22 Feb 2003, odds and ends in ERI, ORI and LEO at Lake Sonoma (17")

by Robert Leyland

I arrived about 5pm to find a small group already gathered and setting up, by the end of the evening we had 9+ vehicles and a dozen people at Grey Pine Flat. Telescopes ranging from a TV Ranger and ETX 90, through a pair of C8s to a gaggle of 17 and 18" Dobs.

Some of the early evening was spent helping Greg get his ETX 90 set up and going. It's a nice telescope with good optics, and I think with practice he will do well with it. We bounced around the big planets, and M42 which neatly showed the Trapezium stars.

I also spent some time just chatting, and catching up, as this was the first observing night of the year for several observers. A big part of the amateur astronomy scene.

I didn't have a specific plan for the evening, just a few objects I wanted to catch, and to break in a new log book. We had several welcome diversions during the evening, some are noted below, but also: Jupiter's Red Spot transit in Doug's 17" with bino viewer; the humourous FU Orionis search; and finding the "37" cluster.

ObserverRobert Leyland
Date22 Feb 2003
Time1900-1230 PDT (UT -8, or 0300-0830 23 Feb 2003 UT)
LocationLake Sonoma CA, 3843'N 12302'W Elev ~900 (Grey Pine Flat)
Weather11-13C Temp, 59%-75% Humidity
SeeingLM 6.1, transparency 7/10, steadiness 8/10, very little wind
Equipment17.5" F5 Dob, Telrad + 9x50 finder scope, Pentax XL EPs

I started observing at the top of Eridanus, intending to get to NGC 1725 (an active galaxy and radio source), but hitting a few other objects on the way.

NGC 1726 and NGC 1720 are a nice pair of galaxies forming a diamond shape with two 10th mag (?) field stars. 1726 is brighter and forms a 2:1 elliptical spot. 1720 is also easy to see but dimmer and more diffuse. It has a couple of embedded stellar points. This pair is an easy starhop from Rigel.

I spent a little time looking for the Witch Head nebula (IC 2118) only seeing a mild brightening of the background in the general area. NSOG lists observations with binoculars, so I think (as at time of transcribing) I may have been looking "too hard" i.e. too high magnification.

I checked the seeing on the trapezium, easily seeing both the E and F stars at 210x, and catching the Horsehead nebula with an H-Beta filter (it was a little soft compared with my memory of previous encounters).

Steve G. called several of us over to look at IC 418 (the Raspberry or Spirograph Nebula). At relatively low power (100x) the red tint in the halo of this delightful planetary nebula was quite clear, and an H-Beta filter enhances the view of the halo (and dims the center star), which is very unusual, most PNs respond better to an O-III filter and very poorly to an H-Beta. At higher power (350x?) the nebula loses it's color and becomes a bit asymmetrical being less well defined on the E edge, and loses some of the sharpness of it's edges that was more noticeable at low power. Well worth checking out.

Back to Eridanus, and NGC 1700, an easy hop between Beta ERI and Omega ERI, to a faint arc of stars in the finder. 1700 is an easy circular galaxy with a faint stellar core at 100x, while at 210x the core is much more obvious and appears disc like.

NGC 1667 id s very nice galaxy. At a glance it looks oddly shaped, being mostly a diffuse ellipse with a bright non-stellar nucleus. With averted vision (and maybe some imagination) I thought I could see a central bar and and arms extending counter-clockwise off the bar.

Steve G. had another diversion for us, this time NGC1999 in Orion, one of my favourite nebulae. It has a really cool dark region wrapping partly around a central star, embedded in a nice circular glow. Steve was looking for a coiuple of Herbig-Haro objects (HH1 and HH2) that are adjacent to this nebula. HH objects are believed to be early stars, just forming from the dust and gas and beginning the fusion process. HH2 was seen with averted vision and held intermittently, while HH1 which is closer to 1999, was only glimpsed. Matt M, also saw it, and remarked on how interesting it was to see a star just about to light up. I later viewed the region in my telescope, with the same results. Without a finder chart, I would never have noticed these faint glimmerings.

By this time my viewing of Eridanus was pretty much gone behind a tree, so I missed my chance tonight to catch that galaxy group. Next time remember to go there first!

So I took a look at a few old favourites in Leo. Beginning with the Leo triplet, M65/66 and NGC 3628. I had a copy of a paper describing the many quasars in this area, most concentrated around NGC 3628, with a few near M66. Sadly they are all mag 19 or dimmer, and beyond my reach. Still NGC 3628 is a delightful galaxy, and has a wonderful dust lane, set amid a nice grouping of stars, and two non-slouch adjacent galaxies for company.

From the triplet, I scanned N to NGC 3596 a nice oval galaxy with a compact core and a 6:5 ratio elliptical halo. It is positioned inside a nice triangle of stars, that creates a quite pleasing view.

Further N between Theta and Delta LEO is a nice group of galaxies, NGC 3599 and he trio of NGC 3605/7/8. 3599 is larger and more diffuse with little in the way of a nucleus. Then 3605/7/8 form an arc, two are significantly brighter than the third, all three are circular with bright central nuclei. All four just fit in view at 100x.

All in all a very nice night, the weather forecasts had been a bit iffy, projecting 45% cloud cover, but instead we had quite acceptably clear skies, and along with good company a fine evening of astronomy.