DEEP SKY TREASURES The Observers Notebook Falls Faint Fuzzies

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DEEP SKY TREASURES The Observers Notebook Falls Faint Fuzzies Powered By Docstoc
					                                                             Further S in Cetus barely over 3˚ SSE of Diphda (β
           DEEP SKY TREASURES                                Ceti) is the large and lovely NGC-247, a nearly edge-
                                                             on spiral galaxy. Its slim and misty low surface
           The Observer's Notebook                           brightness mag. 9.2 glow is spread out over its nearly
              “Fall's Faint Fuzzies”                         20' extent. In most telescopes it appears to be
                                                             “dangling” from a 9th mag. star at its S tip.
                     by John Davis                           Swinging our gaze up northward now to our guidepost,
                                                             the W end of the fairly bright and “flattened out”
                                                             triangle of Aries, let’s scan 61/2˚ SW of γ Arietis
                                                             (Mesartim, a very nice double star) to locate mag. 3.7
For anyone who wants to experience pleasurable
                                                             Eta (ή Piscium in the dim constellation Pisces. Now
observing, the fall skies offer a wealth of opportunities.
                                                             slide back about 1˚ 20' ENE of ή and 1˚ SW of a pair of
Looking back over almost a year here in the northeast,
                                                             stars of 6th and 7th magnitude where you should pick up
we have seen at first an unusually warm and mild start
                                                             the faint soft glow of the 9.4 mag. face-on spiral galaxy
to a winter ending up with lots of snowstorms; a late
                                                             M-74. Its low surface brightness reveals only mottling
spring, then a summer filled with a chain of violent
                                                             in most scopes under 10” with a brighter condensed
damaging thunderstorms, followed by some beautiful
                                                             core. Discerning M-74’s spiral arms can be very
weather in the late summer and early fall. So, after a
                                                             difficult but they can be detected in larger scopes of
crazy year of extremes in the weather, most of us will
                                                             about 10” and up.
welcome a “normal” and “typical” autumn season with
cool, clear and crisp evenings providing dark
                                                             About 15˚ further N in the small constellation
transparent skies that offer some of the best
                                                             Triangulum, in a spot about 11/2˚ SW of a point lying
opportunities of the year to observe a few of “Fall’s
                                                             one third of the distance on a line drawn from 3.5 mag.
Faint Fuzzies.” There are many to be seen, especially
                                                             ά Tri to 2nd mag. β Andromedae (Mirach), we can find
those dim objects with low surface brightness that
                                                             the large (67' x 42') mag. 5.7 glow of M-33 the
present somewhat of a challenge, while at the same
                                                             Triangulum (or “Pinwheel”) Galaxy, with M-31 a
time giving us a lot of satisfaction when we are able to
                                                             major member of our local group of galaxies. M-33 is
find and observe them. In previous “DST” columns
                                                             a beautiful but dim (mag. 14.2) low surface brightness
over the years, we’ve featured a large number of these
                                                             near face-on spiral, one that we’ve covered in depth in
dim challenging objects. In fact, several immediately
                                                             at least two of our past “DST” articles. If you have
come to mind. We’ll call them the “Top Ten” of
                                                             excellent eyesight, under perfect transparent dark sky
“Fall’s Faint Fuzzies.” By the way, an excellent aid in
                                                             conditions you can even glimpse M-33 with the naked
planning your observing, I find, is Sky & Tel’s superb
                                                             eye. In medium and especially larger aperture scopes
little Pocket Sky Atlas by Roger Sinnott.
                                                             14˜ and up its dramatic S-shaped spiral structure
                                                             becomes very evident along with several distinct knots
Most of these “Top Ten” as you might expect are
                                                             of star clouds and H-II regions, most notably, NGC-
galaxies, but we’ll start with two very nice planetary
                                                             604, a very bright and large star cloud / H-II region
nebulae. In the southwestern sky in Aquila (a summer
                                                             near the NE end of a prominent spiral arm and adjacent
object as well) look just under 4˚ NNW off 3rd mag. δ
                                                             to a star in the foreground. As you’ve noticed, we’re
Aquilae to find the gauzy round shell, 1.8' across, of
                                                             skipping over the brighter galaxies of the fall sky in
11th mag. NGC-6781. It lies half a degree E of a 6th
                                                             this tour of faint fuzzies, including Andromeda, M-31,
mag. star. You might notice a slightly darker center to
                                                             and its adjacent satellite galaxies, M-32 and M-110.
its disk, and a brighter southern rim.
                                                             We will however look for two more even dimmer
                                                             satellites of the huge Andromeda galaxy. We’ll start
Moving now to Cetus, look just over 7˚ N of 2nd mag. β
                                                             our star hop from M-31 and head directly toward bright
Ceti (Diphda) where you’ll spot 5th mag. phi (ф1, at the
                                                             2nd mag. α Cas. (Schedar). Slightly less than halfway
W end of the 3˚ long arc of two other 5th mag. stars:
                                                             to α Cas. or roughly 7˚ NNE from M-31 you’ll
phi3 and phi2. Now slide to a spot 11/2˚ SSE of ф1 and
                                                             encounter a 11/4˚ long row of three stars oriented N-S
11/2˚ SSW of ф2 and forming an equilateral triangle with
                                                             along your line of sight: 5th mag. π Cas., then a 6th
those two, where you’ll discover the beautiful mag.10
                                                             mag. star, and at the N end of this little row 4.5 mag.
NGC-246, a large (3.8') misty round planetary with a
                                                             omicron Cas. (ο or 22 Cas.). Now make a 90˚ right
12th mag. central star and two other embedded stars.
                                                             angle turn from ο Cas. and slide just 1˚ W to find the
                                                             very dim glow of 9.2 mag. NGC-185, a dwarf elliptical
and satellite galaxy of M-31. With a surface brightness       due S from there (directly away from Polaris) and
of only mag. 14.7, NGC-185 is spread out to over 10'          sliding just under 3˚ we’ll find a 6th mag. Star, and one
though much less of its oval glow is visible in amateur       more 6th mag. star 1.4˚ SSW from there. The large and
scopes. In larger apertures of 16˜ and up it will show a      very dim (surface brightness 15.0) glow of the face-on
little mottling in the brighter core. Now slide another       spiral galaxy IC-342 lies between these latter two 6
degree W past two diagonally aligned 7.5 and 8th mag.         mag. stars somewhat closer to the more northerly one
stars where you’ll arrive at the very faint mag. 9.5          and slightly to the E of a line connecting the two.
dwarf elliptical NGC-147, with a surface brightness of        Another star hop I use is by star hopping from γ Persei
only 14.7 and its oval glow spread out even more than         in the “head”of Perseus 11˚ NE to a row of four mostly
its neighbor. Both of these dim, low surface brightness       5th mag. stars aligned roughly E-W, and with the well
elliptical satellites of The Andromeda Galaxy, M-31           known (and beautiful) asterism, “Kemble’s Cascade,”
are challenge objects, with NGC-147 significantly the         running NW-SE directly through the eastern end of that
tougher challenge. You’ll need a very dark transparent        row of four stars. From the middle of that 4-star row I
night to see them well, but they are visible in scopes as     hop due N 2.7˚ to a 4th mag. star and on further 1.7˚
small as 4” aperture.                                         NNW to that aforementioned 6th mag. star that lies just
                                                              55 S of IC-342. This galaxy appears quite large,
While you’re in the neighborhood you might want to            spanning well over 20'. In a scope at low power you
check out a “not-so-dim” galaxy NGC-278. You’ll               will likely see a glow about 12' – 15' across and a fairly
find it on the “other side” of that 11/4˚ long row of stars   bright core sprinkled across with many foreground
11/2˚ SE of 4.5 mag. ο (22 Cas.). At mag.10.8, its small      stars, including a prominent straight line of stars in the
round (2.6') g'low is easily visible and brightens            halo just SW of the galaxy’s brighter core. With
sharply at its core.                                          exceptionally good sky conditions and good optics in
                                                              larger scopes you might be able to trace a very dim
An easier “faint fuzzy” is the very popular NGC-891           pattern of spiral arms through the halo. The dim
in Andromeda, 31/2˚ due E of the beautiful gold and           appearance of (fairly near – 12 million LY) IC-342 is
blue 2nd mag. double star, γ And., Almach. You can            the result of its unfortunate position near the edge of
also slide your finder just over 31/2˚ ESE of Almach          the Milky Way, where it is obscured by the gas and
where you’ll see a binocular double. Its 7.5 mag.             dust in the plane of our own galaxy. Nonetheless, I
companion, 5' away on the north, points NNE 44' to            have viewed IC-342 with 20 x 80 binoculars from
another 6.5 mag. sun. Now, just 20' NW from that star,        Arunah Hill, and it has reportedly been glimpsed with
your scope should show the thin 13' x 2.8' elongated          smaller binoculars.
low surface brightness glow of the beautiful edge-on
9.9 mag. spiral NGC-891. It ranks second only in              In any discussion of “Fall’s Faint Fuzzies” we
popularity to NGC-4565 in Coma Berenices for edge-            shouldn’t leave out Stephan’s Quintet, that beautiful
on galaxies among amateur observers. However, its             and remote little clump of 13th magnitude galaxies just
low surface brightness (13.7) makes it difficult in           half a degree SSW of the bright spiral galaxy NGC-
anything less than a very clear dark sky. Under good          7331 in Pegasus. This makes a nice challenge for
conditions in apertures in the range of 12˜ you’ll be         scopes in the 10˜ – 13˜ aperture range.
challenged and will need averted vision to make out
the dark dust lane bisecting the thin “needle” of this        We could go on to discuss many more faint fuzzies
edge-on galaxy. Larger apertures will reveal a brighter       because as observers we can never run out galaxies.
core, bright mottled patches, and some embedded faint         Space here does not allow that, however. So instead,
stars along its length. The dust lane also becomes            why not pick up your gear, and head out to those dark
more distinct in larger scopes and at magnifications of       skies such as what you’ll find at Arunah Hill.
100X to 150X especially in apertures of 16˜ to 20˜ or

Finally, our last “faint fuzzy” is a somewhat difficult
star hop into the dim region of Camelopardalis. At the
“left end” of the “W” of Cassiopeia, if we extend a line
from δ to ε Cas. the same distance, 5˚, out toward the
NE we’ll come to 4.5 mag. iota (ι) Cas. By continuing
in the same NE direction a little over 8 more degrees,
we arrive at 4.6 mag. γ Camelopardalis. Now turning
Photo of IC-342 courtesy of National Optical Astronomy