Journal

Eastern arm of the Veil nebula

I remember when I went through my boyhood comics stage I read an issue of Flash Gordon with Flash of course on his way to some important mission. He stopped on some other-worldly planet to “witness one of the universe’s most astounding events – a star about to go supernova.” I distinctly remember him using special glasses to protect his eyes. He stood there entranced as the star proceeded to briefly outshine an entire galaxy in its final explosive death throes. I wonder if anyone else out there remembers that scene so vividly. The scene above is the partial result of a supernova which occurred between five and eight thousand years ago. It is around 1,500 light years away and is a mere 100 light years (!) across. When some stars die, they really do it right. The Veil nebula lies in the constellation Cygnus, which is in the galactic plane – thus the profusion of stars. This image is the result of 16 4-minute exposures and 7 darks. Sans lens, the rest of the imaging details are described under the Iris nebula.

M74 spiral galaxy

M74 (NGC 628) is a face-on spiral galaxy in the constellation Pisces. Even if Charles was only interested in cataloging these, to him, “fuzzy objects” in order to distinguish them from his real passion – comets – he would have struggled with this galaxy. It has the lowest surface brightness of any of those he cataloged. Its size is a respectable 10 x 9.3 arc minutes. Its visual mag is 9.14 and it lies 35 million light years away. It is about the same size as the Milky Way. This is a bit of a challenging object to process since the outer portions of the spiral arms are of very low surface brightness.  The three bright stars, clockwise from the one at nearly 3 o’clock, are 105, 101 and 104. (These are their Flamsteed designations). Their visual magnitudes are 5.98, 6.23 and 6.74, respectively. I combined only 14 4 minute light frames (20% of which discarded) and 10 darks to acquire this image, mainly because I didn’t think I had sufficient reach to attain a pleasing image. The results encourage me to revisit this soon, however, and get a lot more data. The rest of the equipment details, sans filter, is here.

The elusive Witches Head

I applaud whomever made the movement to name some of these deep sky objects so interestingly. If more nebulae, star clusters and galaxies had such intriguing names as “Fireworks,” “The Crab” and “The Witch Head” I think we would see an increased interest in amateur astronomy, which may result in less light pollution. It’s always a fun moment when late at night a fellow observer walks by as you slew your telescope and asks, “what are you going for?” and you reply “I’m after the witch!”  The Witch Head nebula, so named because of the obvious facial structure (she’s looking downward toward Orion’s legs in this image), is a very faint reflection nebula with a visual magnitude of 10, in the constellation Eridanus, very near Orion. It is a massive object, measuring 180 x 60 arc minutes. At the top of the image, just to the right of center, is the 4.8 mag star Psi Eridani. In the witch’s nose lies the visual mag 8.22 red giant star HD 32841. Its diameter is equal to 31.5 suns. The image is uncropped.  Only 3 unguided 5 minute exposures were taken, along with 7 darks and no flats. (Morning was approaching and I was very tired). Other than unfiltered, the rest of the acquisition details are the same as the Iris nebula.

The Fireworks galaxy and an open star cluster

This beautiful face-on spiral galaxy is called the “Fireworks galaxy” (NGC 6946) and lies in the constellation Cygnus. The field of view forms a wonderful pair with the open cluster NGC 6939. It lies 10 million light years away and is 40,000 light years across. It is called the Fireworks galaxy because it is undergoing a greatly increased rate of active star formation without obvious cause. This is a dim target for visual observers, with a magnitude of 9.06. Its apparent size is 11.5 x 11 arc minutes.  I imaged this galaxy the same night as the very nearby Iris nebula before it dipped into the treeline. The imaging details are identical as the Iris nebula except for 20 light subs instead of 26. A bit of the left side was cropped off in order to compose it nicely with the two mag 6 stars at one o’clock, from the center out: HR 7925 and HR 7938. The FOV is approximately 2.6 x 1.8 degrees.

10.21pm EST

11.21pm EST

Iris nebula and red giant in Cepheus

The Iris nebula (NGC 7023/Caldwell 4) is a bright reflection nebula in the constellation Cepheus. Its magnitude is near 7, apparent size 18×18 arc minutes, real size 6 light years across and distance of 1,300 light years. In its center lies a massive hot young star in its formative years. The dominant color blue is characteristic of dust grains reflecting starlight. Mostly obscured by dust is the loose open cluster Collinder 427.

Looking down on this beautiful nebula at the upper right is T Cephei, a massive pulsating red hypergiant. It is a Mira variable star, fluctuating in magnitude between 5.2-11.3 over a period of 388 days. At the time of image it was approximately 7.36. Its radius is 540 times that of our sun.

Acquisition details: Late Oct 2011 MASP using tv85/em-11/canon 40d unmodified/tv 0.8 reducer/IDAS LPS. 4 minute unguided exposures, 26 light/25 dark/10 flat. (Nearly no other images from MASP had flats). ISO 800. 1.6 camera crop factor for an end result of 768mm focal length. F7 became F5.6 with the reducer/flattener. Cepheus was entering down into a light dome in the north so I put on the IDAS filter but most other images from this series were sans filters. Acquired with Maxim DL, RAW Monochrome.

Processing details: Color convert in Maxim. Stacked with DeepSkyStacker. Levels and Curves in Photoshop CS4. Gradient removal with GradientXTerminator. Noise reduction with NoiseNinja. Often a slight crop is performed to obtain a more pleasing composition. Resized from 3908 x 2602 down 75% and converted to jpg to get a reasonable image size of ~ .5 mb or so from a start of around 60mb.