Staring at the Sun, 8

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7/6/2010. We're back from Taos to a hard blue sky (despite being over 6,000 feet lower) and to an afternoon sauna with daily high temperatures 20 - 25 degrees warmer. The Seibert Optics observing hood was waiting in the held mail. It's two swaths of heavy cloth (cotton? muslin?) stitched at the edges. One is dead black, the other snow white. It works fine to block light and shed heat. It could be improved with some tabs, clips, velcro, snaps, or something to help it stay arranged and in position, and maybe some weights along the edge, but simplicity has its virtues, too.

Despite the heat here in the east (97°), the white exterior keeps life at the eyepiece tolerable and relatively sweat-free. Solar viewing is much better than with no hood and better than when wrapped up in a black plastic garbage bag, too. It's easy to read the A-P controller under there. There's a good bit more solar detail visible than without the hood. At first I thoguht that some of that may be due to the unusually clear sky, but some with and without comparisons seemed clear. [Also, even on hazy, partly cloudy 7/8/2010, the view with a high power 7mm eyepiece is obviously improved.] Even more advantage flows from being able to keep both eyes open when the cloth is suitably arranged. It'll be fun to try this out at night to see how much dark adaption ("adaptation"?) is improved.


Seibert hood, etc

Using a Seibert observing hood.
Lunt LS60Ha with DS50 on A-P Mach1.
Electronics in blue faux Tupperware box.
"Contractor bag" for covering mount in faux milk bottle carrier.


Here's the URL. Expect a somewhat primitive shopping experience -- no Paypal shopping cart, for instance -- and don't be surprised if shipping comes in a little higher than advertised ($6.50 rather than $5).




Pretty good detail today. Two sets of four images opened in Maxim DL5, red Bayer plane extracted. Telescope shifted about 10 arc minutes between first and second group. Each group added using Photoshop then blended in Photoshop to remove dust. Canon 50D, 1/40s, ISO 400, barlow on 1.25-inch adapter, double-stacked Lunt LS60Ha.


I felt the urge to avoid webwork for one more day, so in addition to copying the latest New Mexico take from CF cards to hard drives, I spent some time on the Unitron restoration project.

It's a 3-inch F16 OTA that once belonged to Ed Szczepanski and then to Nancy Hendrickson. I've remounted the lens and original focusser in a fairly heavy brass tube using adapters I machined from some species of bronze. It has some heft. The tube still needs flocking and some baffles for which I have ideas. It could also use a better means of collimating the lens cell.

The mount was damaged in shipment home from New Mexico Skies a decade ago, and I am still sketching and thinking about how to repair it using the lathe and whatever brass (or maybe aluminum) stock is tempting on eBay. I am mostly over the urge to build a knock-off of a Unitron gravity drive, but I'll wait till I get the mount working to say so for sure. In the meantime, here's a vintage Unitron OTA riding a not-so-vintage A-P Mach1:

brass unitron



I used a 20mm TeleVue Plossl to check out Saturn just before the planet disappeared behind the treeline. I can't say it was a particularly detailed view, but it was sharp and satisfying. There's some light flare to one side of the image which underscores the need to baffle the tube and recheck collimation. So far, so good.


7/9/2010: Something bright was coming onto the disk of the Sun in the late afternoon day before yesterday. A very bright "solid" wall of light elevated the rim of the Sun by 8-10 arc seconds. Yesterday, before clouds closed the sky, sunspot group 1087 had become by far the most prominent visible feature: a bright, twisted region encroaching on the Sun's face. described it as "crackling with B and C class flares." Here's today's best effort which does not do much to show off the bright drama on the Sun but does demonstrate a new workflow:


Disk: two sets of five, 1/10 second exposures. Barlow on EP adapter, ISO 200. Rim: two, 2-second images. All with double-stacked Lunt LS60 and a Canon 50D. Each image opened in Maxim, red plane selected, saved as TIFF. Then each image opened in Photoshop, histogram equalized, manually aligned, and overlayed. The two sets of five with a shift in between, aligned and merged in "lighten" mode eliminated dust. The 2-second rim shots were not equalized, just stretched to bring out prominences. Is it the workflow or the hot, white haze that produced the distractingly bright sky? I think it was the weather.


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                   © 2010, David Cortner