The night sky

Spending the weekend on lake Pokegama (Po- Keg-Ama, not Pokey-Gamma) in  Grand Rapids gave a nice opportunity to get some really dark skies for astronomy and astrophotography. The first evening was overcast until well past my bed-time. The second evening was pretty special.

Around 10pm, the milky way was glowing overhead,  the constellations were hard to pick out as there were many more background stars than a London based sky-watcher normally sees.

Ursa Major & Minor
Ursa Major & Minor

I took some photographs, of course. The settings were 18mm focal length, infinity focus, 20sec exposure time, and remote control shutter release (to avoid camera shake).

Continue reading The night sky

Touching Mars

The Natural History Museum in London is one of my favourite places in the world, so it was wonderful to spend two days there last week at a conference on X-raying stuff.
On the last day there was a presentation by Dr Caroline Smith on Martian meteorites. She spoke on how X-ray imaging allowed the detection of voids and inclusions in the meteorites, possibly sampling ambient conditions on Mars at the time the meteor was ejected from the planet.
As part of her talk she handed around a small piece of a Martian meteorite.
I got to hold a piece of Mars!


Astrophotography & Star Trails

While trying to photograph meteors in the Perseids shower recently I ended up taking a lot of longish exposure photographs of the same patch of sky. I was hoping to catch a meteor or several shooting though the frame. Reviewing the photos when I got home I found I caught no meteors, indeed I saw none either, but I did have a set of images I could make a star trail image from.

The usual way to make star trail images is to load the separate images into layers in Photoshop or Gimp and them blend them together. I’ve since found a nice piece of software that automates this process, StarStaX. The following two images were generated with this software. I only had a small number of images usable for the stacking, and there were quite large gaps in time between image, so the results are not as great as they could be. This is not the fault of the software.

StarStaX Test 1
Stacking some star photos. Originals were 20s exposures with 5sec between images, hence the dotted look to the trails.
Some shorter exposures stacked. Was looking for meteors, but saw none. Camera must have moved, giving the jump in star positions. There’s at least one airplane / satellite trail in the stacked image.