November 27, 2008


I'm not too satisfied with this image of M52. Probably I need longer sub-exposures. This is about 150x15" at 800 ISO with the XTi and the AT66ED. I figured this would be enough for this bright Messier object, but the dimmer stars in M52 are quite dim still. On the other hand, some reports of M52 put its dimmer members at magnitude 16 or fainter, and that is surely the case. M52 is 3,000-7,000 light years away from earth, and has around 200 stars (that have been found; what are the chances a cool dwarf star or two were missed?), more than I see here. In other words, I am not likely catch all the stars in the cluster with this casual imaging setup and method, so in my image the stars go from quite bright to fading out, and a few more lie beyond the reach of this set of exposures. Here's a deeper, better image. M52 is very near the Bubble Nebula, as shown in this fine image and also in this fine image and this one, too.

November 26, 2008

AR6 on the Giro III

Tonight I took a whirl with the AR6 again, mounted on the Giro III. The mount handles the big refractor easily. Tonight I left the Orion V-block filter on the 2" diagonal.

I stuck with wide fields tonight, generally: The Double Cluster, M38, M36, M37, M35. These big clusters are amazing in this scope. Stars are pinpoint, sparkling jewels against a deep midnight blue background. I switched to 152x with the 8mm Hyperion on M37 and a double star just south of M37, nicely split. A magnification of 152x on this scope yields a 1mm exit pupil. Images stay quite bright but are magnified nicely, and in the 8mm Hyperion's wide field I do not need to move the scope often (the true field is nearly half a degree). Even so, the movements with the Giro III are smooth and easy. The first time I took the scope out I used a 5mm Stratus (less than one-third of a degree true field), and this is easily doable and enjoyable with this mount, though one has to move the scope more often.

I ended the night by splitting Rigel, a nice wide double at 152x, with a yellow white primary and a bright blue secondary. Then I went to pick up my daughters from a movie and came back to a cloudy sky and a fogged lens. Time to pack it in.

November 19, 2008

First Light with the 6" Achromat

Tonight I viewed for the first time with a new (used) Meade AR6 achromatic refractor. I saw some very nice views of the Double Cluster, Eta Cass, and Rigel. But after waiting for the lenses to cool, I went back out to look at the Trapezium. In this scope, at 240x, E is for Easy, and F is for Frequently Seen. In fact, the E component of this group was easily visible at 120x. It was grand, I tell you, and the nebula itself was more detailed than I have seen it in a long time. Looking through this scope is for me a new and impressive experience.

November 17, 2008

First Light with the Atik 16: The Bubble Nebula

I am very much an amateur at this sort of thing, but earlier this year I was able to buy at a good price an almost new Atik 16. It is an impressive camera in several respects. This image, in particular, is remarkable because it is unguided. It is 401 x 10" exposures processed and combined in Nebulosity then stretched in Registax and further stretched and modified in Photoshop Elements (including a framing effect from the Noel Carboni package, just received). The camera has remarkably high sensitivity to the Ha wavelength and generates very little noise, including remarkably low read noise. Capturing frames with it in Nebulosity is very easy.

Now, of course, this image is far from perfect. It is monochrome, unlike the sky itself, for instance. My goal was to get all the edges of the Bubble so that its shape was obvious. I also wanted to refrain from blowing out the central portion of the nebula that is the brightest. That brightest part is visible as a twisted line just under the star in the upper right of the bubble. The star above the twisted line is the one whose radiation is creating the bubble in the cloud of gas around the star and also the glow of the surrounding gas. The brightest part of the bubble is just around that star.

The Bubble Nebula is such an intriguing sight. I wanted to get in on the action of others who have seen it. Only a quite large scope would show the whole bubble structure to the eye, but I can capture it in a camera with a 135mm f/5.3 newtonian reflector from my suburban backyard. Truly great images include Croman's, the Hubble Space Telescope's, NOAO's, and Christen's. The first two of these links give more information about the nebula itself.

November 8, 2008


This image of open cluster M34, in the constellation Perseus, was taken with the AT66ED and the XTi, and is just over 23 minutes of exposures, or 93x15". It was also taken on the night of October 18-19. I think the cluster looks better in a telescope than in any image, but the image reminds me of what the cluster looks like.

A newly processed version of the same image data using PSE7 and looking much more like the cluster looks in a telescope:

November 7, 2008

M45---The Pleiades, The Seven Sisters, Subaru

Even folks without a telescope should recognize this group of stars, the Pleiades, which rises around sunset on November evenings and is a familiar sight throughout the winter in North America. It is an open cluster of stars between 393 and 449 light years distant according to the latest studies. In binoculars and especially in a telescope, the blue-white color of the cluster's stars appears. This image only captures the center of the cluster. The Pleiades group contains at least 500 stars, some too dim to be caught in such a short exposure through such a small telescope. The cluster is passing through a cloud of dust and gas. This image does show a small bit of the starlight reflected in blue on the dust around some of the brighter stars. Much more reflected starlight appears in the Hallas's much deeper image. My image was take with the 400D through the AT66ED, unguided on the LXD75 mount. Total exposure time was 17 minutes, or 68 x 15". Data was gathered on the night of October 18-19.