Wednesday, March 28, 2018

The Rosette Nebula (NGC2237)

The Rosette Nebula has a large angular diameter, making it difficult to fit into the field of a small imaging chip like that in my Mallincam DSm imager.  But even parts of the nebula have their own beauty. This image, taken with the DSm and 8 inch Newt, shows dark globules of gas and dust. These globules are being eroded over time by the winds from massive stars in the nebula (such as those on the left side of the image).  These globules have the potential to form new stars, but are unlikely to do so as they are swept away by these stellar winds.

Saturday, March 24, 2018

M82--The Cigar Galaxy

When galaxies interact gravitationally, one of the consequences can be a burst of star formation. One such "star burst galaxy," is M82. M82 is five times brighter than our galaxy, with a center that is a hundred times brighter than that of our galaxy. Like Bode's Galaxy, M82 was also discovered by Johann Bode. The Hubble Space Telescope discovered almost 200 starbirth regions in M82's core, each with an average of around 200,000 solar masses.

This image was taken with the same platform as that used to image M81. This is a stack of 34 x 20s images.


M 81 -- Bode's Galaxy

Discovered by Johann Bode in 1774, Bode's Galaxy is the largest galaxy in the so-called M81 Group in Ursa Major (a group of 34 galaxies). The galaxy has a strong gravitational interaction with M82, the Cigar Galaxy (see the next post).

This image was captured with an 8 inch f/3.9 Newtonian and a Mallincam DS 2.3+ imager. This is a stack of 93 x 20-second integrations. Stacking was in DeepSky Stacker and the image was adjusted in Photoshop.


The above image was processed for contrast. Here's another version that has more skyglow, but is more contrast balanced.


Sunday, March 18, 2018

M1--The Crab Nebula

In 1054, Chinese astronomers observed a bright supernova (what they called, a "guest" star). The nebula was first observed in 1731 by John Bevis, and became the first object to be associated with a supernova. In 1840, Astronomer William Parsons observed the object with a 36 inch telescope. To Parsons, the object looked like a Crab--hence the name we popularly call this object today.

The Crab is one of my favorite objects in the sky, and, as I had not imaged it since 2016, I decided it was time to take another look at an old friend.

The nebula is "energized" by the Crab Pulsar--the neutron star remnant of the supernova that created the nebula. The pulsar is around 30 km in diameter and spins at 30.2 revolutions per second. In an incredible achievement, an amateur with a webcam and a small scope built a "chopper" that enabled him to image the pulsar's energy rippling through the nebula. Here is the link: http://www.threehillsobservatory.co.uk/astro/astro_image_33.htm

My own image shows clearly the filamentary structure of the image:


The image was captured with an 8 inch, f/3.9 astrograph and imaged with a Mallincam DS 2.3+ imager. This is a stack of 40 x 20s integrations.

Here's a slightly more processed image to bring out contrast:

and finally, here's an inverted image, processed to show the filamentary structure in a little more detail:


Sunday, March 11, 2018

Platform Automation--Some Further Thoughts

I've been using the automated platform described in the previous four posts for a while. Here are some further thoughts from this experience (with many thanks also to other users of this platform who have send me comments):

Hardware: the modest W5 I use is perfect for my purpose (automating a driveway scope). However, if I were to add extra functionality (a filter wheel and focuser, for example), I would suggest a "beefier" stick (with an i3 or i5, rather than an atom-based processor) with more RAM. In addition, these higher end sticks come with Windows 10 Pro (rather than Windows 10 Home), which supports Windows Remote Desktop, eliminating the need for TeamViewer. Performance of the system is also very dependent on network performance, so it's important to ensure that your router is no so far from the stick that network speed is compromised. For most users, this issue will not be a problem, but, if you experience latency or lag in operation, the quality of your network connection is the first place to look.

Image Quality (TeamViewer) and resolution: TeamViewer has an image quality optimization tab:


To optimize image quality, click on the tab furthest to the right in the Quality box (shown above). The tab next to it allows you to optimize connection speed at the expense of image quality. In practice, with a good connection, you will always want to optimize image quality. In addition, I have found it to be advantageous to set the resolution of the remote desktop (that of the stick), to be the same as that on the "home" system that I use to connect to the stick via TeamViewer.

The Horsehead Nebula

This image of the Horsehead Nebula consists of just over 4 hours of total integration time. Stacked and processed in Siril, GraXpert, Affini...