As it looks right now at 4pm I should be coming up to the gravel quarry east of Park City tonight sometime (when the chores get done) if anyone wants to join me. Rich __________________________________ Do you Yahoo!? Exclusive Video Premiere - Britney Spears http://launch.yahoo.com/promos/britneyspears/
Hi all, please let us know how the expedition or expiditions went over the weekend. Was the cold frightful? Was it windy? I am curious because I chickened out at the last minute. Best wishes, Joe
Joe, It turned out to be very good until about 11pm when the high thin clouds started spoiling the view. 5 of us showed up (4 scopes), and for me personally it was another successful night with the Herschel-400; I logged 16 more objects: NGC 6939, 6946, 6755, 6756, 6910, 615, 720, 779, 613, 908, 1022, 1052, 1027, 1023, 1245 and 1513 (in that order) -- 9 galaxies and 7 open clusters. My favorites were NGC 1023, a pretty spiral galaxy in Perseus lying in a very rich star field, NGC 1245, a lovely group of approx 3 dozen faint stars in Perseus also lying in a fairly rich stellar background. NGC 6939 in Cepheus and 6910 in Cygnus are also open clusters well worth visiting (this journey though the H-400 has helped me appreciate OC's much more). It was a bit too soupy close to the horizons to fully appreciate those sometimes faint galaxies in Cetus and Sculptor. As to the temperature, it was definitely cold, but not oppressively so; it hovered right about freezing, but I managed fine without gloves most of the time in spite of that (my insulated Carhart overalls and thermos of hot cocoa helped). So you missed some good company and some good seeing! But I'm sure that we are not through for the winter. I plan to get out whenever I can this winter and spring and brave the cold -- I still have two-thirds of my list to go, and most of those are winter/spring objects. I realized last night that even with a little snow, the gravel pit is paved, and could easily be shoveled for space to set up... worth a try anyway. -Rich --- Joe Bauman <bau@desnews.com> wrote:
Hi all, please let us know how the expedition or expiditions went over the weekend. Was the cold frightful? Was it windy? I am curious because I chickened out at the last minute. Best wishes, Joe
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Sounds really nice, Rich. I'm thinking about going to the Wedge next weekend and doing some astrophotography after the moon sets. It shouldn't be too horribly cold, I suspect. Thanks for a great report. -- Joe
Dear Friends, I have two questions for the group, which I hope someone can help me with. 1. On the subject of film for long exposures, what's your feelings about 400 vs. 800 films? I heard that you don't really reduce the exposure time with 800. If that is so I'd be better off using 400 as I assume it's not as grainy. True or false? 2. I'm especially interested in M31. Does the darker sky at the Wedge pose any real advantage for photography over results I would get at the gravel pit? I shot two Andromeda photos a while ago at the gravel pit. Overall they weren't as good as I would like because I did not expose one of them long enough and the wind kicked up and caused a sort of double-exposure effect on the other and it also could have used a longer exposure. Still, I was surprised how good the contrast is, with fine gradiations, bright center, dark outer reaches. These results make me wonder if there's anything to be gained by driving to a darker site for photos of something like a relatively bright galaxy, star cluster or nebula. If anyone has opinions about these queries, I would very much like to get them. Thanks, Joe
I'm not an experienced astrophotographer by far, so take this with a grain of salt. The ISO rating of film is determined for 'normal' photographs; so unless you're shooting faster that about 1/30 the ratings don't reflect what's happening on the film. Reciprocity failure starts to creep in for longer exposures. Astrophotography requires film with lower reciprocity failure (with a few exceptions). I've seen websites which measure reciprocity failure for common films and typically the faster films had higher reciprocity failures. If I remember correctly the better films were rated around 200. Also since color films are three layers stacked, with one for each primary color each layer can have a different reciprocity failure resulting in color shifts. The recommended films were Kodak Royal Gold 200, another Kodak professional 400 print film and the 200 Ektachromes. The two print films have been reformulated by Kodak to lower the response to red, which is one of the primary components of a lot of astro photos leaving the Ektachrome 200 films. Both the professional (Ektachrome) and consumer (EliteChrome) have a reasonable reciprocity failure and good responses to reds. For b/w the Agfa 400 c41 process film also has good reciprocity characteristics. As always, YMMV Bill B. On Sunday, October 26, 2003, at 03:36 PM, Joe Bauman wrote:
Dear Friends, I have two questions for the group, which I hope someone can help me with.
1. On the subject of film for long exposures, what's your feelings about 400 vs. 800 films? I heard that you don't really reduce the exposure time with 800. If that is so I'd be better off using 400 as I assume it's not as grainy. True or false?
2. I'm especially interested in M31. Does the darker sky at the Wedge pose any real advantage for photography over results I would get at the gravel pit? I shot two Andromeda photos a while ago at the gravel pit. Overall they weren't as good as I would like because I did not expose one of them long enough and the wind kicked up and caused a sort of double-exposure effect on the other and it also could have used a longer exposure. Still, I was surprised how good the contrast is, with fine gradiations, bright center, dark outer reaches. These results make me wonder if there's anything to be gained by driving to a darker site for photos of something like a relatively bright galaxy, star cluster or nebula.
If anyone has opinions about these queries, I would very much like to get them.
Thanks, Joe
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Wow, that's a great answer. If Kodak knocked down the red response, are any off-the-shelf print films good for astrophotos? Thanks again, Joe
Do you belong to the astrophotography mailing list (apml); I'm sure you'll recognize some of the members. http://seds.org/mailman/listinfo/astro-photo A search of the apml archives may turn something up. http://astro.umsystem.edu/apml/ Let us know what you find out. Bill B
Hi Bill, this is the first I've heard of that newslist -- I've been looking at it ever since I got your note. I will not join because I get so much email that I sometimes overlook things that are important, but I've bookmarked the site and will look there, because it seems most informative. So far I haven't found a firm recommendation on print film to use, but I'll keep looking. I am leaning toward a Fuji or Kodak 400, however. Thanks again, Joe
participants (3)
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Joe Bauman -
Richard Tenney -
William Biesele