haapanen@watdcsu.UUCP (Tom Haapanen) (12/14/85)
I posted the following article to net.rec.photo, and somebody suggested posting it net.astro as well. Since this is net.astro, I suppose it would be nice to know when an opportune time for photography would be --- am I already too late? I know I have to avoid city lights and a full moon... (I'm located near Toronto (east of Detroit)). As the Halley's comet is around, and I probably won't be the next time it is ( :-), I'd like to shoot some pictures. But, but, but, I have really no idea as to how to go about this. Just taking random pictures with random lenses, film and exposure doesn't seem like a good idea. So, what kind of film should I use (I'd prefer slides, but...)? What about exposure times and apertures? The lenses I either own or can borrow include a Canon 100-300/5.6, Tamron 70-200/3.5 and a Vivitar 75-205/3.8. I also can use a Vivitar 3x multiplier and a Makinon (el cheapo) 2x multiplier. What kind of combination should I be using to avoid huge grain and massive lack of sharpness? Thanks for any help. \tom haapanen watmath!watdcsu!haapanen I'm all lost in the Supermarket I can no longer shop happily I came in here for that special offer Guaranteed personality (c) The Clash, 1979
andrew@cadomin.UUCP (Andrew Folkins) (12/16/85)
In article <1970@watdcsu.UUCP> haapanen@watdcsu.UUCP (Tom Haapanen) writes: > > >So, what kind of film should I use (I'd prefer slides, but...)? >What about exposure times and apertures? The lenses I either own or >can borrow include a Canon 100-300/5.6, Tamron 70-200/3.5 and a >Vivitar 75-205/3.8. I also can use a Vivitar 3x multiplier and a >Makinon (el cheapo) 2x multiplier. What kind of combination should I >be using to avoid huge grain and massive lack of sharpness? > >Thanks for any help. > > \tom haapanen > watmath!watdcsu!haapanen I would recommend digging up the last few issues of Sky & Telescope or Astronomy magazine. They have a regular column on photography, but lately, due to Halley's, they have been keeping the material on an introductory level. I've done a bit of astrophotography, all unguided (you point your camera at the sky and open the shutter). Ektachrome 400 slide film gives fairly good results, with exposures of ~30 seconds using a 50mm lens at f2.4. Keeping the exposures short will minimize star trailing, a faster film will record fainter objects before the images start to trail. With a film this fast though, the longer exposures tend to fog the film due to skyglow and light pollution. Also, the larger your lens, the smaller an area of sky you will photograph (the 50mm will easily get all of the Big Dipper), but the faster the stars will move through the camera's field of view. If you want to go for longer exposures, in the 10 - 60 minute range, the solution is to guide your camera. One of the magazines mentioned above had an article (sorry, I don't have the reference, but I can dig it up) describing a simple Poncet mount, which you can use to guide a camera for several hours. It is very simple and cheap to construct (~$50, if I remember correctly). Two important thing to remember : 1) a dark sky will greatly improve the quality of your pictures, and 2) you will have to experiment with combinations of exposure times, f/ratios and lenses. Have fun! -- Andrew Folkins ...ihnp4!alberta!andrew All ideas in this message are fictional. Any resemblance, to any idea, living or dead, is purely coincidental.
hdc@trsvax (12/23/85)
You had better shoot those pictures soon, unless you're planning a trip south in March/April. From Toronto Halley will be impractical, if not impossible, to shoot after it passes the sun. Further Halley is moving rapidly into the evening twilight which should be significant by January 15. Currently moonlight is a problem. The second week of January (7-12 or so) would probably be a good time for a shooting marathon. I'm not an astrophotographer, just an observer, so I'm afraid I don't know a lot about how these conditions can be factored out with different photographic techniques. Wish there were cheerier observing prospects but this just isn't a well placed return for northern observers.