Wednesday, April 04, 2012
The reason I took photos of Venus and the Pleiades the last two nights was in case it was cloudy tonight, when they were supposed to have their closest encounter. It started out cloudy and Venus wasn't visible at all. Then the clouds thinned, and Venus became visible, glowing in the clouds, but the Pleiades weren't visible at all, overwhelmed by the clouds and the brightness of both Venus and the ambient moonlight, brighter than last night, and far brighter than the night before. But the clouds seemed to be thinning, so I set up the tripod and hoped the wispy bits of cloud would part enough to reveal the Seven Sisters. Eventually they did.
Back to the long lens again, 200mm -- f/11, 2 sec., -1EV, aperture priority. High ISO Noise reduction turned up. Also turned Active D Lighting to High, in hopes it would keep the very bright Venus from totally overwhelming the dimmer stars. Slight tweaking in Photoshop. It is what it is.
Tuesday, April 03, 2012
Another clear sky last night, so I made another stab at photographing Venus with the Pleiades, the Seven Sisters of Greek myth. Quite a bit closer last night than Sunday night. The moon was brighter last night, tending to wash out some of the dimmer stars in the cluster. On the other hand, the exposure did emphasize the brightest, the Seven Sisters of legend.
Changed tactics last night -- went with a shorter focal length and lower ISO -- f/2.0, 0.8, ISO 400, EV-4 with 50mm lens, which provided a nice starburst effect around Venus.
Monday, April 02, 2012
Venus is on a rendezvous course toward the Pleiades, the Three Sisters of Greek myth. Twenty days ago, Venus was about 3 degrees from the Pleiades. When I took the photo last night, the gap was closed to only 1 degree. Tuesday night (election night here in Wisconsin) they will be even closer, separated by only 0.5 degree. But it's likely to be cloudy the next two nights -- though, who knows, there might be a break in the clouds. But I took my insurance shot last night.
Nikon D90 DSLR -- aperture priority, f/5.6, 1.6 sec., ISO 3200. Had to shoot at a high ISO since I was shooting with a 200mm lens on a tripod at pretty small aperture.. (I couldn't use a longer shutter speed to lower the ISo because, at that focal length, had to keep my exposure under about 2 sec. to keep the stars as point light sources rather than star trails). And, yes, I used the Exposure Delay Mode to hold the mirror upbriefly and minimize camera shake from the mirror.
Note: Rule of thumb to avoid star trails shooting with different lenses -- divide 600 by the focal length of the lens to get the maximum shutter speed. No wonder so many star photos are taken with superwide lenses. They not only give you great sky-to-horizon coverage, but also make posible possible much longer shutter speeds, picking up fainter stars.