Lake Sonoma 2/23/06

by Steve Gottlieb

On Thursday, I met Bob Douglas for dinner in Healdsburg and then headed up to Lake Sonoma on a beautifully clear afternoon. Although Bob had notified the visitor center at LS to leave the gate open at Lone Pine (the most popular observing site) when we arrived the gate was locked. So we drove over to a small turnout a couple of miles west on Skaggs Springs road (see http://geography.berkeley.edu/personalpages/l_bennett/BennettVR/HTML/West/NorthBay/SkaggsSpringsRdM.html for a 360 degree QTVR panorama of the region). This small lot is surrounded by some trees that somewhat limited the southern and eastern horizon but was not too obtrusive once it was dark. Conditions were surprisingly mild and totally calm so I never found myself even putting on a heavy jacket.

Here's a few of the more interesting objects I viewed in my 18-inch f/ 4.3 Starmaster. As far as I know quasar APM 08279+525 holds the distinction as the most distant object visible in amateur scopes (z = 3.9!)

IC 443 = Jellyfish Nebula	06 16.9 +22 47	Size 50
18" (2/23/06): this supernova remnant was easily visible at 73x and OIII filter. The brightest portion is a 5' elongated strip that very gently curves WNW-ESE. Faint haze extends out from this strip towards the south and west. An extremely faint extension of the strip continues to the SE and curves towards a an obtuse triangle of three stars increasing the length of the edge of the shell to over 10'.
Cederblad 90 = Gum 3 = Sh 2-297 = vdB 94	07 05 16.7 -12 19 35	Size 10x10
18" (2/23/06): moderately bright, round, 3' glow surrounding a mag 8.5 star. Only a small contrast gain using a UHC filter but best using the H-beta filter at 73x. With this combination the surface brightness is fairly high and the object is prominently displayed in the field. 17.5" (3/2/02): at 64x appears as a faint, round, 3' haze surrounding a mag 8.5 star. Two mag 10.5 stars are collinear off the east side, 2.5' and 3.3' from the center and several mag 12 stars are involved at the south edge. The H-beta filter noticeably improves the contrast and makes the nebulosity an moderately bright, direct- vision object. With averted vision the glow increases to 4'-5' in diameter with some very faint haze extending east. The star density drops off immediately to the west, except for a few stars. Ced 90 is located at the extreme southern tip of the 2.5 degree giant emission nebula IC 2177 which extends north into Monoceros. This is one of a select group of low-excitation nebulae that can be added to the list of H-beta objects.
APM 08279+5255 = IRAS F08279+5255	08 31 41.6 +52 45 18	V = 16.0
18" (2/23/06): I carefully starhopped over to the position of this extremely distant QSO and then used a photographic finder chart to pin down the location with respect to nearby faint stars. With averted vision and extremely faint "star" was visible ~25% of the time. I couldn't hold the object steadily for more a few seconds at a time, but the detection was not difficult to repeat. The QSO forms the northern vertex of a small triangle with two mag 15-16 stars less than 1' SW and 1' SE. 18" (2/3/05): This mag 15.2 "star" is a superluminous QSO at a redshift of z = 3.9 (discovered in 1998), which implies a distance of roughly 12 billion years! Used a DSS finder chart (not a GSC star) to positively identify this object which appeared extremely faint (only visible occasionally) at 225x. Located ~50" NE of a slightly brighter mag 15 star (also not on GSC). I'd estimate the magnitude as ~16.
Ton 490	10 13 53.4 +24 49 16	V = 15.4
18" (2/23/06): it was easy to track down this distant quasar as it is located close west of an attractive string of three stars with the brightest star at the SSE end a delicate equal mag double (h477 = 10.3/10.3 at 4"). Ton 490 is also situated 1' N of a mag 14.2 star and it appears between mag 15 and 15.5 (estimate). It could easily be glimpsed but not held steadily at 257x. With a redshift of z = 1.636 this high luminosity quasar is located at a distance of over 9 billion light years.
MCG -01-23-019 = PGC 25555	09 06 34.0 -07 14 27	V = 13.0; Size 0.8x0.5; Surf Br = 11.9; PA = 99d
18" (2/23/06): immediately picked up at 160x just 1' NE of mag 8.6 HD 78157. At 257x appears fairly faint, small, round, ~20" diameter, gradually increases to a very small, bright core. This is a striking object in the field of a bright star. MCG -01-23-021 lies 11' SE. Located 20' WSW of triple star ·1316 (same separation as MCG -01-23-021).
NPM1G -09.0310 = PGC 25714	09 08 32.4 -09 37 48	V = 13.2
18" (2/23/06): this galaxy is by far the brightest in the distant galaxy cluster Abell 754 (z=.055). At 257x it appeared very faint, small, oval, 0.4'x0.3', low fairly even surface brightness with just a broad, weak concentration. With averted vision the halo occasionally increases in size. During a few moments, an extremely faint companion popped into view as a small knot off the SW edge.
MCG -01-24-001 = UGCA 150 = PGC 25886	09 10 48.8 -08 53 38	V = 11.3; Size 5.2x0.9; Surf Br = 12.8; PA = 33d
18" (2/23/06): this unusual galaxy appears as a fairly faint edge-on oriented SW-NE, ~2.0'x0.4'. A mag 9-10 star is strikingly superimposed just SW of the center and detracts from viewing. Still, the galaxy is easily visible as a fairly faint streak extending mostly to the NE of the star! A 13" pair of mag of 14/15 stars are superimposed on the NE extension. Located 19' ESE of mag 5.5 20 Hydrae.

Posted on sf-bay-tac Feb 25, 2006 14:59:49 PT
Converted by report.pm 1.2 Mar 02, 2006 19:40:27 PT