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M-47, Open Star Cluster in Puppis; plus star clusters NGC 2423 and NGC 2425
Not much imaging going on in New York lately!
Mostly snow! On the few clear nights it's cold: for example -18F a few days ago - not counting wind chill. However, I did get a chance to take a few images last week. I'm working on completing my collection of Messier Objects and most that I don't have are so large that they require a small scope for imaging. The attached is a 10-minute exposure with a Canon Rebel DSLR thru a Brandon 80mm triplet. However it a crop of the full field. The scope has a lot of field curvature and I have been unable to find a corrector that will work with its 1.25-inch focuser. For those with fast internet connections, here is a large full rez version: www.kopernik.org/images/archive/m47.jpg George N |
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M-47, Open Star Cluster in Puppis; plus star clusters NGC 2423and NGC 2425
George Normandin wrote: Not much imaging going on in New York lately! Mostly snow! On the few clear nights it's cold: for example -18F a few days ago - not counting wind chill. However, I did get a chance to take a few images last week. I'm working on completing my collection of Messier Objects and most that I don't have are so large that they require a small scope for imaging. The attached is a 10-minute exposure with a Canon Rebel DSLR thru a Brandon 80mm triplet. However it a crop of the full field. The scope has a lot of field curvature and I have been unable to find a corrector that will work with its 1.25-inch focuser. For those with fast internet connections, here is a large full rez version: www.kopernik.org/images/archive/m47.jpg George N Full image looks good. A little cropping and the curved field would vanish. I know, I hate to crop out one star. Actually it's not all that bad. I've got a lot of eyepieces that would do worse on that size field. I remember the first time in the early 60's when I went after M47 in my 10" F/5. It was easy in the finder but when I looked in the eyepiece I didn't see it. Figuring the finder was off I panned around and ran into NGC 2423. It looked so much like M47 in my old 2.4" refractor I thought it was it. But looking in the finder I saw it faintly right on the cross hairs. I finally realized I'd seen 47 after all but didn't recognize it as a cluster. I think 2423 is in the Herschell 400. I know 47 is which never made any sense why they included it and left out 2425. Of the 3, it was my favorite, and most challenging as well. I do like the full image even with the curved field. Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
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M-47, Open Star Cluster in Puppis; plus star clusters NGC 2423 and NGC 2425
Very nice picture George. Apart from the edges of the field stars look good,
the scope has good colour correction. Stefan "George Normandin" schrieb im Newsbeitrag ... Not much imaging going on in New York lately! Mostly snow! On the few clear nights it's cold: for example -18F a few days ago - not counting wind chill. However, I did get a chance to take a few images last week. I'm working on completing my collection of Messier Objects and most that I don't have are so large that they require a small scope for imaging. The attached is a 10-minute exposure with a Canon Rebel DSLR thru a Brandon 80mm triplet. However it a crop of the full field. The scope has a lot of field curvature and I have been unable to find a corrector that will work with its 1.25-inch focuser. For those with fast internet connections, here is a large full rez version: www.kopernik.org/images/archive/m47.jpg George N |
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M-47, Open Star Cluster in Puppis; plus star clusters NGC 2423 and NGC 2425
"Stefan Lilge" wrote .... Very nice picture George. Apart from the edges of the field stars look good, the scope has good colour correction. Stefan, Those old Brandon 80mm's have Roland Christen made triplet lenses. When sold back in the 1980's they were optimised for visual and film, not CCD or digital. We have two of them. One is the "finder" on the RC20 and the second will go onto the Astro-Physics refractor as soon as we get around to it. They came with a special Barlow lens to screw into the diagonal to correct the field curvature. However that also extends the focal length. I've looked into purchasing a corrector, but so far I've not found one for a 1.25-inch focuser. The owner of VERNONscope has looked thru his "junk pile" of old parts for a 2-inch focuser, but he has been unable to find one. So I guess I'll have to live with the fuzzy corner stars, or longer exposures. George N |
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