(IAAC) Obj: M38, NGC1907, NGC1857, Czernik 20, Czernik 21 (OPEN CLUSTER SMORGASBORD) - Inst: 17.5" f/4.5 dob
Observer: Lew Gramer, Michael Carnes
Your skills: Intermediate (some years)
Date/time of observation: 2130 EST, 24 Nov 2000
Location of site: Westford MA USA (Lat 43N, Elev 80m)
Site classification: Exurban
Sky darkness: 5.9 <Limiting magnitude>
Seeing: 7 <1-10 Seeing Scale (10 best)>
Moon presence: None - moon not in sky
Instrument: 17.5" f/4.5 ATMs of Boston club dobsonian
Magnification: 60x, 90x, 220x
Object(s): M 38, NGC 1907, NGC 1857, Czernik 20, Czernik 21
Category: Open cluster.
Class: III 2m/II 2r, II 1mn/I 1m, II 2m/I 3m, II 2r, IV 3r
Mag: 6.4 9.5m*, 8.2 11.26m*, 7.0 7.4m*, ?, ?
Size: 21' irr, 7' round, 6', 18', 9'
Position: RA 05:28.6 Dec +35:50
During a period of broken cirrus overcast, we decided to focus on
what would still be observable within less-hazy "holes", and that
meant the wonderful array of Open Clusters in the Winter Sky! In
particular, while taking a peak at the "chestnut" OC M38 with new
but very knowledgeable ATMs member, Michael Carnes, the idea some
how came about of exploring fainter OCs in that area of Auriga...
So we spent little time on that lovely Messier Open Cluster tonight:
it was in effect just a stop-over on the way to fainter game! Stiil,
at 220X, this mighty object was a breathtaking scattering of stars,
all falling in a narrow brightness range of from mag 10 to mag 12,
which completely filled the 22' field of view of a 9mm Nagler.
Moving SSW a mere 30-40' at 60x, Michael immediately happened on a
gorgeous *tight knot* of bright stars, impossible to miss at mags 8
and 9 and only maybe 5' wide - NGC 1907. (Note the disagreement with
catalog magnitudes?!) At 90x and then 220x I counted 12 stars, all of
them mostly mag 10 or brighter, with little or no background seen of
fainter stars, nor any hint of unresolved stars. Amazingly tiny and
bright to be so poorly known, this OC should be observable in an 8"!
Heading back up to M38 and then NW just 20', we encounter a third OC
in this little Winter tableau, the very faint Czernik 21. This is a
smudge of unresolved stars, only just visible to averted vision half
way from M38 to a bright, pretty pair of stars mag 8, colored orange
and yellow (HD35202 and HD35089). The smudge was quite small, making
it fairly distinct at 220x in spite of its faintness.
Using Herald & Bobroff's fine AstroAtlas to extend our OC hunt a bit
further afield, we headed north of M38 more than three field widths
in the 35mm (about 4o): Just before hitting mag 5 lambda Aur, I hit
on a field containing a lovely group of asterisms. Filling the 35mm
field just SE of lambda Aur is a lovely "Crux" (Southern Cross-like)
pattern of stars mags 7 to 9. At the center of this crux is a pretty
triangle of stars mags 9 to 10, colored yellow, blue, and gray. At
the S (bottom) point of the 'crux' is a stand-out orange star of mag
9. Just inside and involved with this southern point of the cross is
a sparse but diverse clustering of stars from mags 9 all the way to
the point of resolution (maybe mag 14 or 15), and apparently beyond.
The faintest stars of this subtle grouping continued to be confirmed
at 90x and even 220x. This bottom of the cross group was NGC 1857.
Just North of NGC 1857, between the orange cross-point and that trio
of colorful stars at the center of the Cross, a subtle scattering or
smudge of very faint stars - perhaps mag 13 and fainter - could just
be seen with averted vision. Though I cannot confirm their identity,
I assume these were the obscure OC Czernik 20 - or perhaps its core?
All in all, this was certainly an enjoyable way to spend a hazy hour
at the eyepiece... Thanks to Michael for the inspiration to do this!
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