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

From: Robert Leyland (r.leyland@No-Spam)
Date: Mon Feb 24 2003 - 15:25:38 MST

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    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.

    Observer: Robert Leyland
    Date: 22 Feb 2003
    Time: 1900-1230 PDT (UT -8, or 0300-0830 23 Feb 2003 UT)
    Location: Lake Sonoma CA, 38°43'N 123°02'W Elev ~900 (Grey Pine Flat)
    Weather: 11-13°C Temp, 59%-75% Humidity
    Seeing: LM 6.1, transparency 7/10, steadiness 8/10, very little wind
    Equipment: 17.5" 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.

    -- 
    --
    Seen in a cubicle in the Ladie's loo in the University of Queensland, 
    Saint Lucia: "Better the cold blast of winter than the hot breath of 
    a pursuing elephant."
    

    r.leyland@No-Spam ... rleyland@No-Spam



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