The exceptionally red N-type semi-regular variable
TX (19) Piscium is worth locating. It is easily found, near
the ‘circlet’ made up of È, ı, Áand Ï; as it never falls
below magnitude 7.7 it is always within binocular range,
and its hue is almost as strong as that of the famous Garnet
Star, ÌCephei.
The galaxy M74, discovered by Méchain in 1780, is
one of the less massive spirals in Messier’s catalogue; it
can be seen with a 7.6-centimetre (3-inch) telescope, but
can be rather elusive. It lies within a couple of degrees of
ËPiscium. There is a fairly well-defined nucleus, but the
spiral arms are loose and faint, so that even Sir John
Herschel mistook it for a globular cluster. The distance is
around 26 million light-years.
One object in Pisces which is worth finding, though
requiring at least a 25-centimetre (10-inch) telescope, is
the white dwarf Wolf 28, better known as Van Maanen’s
Star; it was discovered in 1917 by the Dutch astronomer
Adriaan van Maanen. Its position is R.A. 00h 46m.5, dec.
05 degrees 09 minutes, about two degrees south of ‰
Piscium. Its visual magnitude is 12.4, and it is one of the
dimmest stars known, with a luminosity only about^1 / 6000
of that of the Sun. The diameter is about the same as that
of the Earth, but in mass it is equal to the Sun, so that the
density must be about a million times that of water; if you
could go there and stand on the surface, you would find
that your weight has been increased by about 10 million
times. The proper motion amounts to nearly 3 seconds of
arc per year, and the distance is less than 14 light-years, so
that this is one of the nearest known of all white dwarfs.STAR MAP 13
The globular cluster M15
in Pegasus, photographed
by Bernard Abrams using
a 25-cm (10-inch) reflector.
It can be found near to Â.BRIGHTEST STARS
No. Star R.A. Dec. Mag. Spectrum Proper name
hm s ° ‘ ”
8 Â 21 44 11 09 52 30 2.38 K2 Enif
53 ‚ 23 03 46 28 04 58 2.4 (max) M2 Scheat
54 · 23 04 45 15 12 19 2.49 B9 Markab
88 Á 00 13 14 15 11 01 2.83 B2 Algenib
44 Ë 22 43 00 30 13 17 2.94 G2 Matar
42 ̇ 22 41 27 10 49 53 3.40 B8 Homan
48 Ì 22 50 00 24 36 06 3.48 K0 Sadalbari
Also above magnitude 4.3: ı(Biham) (3.53), È(3.76), l(4.08), Î(4.13), Í(Al Suud al Nujam) (4.19), (4.29).
Alpheratz (·Andromedae) was formerly included in Pegasus, as ‰Pegasi.
VARIABLE
Star R.A. Dec. Range Type Period Spectrum
hm °’ (mags) (d)
‚ 23 03.8 28 05 2.4–2.8 Semi-reg. 38 M
CLUSTER
M NGC R.A. Dec. Mag. Dimensions Type
hm °’ ’
15 7078 21 30.0 12 10 6.3 12.3 Globular clusterThe brightest star is Ë(Alpherg), R.A. 01h 31m 29s, dec.+15° 20’ 45” mag. 3.62. Also above magnitude 4.3: Á(3.69),
·(Al Rischa) (3.79), ˆ(4.01), È(4.13), Ô(Torcular) (4.26), ı(4.28), Â(4.28).
VARIABLE
Star R.A. Dec. Range Type Period Spectrum
hm °’ (mags) (d)
TX 23 46.4 03 29 6.9–7.7 Irregular - N
DOUBLES
Star R.A. Dec. P.A. Sep. Mags
hm °’ ° ”
· 02 02.0 02 46 279 1.9 4.2, 5.1 Binary, 933y
̇ 01 13.7 07 35 063 23.0 5.6, 6.5
GALAXY
M NGC R.A. Dec. Mag. Dimension Type
hm °’ ’
74 628 01 36.7 15 47 9.2 10.2 9.5 Sc GalaxyPEGASUSEXTINCTION
TABLEPISCESAltitude above Dimming in
horizon, ° magnitude.
1 3.0
2 2.5
4 2.0
10 1.0
13 0.8
15 0.7
17 0.6
21 0.4
26 0.3
32 0.2
43 0.1
Above this altitude, extinction
can be neglected.Gb Atl of Univ Phil'03stp 2/4/03 7:42 pm Page 243