 9.8'x6.8' 09 46 07 -31 14 38 MCG-5-23-12
24" 17mm 152X A large face-on spiral galaxy having a bright condensed core and ghostly broad spiral structure radiating clock wise from the center. This is a large isolated galaxy that deserves your time observing but requires good seeing and transparency due to its southerly location at -31°. Hints of good detail of the spiraling arms and lanes was directly visible.

PK 283_25.1 Hya PN 12.1 186"x174" 11 27 00 -34 25 00 "Southern Owl Nebula"
24" 17mm 152X A large faint planetary nebula reminiscent of the Owl Nebula in Ursa Major, but visually a lot fainter due to its low position in the south of -34° Dec. Appears as a faint gray disk with uneven illumination within and soft irregular edges.

NGC 3242 Hya PN 8.6 40" 10 25 17 -18 41 57 "Ghost of Jupiter" Nebula
24" 8mm 324X A very bright medium-sized planetary nebula with an oval shape and a brilliant blue color. Within its soft outer shell is a well-defined brighter outline of the shape of an eye; and at its center lies its visible central star. This planetary should be called the "Eye of Jupiter", for it appears like it is looking back at you.

NGC 2903 Leo GX 10.0 11.5'x4.2' 09 32 46 +21 27 13
24" 13mm 200X A very striking spiral galaxy exhibiting a visible classic Sb category bar-shaped core surrounded by extensively curved counter-clockwise arms and lanes. This spiral is large and easy to see. Surprisingly was missed by Charles Messier and therefore isn't a Messier object. This galaxy is 22 million light years away from ours - it's relatively close.

NGC 3115 Sex GX 10.0 7.6'x3.5' 10 05 46 -07 46 21 "Spindle Galaxy"
24" 8mm 324X A very bright lenticular galaxy; that is a disk-shaped galaxy but without any spiral structure and similar to an elliptical galaxy. It appears as a edge-on galaxy with a bright central bulge, a vey bright bar-shaped core, and long oppositely opposed appendages extending out and away from the core until they fade to a point. It is visually quite a unique galaxy to see and reminds me of NGC 4565 in Coma Berenices and M104 in Virgo, but without a dark lane.

Peter Natscher
Monterey, California
24" f/3.7 Starmaster