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(IAAC) Obj: ngc 2024 (Flame Nebula) - Inst: 20" f/5 dob newt



Observer: Lew Gramer
Your skills: Intermediate
Date and UT of Observation: 1997-10-30/21, 05:30 UT
Location: Miles Standish State Forest, MA, USA (41N, elev 30m)
Site classification: rural
Limiting magnitude: 6.5 (zenith), intermittent cirrus and fog
Seeing: 7 of 10 - pretty good, but variable down to 4
Moon up: no
Instrument: 20" f/5 Tectron truss-tube dob Newtonian reflector
Magnification: 70x, 210x, 420x
Filters used: None, UHC
Object: ngc2024 (Flame Nebula)
Category: Emission nebula
Constellation: Ori
Data: mag 2.05 (star)  size 30'x30' (catalog)
RA/DE: 05h40m  -02o27m
Description:
The famous spreading Flame, so easily found just a wide eyepiece
field ESE of Alnitak (zeta Ori), is a probing test of truly dark
skies. From the suburbs, it is hardly to be seen at all even with
well trained averted vision. From an extremely dark site however
(such as Evans Notch in northern New Hampshire or Long Key, FL),
it leaps up to become one of the most fascinating emission nebulae
in the sky, fairly showing the wispy multifold shape (and yes even
the color) that gives it its name. With memories of this latter
view firing my imagination tonight, I swung my dob to face this
flame amid the glittering white myriad of Orion's stars. At first
glance with a 55' field at 70x, the nebula was nearly obliterated
by Alnitak so close by. Clearly, the skies at Miles Standish are
not the very darkest on earth, but do offer the best view of this
object I have so far seen in Eastern MA. Switching to a 25' field
at 210x to edge the star out of view, n2024 suddenly springs up
to fill the eyepiece. Particularly striking in this narrowed view
is a dark arc in the brightish nebula, sweeping gracefully from
SW toward center and then SE again. Just W of this arc is a very
bright bar of nebulosity, with 3 mag 9 and 10 stars involved. On
a very transparent night from even this site, an hour might be
spent tracing the wisps leading off this bright bar. Switching
back to 70x with the UHC, and carefully avoiding zeta and nearby
multiple sigma Ori, the "Flame" suddenly turns into a "Box" of
false-colored haze, empty in the center and "opened" on the N end
by a dark nebula. Comparing this view with the one at 210x, the
bright bar described above becomes the W edge of the box, while
the E edge of the box - so striking with UHC at 70x - had hardly
been distinguishable at 210x. Going to yet higher magnification
(420x) to increase contrast in spite of the intermittent fog,
the S edge of the box was dissolved into indistinct fragments by
previously unnoticed bifurcations of the dark arc (noted above).
Finally back at medium power with the UHC, the inside of the box
began to show mottled and wispy hints of faint nebulosity. Another
object worthy of study on those crystalline-clear Wintry nights!
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Karen Simmons & Lew Gramer dedalus@alum.mit.edu http://www.tiac.net/users/lewkaren
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