Archive for the ‘Astronomy’
I’m still playing with the 500mm lens I wrote about a few days ago and took these from my balcony this evening:
And with a bit of luck, I was able to capture Saturn, too:
Saturn required a bit of processing to remove the sensor noise and clean things up a bit. But, I’m still very impressed that you can make out the planet and the gaps of the rings around it.
I’m thinking about buying a Tamron SP 500mm lens from a friend, so he’s let me borrow it for a few days to try it out. It’s a manual focus lens and appears to be a fixed aperture (or I need to RTFM), so shutter speed and ISO speed are the things you play with to get the right exposure.
I set up my tripod on the balcony and aimed it at the moon. Other than cropping and some light processing using Lightroom Mobile on my iPhone, these are pretty impressive.
One of the appealing things about the lens is that it’s roughly the same length as my 18-200mm at its shortest length. The lens is more like a little telescope than a traditional telephoto lens because it has a configuration of glass and mirrors that’s used in compound telescopes, aka a catadioptric lens.
The bokeh (the blur of things outside the in-focus range) is pretty cool. Instead of the traditional “dots” you end up with “rings”.
The photo I posted earlier is a bit small. I downloaded the photo directly from my camera to my iPad and I think it lost some quality in the process. I’ve reprocessed it and some of the other photos to see what I could find.
This is one of the better photos I took:
Inside the circle is a tiny dot that is the planet Mercury. You can click the image to see a larger version.
I managed to take this photo by using my 18-200mm lens fully zoomed, holding a piece of #14 welder’s glass in front of the lens and experimenting with the exposure until I found a combination of shutter speed and f-stop that wasn’t massively overexposed. No tripods, no telescopes, just handheld while sitting on a bench in front of the building I work in. I’m sure this looked very odd to the people walking past, but who cares? They didn’t end up with a picture of Mercury transiting the Sun.
I brought my DSLR to work along with my piece of #14 welder’s glass in the hopes that the sun would be visible at lunch. A small break in the clouds allowed me to capture a bunch of photos, including this one:
I believe the small dot in the bottom right quadrant is Mercury. Or dust on the sensor, but it’s appears in more than one photo taken on different parts of the sensor, so I think it’s Mercury because it matches the maps I’ve seen.
Hey, it’s mid-March, so that means it’s time to move the clocks forward in a futile attempt to save energy. Or so they say. As I’ve mentioned in previous years’ versions of this post, daylight save time hasn’t been shown to actually save energy.
What it has been shown to result in is an increase in accidents because people are discombobulated by the change in their sleep pattern, much like being jet lagged, and a 10% increase the likelihood that you’ll experience a heart attack during the days immediately following the time change. And you’ll probably feel a bit jet lagged, too. I’m really not convinced it’s worth it. (more…)