Up at a decent height in the northeast sky by 1:00 AM last night one of my favorite subjects, FIREWORKS! Well the galaxy at least! 9 subs of 360 seconds each at ISO 1600 for this dim object brings out a crowded field of stars along with the much closer open cluster know as NGC 6939
(Fireworks Galaxy) “Discovered by William Herschel on 9 September 1798, this well-studied galaxy has a diameter of approximately 40,000 light-years, about one-third of the Milky Way’s size, and it contains roughly half the number of stars as the Milky Way. The galaxy is heavily obscured by intersteller matter as it lies quite close to the galactic plane of the Milky Way.”
“NGC 6939 is located near the border of the constellations Cepheus and Cygnus, at the southwest corner of Cepheus. The open cluster is located 2/3° northwest from the spiral galaxy NGC 6946 (The Fireworks Galaxy), which has visual magnitude 8.8. They appear as two patches of haze with 10×50 binoculars. NGC 6939 can be glimsed with 7×35 binocoluars where as 25×200 binocoluras are required to start resolve the cluster. The cluster can be glimsed with a 4 inch telescope and is resolved at x72 magnification.”
Located approximately 52 million light years from Earth in the constellation Ursa Major, this galaxy was nearly straight overhead toward midnight last night. No moon helped and guiding was very good in this mount orientation. It was warm though for my un-cooled DSLR camera so noise levels were up. 19 subs at 240 seconds each or around 1 hour 15 minutes combined for this image.
Some information on this region from “http://www.astronomersdoitinthedark.com” :
“NGC 3718 is classified as a peculiar barred spiral galaxy. The galaxy’s spiral arms are quite warped due to the gravitational interaction with its close neighbor on the left of this image, NGC 3729. NGC 3718 features a prominent, dark spiral dust lane wrapping around its nucleus. The core of the galaxy probably contains a supermassive black hole.”
If you look at the full screen image you can see another galaxy group.
“The group of 5 galaxies (To the left and up a bit) is Hickson 56. The Hickson 56 group is a background group of galaxies that is 400 million light years from us – 8 times farther than the foreground group”
From April 19th around 1:00 I was able to find this group shot of galaxies known as Markarian’s Chain in the Virgo Cluster. The brighter ones are M84 and M86. An American astrophysicist Benjamin Markarian, found that a group of seven galaxies in this region are traveling together at about the same speed, with M86 (as the highest “blue shifted” object in the Messier Catalog) traveling toward us at 150 miles per second. Even though they are headed our way right now, in the long run they are attracted to the Virgo Cluster which is between us. Two galaxies just left of center are distorted by gravitational interaction and the one above is clearly asymmetrical.
Just spent a little time on the exact same stacked image from 03/11 with a few more tricks. Just an example of what happens in photo development. Lots more could be done especially with more advanced software, but for now this is just an earmark of my current workflow. Arguably over worked but an interesting comparison to the previous rendering.
As the night went on, tracking improved as the target moved nearly straight overhead. Guiding was around 0.80 arc seconds RMS toward the end of the run. At first it was around 1.30 which was disappointing. I did tweak the settings in PHD2 which may have helped a little but mostly it is just the better viewing near zenith I think. Around 2 hours total in this stack. I should try a smaller stack of the better frames and see if it gives more detail. Of course I am just using some very basic post processing in Photoshop with help from some actions and AstroFlat Pro so my data could be worked harder.
From the web site messier-objects.com :
Messier 108 (M108), nicknamed the Surfboard Galaxy, is a barred spiral galaxy located in the constellation Ursa Major.
The galaxy lies at an approximate distance of 45.9 million light years from Earth and has an apparent magnitude of 10.7. It has the designation NGC 3556 in the New General Catalogue.
Messier 108 occupies an area of 8.7 by 2.2 arc minutes of apparent sky, corresponding to a spatial diameter of 110,000 light years. The galaxy is inclined 75 degrees to our line of sight. Even though it appears almost edge-on, M108 is a popular target among amateur astronomers and astrophotographers because details of its structure can be seen even in amateur telescopes. The galaxy is easy to find as it lies only 1.5 degrees southeast of the magnitude 2.37 star Merak, Beta Ursae Majoris, one of the Pointer Stars in the Big Dipper . M108 appears in the same wide field of view with the Owl Nebula (M97), which is located only 48 arc minutes southeast of the galaxy. The best time of year to observe M108 is during the spring.
I was able to get set up last night and capture a decent image of the Leo Triplet. The seeing was fair with some moisture and freezing temperatures so I had some frost to chase away. Guiding was not the best possibly aggravated from the location in the southern sky. Different areas of the sky have inherent atmospherics often discernible from the tell tale twinkling stars. They may look pretty, but they indicate thermal instability that make things appear to move around. This drives guiding crazy and is referred to as ‘chasing seeing’. This was stacked from 22 frames of 220 seconds each or about 1hr 20 min total. Using dithering again with no dark frames. I need to try some comparisons with some dark frames I guess but this works surprisingly well.
The Leo Triplet (also known as the M66 Group) is a small group of galaxies about 35 million light-years away in the constellation Leo. This galaxy group consists of the spiral galaxies M65, M66, and NGC 3628.
My first run of the night ended unexpectedly. Not sure what happened but it seems my computer decided it was a good time to restart or update or something. So on to another target in the neighborhood. The Pinwheel Galaxy or M101 is front and center. Low to the right is NGC 5474.
NGC 5474 is a peculiar dwarf galaxy in the constellation Ursa Major . It is one of several companion galaxies of the Pinwheel Galaxy (M101 , a grand-design spiral galaxy . Among the Pinwheel Galaxy’s companions, this galaxy is the closest to the Pinwheel Galaxy itself. The gravitational interaction between NGC 5474 and the Pinwheel Galaxy has strongly distorted the former. As a result, the disk is offset relative to the nucleus ] The star formation in this galaxy (as traced by hydrogen spectral line emission) is also offset from the nucleus. NGC 5474 shows some signs of a spiral structure. As a result, this galaxy is often classified as a dwarf spiral galaxy , a relatively rare group of dwarf galaxies.
I was also running dithering for the first time on an actual imaging run. This is a concept where the scope moves a bit between each sub, or individual photo. Some people swear by this as a great way to improve results, and as I did this time, avoid taking dark shots. “Darks” take the same time as “Lights” and are super boring time hogs looking at the black interior of the telescope cover. The idea of darks is to subtract the noise. The idea of dithering is to randomize the noise and thus it keeps reducing the more individual subs are compiled together, or “Stacked”. Stacking is fundamental to modern astrophotography and the whole digital revolutionary leap that makes all this amateur stuff so much fun!
In this photo:
• NGC 5486
• NGC 5485
• NGC 5477
• NGC 5474
• NGC 5473
• M 101
• NGC 5457
Yeah, I finally have a coma corrector for the Orion 6″ f/4. These are necessary for any Newtonian telescope with “FAST” optics. Parabolic mirrors have no chromatic aberration nor spherical aberration, but they do have focal plane curvature. Actually, any curved lens or mirror produces a curved focal plane. Optical designers have to come up with corrective lenses to overcome this issue since optical sensors are flat. Hmm, maybe they should make the sensors curved……?? No, not going to happen but it would be in theory the better solution. Just need it custom curved to each optical system!
This is the Whirlpool Galaxy in the center, but a casual close look will find another galaxy on the left edge and two more over on the right side. A quick check on astrometry.net confirms this and a few more objects seen at this focal length. I included the annotated version. Check it out full screen!
In this image:
• NGC 5229
• NGC 5198
• NGC 5195
• Whirlpool galaxy
• M 51
• NGC 5194
• IC 4263
• NGC 5169
The Whale Galaxy and the Crowbar Galaxy are close neighbors from this perspective. Some wiki info:
NGC 4631 (also known as the Whale Galaxy or Caldwell 32) is a barred spiral galaxy in the constellationCanes Venatici. This galaxy’s slightly distorted wedge shape gives it the appearance of a herring or a whale, hence its nickname. Because this nearby galaxy is seen edge-on from Earth, professional astronomers observe this galaxy to better understand the gas and stars located outside the plane of the galaxy.
NGC 4656/57 is a highly warped barred spiral galaxy located in the constellationCanes Venatici and is sometimes informally called the Hockey Stick Galaxies or the Crowbar Galaxy. The galaxy is a member of the NGC 4631 Group. A Luminous Blue Variable in “super-outburst” was discovered in NGC 4656/57 on March 21, 2005.
Imaged last night with a bit less than an hour of integration time. 180 second subs at 800ISO. Good dark area of the eastern sky for my location, but rather late in the night before they get up enough for a good look.
Around 6 degrees Fahrenheit last night while catching some images. This from Wikipedia:
NGC 2403 is an intermediate spiral galaxy in the constellation Camelopardalis. NGC 2403 is an outlying member of the M81 Group, and is approximately 8 million light-years distant.
Just north of straight up around 10:30 last night, I took 21 light frames of 180 seconds each at ISO800 plus darks, flats, and bias frames processed in Deep Sky Stacker and Photoshop CS2. Tracking was rather good for my setup on this high target with end of run RMS error just over 0.8 arc seconds. This is a cropped photo, since I still do not even have a Coma Corrector for this setup. Basically the edges of the picture are very distorted without the corrective lens. That is just the way optics work in a “fast” Newtonian telescope.
The Canon camera at this telescopes focal length of 610mm covers about 1.6 arc seconds per pixel, so if I believe the numbers, most of the time the imaging will stay within one pixel during exposure. Kinda mind boggling actually.