space@ucbvax.UUCP (01/14/86)
I'd like to take a photo of Halley's Comet, and somehow get a reasonable shot of the comet with my two kids in the same frame. Does anyone out there have any ideas how to go about this? Somewhat incidentally, I plan on being in Hawaii in April, and I understand April 11 is the closest approach. Aside from the problem of keeping my kids still and awake on top of a Hawaiian mountain, what are the obstacles? I have a Canon AE-1. I've been thinking about a long exposure of the comet, followed by a flash of the kids with the shutter open. But I have no idea how long to expose on the comet. I have a 50mm, a 75-210 zoom, and a 2x extender. I'm not above double exposure if I knew how to do that with the Canon. Please mail to me directly and I will summarize. Chuck Collins ...hplabs!ames!amelia!cpc cpc@ames-nas
bilbo.niket@LOCUS.UCLA.EDU ("Niket K. Patwardhan") (01/15/86)
There are two problems..... One is to get the brightness of the kids and the comet comparable in the final picture, and the other is to get the sizes comparable. If the AE-1 has aperture control (that is, you select the aperture and the camera figures out how long to keep the shutter open) then you choose the largest aperture (smallest number) and the camera should get you a reasonable picture of the comet. If the time it picks is a few seconds, then you flash the kids near the end of the time, and get your picture in a single exposure. You of course need a manual flash. If you are willing to borrow a friend's camera for this, try using an Olympus OM-1, it has aperture control, with a very long time limit. One of the biggest problems with using this technique is making sure that the camera is reacting to the light from the comet, rather than something else in the picture, and you make sure of this by letting its image cover enough of the field of view, and that there are no artificial light sources in the picture (street lights, the moon, etc). To get the sizes comparable, you need to put the kids far enough away from the camera, just like when you take a picture of people walking into a sunset, and blow them up to the right siz with a telephoto (which you need anyway, since a straight shot of the comet wouldn't be visible). Since I am not quite sure how much magnification the comet needs for a reasonable picture, I can't even begin to guess how far this needs to be. (A mile???? 100 yards? You might need a walkie talkie to work the flash right). A double exposure could be simpler because of the size problem.... you first take a picture of the comet (borrowing somebody's telescope if necessary), and then take a picture of your kids against a dark and even background. The only problem would be stars in the middle of the kids. If somebody knows the right telephoto to use to get the comet to occupy a least 5% of the field of view, please let us know.
space@ucbvax.UUCP (01/15/86)
I think the way to do it would be to use the 50mm wide open and
let it stay open for 30 seconds use some of the new 1600 asa film
I think the problem will be getting them up and in position to pose in the
morning because it will be an hour or 2 before sunrise .
I would also take several pictures without the kids in the picture
at different exposures and then you can splice the pictures together
in the darkroom.
Name: John Cincotta
Mail: Saber Technology, 2381 Bering Drive, San Jose, California 95131
AT&T: 435-8600
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...{amd,ihnp4,ittvax}!saber!jcmcgeer@JI (Rick McGeer) (01/16/86)
Will you really need a telescope to see the comet in April? I'd heard that the tail will be 20 degrees or thereabouts, and magnitude 3 -- which would make Halley's look more or less like a wide milky way of about the size of Orion. Is that not accurate? -- Rick.
bilbo.niket@LOCUS.UCLA.EDU ("Niket K. Patwardhan") (01/16/86)
> Will you really need a telescope to see the comet in April? I'd heard >that the tail will be 20 degrees or thereabouts, and magnitude 3 -- which would >make Halley's look more or less like a wide milky way of about the size of >Orion. Is that not accurate? That's wonderful..... I was very disappointed with the current view..... It really isn't a spectacle if you have to use binoculars to see it. Now I'll be motivated to get up early to see it, or even camp out, given LA skies.
space@ucbvax.UUCP (01/16/86)
In article <prandt.8601141912.AA00708> you write: >I'd like to take a photo of Halley's Comet, and somehow get a reasonable >shot of the comet with my two kids in the same frame. Does anyone out there >have any ideas how to go about this? Somewhat incidentally, I plan on being >in Hawaii in April, and I understand April 11 is the closest approach. Aside >from the problem of keeping my kids still and awake on top of a Hawaiian >mountain, what are the obstacles? > >I have a Canon AE-1. I've been thinking about a long exposure of the comet, >followed by a flash of the kids with the shutter open. But I have no idea >how long to expose on the comet. I have a 50mm, a 75-210 zoom, and a 2x >extender. I'm not above double exposure if I knew how to do that with the >Canon. > >Please mail to me directly and I will summarize. > >Chuck Collins ...hplabs!ames!amelia!cpc cpc@ames-nas One possibility is to photograph the comet, photograph the kids against a dark background, then mix the photos on the prints. Another possibility MIGHT be to use a long exposure for the comet, then sometime during the photo of the comet, have your kids get into place and use a dim flash to briefly illuminate them, getting them in the picture too. You would have to put some effort into getting the flash just right. You would also have to be sure there was absolutely NO background behind the kids to mess up the picture (say a dark night, camara pointed above the horizon, kids standing on chairs, etc.)
ems@amdahl.UUCP (ems) (01/16/86)
I have not yet seen the suggestion of doing a darkroom composite.
Take one picture of the comet, a light object on a dark background.
Take one picture of your kids. On a black background. The dark
backgrounds will be clear in the negatives. Overlay the two
negatives and print. (Or double expose the print with various
darkroom magic. Like a cutout about the size and placement of the
kids layed on the paper when printing the comet...)
Even if you don't plan on doing this as the primary approach, I
would suggest that you take a few pictures of the comet that could
be put together this way. Just as insurance...
--
E. Michael Smith ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems
This is the obligatory disclaimer of everything.space@ucbvax.berkeley.edu.UUCP (01/24/86)
There is an article in the January issue of Sky and Telescope on photographing Halley's. It recommends trying exposure times of from 10 sec to 30 sec at widest aperture, with fast film (ISO 800 to 1600). These short exposure times will not show star trails. The article suggested trying longer exposure times of up to 2 min. just for the heck of it. Steve Poole
space@ucbvax.UUCP (01/29/86)
HELLO!!!! Please respond!
space@ucbvax.UUCP (01/30/86)
A few weeks ago, I put out a request for info on how to go about taking
a photo of Halley's comet with my kids in the same frame. I've received
enough good information to write a small book. I plan to post a summary
next week. Thanks to all who replied.
To make the summary complete, I would appreciate anyone who can point me to a
reference on how to construct a "Poncet mounting" for tracking stars. I have
seen the writeup in the November Sky & Telescope, but would appreciate more
details. If anyone also knows a reference that describes the "barn door"
tracking mount, I would appreciate it.
Please reply by mail.
Chuck Collins ...{ihnp4,hplabs}!ames!amelia!cpc cpc@ames-nasspace@ucbvax.UUCP (02/03/86)
Responding!!! All I can suggest is checking some of the astro magazines at the library. There may also be an L5 modem in your area where you could put in a request and/or find some free advice. good luck, hope to try it myself -brian Brian C. Grande ...ihnp4!umn-cs!ncs-med!bcg National Computer Systems Work 612-893-8158 Health Systems Division Home 612-938-2437 5700 Green Circle Drive Minnetonka, MN 55343