Fuddland

Experiments with long exposure times.

This category is a subcategory of Photos.

This is really quite nifty: if you’ve dabbled in night-time photography of stars, then upload the photo to Flickr, submit it to the Astrometry group, and wait a little while. The automated tools of Astrometry.net will analyse the photo and leave a lovely comment telling you what the major stars and astronomical objects are, as well as actually notating the photo. Head on over to a photo I took almost four years ago to see what I mean. Apparently it contains:

• The star Rigel (βOri)
• The star Betelgeuse (αOri)
• The star Bellatrix (γOri)
• The star Alnilam (εOri)
• The star Mirzam (βCMa)
• The star Alhena (γGem)
• The star Alnitak (ζOri)
• The star Saiph (κOri)
• The star Mintaka (δOri)
• The star Arneb (αLep)
• The Witch Head nebula
• The Great Nebula in Orion
• Horsehead nebula
• Christmas Tree cluster / Cone nebula

Sadly the chances of taking any starry photos while living in Sūzhōu (苏州) are close to zero, but hopefully one day I’ll be in less polluted climes, and this tool will make it a lot easier to find out exactly what I’m gazing at, instead of all that tiresome “learning” stuff.

I’m fast running out of bat-based puns for these entry titles.

Patience is a virtue…

I’m not sure if it’s because of the new night lights in the back garden, or because it’s the time of year, or because they’ve just moved into the area, or because I’ve just never noticed them before, but for the last week or two, around the same time every night, I’ve been treated to the sight of some bats looping around the garden.

There’s a definite pattern: around nine-thirty or ten o’clock, when it’s just dark enough for the sensors on the night lights to turn them on, and for about fifteen minutes, two or three bats do a circuit which encompasses my garden and those of the adjacent houses, catching the moths and other bugs which are flitting around, before heading off elsewhere.

Last night I decided I’d see if I could manage to get a snapshot of one, but I knew I was up against it because,

• they move pretty quickly

• they’re quite small

• it’s dark

Not ideal photography conditions! In fact, the very first shot out of the eight that I took is the only one in which a bat appears, and even then it’s not the best capture, although it’s definitely a bat [I promise I haven’t just superimposed a low-quality bat photo onto a picture of a hedge].

As well as figuring out a better way to take a photo of them [I think my camera battery could do with a charge so that the flash is at its fastest and brightest], I’m hoping to somehow identify what type of bat it is. I’d estimate their wingspan to be about seven or eight inches. Any experts out there?

The blustery day resulted in a very clear sky last night, so I thought I’d have a go at photographing the night sky from my back garden — something I’ve always wanted to try. The trouble with conventional film-based cameras and no experience is that you have no real idea whether the settings you’ve chosen were right or wrong until you’ve processed the film; it’s a very slow learning process. Digital cameras of course allow you to see the results immediately and this allow you to hone in on the right settings rather than having to work them out from experience.

Armed with some Blu-Tack and a couple of books for a makeshift tripod [I really need to get around to finding a proper one], I stood on a chair beside my garden shed and set about finding the right settings. The first thing I learnt was that the night sky moves a lot faster than I’d ever given it credit for — my camera has a maximum exposure time of sixty-four seconds, and I initially thought that I’d have to use that if I was to stand any chance of capturing a few stars. Yet when I checked out my first few shots, I found that the stars had formed definite streaks rather than just points of light. However, to me the streaks looked a bit too short to appear “intentional” — they almost just look like camera shake, and spoilt the overall effect.

So I dropped down to shorter exposure times of twenty-four, thirty-two and forty-eight seconds, with nicer-looking results. The other thing I found was that unless you can capture astounding detail such as clouds of interstellar gas, a photo of a bunch of stars doesn’t look all that interesting without some context at the bottom of the image — treetops and chimney-stacks really help to get things in perspective.

The third thing I [quickly] noticed is that at this time of year, you can only take three or four long-exposure night-time shots before your fingers are so cold that you can no longer feel the buttons to adjust the camera-settings. Much ducking indoors is required to avoid chilblains.

After a dozen or so attempts, battling with aeroplanes blipping across my chosen area of sky and the yellow glow of the city’s light pollution, I finally hit upon a shot I was pleased with.

It’s a far cry from what can be achieved with much longer exposures and equipment which tracks the stars as they move, but for a bloke balancing a camera on his shed roof in the middle of a city, I’m pretty pleased.

[There’s also a Flickr version of this photo with a couple of notes on the visible stars.]