Flaming Star Nebula - New Camera

I've held off posting this one for a few months because, frankly, I'm not at all happy with it. This is the Flaming Star Nebula, located in the constellation Auriga.

Flaming Star Nebula; Canon Rebel T3 (1100D), ST80 on Vixen SP mount; 10x120 at ISO-6400

The reason I decided to post it here is to give an example of what a long exposure looks like on my new camera. I've had this camera for a while, but haven't had the opportunity to use it much for astrophotography. It is a Canon EOS Rebel T3 (1100D) that I got for cheap. It's main selling point was its low noise on long exposures. I was never able to separate the Flaming Star Nebula from the ambient noise of the old Rebel XS.

Another advantage of the new camera is that it will take exposures at ISO-3200 and ISO-6400, unlike the old camera that only went up to ISO-1600.

As those of you who keep up with this blog already know, I use an Orion ShortTube 80 on an old Vixen Super Polaris mount when I view and image from home. The Super Polaris is a great little mount, but it does not have autoguiding or any kind of fancy computer control, like GOTO. The polar alignment scope is out of date (it was probably made in the mid-80s), so I have to estimate where to place Polaris in the reticle. As a result, the best I can usually get out of it are 3-minute exposures. Therefore, I figure that the higher ISO and lower noise of the T3 will help me capture more detail.

Here is a portion a single shot from the run that was used to produce the image above. I limited the exposure time to two minutes because the light pollution was swamping the nebula at higher exposures.

Two-minute exposure at ISO-6400. The nebula is barely visible, but can be separated from the relatively even noise.

Here is another example frame. It is a portion of a shot of Messier 101:

Three-minute exposure at ISO-1600 of Messier 101.

I'm looking forward to trying this camera on the astrograph at the observatory.

Experiments and Failures

I'm always trying to think of ways to improve my imaging techniques, especially given the fact that the equipment that I am using is not well-suited for astroimaging. I have four major limiting factors:

• My primary imaging scope is an achromat with a fast focal ratio (f/5), which means there is significant chromatic aberration (CA) in images of bright objects and long exposures of stars. One form of CA that is common in long exposures is purple fringing, which creates blue and purple halos around bright stars.
• The mount is unguided and was probably never intended for making exposures that last longer than a couple of minutes.
• The DSLR that I use for imaging does not have a mechanism for cooling the imaging chip, so it generates a lot of heat-related noise.
• The IR-cut filter on my DSLR filters out the Hydrogen Alpha (H-alpha) wavelength of the spectrum, which is where a lot of the "action" is happening in the sky, color-wise.

All of these issues could be solved if I had more money in the astronomy budget. But, since that won't be improving in the foreseeable future, I try to make the best of what I have. (Which I've very thankful to have, by-the-way!)

The images below mostly represent failed attempts. One or two may look pretty, but I assure you that something in the process did not work as I had intended. Regardless, I learned something from each, as described below.

I avoid using my ShortTube 80 for lunar and planetary imaging--the chromatic aberration is just too severe to get a sharp image. It comes with a special lens cap that permits the scope to be stopped down to about f/9, but even at that focal ratio the scope still produces a blurry image on bright objects.  The Orion SkyGlow filter seems to mitigate the purple fringing around stars a little, so I thought I'd see how well it performed with an image of the moon. The results were far from impressive, as the following image illustrates:

Effects of chromatic aberration (colors have been enhanced). CA blurs images because the individual colors do not come to focus at the same point. The inset images highlight the blurring effect on the lunar limb and Copernicus crater.

I separated the image into its red, green and blue components. It was out of focus in red and blue, but pretty close to focus in green. Here is the green channel in grayscale:

Moon in Green, April 1, 2012.

Here are the same areas from the insets, above, except only in the green channel. Note that the focus is sharper.

One night back in January 2011 I imaged NGC 2264, the Christmas Tree Cluster and Cone Nebula, hoping to improve on an earlier attempt that I made with the Epsilon-200. I took a few test shots and wasn't impressed with the results, so decided not to continue. Recently, I was going through my imaging archives and came across the test images and decided to see if I could salvage something out of them.  Here is the result:

NGC 2264, the Christmas Tree Cluster and Cone Nebula; ST80 on Vixen SP; 3x180

The individual images from which it was composed were VERY noisy, and there wasn't much nebulosity. Running the image through a noise reduction filter a couple of times and resizing the image helped to hide the noise. There are a lot of stars, and the dark nebulae are fairly easy to identify. Perhaps I shouldn't have been too hasty to judge the test frames. If I had taken more images then I might have gotten a decent result despite the limitations of my imaging equipment (i.e., lack H-alpha sensitivity).

Below is the earlier image that was taken with the Epsilon-200:

NGC 2264; Epsilon-200 on NJP

Finally, the image below was taken while experimenting with visual solar imaging using a full aperture solar filter on my ST80:

Focusing on the Sun is tough! The image constantly shimmers due to the atmosphere being heated by solar radiation, and the image in my DSLR is rather small. Add in the effects of CA, and getting a sharp image is nearly impossible. This image was heavily processed to bring out the surface granularity and the details around the sunspots.

Heart of the Scorpion

Antares is a supergiant star in the constellation Scorpius. It is nearly 300 million miles across, which is larger than the orbit of Mars! Antares is sometimes called the "Heart of the Scorpion."

The area in the sky around Antares is full of exciting objects. I imaged a small part of it while waiting for M8/M20/M21 to rise one morning. I took only a few images, but after heavy image processing I came up with the following:

Antares, Messier 4, NGC 6144 and IC 4605; ST80 on Vixen SP; 6x180

Antares is the yellow star at the bottom of the image. It appears orange to the naked eye. The yellow color here is due to the fact that the star is overexposed, and the camera is less sensitive to the red part of the spectrum.

Clouds of interstellar gas and dust fill the area, adding unusual patterns and colors to the scene.

Messier 4 is the large globular cluster at the top. It is about 7,200 light years away and is one of the closest globular clusters to Earth. Messier 4 is also called the Cat's Eye cluster because of the conspicuous bar structure across the middle.

Globular cluster NGC 6144 is located to the upper-left of Antares. It is about 33,000 light years away.

The blue reflection nebula IC 4605 is in the lower-left corner.

I plan on revisiting this and the surrounding area one day. There is a lot more to see!

Broke California

Sometimes, imaging sessions don't work out so well. Unexpected changes in the weather, equipment problems, and even poor planning can bring disaster. Take, for instance, the other night...

I set up in the ObservaRory (my yard) to image Messier 77. I quickly realized, though, that M77 was way too small for my ST80--there's not much to see at that magnification. I wouldn't have wasted my time if I done sufficient research on my target.

Auriga was above the trees, so I decided to try something really ambitious: the Flaming Star Nebula. No good, though. It wasn't nearly dark enough, and even with a 3-minute exposure there wasn't much to see. Again, poor planning on my part.

I've been wanting to image the California Nebula (NGC 1499) for some time. It's a large nebula, from our perspective, but it's also very faint. I figured that if I could get a minimally decent image of the Witch Head Nebula, then I could get the California.

Within a few minutes I was set up and taking 3-minute exposures. It was faint, but I was happy that it showed up at all. Maybe the night wouldn't be a complete loss.

Time was not on my side. For one, the Moon was rising at 10:23 that night, and it was already nearly 9:30 by the time I got everything going. Also, my infant son was asleep and would likely wake sometime between 10:30 and 11:00 to be fed and have his diaper changed. Once everything was set up I went inside to watch a movie with my older son.

I went outside around 11:00 (just as the little one was starting to stir) to check things out, expecting the sequence to be just about done. To my dismay, however, I discovered that the laptop that was controlling the camera had gone into sleep mode due to inactivity. UGGGG!!! (I know that I had disabled the auto sleep mode. How it came to be turned back on again, I have no idea...) The sky was too bright to continue imaging the California Nebula, and I had baby maintenance duties to perform, so I shut everything down.

Upon examining the images later, I discovered that there was an odd blemish--probably something to do with dust and/or dew on the objective lens. I had forgotten to take flats, so I was stuck with it. Add to that the fact that I didn't get nearly as many subs as I wanted...

But, here it is, anyway. Like the real state of California, mine is broke(n), but it's still a pretty nice place:

NGC 1499, the California Nebula. ST80 on Vixen SP. 22x180 at ISO-1600.

The nebula lies approximately 1,500 to 1,800 light years away, and resides in the Orion arm, which is the same spiral arm of the galaxy as the Sun. It is about 100 light years across.

To the south of the nebula is the bright star Xi Persei, also known as Menkib. It is on the right-hand side of this image. Menkib may be providing most of the light that is energizing the nebula

Menkib means "collarbone" in Arabic, and it is part of an old Arabic constellation that includes the nearby Pleiades. Even though Menkib is relatively faint in our skies (apparent magnitude of 3.96), it is actually about 13,500 times brighter than then Sun in the visible spectrum. That makes it the most luminous star that we can see with the naked eye. It appears so dim to us because of its distance and the vast amount of light-absorbing interstellar dust between us.

Menkib is also a "runaway star." It is moving away from us at an unusually high rate of speed (about 20 km/s). Its speed may have been gained from a gravitational encounter with another star, or by the supernova explosion of a previous companion star. Menkib itself is a supernova candidate, and may explode anytime within the next million years.

Helix Nebula

I took this image of NGC 7293, the Helix Nebula, the same night that I imaged the Cocoon Nebula.  It was way hotter that night than it needed to be, and my DSLR was showing definite signs of heatstroke.  Still, I plowed forward, taking images on the Epsilon-200.  The NJP mount was giving me fits, too, but I managed to make it behave enough to get a few decent subs of the nebula.  Anyway, after many attempts at processing and reprocessing what, for all intents and purposes, was a whole bunch of crummy subs, I got this:

NGC 7293, the Helix Nebula

Cocoon Nebula - Redo

I went back and reprocessed the Cocoon Nebula image from a few days ago. It looks a little better to me now. I'm not 100% satisfied with it, though. One thing I like about this version is that the colors of the surrounding stars are more pronounced.

IC 5146 (Cocoon Nebula) and Barnard 168

Cocoon Nebula

The Cocoon Nebula (IC 5146, also Caldwell 19) is located in the constellation Cygnus.  Dark nebula Barnard 168 extends from the Cocoon Nebula to the edge of this image.

Heat is one of the worst enemies of imaging chips.  I do not have a rig to keep my DSLR cooled down, and it was VERY hot the night that I imaged the Cocoon Nebula.  There was a significant amount of noise in each of the subs.  I removed a lot of the noise, but I think that the overall image quality suffered pretty terribly.

IC 5146 (Cocoon Nebula) and Barnard 168