The Pelican Nebula is seen near the top of this image from last night along with more of the American Nebula it is a part of. I managed 1 hour 33 minutes of integration time with 200 second subs. As usual I am not so sure of the post processing but I pushed it to make it interesting. The vertical band through a minor star in the Pelican was obvious in the subs as I was imaging but I think this is an artifact. I actually processed out vertical banding to minimize this. There is often something which puzzles the shot that can be more trouble than it is worth to track down. It does not seem to be real, as I don’t see this in other peoples images on the web. I have had some vertical anomalies before, so I think it is my camera doing something crazy! After all it is just a normal DSLR so it is not exactly designed for Astrophotography.
I was just looking for a target in the dark area of my sky for the short time between dusk and moon rise. I cam across this region searching in Stellarium, and was surprised it had no common designation. Captured around 1.5 hr of data to produce this image from the depths of the milky way, A myriad of colorful stars stand out from the thousands in this image. Astrometry found 4686 stars to work with identifying the center position as:
RA 19hr 59m 48sec
Dec +35deg 24m 46sec
The brightest star is the crook of the neck of Cygnus designated “n” or the abreviated “n Cyg”. It can also be described as the southern star of the “northern cross” which makes the body of the Swan. At the northern end of the cross is the better known star, Deneb. The Crescent Nebula lies just north of this region.
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”
The Iris Nebula is a reflection nebula in the constellation Cepheus that I was able to image on the 24th. The moon was bright so I was looking for targets in the North East for the darkest skies. I got 22 subs at 240 seconds with ISO 800 but the tracking was only fair. Transparency was not the best and a bit of breeze caused some shifting I think. That and or “chasing seeing” where the guide scope image is wavering around. It still just amazes me what can be pulled from the data I start with. Never give up on washed out subs!
I need to try adding a little more distance to my Coma Corrector as it still shows under-correction toward the corners, but some of that is tracking. Some images I adjust a bit using the lens distort effect in Photoshop but not on this one. You can tell because it will distort the angle of the diffraction spikes across the field when software corrected.
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