Saturday night was listed on my observing calendar as a Pacheco State
Park star-party outing, so my only reason for venturing out this
particular evening was to support this public venture. The late
afternoon conditions didn't look promising for observing: about
75-percent cloud cover over the South Bay when I departed San Jose, and
about 90-percent cloud cover over the Pacheco Pass area when I arrived.
Observer: Bob Czerwinski
Date: April 5-6, 2003
Observing Time: 6:30pm to 1:00am PST
Location: Pacheco State Park, Approx. 37°04'N 121°13'W,
El. ~1400-feet
Moon: Waxing crescent, ~4-days-old, 10:30pm set time
Equipment: 14.5" f/4.3 Newt/Dob e/w Telrad and Paracorr
Eyepieces: 17mm-107x (default) & 12mm-152x TV T4 Nagler;
31mm-59x TV T5 Nagler; 9mm-202x TV Nagler (all magnifications include
Paracorr)
Filters: None in use
Sky Conditions: Zenith LM 5.9-6.0; transparency 6/10; seeing 7/10
Temp/R.H.: 7:00pm: 45F/69%; 9:00pm: 43F/72%; 11:00pm:
39F/88%; Midnight: 39F/89%; 1:00am: 39F/90%
Comments: Heavy cloud cover dissipating at sunset.
Occasional light breeze during the evening. Transparency: Relatively
poor, with jet contrails visible "horizon to horizon" all through the
observing session. Seeing: Average, with occasional periods of "very
good." Light moisture on my charts noticed after 10:00pm. Although the
temperature dropped to 39F, humidity and the occasional breeze made it
feel more like freezing. Clear Sky Clock prediction fairly accurate.
In brief:
I didn't count instruments, but I'd guesstimate that about ten of us
ended up setting up 'scopes for the public session. As predicted by the
forecasters, the clouds started to dissipate just about sunset, but
moisture high overhead was still evident by long jet-contrails.
The public turnout was very light, at least in my little corner of the
star party. I believe I provided views of the Moon, Jupiter and Saturn,
a few of the brighter Messier objects, and a few double-stars to less
than a dozen visitors. I think most of us with 'scopes spent our
"public time" just trading views with one another.
Castor was a very easy split in the early evening hours, and the E & F
stars of Orion's Trapezium were easily visible as well.
An early thrill was a nekked-eye view of Mercury, sitting about
5-degrees above the western horizon. 77% phase, about magnitude -1 ...
and really swimming in a rainbow of colors when viewed through my
'scope.
Jupiter provided us with a nice Europa/Europa shadow transit, as well as
with some interesting activity in the Equatorial Belts.
Following the public session, I spent about an hour's time playing
around in Leo's Abell 1367, but the transparency didn't permit me to log
any new cluster members. For the moment, I'm stuck at 52.
I spent the remaining part of the evening chasing galaxies in UMa that
I'd only "suspected" in my 12.5". Despite the poor transparency, I had
no real trouble identifying and confirming about a dozen galaxies.
A bit after midnight, Jerry Elmer spotted Omega Centauri, NGC 5139, just
skirting the southern horizon, so a few of us briefly turned our 'scopes
that direction. Although too low in the muck for any resolution, the
glow of this magnificent globular cluster certainly filled up the
eyepiece.
Although transparency conditions were far from ideal, the surprising
dispersal of the afternoon's cloud cover left us with a clear sky for
the public activity; the seeing was fine for most activities. I think
the heavy cloud cover earlier in the day kept people away from Pacheco.
I had a fine time.
...Bob...
Bob Czerwinski