OF THE ROGER N. CLARK

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M74 (NGC 628), GALAXY IN PISCES
R.A. Olh 36.7m, Dec. 15° 47' (2000.0)
Technical. M74 was first seen in 1780 by
Pierre F. A. Mechain. It is a face-on spiral
about 30 million light-years distant and
80 000 light-years wide. Its mass is estimated
at about 40 billion suns. On deep photographs
M74 shows beautiful spiral arms about
3000 light-years thick, with dust lanes
tending to outline their inner edges.
VISUAL ASTRONOMY OF THE DEEP SKY
Visual. M74 is often regarded as the
difficult Messier object to locate. With a
meter of 9 arc-minutes and a total
of 9.0, M74 ought not to be hard. T
culty is probably due to improper use of
nification. Again, guides often suggest
low powers, since the average surface b
ness is low at 22.4 magnitudes per
arc-second. But most of the light is
trated in the small nuclear region about
arc-seconds in diameter. So at low power
galaxy can look like a field star. Higher
ers show the nuclear region as a disk.
In the 8-inch under only moderate
188x gave the best view. The bright
region was surrounded by a faint,
glow. M74 can be seen in telescopes as
as a 2.4-inch refractor. Under excellent
I have seen it in the 3-inch finder at 31 X
even the 2.4-inch finder at 7.9x.
A VISUAL ATLAS OF DEEP-SKY OBJECTS
Photograph of M74. South is up . (Courtesy National
Optical Astrononry Observatories.)
5'
Scale 1.2 arc-min/cm
8-inch filLS Cassegrain
12.4mm Erfle (188X,
best view)
20mm Erfle (117X)
Drawing of M74.
Viewing Distance (cm)
25 X : 1 15 200 X: 14
50 X: 57 300X: 10
100X: 29 400 X: 7
air mass: 1.21, faintest star: 14.0 at zenith, 188x;
no tracking
1/16/83 6:45-6:55 UT at Barbers Point, Hawaii;
R. Clark
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