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(IAAC) Obj: M33 (Tri Pinwheel) - Inst: 5" f/5 refractor
Observer: Lew Gramer
Your skills: Intermediate
Date and UT of Observation: 1997-07-4/5, 05:10 UT
Location: Savoy, MA, USA (42N, elev 700m)
Site classification: rural
Limiting magnitude: 7.2 (zenith), intermittent cumulus
Seeing: 5 of 10 - mediocre, intermittent cumulus
Moon up: no
Instrument: 5" f/5 Jaegers refractor on altaz mount
Magnification: 25x
Filters used: None, UHC
Object: M 33 (Triangulum Pinwheel Galaxy)
Category: Spiral galaxy
Constellation: Tri
Data: mag 5.7 size 70'x40'
RA/DE: 01h34m +30o40m
Description:
Easily found sweeping W of alpha Tri. M33 fills the center of the
2o field of view very nicely, even showing a clear enough outline
to render its inclined disc-shape visible (with some imagination).
Several tiny fuzzies revealed the locations of unquestionable HII
regions in the galaxy - easily confirmed by "blinking" them with
a UHC filter. [These might variously have been ANY of M33's named
nebulae, including ngc588, ngc592, ngc595, or ngc604 - or even the
fainter ic135, ic138, ic142, or ic143! Just a painful reminder to
always note both number and POSITION when observing possible sub-
objects in M33, M31, M101, or similar large objects!] In addition,
an indescribable myriad of stellarings were occasionally noted in
the disk, although it seemed impossible with such a low power to
readily distinguish mere stars involved in the foreground from the
true smaller HII regions. Neither the unfiltered view nor the UHC
would reveal any direct hints of M33's spiral arm structure, in
spite of the fact that the entire face of the disk was a mass of
mottlings and brightenings. M33 was QUITE A SIGHT sitting in the
midst of an almost-black wide field! Maybe worth a look later on
this year, with a labelled photograph in hand, (such as the one in
the Luginbuhl&Skiff _OH_) just to be able to say what true features
can actually be visible at such a low power in such a small scope!
NOTE: Another fine image of M33, with all its brighest HII regions
and/or star clouds labelled, can be found on the Web at:
http://www.seds.org/messier/more/m033_map.html
(Formerly, an even more detailed map resided here - but no more:
http://www.ezinfo.ethz.ch/astro/atlas/tri/m33.html
)