Spent from 1 to 4:30 pm MST 4/29/2007 observing solar active region 953 consisting of a large group of four sunspots with a light filament on one side. This is a nice region and I recommend it in either Ha or white light. The observing point was Copperton Park at 11th Ave and Virginia Street. About 5 small prominences were viewed in Ha on a PST mounted on an Orion Atlas EQ-5 mount. Prominences could still be seen after 3pm when the Sun is at a lower altitude - a unusual level of seeing. Unlike my experience with lunar tracking, solar tracking of the Atlas EQ-5 was dead-on - holding a center easily for about 10 minutes at a time. I also began some preliminary work with the DSI I mounted on this EQ-5 inorder to make solar images. I didn't get any useable images, but was able to locate the prime focal length and get the camera to prime focus. Lessons learned follow, if it is of any use to others here. The prime focal plane on a PST is 70mm above the top body metal. The PST works the best with a 20mm down to a 12mm eyepiece. A 9mm e.p. if screwed home will not reach prime focus. I didn't try backing a 9mm e.p. out of the holder to test achieving visual focus with shorter length e.p.'s. A 2x barlow gives the best visual experience. Higher magnifications could be had with a shorty 2x barlow (Orion) and a 20 or 15mm e.p. My 3x barlow would not yield a useable focal plane. I'll have to compute the AB distances between the barlow and the PST prime focal plane and try again. Measuring calibers are a useful tool to have when working with a PST and various eyepieces. After estimating the inset of the DSI CCD chip relative to the body, I used measuring calibers to position the DSI chip at the PST prime focus 70mm above the base. My imaging laptop was placed on a small table next to the scope. A carboard banker's box with suitable holes cut out for my hands and a small hole viewing the laptop screen was placed over the laptop. The viewing hole was cut across an edge of the box. A dark coat went over the box. On the front side, I taped a black plastic bag, laping the black plastic under the coat. This made the set up sufficient light tight so I could focus the scope on the laptop screen, adjust the tracking controller and run the laptop. Of course anyone walking by, legitimately found the whole scene amuzing and comical. I was working in monochrome mode which probably was a mistake. Getting a sharp focus still proved illusive in monochrome mode. Dust in the optics was a significant problem. I'll have to go back through the DSI and the PST optics to make sure everything is blown out. The Meade Autostar software would not properly estimate a color or black and white exposure. I had to manually drop the gain to 50 and the exposure to 0.007 seconds. Next time around, I'll probably work in color mode. I've had better results in color in the past. I probably will also try a Hartman mask (that I fabricated for my SLR camera) on the PST to see if the focusing process can be made to work faster. Finally, I'll expand to trying the DSI with the 2x barlow. I'm not sure how one would go about taking white flats with a PST. Any tips would be appreciated. - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net