Gallery - AstroPhotography

Having read about the recent BBC Stargazing Live event in the UK (A three day television event featuring live hosts discussing star gazing and presenting a variety of pre-recorded related short films) one of the parts that piqued my interest was the astrophotography. Particularly how they stressed that it was possible to get decent results with fairly modest equipment - primarily you needed an SLR camera and a tripod. So I read the advice they gave and figured I would give it a go myself. The results from that are what you see below.

Now while I enjoyed myself I would temper their advice a bit. A cable release I think is horribly important to have. You can kinda make do with using the shutter release timer but in my experience without a heavy tripod that can damp down the vibrations quickly you still get a fair bit of camera shake - even with a good ten second delay from button press to shutter release. The suggestion of using a piece of card suffers from two issues - first unless your card is matt black then stray side light can be easily reflected into the lens. Second using the card you cut into the exposure time your camera supports - most prosumer models do support a bulb mode (but you definitely want a cable release to use it) and otherwise have an upper limit of thirty seconds to work with. Because of the earth's rotation most of the time you will only want about fifteen seconds of exposure to avoid the stars begining to streak so the card doesn't hurt there too much but if you really want the full thirty seconds then the card simply isn't good.

But otherwise they were on the money - it is actually amazing what you can capture with fairly simple equipment. My other big tip is simply to use the fastest glass you have. For all the star field shots here I used my 50mm prime F1.8 lens. Nikon and Canon both have extremely cheap versions of these lenses and they should part of any semi serious camera enthusiasts kit. The fast glass gives you the deeper star fields thanks to the extra light collecting ability and while focus is a huge issue at F1.8 there is a really simple trick to help here.

That trick is Liveview. My 450D has this and it is an older model now so pretty much any new SLR camera bought in the last three years (so 2007 or newer) will most likely have it. This simply drops the shutter down and feeds the sensor output directly to the LCD screen. You can then use that for composition and focusing. Particularly useful is the 5x zoom rectangle - simply position this over a bright star in your selected composition and then zoom in to adjust and get the focus bang on. From the camera's point of view the stars are all off at infinity anyway so focusing on one star somewhere in your field of view will get them all in focus. As can be seen below.

A little harder to see and definitely harder to capture an image of with a camera is the Large Magellanic Cloud. This companion dwarf galaxy orbits the Milky Way at around 160,000 light years away.

This shouldn't be hard to identify - it is of course our Moon seen halfway through waxing. This gives the craters on the terminator line nice deep shadows that really make them stand out.

Here we see Orion, upside down compared to the Northern Hemisphere view with his sword extending upwards. If you look closely at the sword you can see the middle start isn't a star at all - it is the Orion Nebula.

This is a little harder to see, but down the bottom slightly to the left of the middle is the Pleiades cluster. A small stellar nursery of new stars about 440 light years away - comparatively speaking moderately close neighbours. Locally called Matariki it is used as a marker for the start of the new year hew in New Zealand.

This is a very familiar constellation in the Southern Hemisphere - the Southern cross with the two pointer stars. Perhaps most surprising to see once captured is the variety of star colour in the cross itself. To me they just look white and close to one of the horizonal stars of the cross is the very colour Jewel box cluster - sadly not quite visible in all its glory here.

I need to experiment a little more in how to reduce the light polution and noise which still has softened these shots a bit. But still for a first attempt at this I am pretty pleased with the results obtained. The other big issue is simply sensor noise. I shot these at ISO 400 which is about as high I dare go with the 450's sensor. Newer cameras are getting into acceptable ISO performance even up around the 6400 mark so I have great hopes for replacing the camera with a newer body and using that. In the meantime till I have some money to do that I should explore my camera manual and see if there are some longer term noise reduction features I can turn on. I have a vague recollection I deliberately turn them off because for the other uses I put the camera to they tended to get in the way.

Still as can be seen you definitely don't need a lot of kit to have a go and it was a great deal of fun to go out for an evenings stargazing with my cousin (who was also working her camera, so it will be interesting to see what she got).

Philip R. Banks
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