Most of the astrophotography you see has a common theme, beautifully colored and highly detailed images of some nebula or galaxy somewhere, unlike Clark 549. People don’t shoot the stuff without tons of detail and/or colors. Shame really. Here is an image of a dark nebula, or a nebula that is dark (duh!). The only way you see it is because you can see where it blocks the stars behind it.
This example of dark nebula is Barnard 143, or Clark 549, or as I refer to it, the Lyre Nebula (I hope you can see why). I have shot this image before in October of last year but it really did not do it justice. I am not sure this image does either but it certainly conveys more of the feeling I wanted to with this target so here it is. Sometimes it isn’t what you see, but what you don’t see that is interesting.
I am sure this will continue to be a favorite target of mine as I try to get the dark dust lanes to stand out more. You can see some wonderful dust lanes in my images of the Orion Nebula for example. If I stretch the image far too much I can see the start of the dust lanes jumping out. Maybe when I get a CCD and get really good with it I can make this a priority target. I have a feeling that a mono CCD will really bring those details to life. Unfortunately the mono may increase detail, but it will lose those wonderful blue and yellow stars surrounding the dust lanes.
I plan on checking out many more of these nebulae in the future. Stay tuned to hopefully see many more images of these kinds of targets.
You can find out more about a dark nebula such as Clark 549 at Wikipedia.
Stellar spectroscopy is a really interesting field, and since I have never been content on doing one thing and always being fascinated by things I don’t understand I decided to look into it. Stellar spectroscopy is the study of the spectrum of light being emitted or reflected by an object in space. This can tell you a lot of things, for example what the chemical makeup of a star is (which tells you the star type), or the speed at which an object is moving towards or away from you. My primary reason for wanting to look into this is to learn more about the stars themselves instead of just imaging them. In my mind spectroscopy and stars seem to naturally go together. To this end I ordered a Star Analyser 100 from Rspec Astro, great guy to deal with, you can visit his website at http://www.rspec-astro.com. Once I received the grating filter I have to try and figure out how to use it, so I made an exposure chart to see what the spectral lines (or stellar lines) look like. This is the stellar spectra of Arcturus:
Stellar Spectroscopy and star types
There are many different types of stars. Each star type or stellar classification can be determined through spectral analysis. As light passes through the filter a specific pattern of light emerges, including bands of darkness called absorption lines. Reading these patterns and comparing them to the known star types allows someone to identify the type of an unknown star.
All the different types of stars fit into seven basic classifications of typical stars, and a few more for stranger types which we believe are far less common. As I learn more about stars I plan on being able to come to my on conclusion about what type of a star my target is, and then compare it to what the real scientists say. Hopefully I will be able to match my results with theirs. Even if I don’t start off that way, it should be a lot of fun learning stellar spectroscopy!
Saturn is probably the single most imaged planet, besides Earth of course. The rings are just mesmerizing. Imaging planets is a lot different than my normal fare of DSOs, it uses a video camera instead of a normal DSLR/CCD. Because of the unsteady air and extreme magnification you have to take thousands of images and stack them keeping the best parts of each and discarding the rest. The result, can be very nice:
Supernova SN2012aw was one of those times where you just get lucky. I was fortunate enough to image M95 on February 25th and just discovered there was a supernova in the very outer lanes of that galaxy so I imaged it again, the supernova is clearly visible. This was probably one of the closest supernova to Earth in the history of humans.
Almost exactly a month apart and the difference is obvious. One interesting thing to put this into perspective is that this did not happen in March 2013, in fact, not in this year, not in this century, and indeed, it happened some 38 million years ago. The distance of M95 is approximately 38 million light years away. This means somewhere between the extinction of the dinosaurs and the evolution of the Homo species is when the event happened but the light from it is just now reaching the Earth. Really makes you think.
The other amazing thing to me is how obvious it really is. You hear about how bright and violent a supernova explosion is but it takes something like this to really show you. That little dot is not much larger than any of the other stars in the image, except the other stars are not in that galaxy. If you look close at the galaxy and see the hazy dust that forms it’s structure, that dust is millions of stars. One of those little particles of dust way out on the edge of the galaxy exploded with such force that it is as bright as the central core of the galaxy it is in. Wow.
The magnitude of this supernova was around 13 when this image was shot.
Hopefully there weren’t any life supporting planets anywhere in that area! There is a fantastic little article on this spectacular supernova in the M95 galaxy on National Geographic’s website.
Comet Gerradd was discovered by G. J. Gerradd on August 13, 2009 in Australia’s Siding Spring Observatory.You can find out more about C2009 p1‘s creator on Wikipedia.
Here you see the comet visually near the galaxy NGC 6015 (upper right corner) in the constellation of Draco. Notice that the comet sports two tails, this is because the gas that vaporizes off the comet due to the sun’s heating is being blown by the solar wind in one direction while the particles of debris and dust fall off in a different direction since they are not affected by the solar winds as much.
In the main image the comet is about as close to earth as it was going to get and is well inside the orbital distance of Jupiter, about half way between that distance and the orbit of Mars, sitting above the orbital plane of the planets. The smaller images show comet Gerradd moving across the frame in its travels across the sky. As you can tell I imaged comet Gerradd for over an hour. It was also a wonderful comet to view with binoculars. There were several of us out that night and I was certainly not the only one imaging the comet.
Read online and you will hear how you can not shoot ha with a DSLR, specifically DSOs that contain Ha with an unmodded DSLR (one that has had it’s IR filter removed) because the current line of DSLRs are not sensitive to the Hydrogen Alpha part of the spectrum. Rubbish. Sure modded cameras are more sensitive, but that doesn’t mean you “can’t” shoot Ha with a DSLR that hasn’t been modded, you just have to use the “right” camera and be prepared for some really long exposures. Below is NGC1931 bottom center and IC417 in the upper left, the Spider and the Fly:
This is shot with my Nikon D7000 of course, using a Baader 2″ 7nm Hydrogen Alpha filter, 20 25minute ISO 1600 exposures. That’s right, 20 exposures of 25 minutes each. I think I threw out one, maybe two frames because something happened. This Sirius mount just rocks.
Can you shoot a “better” image with a modded or monochrome camera? Absolutely! But you certainly can shoot hydrogen alpha with a DSLR or even full narrowband with a DSLR that has not been modded. The filter that they talk about is on the front of the sensor in the camera and reduces light at the wavelength of hydrogen alpha by sixty to seventy five percent. While this certainly makes for long exposures and introduces a lot of chances for things to go wrong, it does not eliminate your ability to capture ha with a DSLR. In fact, virtually all red nebulous regions in astrophotography taken with a DSLR are hydrogen alpha areas that are showing up even without modding.
In addition the manufacturer of camera is really not an issue. This image was shot with a Nikon SLR digital camera, but you could just as easily have used a Sony digital SLR or Canon.
If you would like more information here is an excellent, albeit long article on shooting IR and hydrogen alpha with a DSLR including camera modification.
I hope you enjoy my Ha with an unmodded DSLR article and HA with a DSLR image!
Back on September 21st of last year my first ever DSO (Deep Space Object) was Messier 31 (M31 for short), the Andromeda Galaxy. This is a common target along with the Orion Nebula for newcomers to astrophotography because it can be captured relatively well without spending all night and locating the Andromeda Galaxy is fairly easy. I thought it was about time I revisited that target and see what kind of improvement I could muster up after four months of work. Here is the image I captured on January 13th of this year:
Here is the Andromeda Galaxy image from September 21st of last year for comparison:
Much better! I still have issues to work out but the amount of data, quality of the image and colors are far superior to my previous attempt. The blue on the lower left is particularlly pleasing as I have seen that in images of the M31 Galaxy and wondered why I can’t seem to capture it. I attribute the improvement to things like more light frames taken, more dark frames taken, much better focus, using a field flattener, better skyglow filter and of course, better technique.
With the exception of the field flattener and new skyglow filter all the equipment was the same, as was the software used. The new image was 20 lights of 300 seconds each at ISO800. I stacked those lights with 10 darks for the final image. It is taking me a while to get the correct length of exposure and ISO to minimize noise while making sure I have enough signal to stack and stretch. I think I am going in the right direction.
My setup provides a little too much magnification to get everything in the frame which is a shame. Maybe if I ever switch to a full frame camera or CCD I can get the entire Andromeda Galaxy in the image. Even so, not too bad.
I hope you enjoyed my images of the Andromeda Galaxy!