[AZ-Observing] Celestial Spelunking
- From: billferris@xxxxxxx
- To: az-observing@xxxxxxxxxxxxx
- Date: Sun, 28 Aug 2005 20:06:44 -0400
Last night, I was able to take advantage of the current lull in the Southwest
US summer monsoon and do some observing from a dark sky site north of Flagstaff
at Sunset Crater Volcano National Monument. Here, are excerpts of my notes on
four objects, all observed with my 18-inch Obsession.
Palomar 6: http://members.aol.com/billferris/pal6.html
"Invisible under direct scrutiny, the cluster appears intermittently at first
with averted vision. After several minutes observation, the 2' diameter patch
of fog is consistently visible with an averted stare. There is no hint of
granularity in this 11.6 magnitude globular, which is not surprising
considering the typical cluster member glows dimly at 19.1 magnitude."
Palomar 11: http://members.aol.com/billferris/pal11.html
"The globular star cluster emerges from the late summer sky under direct
vision, a 7' diameter patch of light. Its estimated brightness is 9.8
magnitude. Several brighter members are visible and these give Palomar 11 a
salty or slightly grainy appearance. The
typical cluster member shines in the mid-16th magnitude range. I wonder what
Palomar 11 looks like in a 25-inch or larger instrument."
IC 5146 "Cocoon Nebula":
http://members.aol.com/billferris/ic5146.html
"My sketch combines two views. The first is unfiltered through my 22mm Nagler
Type 4. The nebulosity is smooth and rangy, seemingly filling most of the
field. The second is through the same eyepiece fitted with a UHC filter. The
nebulosity is better defined, an
obvious dark lane bisecting the central brightest portion of the nebula into
eastern and western halves."
Sharpless 2-155 "Cave Nebula":
http://members.aol.com/billferris/sh2155.html
"My sketch presents a 109X view in the 18-inch Obsession. The 22mm Nagler
produces a 45 arcminute diameter true field, much of which is dressed by a
gauzy nebulosity. Fitting the widefield eyepiece with an OIII filter produces a
better defined view, the one presented at left. 6.5 magnitude HD 216945 anchors
the southwest quadrant. There appears to be a noticeably brighter patch of
nebulosity immediately south of this star. From here, Sharpless 2-155 spreads
north toward a clump of some 20 stars, the brightest of these being 7.7
magnitude HD 217086. Then, the delicate ribbon of light bends to the east and
six stars drawn just inside that border. Returning to HD 216945, a broad
section of filamentary glow extend to the south. Just below center in my
rendering, a patch of foggy light has collected alongside a string of four 10th
to 12th magnitude embers. It's all very delicate and subtle, often appearing
best to the averted gaze."
Regards,
Bill in Flagstaff
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