December 20, 2007

December 18, 2007 Lunar Shots

On the evening of December 18, the air was quite still and the moon was a waxing just-past-quarter. I had the XT8 out with a ClearVue 30mm 80-degree eyepiece. This eyepiece sports threads under the eyecup which allow the eyepiece to be directly attached to my Sony DSC-75 digital camera. The images here are the result (click on each image for a larger, clearer view). In particular, the area from Copernicus (the very dramatic crater in the top image) to Montes Apenninus (the mountain range to the crater's left) is interesting. Also, I was able to catch the Straight Wall, a curious fault line that runs in nearly a straight line north and south, allowing a shadow to be cast that makes the feature stand out. My favorite discussion of this Straight Wall, by Charles Wood, is found here. Notice (after reading Wood's commentary) that in the image focusing on the Straight Wall, part of Rima Birt is visible as is the dark area at the northern end of Rima Birt (north is down in this image). You may have to enlarge the image quite a bit to see it.

December 17, 2007

Deep Sky Standby Survey!

Do you keep coming back to the same objects each time you observe? For me, some objects continually find their way into my scope, often at the beginning or end of an observing session. M57, M42, the Double Cluster, the Double Double, Albireo, Polaris---these are my permanent friends in the sky. Please take the survey and name your old standbys. I would like to know what objects bring you back again and again.

December 16, 2007

December 16, 2007 - NGC 40

Tonight I was looking for Comet Tuttle again but ended up observing NGC 40. This planetary is an exceptional sight at 240x in the XT8, even from the light-polluted Woodlands skies. The central star is obvious in the 8-inch, and so is the blobby nebulosity that surrounds it. Burnham's says the central star is mag 11.5. It sits in between and just to the north of two slightly brighter stars. After I had seen the nebulosity at the higher magnification, it was obvious at 40x, also. I believe I had a glimpse of it at the lower magnification before looking more closely. Definitely worth the look!

December 12, 2007

December 12, 2007 Comets

The clouds broke last night for a few minutes between 12 and 1. Comet Holmes is still visible to the eye, even from my moderately light polluted street! It was more visible with averted vision, but it was plainly there, a ghostly glow about twice the diameter of the full moon. It is just southeast of Iota Persei, and forms a glowing corner of an isosceles triangle centered on Mirfak. The long side of the triangle runs between Delta Persei and the comet, which are both about the same apparent distance from Mirfak. I could see the comet a week ago at this time when the sky was last clear. This week I was sure it would be too faint, but there it is still!

Last week I tried to find Comet Tuttle, but nothing like a comet appeared in my XT8. Polaris is pretty low and through the trees here in my neighborhood, however, and the comet is not bright yet. Even a non-observation is an observation!

November 19, 2007

November 19, 2007

I was back out with the XT8 tonight before the fog rolled in. Comet Holmes is now a large, diffuse blob near Mirfak, the bright star in northern Perseus. I could not see the nucleus at all, though I did see stellar objects through the tail.

The moon is out tonight, a waxing quarter. It was over behind a pine tree, but it was washing out the dimmer objects, I'm sure. Still, Holmes is visible to the naked eye as a diffuse glow near the star. I saw it as soon as my neighbor turned out his porch light. Even so, Holmes is not terribly interesting any more, visually. NHAC club members are still getting good images of it, though.

Next I explored the brighter clusters of eastern Cassiopeia! Beginning at Ruchbah, I traveled east to M103. At 240x, I see about 27 or 30 stars in the cluster, depending on what counts. M103 is easy to find and nice to look at.

Next I found NGC 659 and 663. 663 is a grand sight.

But the most interesting cluster I saw tonight is NGC 654. I have decided to name this one "The Brain Cluster." At 240x, the cluster looks like a brain, pickled in a jar. The top of the head is pointing off to the northeast. The bright star on the eastern edge is, I imagine, the point in the lower cerebral cortex where consciousness seems to sit. The cluster even sports a brain stem moving off to the southwest, where the second-brightest star in the small field is located at the end of the stem. NGC 654, I dub thee, "The Brain Cluster."

Nearby I found NGC 559 and 637, and before going back to Ruchbah I also took a look at the Double Cluster. What a stunning sight, always!

But Stock 2 is also very interesting. I never noticed this large cluster before, probably because it is so large. It seems to cover nearly as much ground as the Pleiades' brighter members. It is dimmer than the Pleiades, of course, and I suppose in binoculars would look like a fuzzy, brighter patch of light.

I also took a look at NGC 457, always one of my favorites. In fact, the highlights of the night were NGC 457, the Double Cluster, and the Brain Cluster! Viva la Brain!

November 17, 2007

November 10, 2007

Times change. My family life has become much busier over the last two months, and that means I have not had time to set up the camera and gather images. I will probably stay in this non-imaging mode for some time, perhaps 18 months. But I feel a need to be out under the sky, even if I can only make it as far as the back yard. And I feel like I ought to be producing something while I do that, so here I am writing.
I was out on the night of November 10. Comet Holmes is the big attraction. It was shaped like a large, diffuse C. I was using the 8-inch dob, and I was unable to see any nucleus that I could clearly identify, though a very stellar light source shone where I thought the nucleus should have been. It was still stellar at 240x, however, so I doubted whether that was it. Several stars shone through the tail.
Mars is rising. I could see some markings on the planet, but it is so bright in the dob that I would need a filter to see anything, preferably a blue filter. I had none with me. The planet is getting large, almost as large as Saturn in the eyepiece.
M42 and M43, I saw, and six Trapezium stars. The Trapezium is a small cluster of stars at the heart of M42. Most any scope will show four stars, named A-D. I have seen four stars even when using very small scopes. Usually I see five stars with the dob from my backyard, but I saw both the E and F components this night. F was visible most of the time, and E was apparent when seeing was steady at 120x and a little less apparent at 240x. It's a grand thing, to see these other stars. The Trapezium is one of my favorite targets.
M78, I also found.
R Leporis, sure enough, is a very red star. It is said to be a carbon star, one that has fused most of its hydrogen and in the process of fusing helium and heavier elements has developed a surface of carbon, which glows redder than other elements. The color was obvious against the other stars in the vicinity. I noticed the color in my 50mm finderscope.
I also saw M79, a globular cluster in Lepus. And I found S478, a beautiful, easy double star in the Lepus quadrilateral. Each component of S478 is about the same magnitude and appears white or white-blue to me.
I finished off with IC 418, a bright, oval planetary nebula (also in Lepus). It looked stellar to me at 40x, and about as bright as the 7th magnitude stars in the coathanger-shaped asterism that points to it. At 120x, the nebula looks like an out-of-focus star, but I knew it because the rest of the stars in the view were in focus. At 240x, the nebula is a bright oval. I could see no details, really, except the central star. It is such a bright object that it would have been obvious in a
much smaller telescope that can handle the magnification.
As is usually the case, the yard was quiet and dark. Many thanks to my two closest neighbors who keep their back porch lights off.

November 5, 2007

M42 & M43 October 2007

I took this early one morning around the time of the October new moon with the Vixen R135S at f/5.3. Mount: LXD75, unguided. Camera: DSI Pro. The sky was beautiful and the neighborhood was quiet. (Please click on the image for a better view.)

September 29, 2007

NGC 6888 Crescent Nebula September 2007

Here is a new Crescent! This is the prior image but added to it is nearly 27 minutes of additional 5.7-second exposures taken through a 13nm H-alpha filter. Like the earlier image, this additional data was gathered through the Vixen R135S at f/4.8 with the DSI Pro, unguided on an LXD75 mount. The H-alpha data was stacked in Registax and then combined with the older image in DeepSkyStacker. Further processing was done in Registax. The natural next step would be to combine these in color, but I have not figured out how to do that yet, especially for these images which would not process in Envisage. In the meantime, I am delighted to see more of the nebula!

The Core of M31 September 2007

Here is another of the three images from this last week. This is the core of M31, the Andromeda Galaxy. Imaging with the DSI Pro through a scope with a focal length of 720mm, I can't fit the entire galaxy in the frame (not even close). But these dust lanes around the core are more than I can see visually, and much more sharply defined. The image is about 15 minutes 40 seconds of 4-second exposures, taken through the Vixen R135S at f/5.3 on the LXD75, processed in Registax.

NGC 7789 September 2007

The nights were beautiful the week of the new moon in September. I had one great night of imaging. Here is one taken toward the end of the night. I was waiting for the Pleiades to come up over the trees, and was too tired to think of another target than this one, a visual favorite. The cluster NGC 7789 in Cassiopeia is too large to shoot with the DSI Pro at a 720mm focal length (the Pleiades are even larger, and I didn't even try), but I aimed well within NGC 7789's borders and started shooting, anyway. The stars in this shot are within the cluster. I think they are lovely. Yes, they need color. I will get to that, eventually, but I am still so amazed to see these images, even in black and white, that I just haven't bothered yet. The scope was the Vixen R135S, at f/5.3, unguided on the LXD75. This is 11 minutes 16 seconds worth of 4-second exposures processed in Registax.

M29 September 2007

In early September, on a Saturday near the new moon, the skies cleared off and water vapor was down to an acceptable level. I didn't get the camera working until quite late and did not spend much time imaging, but towards the end of the session I turned the camera on M29. This image is about 10 minutes worth of unguided 4-second exposures with the DSI Pro through the R135S. Surely it would be better in color. I will be trying that, soon (though maybe not on this cluster).

M29 is called "M29" because it is #29 in Messier's catalogue of things that might look like comets but are not (he wanted a checklist to avoid mistaking a non-comet for a comet). M29's appearance always confused me until last night, because it could never be mistaken for a comet, I thought; it is quite obviously a small group of stars. But last night I saw M29 in my 50mm finderscope. Sure enough, it looked like a patch of fuzz, perhaps a possible comet. Of course, through the much larger R135S, as in the image, one would never think that.

NGC 6888 August 2007

The Crescent Nebula, NGC6888, is on the cover of September's Sky & Telescope. I wanted to see what I could do from the backyard. I also wanted to try out a new Vixen focal reducer designed for use with the R135S. With the focal reducer, I am imaging at f/4.8. That's still 648mm, but faster than the images at f/5.3, stacked below, of M57. This image of the Crescent is about 38 minutes worth of 8-second, unguided images, stacked and stretched in Registax. It is not as deep as I'd like. I thought I'd see more of the nebula. Perhaps under darker skies, or with an Ha filter. Next time, maybe.

M57 August 2007

I've been working toward a new image of M57. I wanted to capture both stars in the middle of the ring. The clouds here finally broke in August. On August 9th, I was able to set up the Vixen R135S on the LXD75. The image posted here was taken at f/5.3 through the DSI Pro. The stars are smaller points in the Vixen than through the achromat. Also, with the newtonian, I need no IR filter, as all wavelengths line up on one plane. This image is 10 minutes worth of 8-second exposures stacked and stretched in Registax, unguided. One can see three stars inside the loop of the ring, and one star on the outer edge. If the photometric measurements of others around the web are correct, stars dimmer than magnitude 16 appear in this image.

M27 June 2007

In late June we had a brief break in the monsoon---one night of clear skies, not very transparent, until around 3 am. I used the Orion 100mm achromat, the LXD75, and the DSI Pro. Once again, the exposures were unguided. This image is a combination of 239 2-second exposures and 131 2.8-second exposures; that is just over 14 minutes total. The exposures were dark-subtracted, combined, and processed entirely in Envisage. The result shows less detail than I had hoped, probably because I was so excited to get set up and start taking pictures that I forgot to install the V-block filter in the achromat. That may explain why some of the stars are so large. Also, I was still learning the software, and I saved the individual frames in a format that made them harder to process afterward. Moreover, transparency was not great. As I stretched the histogram, I found that, in order to make the background black, I had to sacrifice lots of nebular brightness. Finally, I took this from my backyard, which sports Bortle scale 4.5-5 skies.

M22 June 2007 Redux

I was delighted to receive great advice from a few members of my club, the North Houston Astronomy Club. One, Paul Downing, downloaded my image from here, applied a Kernel low pass filter to the image and did some additional stretching. His result is posted here, with mine on the left and his on the right:

I was surprised that this image could be obtained from my data. I do not have the filter capability in the free software that I own (that I know of---I haven't explored all of its contours yet), but I realized that I have been using rather blunt instruments for stretching. Here is a better stretch obtained using DeepSkyStacker:

It looks much more like a globular cluster now. I am surprised that the data was there. Compared with a visual observation, this is pretty astonishing.

M57 June 2007

This image is just 6 exposures, 5.7 seconds each. Like the others posted before this one, the exposures from which it was created were captured, and darks were subtracted, in Envisage. But these exposures were also combined and processed in Envisage. Actually, I had reached the end of an imaging session and wanted to see if I could glimpse M57 on the computer screen in a 1 second exposure (what I have used as my “Live” setting in the Autostar capture software). I could, so I decided to take a few more exposures. What surprised me about the image is that, notwithstanding the short exposure time, the central star is visible, something I had never seen before. Scope: Orion 100mm f/6 achromat. Mount: LXD75. Camera: DSI Pro. This image was also unguided.

M8 June 2007

This image is 266 exposures of 4 seconds each. They were captured, and darks were subtracted, in Envisage. They were stacked and processed in Registax 4. Scope: Orion 100mm f/6 achromat. Mount: LXD75. Camera: DSI Pro.

M22 June 2007

This image is 107 exposures: 20 images 1 second long and 87 images 8 seconds long. The exposures were captured, and darks were subtracted, in Envisage. They were stacked and processed in Registax 4. Scope: Orion 100mm f/6 achromat. Mount: LXD75. Camera: DSI Pro. This image was also unguided.

The Images

Thanks to all who view the pictures posted here. Please feel free to comment with advice on how the shots may have been improved, whether in the framing, shooting, or processing. I would like to be better at this than I am.