The Pinwheel Galaxy and What's Inside

Spring is Galaxy season. This year I decided to start an imaging project that would reveal (hopefully) some of the non-stellar objects inside of the brighter galaxies. There was no better place to start than Messier 101, the Pinwheel Galaxy. 

This galaxy is in Ursa Major. It is a lovely face on spiral galaxy. I count 4 spiral arms, with one on the left being somewhat distorted and stretched. This is most likely due to tidal affects from a close encounter with another galaxy, but more on that later.

M101 lies about 21 million light years from us. To put that in perspective, the Andromeda galaxy is about 2 million lightyears away. M101's diameter is about 200,000 lightyears, twice that of our own galaxy and it has about 4 times the number of stars as our own galaxy. 

A strange thing about M101 is that it does not have a single massive central black hole like most spirals but has several 3 - 30 solar mass black holes. Our own galaxy has a central black hole of well over 4 million solar masses.

Face on spiral galaxies like M101 make ideal targets for astrophotography and allow us to examine the structure more closely. The image above was transformed into a black and white image and then inverted. This gives a high contrast image below that makes it easier to spot some of the structures. 

You can see "clumps" within the spiral arms. These are hydrogen II regions, areas where the interstellar hydrogen gas is reflecting light of massive young stars, forming reflection nebulas similar to our own Orion Nebula, pictured here. 

The large HII regions are an indication that there is a lot of star formation occurring. Why so much? The clue is that arm on the left of the image above, seems to be stretched out and separated from the other arms. This is a result of an interaction with a nearby galaxy, most probably NGC 5477, the galaxy identified by the red cross on the far left. This galaxy is actually a dwarf galaxy, meaning that most of its stellar mass has been stripped off, most likely by M101. The gravitation interaction by these two galaxies has resulted in the collapse of gas within M101 to form new stars.

M101 is great object both visually and photographically. Many of the HII regions can be visually identified through telescopes of 8" apertures. The M101 image above is about 2 hours of 30 sec sub exposures taken through an Astro Tech 80mm telescope with a ZWO533 MC Pro from a Bortle 4.5 sky. 

Next up will be a spiral galaxy in Coma Berenices, NGC 4559.

Clear skies!

The Orion Nursery

 

The other night I spent about 30 minutes imaging the area around the Horse Head Nebula. This was the first time I had captured it, and I was relatively pleased with the results. The area is a fascinating example of the mechanisms involved with stellar formation.

At the center of the image is a blue giant star, Alnitak. This is the western most star in Orion's belt. This star has a mass 33 times that of our Sun and 20 times the radius. Its energy is predominately in the ultraviolet area of the spectrum. This UV light excites a region of hydrogen gas just to its upper left in the image, the Flame Nebula.

The Flame Nebula glows from the excited hydrogen gas. Through its center are lanes of dust, so dense. it blocks the light from several hundred new stars behind the cloud. The presence of these stars was detected by the Chandra X-ray telescope. However, to us, it adds the illusion of a dancing flame.

The red veil that runs from the lower left to Alnitak is a Hydrogen II, HII, area. It glows from the energy emitted from Sigma Orionis which is just off the bottom of the frame. The hard edge on the left side of this area is caused by another dust cloud which is in front of the HII area. We know this as there is an observable difference in stellar densities from the left and right side of the HII region, i.e. there are more visible stars on the right side of the image than the left side.

In the center of this red veil is the Horse Head Nebula. This is a very dense dust cloud which blocks out the glow of the HII region behind it. This is very challenging object visually as the red HII region is not easily seen unless the skies are very dark. It is picked up easier by the camera as it is more sensitive to the red wavelength light.

There are three more emission nebulas in the image, one below the flame and two to the upper right. All are indicated in the annotated image. These areas are interstellar gasses that are excited by stars within the cloud. These stars are typically very young and hot stars like Alnitak. 

This area is all part of the Orion B Molecular cloud which also includes Messier 42, or the Orion Nebula, imaged to the left. This whole area is the closest star forming area to us, only a mere 1,300 lightyears distance. What is not seen in these images but has been confirmed by larger space-based telescopes are the presence of circumstellar discs, which most likely contain protoplanetary objects. 

We tend to think of the heavens as relatively static, however, when you use a timescale of many millions of years, we start to understand the dynamic nature of our universe. Looking up at Orion is like looking through a hospital nursery window, only instead of babies, we see stars.

Clear skies.

RW

 AL Globular List

    Well, I continued my journey through the Astronomical League's Globular Cluster Observing Program and so far, have completed imaging 56 from their list. One of the benefits of the observing programs is that you get to appreciate the differences between the various objects. One of the requirements of the award is that the observer, or imager in this case, must classify the clusters using the Shapely scale for central concentration. This is a scale that runs from I to XII with I the most concentrated and XII the least. Below is a sampling of some of the various clusters and their Shapely classification.

M75, in Sagittarius, is a Class I cluster.

M3, in Cannes Venatici, is a class III cluster.

M15, in Pegasus, is a class IV cluster.

M5, in Serpens is a class VI cluster. 

M22, in Sagittarius, is a class VII

NGC 5466, in Boötes, is a class XII cluster.

    I submitted my observing reports to the AL and have received the certificate and pin. There are still another 120 targets on the list and my plan is to image the brighter ones and possibly a few of the extragalactic ones in Andromeda.  That should be a pretty good challenge! My next project however is to image 100 open clusters and receive the AL Open Cluster Award. 

Clear Skies

rw

 Two Very Different Neighbours

Last night the skies cleared and with the moon not rising to well after midnight it seemed like a good night to observe. I had a list of galaxy targets from the Cloudy Nights Monthly EAA Challenge list. I made my way through the list and then turned my attention to my Astronomical League Globular Cluster list. There were two globs that I had listed, M53 and NGC5053. Both are in the constellation of Coma Berenices and lie less than a degree from each other, shown in the chart below. Coma was still in a good position to image and so I gave them a go.

M53 is a beautiful globular cluster that is 58,000 light years away. It was discovered by Johann Bode in 1775. It is a bright target which is easy to find, lying less than a degree from Alpha Com B. To me, it has the appearance of a pile of white and yellow diamonds against a black velvety background. The cluster has a Shapely Concentration of a V on a scale of I to XII with I being the most concentrated and XII being the least. The stars in the core of the cluster are extremely densely packed, eventually merging into a solid white-yellow glow. 

NGC5053 appears as M53's poor neighbor. William Herschel discovered this cluster in 1784. He described it as an extremely faint cluster of extremely small stars." It is much more diffused as compared to M53. Its Shapley classification is XI making it one of the most diffuse globular clusters that we have. If you did not know it was a globular, you might mistake it for an open cluster. The stars of this cluster are fewer and fainter than M53. Both clusters are similar in size, and both lie at a similar distance from us. NGC5053 is thought to have been stripped off of a neighboring galaxy during a close encounter in the past. It is possible that it may have originally looked similar to M53 but had its stars ripped from it by the gravitational effects of the close encounter.

After grabbing these two globs the clock was showing midnight with the clouds rolling in and so I decided to pull the plug. The total for the night was 9 galaxies and 2 globs.

Clear Skies;

rw

Another attempt - M66

Last month I captured some data for M66. This is a galaxy that is part of the Leo Triplet of galaxies. M66 is a spiral that is tilted towards us enough to show off its beautiful spiral structure. The central core region is a bright glow across which is a bar. The spiral arms are connected at the ends of the bar. Along the wispy spiral arms are clumps indicating high concentrations of stars, or possibly active star forming regions caused by a gravitational interaction of a nearby galaxy. 

M66 is also classified as an Arp Galaxy, specifically Arp 16. Halton Arp classified this galaxy in the group of Spiral Galaxies with Detached Segments. I believe the detached segments that Arp saw were these higher concentrations of stars along the arms. 

I was not really happy with my first attempt at processing this image and so I took another crack at it. The image was processed in Photoshop with the use of Astronomy Tools Action Set for PS. I am finding that as the temperature increases, the noise from the camera is becoming more of a nuisance. My ZWO ASI183MC camera is not of the cooled variety and so I guess this is to be expected. The obvious solution would be to obtain a cooled camera. The other option would be to take more data to increase the signal to noise ratio. Leo is getting low in the west and obscured by my house's roof line, so I will need to wait until next spring for a another try at this one. 

Clear skies;

rw

 Wednesday May 17th Observing Report

Well, the clouds finally parted and allowed me a good night of observing this past Wednesday. The seeing and transparency were average and the sky was cloudless.

The first target of the night was M87. This is a large galaxy at the heart of the Virgo Super Cluster of Galaxies. The galaxy was discovered by Charles Messier in 1781. It is classified as a Super Elliptical galaxy. 

The galaxy itself is pretty non-remarkable for the most part. It appears as a bright oval with a spot in the center where the core of the galaxy is. There are at least three other galaxies visible in the frame. Two to the left of M87 which are NGC4476 and 4478. The other visible galaxy is behind a bright star at the top of the frame directly above M87.

   As I was watching the stack of frames come in from the camera, I zoomed in on the image that was forming by the stacking of the individual frames, I noticed a bright blueish streak on M87 at the 8 o'clock position. I knew from reading that M87 had a relativistic jet streaming from the black hole at its center, but never in my imagination did I think it would be possible to see it in an 8-inch telescope! The image to the right is a zoomed in and cropped image of the photo above with the jet visible.

The next target was M5, a nice globular cluster in the constellation of Serpens. This cluster was discovered in 1702 by German astronomer Gottfried Kirch.

 Globs are one of my favorite objects to observe. On a really good night you can resolve individual stars right down into the core of the cluster.

Next on the list were a trio of galaxies in Virgo, NGC 5360, 5363 and 5364. NGC 5364 is the brightest and is at the lower right in the image. It looks like there is a bright star superimposed on the left hand side of the galaxy.  NGC5363 is a spiral at the top of the image. You can just make out its spiral structure. Lastly, NGC5360 is a faint (Mag 14) edge on galaxy to the left of NGC 5363. You have to look hard to see it, but the little streak is visible. 

The last target for the night was M57. This planetary nebula is bright and easy to find. You can see the little 15th magnitude star at the center of the ring which provide the energy to make the gas ring glow.

It was 2 o'clock and dew was starting to come in pretty heavy, so I threw the switch and rolled the roof back on the observatory. 

Clear skies

rw

 

Welcome

Welcome to my blog. This blog is meant to be a companion to my Instagram @astro_shed, where I share my photos of my endeavors in amateur astronomy. The idea of the blog is to add a commentary to the images that I share on Instagram, as well as be a place for the simple ramblings about my images, equipment, or backyard observatory.

The observatory was completed in the fall of 2022. The primary scope that I have been using is a Celestron CPC 800 mounted on a wedge. The scope is guided by a ZWO ASI 120MC camera and image acquisition is done with a ZWO ASI 183MC camera.

My main interest is in Electronically Assisted Astronomy, or EAA. This is done by the substitution of an eyepiece in the telescope with a camera. Software on a nearby laptop takes the images and through a process called stacking, creates an image that is far brighter and more detailed than could be observed though just the eyepiece.

The images are typically of relatively short total integration time, normally about 10 minutes and serve as a visual record of the observation.  The image below is an example of an EAA image of M42 - The Orion Nebula. 

A typical observing session will result in about 5 different objects imaged over a couple of hours. 

I look forward to sharing my images and thoughts through this blog and interacting with the community.

Clear Skies;

rgwood