FSQ fun 15-16 jan 2012

Dick Steinberg

During the unusually clear night of 15-16 january, in addition to the images of 433 Eros presented earlier , a number of wide-field objects were imaged with the 4-inch Takahashi FSQ106 fluorite refractor and Orion SSPro one-shot color camera at Blue Mountain Vista Observatory. (Blatant advertisement: call Frank Colosimo for available space).

The evening started off with a 60-minute wide-field exposure of the Cocoon nebula, IC5146 , with its interesting location at the end of a coal sack in Cygnus, much better seen here than in a recent narrower-field Hyperion image. The central pink region of the Cocoon is a hydrogen emission nebula, while its contrasting bluish envelope shines with Rayleigh-scattered light from nearby stars (a "reflection" nebula). The blue color results from the inverse 4th power wavelength dependence of the Rayleigh scattering process. Thus, blue light at 450 nm is scattered (650/450)^4 or ~4 times more efficiently than 650 nm red light. The same effect gives rise to the blue hue of a clear (remember that?) sky.

The next three objects are familiar fixtures of the winter sky:

• the Pleiades (M45), a very young and nearby (~400 ly) open cluster in Taurus. The nebulous regions of M45 are currently thought to be interstellar dust clouds through which the cluster just happens to be passing;
• the Orion Nebula (M42), one of the few nebulae bright enough to be visible to the naked eye. Its distance, estimated at only about 1300 ly, makes it the closest region in which vigorous star formation is known to be taking place. In about 100 million years or so, the (overexposed ) white region containing the famous trapezium, may evolve to an open cluster similar to today's  M45; and
• the Rosette nebula (NGC2237) in Monoceros, a hydrogen emission nebula, with its emerging open cluster, NGC2244. Other NGC numbers attributed to various parts of the Rosette nebula are NGC 2238, 2239 and 2246.

Other objects imaged were the highly distorted galaxy in Ursa Major NGC3718   (also see a recent DVAA talk ) and the Canes Venatici galaxy pair NGC4631 (the edge-on "Whale") / NGC4656 (the distorted "Hockey Stick"). The latter two galaxies were discussed in an excellent APOD presentation.

--

Astroimage webpage:
http://www.physics.drexel.edu/~steinberg/Astro Welcome.html
Currently 703 files, 84 folders, 2770 MiB