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The top frame is refined from three clips: the full disk was distilled from 400 frames at about 4ms, from which the best 40% were selected and stacked. The limb comes from two clips (top and bottom of the Sun, because there was enough happening beyond the limb that I didn't want to crop closely). Each clip consisted of 400 frames at about 25ms with the same rejection criterion. All clips used 6db of gain. The second image shows just the limb from this composite. The Antares telecompressor was sandwiched inside the 1.25-inch adapter for the wide shots. And the bottom frame is 65ms x 400 using the best 50% with 14db of gain with the telecompressor removed and the barlow mounted at the end of the snout. And here's a white light view today of the sunspots that launched the lovely flare yesterday. It's much more complex than it appeared at first glance. White light, A-P, Baader continuum filter, best 40% of 400 frames, 5ms and 6db:
I haven't worked out how to get subtle tones and rich detail in the white light images. It took a while to get a workflow that would consistently do that for the H-a images, so this is not particularly discouraging. Still, I am sure better stuff is to come. I slewed to Venus after shooting the Sun most of the afternoon. I plugged up the newly-remounted Robofocus motor on the A-P and dialed in the narrowing crescent (works great!). Venus is only 3.6% illuminated today, still 15° east of the Sun. High summer haze kept the seeing reasonable but the contrast low. I tried several clips of 400 - 2500 frames, but ran into (memory?) limitations on the long ones. In the evening, while preparing to turn off the netbook, I brought Venus back into the field and found a very steady image despire the low altitude and proximity of an asphalt roof on an 88°F day. I took more clips, long and short. Venus was about 3.7% illuminated this afternoon (depends on what time you ask). Here are some planetary images with the 5-inch F6 A-P. The first is boiled down from the best 5% of ~900 frames -- one of the 1GB subsets FlyCap writes when streaming video (3ms, 0db, Baader continuum filter). The next is from 10% of 2,815 frames (same tech details). And finally, Saturn is the best 25% of 1,727 frames (64ms, 12db, no filter). Among today's discoveries is how to use VirtualDub to isolate a region of interest and rewrite a smaller AVI for quicker processing and less demanding storage.
21 hours on the battery. I'm not asking it for much (about 0.5A tracking and up to 2-3A slewing), but it's s useful mode in which to use the battery when afield, and it's good to see that it does last. Add the inverter for a 17-inch screen or the CCD, and I think things would be very different. I think the CCD needs its own battery if this sort of operation becomes a habit, and the 17-inch screen would not need to be used for long at a time.
5/27/2012. 29 hours. I got better images of Venus today, one distilled from the best 500 out of 12,735 cropped and concatenated frames acquired in the time it takes to peruse a copy of Martha Stewart's "Everyday Foods" magazine. I shielded the telescope with both the AstroZap flexibile shield and a rolled up piece of black flocking material from Protostar. No sign of a complete ring from Venus (it's still days early for that) but faint extensions of the cusps begin to appear in severely streteched images. Venus was a 3.05% crescent today. After nightfall, I skipped down the lunar terminator with the A-P, the Chameleon, and the continuum filter. This is very promising, despite the limited aperture and necessarily longish exposures (~35ms at 12db). I did this twice with two different exposures and missed a couple of narrow bits on the better sequence. Maybe I'll see if I have the data to fill in the missing sections, or maybe I'll do it better soon. The processing was not my best tonight, either.
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© 2011, David Cortner