NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2010 Sep 11, 09:59 -0700
Greg, you wrote:
"but the 50mm camera ISO setting will have to be at least 800 or may be more combined with a slow shutter speed setting."
Maybe not. I just shot a dozen photos of Venus in daylight around 12:30pm here in Connecticut. The sky is pleasantly clear, blue but not spectacular, with a very few scattered clouds. After I read your message about half an hour ago, I pulled out my phone and launched Google Sky Map. Aha, I see that Venus is right next to the Moon. I stepped outside but couldn't find the Moon. I pulled out the phone again, and aimed it where it told me to, and... aha... there's that pale crescent. Then I just shot a bunch of photos. My camera is an eight-year-old HP 850, nothing fancy. It's not an SLR and has no manual focus. It hates photographing the sky (the autofocus gets lost), so I walked to a spot where the Moon was just above a tree fifty yards away to give it something to focus on. I could NOT locate Venus visually. Although this camera has some limited ability to select ISO and a good range of exposures, I let it go with normal daylight automatic settings. I came back inside, popped the card out of the camera, and there it was, plain as day, about two degrees or so from the Moon. Oh, and look, there's another one! Two Venuses... uh-oh. That's common with this camera. It has a few bad pixels. So I flipped back and forth between two of the images, and then it was very obvious which dot was the real Venus. The real Venus hopped back and forth from image to image maintaining the same relationship relative to the Moon while the spurious star stayed in the same place, by pixel location, in each image.
Daylight exposure settings should work for Venus even at night for the same reason they work for the Moon at night. You're looking at a surface that is in full sunlight. It's just like being in a darkened room and taking a picture of the sunlit outside visible through a small window. You expose for full sunlight.
-FER
PS: photos upon request but they're not really that interesting.
----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------