August 30, 2008

Total Eclipse (on Jupiter)

Tonight (Friday the 29th) my kids and I caught Io's shadow marching across Jupiter. Very cool. Jupiter was a sight tonight, with bands, festoons, and moons. Also, the 100mm f/6 split Epsilon Lyrae very cleanly, with black sky in between each of the two pairs, at 120x. The sky was full of water vapor tonight, but it did not seem to make detail less visible.

August 11, 2008

North America Nebula

Here are the other targets I was hoping to image in the Hill Country: the North America and Pelican Nebulas (Nebulae?). They are at the center of the image. You can see the shape of North America, I hope, and the Pelican (not shaped very much like a pelican) where the north Atlantic would be. The bright star to the right is Deneb. In the upper left is M39, an open cluster. Around about where Ohio or Pennsylvania would be in the North America nebula is another open cluster called NGC 6997.

This image was taken with the same equipment as the Sagittarius Field. This was 38x60" processed in Nebulosity and touched up a bit more in Canon's DPP. A satellite apparently flew through the field. The trail is not apparent in any of the sub-images without stretching, and I did not stretch them. Maybe someday I'll re-process and find it.

August 5, 2008

Get Out the Star Charts of Sagittarius

[Corrected image: Bluer than the original post on the advice of NHAC member and accomplished astrophotographer Dick Locke. This adjustment allows one to see some of the nebulosity just to the east of M8, such as I.4685, and further north I.1283-84. Aesthetically, it is much more pleasing, and the colors are more similar to those I imagine that I see with my eyes. Many thanks.]

This was one of the two images I hoped to obtain in the Hill Country. It is a wide view of the western part of Sagittarius. The center of the galaxy is in the lower side of the left half of the image. In the image are some of my favorite celestial wonders. The best way to view this image is to download it here (there is a download link on the right of the linked page if you are signed in to Google), save it, then look at it in a photo viewer in full size. Not all of it will fit on the screen unless you have a much larger screen than I have, but you can browse about the picture. Almost as if you are looking through a small telescope, you can see some of the things that fascinate me in this area of the sky.

In this image (well, in the full-size image from which this smaller scale version is derived), I find thirteen objects cataloged by comet hunter Charles Messier, including six open clusters, four globular clusters, and four nebulae. But besides this, I find eleven other open clusters and thirteen other globular clusters. Besides these, a number of dark nebulae appear in the image. I have no good catalog of dark nebulae, so I have not counted which I see, but many of the smaller and nearer ones are obvious. They appear as black holes against the background of stars. They are actually clouds of dust and gas that are nearer than the stars, block out their light, and so appear black.

The image is centered on the Lagoon Nebula, a bright cloud of dust excited by radiation from stars forming within and around it. Just to the right of it is the Trifid Nebula, so-called because it appears in small telescopes to split into three parts like three flaps in a pinwheel around a central, bright star. In this image, some of the lines between the flaps appear if you look very closely at the image in full size.

The image was obtained with the Canon 400D through a 50mm f/1.8 lens at f/3.2. Twenty 60-second exposures, taken without guiding while piggybacked on the 100mm achromat on the LXD75, were combined and stretched in Nebulosity, saved as a jpeg, and then color-enhanced, brightened, and contrast-enhanced in Canon's DPP. There is one problem at least with the image: terrible coma in the right lower corner, decreasing some but still present all the way up the right side. I could crop it, but I like to see M16 there on the right with plenty of stars around it.

August 4, 2008

Hill Country Trip

This last week my family and I took a trip to central Texas. One of my daughters had an activity in San Antonio, and we were in the mood for some peace and quiet and starlit skies. We stayed at the Starry Nights Bed & Breakfast. The accommodations were excellent, the surroundings peaceful and quiet. The kids had fun playing with our hosts' dogs, hiking the nature trail, playing on the swings and treehouse, and watching movies. We saw deer, a fox, a jackrabbit, the lizard who lived next to the porch of the cottage, and hawks soaring above. Two of the deer in fact gave me a scare on our last night as I was coming out in the dark to pick up equipment. I scared them, too.

I was able to do some imaging at night. The skies are beautiful. I could see the Milky Way from horizon to horizon. In Cygnus, the galaxy's glow reached at least the tips of the swan's outstretched wings. The weather reminded me only a little of a trip to the Texas Star Party a few years ago when the event was held in central rather than west Texas. On my first night at TSP that year, the skies were dark and clear. I was rolling through my small scope and binocular list looking for M51 when ... huh? ... the stars all disappeared! Clouds! The stars did not come back for at least three days, and I ended up leaving early. Last week, though, I usually had until 1 or 2 in the morning before I was clouded out. Four out of our five nights were cloudless until then.

The image above of Antares & M4 was taken with the 400D through a 50mm f/1.8 lense at f/2.8, piggybacked on the Orion 100m f/6 and the Meade LXD75. It is a single, 60-second exposure at 800 ISO. It has been subject to some (but not much) brightening and color enhancement. The clouds were just beginning to roll in from the southeast. They hadn't reached Antares yet, so I figured I still had some time.