Jan 312018
 

The target of this image is NGC 2149, a small reflection nebula in the constellation Monoceros (the Unicorn). It is quite near the constellation Orion and often gets overlooked due to the more flamboyant objects in “The Hunter”. I routinely exclude images taken of deep sky objects when a satellite intrudes into the photo. The brightness of the intruder skews the desired object’s post processing. I must admit however, last night I intentionally chose NGC 2149 because of the impending satellite pass. The guilty party this time was the Hubble Space Telescope.
 

I decided to attempt the exposure knowing full well the Moon’s brightness would cause a strong gradient in the exposures. After all, the Moon was only a few hours from entering the Earth’s shadow and the resultant total lunar eclipse. Hubble would cross my FOV in just over one second. It takes 10 seconds to download an image from my camera, so in order to not miss the pass I set the exposure to 300 seconds and started it a couple of minutes before the expected arrival. I then joined family members in the front yard to watch the flyby. Hubble silently glided west to east and near the point where it disappeared, it did its best imitation of an Iridium flare. The scope’s solar arrays were at just the right angle to reflect the Sun’s light right back at us. It then faded as its orbit took it into the Earth’s shadow.

Luckily, the satellite’s orbital elements used to predict its path were right on and the 300 second exposure showed the very bright telescope streaking through the image. I then took additional images of the nebula to increase its brightness a little. The result is a stack of one 300 second image and 25 sixty second images.

 Posted by at 15:17
Dec 212017
 

The Horsehead Nebula (Barnard 33) [L:79x60s;TR:26x60s;TG:24x60s;TB:25x60s]

There are 3 basic types of nebulae. This image of an area near Orion’s belt features all three. At lower left, the blue nebula (NGC 2023) is a reflection nebula. Lit by star HD 37903, the gas and dust simply reflect the star’s light. The red background nebula (IC 434) is an emission nebula. Located about 1,500 Ly from the Sun it receives enough energy from Sigma Orionis that the hydrogen in the cloud glows like a neon sign. The Horsehead nebula (Barnard 33) is a dark nebula. This cloud of gas is dense enough to completely block the light from IC 434. The spray of blue light from the left is scattered light from Alnitak, the eastern most star in the belt of Orion.

First discovered by Williamina Fleming on a photographic plate in 1888, the dark cloud remains a very difficult visual object to view in a telescope. It takes a very dark clear sky and a fairly large telescope to just make out the outline of the horse’s head.

 Posted by at 14:29
Nov 182016
 

Once again the diminutive FOV of my system does not lend itself to extended objects. Thus, it does not do the Heart Nebula justice. In fact this image only shows the central part of the heart shaped portion of IC 1805. However, it does show the small very young cluster of stars (Melotte 15) that ‘lights up’ the nebula. Several of the stars have estimated masses in excess of 50 times that of the Sun and it is those stars whose extreme output provides the energy to excite the surrounding hydrogen cloud into emitting the familiar red light. The energy is also what is sculpting the surrounding cloud into the fanciful shapes visible in the image.

The Heart Nebula (IC 1805 detail) [Ha:67x120s ]

The Heart Nebula (IC 1805 detail) [Ha:67x120s ]


This image is taken through a Hydrogen-Alpha filter that limits the light passing through to that with a wavelength of 656.28 nm. In addition to distinctly showing where the energized hydrogen is located, it also is one way to limit the effect of a nearly full Moon and common light pollution. This image was taken on a full Moon night.
 
Chart generated with Cartes du Ciel

Chart generated with Cartes du Ciel

 Posted by at 14:48
Sep 172016
 
The constellation Cygnus (the Swan) has 5 bright stars that forms the shape of the bird in flight. The star at the intersection of the swan’s wings and body is named Sadr; the Arabic word for chest. The Bayer designation is Gamma Cygni (γ Cyg, γ Cygni).

The constellation is bright and easy to identify in the Northern sky. What is not so easy to see is the very large emission nebula located near γ Cyg.

Although γ Cyg lies near the center of the nebula, it is only a chance alignment. The star lies about 1,500 ly’s from Earth but the estimated distances to the nebula average about 3,000 ly’s.

By IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg) via Wikimedia Commons

By IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)
via Wikimedia Commons

(IC 1318)[C:60x60s]

(IC 1318)[C:60x60s]

Since γ Cyg is so bright, I positioned it out of the FOV to prevent it overwhelming the image. Also, this image is only a small part of the nebula since my telescopic field of view is much too small to view the entire object. The dark area that crosses the image is not a lack of stars but is instead a very dense part of the nebula which blocks the background light from reaching us.

Chart generated with Cartes du Ciel

Chart generated with Cartes du Ciel

 Posted by at 12:52
Sep 112016
 

NGC 281 is an HII nebula in the constellation Cassiopeia. Named only ‘recently’, it has been given the common name of “Pacman Nebula” due to its remote resemblance (if rotated correctly) to the video game character. The nebula is about 80 light years in diameter at its estimated distance of 10,000 light years.

Pacman Nebula (NGC 281) [Ha:60x120s]

Pacman Nebula (NGC 281) [Ha:60x120s]


Also visible are several small dark areas known as Bok globules. These are areas of very dense dust and gas and can be the location of new star birth. Additionally, visible in the upper right quadrant are several sculpted columns slowly eroding from the intense output of IC 1590; the star cluster illuminating the nebula.
 
Chart generated with Cartes du Ciel

Chart generated with Cartes du Ciel

 Posted by at 18:41