OR 8/23/14: Willow Springs
by Steve Gottlieb
|On August 23 2014, I met Mark Wagner and Mark Johnston at
Bob Ayers' Willow Springs property, roughly 30 miles southeast of Hollister
and perhaps 20 miles northwest of Pinnacles National Park. Here's the
view from this 3000 ft site, looking south over the rolling hills of rural
San Benito county with my scope in the foreground (24-inch f/3.7 Starstructure)
along with Mark Johnston's 18" f/3.7 Starmaster. Wagner and I had
some equipment issues during set-up -- Mark discovered he forgot a battery
as well as his finder and I had electrical issue causing a short in my
Servocat system. Fortunately, with some help from Mark Johnston the issues
were resolved before it was fully dark.
Observing conditions were good with no wind, clouds or moisture though the transparency was on the low end of typical SQM readings (21.4-21.6) at this site (situated in a dark blue light pollution zone). I observed until 3:00 and then crashed out in my minivan. All in all, a very relaxing, productive evening! The following Wednesday I was off again to observe at Lake Sonoma - more on that adventure in my next report.
This fairly bright gc contains a very bright core and
an irregular 2' halo. At 375x, stars stream out to the east and west
creating an impression of elongation. The core is very lively and
a few brighter stars are clearly resolved, though packed together
very tightly. Roughly 20 stars are resolved in the halo. At 500x,
30-35 stars are resolved (many popping in/out of view) including 8-10
in a clump at the center and close to the core. A single brighter
star is just south of the core and a nice pair (~3" separation)
is in the halo on the NNE side. A string of stars extends out of the
cluster to the north. Easily visible in the 80mm finder at 25x and
the finder field contains M22 just 1.1° SE. This HST image only
includes the central core region of the globular!
Picked up at 200x as a very low surface brightness 2.0'-2.5' glow, peppered with a few stars and a slightly brighter "core" region. At 375x-500x, the brightest mag 14.6 star is on the northwest side with a mag 14.8 star 0.6' SE . A 12" pair of mag 15.2/15.9 stars is near the geometric center (20" SE of the mag 14.8 star) and a mag 16-16.5 star was glimpsed on the northeast side. A brighter mag 14 star is off the northwest side and probably not a member. Pal 12 is situated 2' northwest of a striking mag 11/12 triple, including a 19" pair of mag 11.7/12.3 stars.
This bright, compact triplet is part of the HCG 90 quartet,
along with NGC 7172. At 375x, NGC 7173 = KTS 66A = HCG 90C appeared
bright, moderately large, round, 45" diameter. Contains a relatively
large, very bright core that gradually increases to the center. NGC
7174/7176 (contact pair) is less than 1.5' southeast. NGC 7174 = KTS
66B = HCG 90D is elongated perhaps 3:1 E-W, 0.9'x0.3'. The surface
brightness is irregular with no core region. The galaxy appears to
taper and brighten at the west end with a bend or short kink angling
northwest. The east end merges into the halo of NGC 7176 on the its
southwest end. NGC 7176 = KTS 66C = HCG 90B appeared very bright,
moderately large, round, 1.0' diameter, intense core that increases
to the center, which contains a bright, stellar nucleus. NGC 7172,
just 7' NNW, completes the HCG 90 quartet. This galaxy was logged
as moderately bright, fairly large, elongated 5:2 WNW-ESE, ~1.5'x0.6',
increases in size with averted. Contains a brighter, elongated core
that bulges slightly and the halo has a sharper edge along with south
NGC 7284 is the western component of this double system.
At 375x, it appeared bright, small, round, high surface brightness,
~0.4' diameter. The core of NGC 7285 is cleanly resolved [33"
between center], though very close northeast. The twin nuclei are
encased in a very low surface brightness halo. NGC 7285 is fairly
bright, small, elongated 3:2 E-W, 30"x20", high surface