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MARCH 2011 VIEWING LIST
Object
Type
14” Scopes
M76*
M42*
M1*
Abell 21**
NGC 2392*
M46/NGC2438*
M81*
M82*
NGC 3115**
NGC 4236**
PN
EM/RN
SR
PN
PN
OC/PN
Gal
Gal
Gal
Gal
4” Refractor
M37
OC
M35
OC
UU Aurigae
Carbon star
M41
OC
Alpha Geminorum “
Size
3’
1.5
6’
12’
40”
28’
21’
9’
7’
18
24’
28’
38’
-
Distance
3400 LY
1600 LY
6300 LY
1000 LY?
3000 LY
5400 LY
12,000,000 LY
12,000,000 LY
22,000,000 LY
11,700,000 LY
4400 LY
2800 LY
1800 LY
2300 LY
52 LY
Coordinates
01h 42’
05h 35’
05h 35’
07h 29’
07h 29’
07h 42’
09h 56’
09h 56’
10h 05’
12h 17’
+51 34’
-05 27’
+22 01’
+13 15’
+20 55’
-14 49’
+69 04’
+69 41’
-07 43’
+69 28’
05h 52’
06h 09’
06h 36’
06h 47’
07h 35’
+32 33’
+24 20’
+38 27’
- 20 45’
+31 53’
Abbreviations:
MS = Multiple Star, EN = Emission Nebula, RN = Reflection Nebula, Gal = Galaxy, GC = Globular
Cluster, LY = Light Year, OC = Open cluster, PN = Planetary Nebula, SR = Supernova Remnant,
CS = Carbon Star, * = Video imaging optional, ** = Video imaging recommended
MARCH 2011 OBJECT DESCRIPTIONS
M76 in the constellation Perseus (PURR-see-us) is commonly known as the Butterfly or the Little Dumbbell Nebula. It is a
standard planetary nebula with a 16th magnitude central star. The unusual appearance is due to the angle of the nebular
ring that is expanding outward from the white dwarf at about 42 K/sec. Most of the visible light is emitted in the OIII doubly
ionized Oxygen band so the use of a nebula or OIII filter will enhance the image.
M42 in the constellation Orion (oh-RYE-un) is the brightest diffuse nebula in the sky. Known as the Great Orion Star
Factory, this combined emission/reflection nebula has been found to harbor scores of newly forming stars. Use low
magnification, with and without a nebula or OIII nebular filter, for the extensive nebular structure, and higher magnification
to detect the Trapezium, a cluster of bright young stars in the central portion of the cloud.
M1 The Crab Nebula in the constellation Taurus (TAW-rus) is the brightest and most famous supernova remnant in the
sky. The expanding gas cloud is the result of an exploding star observed in 1054 A.D. At it’s brightest it was four times
brighter than Venus and was a visible daylight object for 23 days. The gaseous shell is about 10 light years in diameter
and is still expanding outward at the high rate of 1800 kilometers per second. Best view can be had with a 22mm
eyepiece with the Broadband filter attached.
Abell 21 is a planetary nebula in the constellation Gemini (GEM-in-eye). Commonly known as the Medusa Nebula, this
crescent-shaped,10th magnitude object is the remnant of the dying gasps of a G-type star such as our own Sun. Fairly
bright, it may be faintly seen either through the 4” with an OIII filter, or fairly reliably through the 14” scopes. Distance
estimates vary widely, from 1000 to 5600 light years. To observe this object you must manually enter the coordinates.
NGC 2392 is a planetary nebula in the constellation Gemini (GEM-in-eye). Discovered by William Herschel in 1787, it is
widely known as the Eskimo Nebula. Through the 14” scopes you will see an 8 th magnitude star surrounded by a faint 10th
magnitude nebulosity. On exceptional nights the nebula displays an intense blue/green glow. The central star is a white
dwarf about 40 times brighter than our sun. The planetary has a diameter of about 6/10 of a light year. This is a good
candidate for either the Broadband or the OIII filter for visual observing in order to accentuate the nebulosity.
M46 is an open cluster in the constellation Puppis (PUP-iss). It is composed of approximately 150 stars of 13th magnitude
or brighter within it’s 30 light year diameter. The cluster is estimated to be about 300 million years old. Superimposed
upon the cluster is a faint Planetary Nebula, NGC 2438, which is about 2900 light years away. From the difference in
object distances it is obvious that the two objects are not associated, but merely in the same line of sight. If the faint
nebula is not easily seen, try using a Broadband or OIII filter and slightly higher magnification to sort it out from the
surrounding stars.
Note: The duo of galaxies below is fairly bright and is best viewed as a pair. Use the maximum magnification that
will show both in the same field of view. Try using the 4” and either the 22mm or the 31mm to observe the pair.
These galaxies warrant much more than a brief peek. Spend some time on them and you may be surprised at the
detail that may be gleaned from the faint light.
M81 is a spiral galaxy of 6.8 magnitude in the constellation Ursa Major (URR-suh-MAY-jer). Seen nearly face-on, it
resides 12 million Light Years away. Over 70 globular clusters have been discovered orbiting this galaxy. M81 and
adjoining galaxy M82 had a close encounter about 600 million years ago, resulting in a prolonged period of intense new
star formation that continues today. This is a prime candidate for the east scope.
M82 is an irregular galaxy of 8th magnitude in the constellation Ursa Major (URR-suh-MAY-jer). Also known as the Cigar
Galaxy for it’s elongated shape, M82 is also about 12 million Light Years distant. The close encounter with M81 described
above distorted the shape of this irregular galaxy, creating many bright, turbulent star-forming regions. Over 100 globular
clusters have been observed orbiting this galaxy.
NGC 3115, common known as The Spindle, is a type S0 lenticular galaxy glowing at nearly 9 th magnitude. Floating in the
dim constellation Sextans (SEX-tanz), it was discovered by Wm. Herschel in 1787. The thin disk is inclined about 24
from edge-on and has a diameter of about 40,000 light years. Compare this to the 100,000 light year diameter of our own
Milky Way. An interesting fact is that, while NGC 3115 has an estimated mass of only 7 billion suns, the Hubble
Telescope has proven the existence of a 2 billion sun black hole in the central core. Once again, compare that to the
100+ billion sun mass of the Milky Way with its 4.2 million sun black hole. There is much more to The Spindle than meets
the observer’s eye.
NGC 4236 is a barred spiral galaxy in the constellation Draco (DRAY-co). Located about 11.7 million light years away, it
has a listed magnitude of 9.6. This seems bright enough to be an easy target to spot, but there is a problem. With an
apparent size of over 18 arc minutes (The Moon is about 30 arc minutes across) the light is spread over a fairly large
patch of sky. While this object is considered a faint target for scopes of 100mm aperture, I’ve had little luck with our 4”
refractor. Since NGC 4236 is a so-called starburst galaxy, the light is unevenly spread along the major axis and appears
clumpy through larger scopes..
M37 in the constellation Auriga (awe-RYE-gah) is a rich open cluster with an apparent diameter of about 24 moa. It is
about 27 light years in diameter. In the 4” refractor you should be able to count more than 150 stars. This is one of the
finest open clusters in the sky when viewed through a small scope. Best view is through the 31mm eyepiece on the 14” or
the 22mm eyepiece through the 4” scope.
M35 in the constellation Gemini (GEM-in-eye) is a large, well-populated open cluster with a diameter of 30 light years. It
has over 120 stars above 13th magnitude. The cluster is about 110 to 150 million years old. About 15 arc minutes away
lies a densely packed open cluster, NGC 2158, that looks more like a globular cluster. This dim apparent companion is
actually much farther away at about 16,000 light years.
UU Aurigae in the constellation Auriga (awe-RYE-gah) is a carbon star with a variable light output. At an average
magnitude of 5, this star stands out to observers due to its notable reddish-orange tint. The color derives from carbon dust
in the star’s relatively cool upper atmosphere. Locate it by keying in the celestial coordinates. It is worth the extra work.
M41 in constellation Canis Major (KAY-niss MAY-jer) is an open cluster slightly larger in apparent diameter than the full
moon. Shining at about 5th magnitude, this is a fine object for small telescopes Look for the reddish star shining at 7 th
magnitude in the center of the cluster. Use the 4” with the 22mm eyepiece for a contrasty view.
Alpha Geminorum commonly known as the star Castor in the constellation Gemini (GEM-in-eye) is a fascinating triple
star with a secret. Each of the stars in this triple system is itself a spectroscopic double star. So when we gaze at Castor
we are in fact looking at a six star system. Star A (Magnitude 1.9) and star B (mag. 3.0) orbit each other every 467 years.
Distant star C is a faint 9th magnitude companion that orbits the A & B pair in a yet-to-be-determined orbital period. While
the optical pair, Castor and Pollux ( Alpha & Beta Geminorum) are visually associated in the sky, they are not physically
associated in any way, being many light years apart.
Forrest Lockhart