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ASTRO: Nova Vulpecula 2007 revisited
Some nova fade slowly, some rapidly. This appears to be a slow nova.
Some stay blue as they fade but those that throw out hydrogen turn red as they fade. It appears this is a slow, hydrogen rich nova. I've tried to match my August 10 shot to the one I grabbed last night just before the clouds cut me off. Seeing was much better which has had an effect on the star colors and size. Not to mention that I used 2 minute subs for this shot and only 1 minute ones for the August shot. So they aren't as comparable as I'd like. I discovered my error just as the clouds rolled in so couldn't retake it to match. The far better seeing also made a difference. Still the change from blue to red is quite evident. It has faded from Mag 9.4 to 10.1. Only a 0.6 drop in nearly a month. The Mira variable SS Vulpecula to the upper right faded as well from 9.4 (same as the nova) to 9.7. 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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ASTRO: Nova Vulpecula 2007 revisited
I think I found the star that blew up on the DSS plates. It appears
very blue. I've attached a small crop of the red and blue images from the DSS plates with an arrow pointing to my candidate. The super slow Nova Delphinus 1967 discovered by that famous English comet hunter George Alcock in July 8, 1967 was the slowest nova I've ever watched. It was a 12th magnitude star before it blew. It was 6th magnitude when discovered but didn't reach maximum until December 13 when it reached magnitude 3.5. It dropped after that but then rose to a secondary maximum of magnitude 4.2 on May 5th, 1968, 10 months after its discovery. It didn't fade from naked eye visibility until it vanished into the sun at year end. It wasn't naked eye when Delphinus reappeared. It still shines about magnitude 12 and is known as HR Delphinus. It too is very blue on the DSS plates. I've attached a shot of Nova Delphinus I took a full year after discovery. I put tick marks around it. Notice no hint of an ionized hydrogen shell like Nova Vulpecula has developed. Slow nova I've photographed have either no such shell or fainter ones than fast nova. I've not seen an explanation why. My sample size is small so that may be the cause right there. The shot of Nova Delphinus was taken with a 135 mm lens on High Speed Ektachome film with the camera piggy back on my 10" f/5 Cave. I no longer remember the time but it likely was about 1 minute as it was taken in town which quickly fogged photos much longer than that. 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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ASTRO: Nova Vulpecula 2007 revisited
Rick, it's amazing how much the colour of the nova has changed.
Stefan "Rick Johnson" schrieb im Newsbeitrag ... Some nova fade slowly, some rapidly. This appears to be a slow nova. Some stay blue as they fade but those that throw out hydrogen turn red as they fade. It appears this is a slow, hydrogen rich nova. I've tried to match my August 10 shot to the one I grabbed last night just before the clouds cut me off. Seeing was much better which has had an effect on the star colors and size. Not to mention that I used 2 minute subs for this shot and only 1 minute ones for the August shot. So they aren't as comparable as I'd like. I discovered my error just as the clouds rolled in so couldn't retake it to match. The far better seeing also made a difference. Still the change from blue to red is quite evident. It has faded from Mag 9.4 to 10.1. Only a 0.6 drop in nearly a month. The Mira variable SS Vulpecula to the upper right faded as well from 9.4 (same as the nova) to 9.7. 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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ASTRO: Nova Vulpecula 2007 revisited
I've found most nova do light up a hydrogen shell that turns them
red/pink like this. That's why I went back to revisit it. I also took a shot after a week as if it was a fast nova the shell would have shown up quickly as the star faded greatly. Only Nova Delphinus didn't show a hydrogen shell of the nova I've photographed. But that one was around for 18 months which in itself is rare. Rick Stefan Lilge wrote: Rick, it's amazing how much the colour of the nova has changed. Stefan "Rick Johnson" schrieb im Newsbeitrag ... Some nova fade slowly, some rapidly. This appears to be a slow nova. Some stay blue as they fade but those that throw out hydrogen turn red as they fade. It appears this is a slow, hydrogen rich nova. I've tried to match my August 10 shot to the one I grabbed last night just before the clouds cut me off. Seeing was much better which has had an effect on the star colors and size. Not to mention that I used 2 minute subs for this shot and only 1 minute ones for the August shot. So they aren't as comparable as I'd like. I discovered my error just as the clouds rolled in so couldn't retake it to match. The far better seeing also made a difference. Still the change from blue to red is quite evident. It has faded from Mag 9.4 to 10.1. Only a 0.6 drop in nearly a month. The Mira variable SS Vulpecula to the upper right faded as well from 9.4 (same as the nova) to 9.7. 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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