July 28, 2009

The Cocoon Nebula

This is the second image from the Squaw Peak session. This one really needed more exposure time, but it was 1:45 am, and I still had to pack up and drive off the mountain. A mere 34 minutes was not enough for the Canon XTi through the AT66ED with the WO 0.8 focal reducer (320mm focal length), unguided on the Vixen GP. Here is a closeup of the nebula:

July 27, 2009

M18, M24, NGC6603, IC 4701, Barnard 93, Barnard 92

Here is the first fruits of the first Utah mountain imaging session. I drove up Provo Canyon about a half mile to the Squaw Peak Road, and up that road about 8 or so miles. About halfway between Hope and Rock Canyon campgrounds, there is a small clearing and camping area. I set up there and waited for the 30% waxing crescent of a moon to stop casting shadows. It was dark, but glow from Orem-Provo lit up the lower part of the western sky. Still, it was a much better sky than I am used to, even a bit better overhead and in the west than the sky at the Huntsville observatory.

Besides the two Messier objects and the two Barnard dark nebulae, the image contains two open clusters, NGC 6603, just to the left of the Barnard objects, and IC 4701, a large open cluster to the right of M18. There are others objects in the image as well, but these were my targets. Here is a closeup of the Barnards:

And here is another of M18:

This image is 64x60' with the Canon XTi through the AT66ED with the WO 0.8 focal reducer (320mm focal length), unguided on the Vixen GP.

July 18, 2009

M13, M27, and Autoguiding

How many images of M13 can a fellow need, really? These two images, and especially M13, were taken through soupy skies. I was out not to image but to test autoguiding. I just received the mount back from Texas Nautical Repair. It seems my mount's failing to respond to dec commands actually signaled a problem. With the new dec drive in place, here are the results. The image of M27 is particularly detailed, I think, for a full-spectrum monochrome image. I kept all but 8 of 75 2-minute subs.

July 15, 2009

M13, Again: First Light with the Vixen GP

This image is very promising. It is just 5x30", but it was taken with the XTi through the AT66ED, mounted on the Vixen GP mount I have owned for almost two years. I bought it on eBay. It came with the R135S, but it was a bare-bones model. I have added an RA motor and polar alignment scope, and a smaller counterweight. Each of the five 30" exposures was dead-on accurate at 320mm. The mount tracks very well at that focal length. That is what I was hoping. This system is extremely portable and easy to use. It requires no computer.

Tonight was also first light with the Bahtinov Mask I purchased for the AT66ED. Here is an image of Deneb in focus with the Mask on. Focusing took about five minutes, and it was extremely accurate.

July 12, 2009

Jupiter and NGC 7789 with the 6"

Early this morning I was out with the 6" achromat mounted on the DS-10. This was first light with the 6" on this mount. Jupiter was high in the sky. At 240x, I was able to tell which moon was Ganymede. It is noticeably larger than the other moons. The planet sported cloud bands and much other detail in and around the bands, of course, and a nice dark spot in the southernmost, lighter equatorial band. The Great Red Spot was round the back of the planet and not visible.

I also enjoyed viewing the Ring Nebula, double star Eta Cassiopeiae, and Albireo. This was a quick session, but I ended up viewing NGC 7789 in Cassiopeia. This is a large open cluster whose brightest stars are about 11th magnitude. This makes the cluster a challenge for a small, backyard city scope. I have seen the cluster in an 8" reflector I owned, and this morning I found it in the 6" achromat. It's a nice view. The cluster's brighter stars were scattered over a wide part of the view at 35x, tiny points of light sitting quietly together. The cluster is large enough to have lasted 1.6 billion years. A photo much deeper than I could see with my eyes this morning is found here.

The DS-10 mount handled the 6" just fine. Tracking was a bit slow at times, perhaps because of RA clutch slippage, but I am working on the balance and other things to get that fixed.

July 5, 2009

July 4th Fireworks and the Moon

I took the camera along. The nearly full moon had risen behind where we were to view the fireworks. The photos don't quite do justice to the scene. Canon XTi, 18-55 kit lens, f/10, 1 sec. Some of these were published at Spaceweather.com (here)!


M92 is the other bright globular in Hercules, besides M13. M92 is a bit further away than M13, and smaller, but its core is brighter. I noticed this visually many years ago, so I was not surprised to see this verified photographically; compare the image of M13 here, taken with the exact same equipment. That image of M13 is well over an hour's worth of exposures, whereas this is only 30x90", just 45 minutes. I have always been glad to find M92 in a small telescope, as it sits somewhat away from other sights. I starhop north from Pi Herculis.

July 3, 2009

M27, the Dumbbell Nebula

This nebula was formed when the star at the center of it aged and grew in size until its outer laters blew off into space. When a star of a certain size ages, its hydrogen spent, its core begins to collapse. As it does so, it grows hotter, and the helium and oxygen created earlier through hydrogen fusion then begin to fuse into heavier elements, such as carbon. In this stage, radiation from the shrinking center of the star pushes out on the outer layers of the star, which expands outward to become what we call a red giant. Eventually, the pressure in the center will be so great, the temperatures there so hot, the radiation outward so energetic, and the other layers so far away from the fusing core that the outer layers will be blown by the radiation out into space, forming a planetary nebula. The Dumbbell nebula is a fine example, as is M57, the Ring Nebula. The Dumbbell gained its name because, when seen visually through a telescope, the brighter parts of the nebula look like two attached lobes.

This image was taken with the Atik 16 through the AT66ED, guided with the DSI Pro through the 100mm f/6 on the Tak EM-10. The 99x90" subframes were processed first in Nebulosity and then in PSE7. Thanks to tips from the Spark labs forum, autoguiding is getting better. Every frame in this over-two-hour set was excellent. It could be better still.

July 1, 2009

The DS-10 Drive

Here is the motor, worm, and drive gear of the DS-10. Adjusting it is very simple. Two allen bolts on the back of the housing plate (not visible in the images) loosen to allow the worm block, which is all one piece, to be moved closer to the gear, largely resolving the backlash problem. The motor is attached to the worm block, so there is no chance of losing torque or creating tension by adjusting the position of the worm. The three screws on the face of the round plate adjust the clutch. Tightening the clutch helped with the backlash, too, and the slight slipping I could feel as the clutch grabbed. Even I can adjust such a simple machine.

Double Doubles in Lyra

Lyra is full of double doubles. Of course, there is the famous Epsilon Lyrae. That's the showpiece. But there are several other optical doubles just as nice to look at (though not gravitationally bound together). For instance, there is Struve 2470 and 2474. At 17x they are distant; at 60x they are nicely framed in my 100mm f/6. Then there is Eta Lyrae, and just next to it another double, also framed nicely at 60x. Beta Lyrae is also a double, widely split at 17x. In the same view as Beta Lyrae, one can also see Otto Struve 525, and this with Beta Lyrae creates a nice contrasting pair of pairs. I could dimly see the Ring Nebula M57 in the same view, on the square corner of a right triangle with the two double stars. Very nice!

Observations were made with 100mm achromat on the elevated DS-10 using S&T's Pocket Sky Atlas. I have discovered that the DS-10 goes back and forth between a bit too slow and a bit too fast. For part of the turn around the gear, its tracking is quite close to sidereal.