It's Galaxy Season--M51

Summer in the Northern Hemisphere means it's galaxy season. For the past few clear nights, I've been imaging galaxies in Ursa Major as they clear the trees on the east side of my property. This image of M51 was taken under conditions of below-average seeing and wind in my Bortle 8 skies. I had to throw away a number of subs, and ended up stacking 104 x 20s integrations--some of which I should also have thrown away. The result, however, was pretty decent, as the resulting image shows:

M51 is an interesting object. The main spiral galaxy is attended by a companion, NGC 5195, which appears to have passed through the main disk of M51 twice. A gas and dust-rich tidal bridge connects the two objects. The interactions between the  two galaxies have triggered a burst of starbirth in the central regions of M51. NGC 5195 has a massive black hole which is "burping" huge waves of gas. M51 is also Seyfert 2 active galactic nucleus powered by a supermassive black hole.

Messier 78

I always feel that M78 gets overlooked by many amateur imagers, who tend to concentrate on other objects in the Orion Molecular Cloud (like M42, M43 and the Running Man Nebula complex). M78 is a similarly complex group of nebulae, consisting of NGC 2064, 2067, and 2071. Two stars,  HD 38563A and HD 38563B, power the nebula and give it its reflected glow. The complex also contains young T-Tauri stars in the process of formation, as well as 17 Herbig-Haro objects.

This image was captured with the 8 inch f/3.9 newt and a Mallincam AG1.2G; it is a stack of 30 or so images. The imager did an excellent job of capturing the subtle colors in the cloud (it reminds me a little of a Turner painting). Below is the Astrometry.Net platesolved image, which labels some of the features of interest.

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.

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.

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:

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.