Saturn

It's that time of year again when Saturn makes an appearance late in the evening. Last night I spent an hour or so trying to get a better photo of it than last year. Out of the 112 shots that I didn't immediately delete, this was the best.



Not too bad I thought, the rings are distinct and the banding is visible. I suspect it's about as good as I'm going to get with my current equipment. It's a bit of an elaborate procedure to take these photos, and goes something like this:

1. Get Saturn in the telescope's field of view and focus
2. Line up camera on tripod, get Saturn in camera's field of view
3. Manually focus camera
4. Set shutter release on timer to allow vibration of telescope and camera to dampen out
5. Take as many shots as possible before it wanders out of the field of view
6. Go to 1.

Trying various shutter speeds, I found 1/40th to 1/80th of a second to be about optimum. Any faster is badly underexposed, any slower and you get too much motion blur. Actually, all the shots are underexposed, the camera is already maxed out in terms of aperture (f2.5) and ISO (400) so there's no where else to go. Short of building/buying a bigger telescope with an equatorial or microprocesser controlled mount, I could possibly make a simple powered mount with rollers acting directly on the ball of the telescope. I'm sure this would work, but the programming to achieve true tracking would be a challenge. However, I think for relatively short exposures of a few seconds or so it might be possible to get away with a simple linear drive, rather than one that tracks the correct curved path..

At the other end of the astrophotography spectrum, make sure you have a look at The Most Detailed Image Of The Orion Nebula Ever Taken. Mindblowing.

Comets and Bloodsucking Parasites

I see it's been a year since I last wrote something. This was never intended to be just a collection of astronomical photos, but here's some more anyway.

We were recently very fortunate to get a clear evening in which to see Comet McNaught. I must admit that I hadn't got around to even looking for it as we don't have a clear view of the Western horizon, but Adrian in his enthusiasm dragged us out to go Comet hunting. I'm glad he did. We ended up at Meadowbank Park looking across the Parramatta River to Homebush Bay and Silverwater (Silverwater may sound like a pretty place, but I've always suspected it was named that because of all the mercury dumped in the river in years gone by). Despite the usual light pollution and even fireworks going off at Homebush, we had a pretty clear view.

My ageing yet trusty Canon G2 can only do exposures up to 15 seconds, so you can only just make out the roostertail effect of the tail, but I still got some reasonable pictures.

This 15 second exposure makes the sky look a lot brighter than it was at this point.

This is only a 4 second exposure, which is much closer to how it appeared to the naked eye.

I also took along the Astroscan telescope for a closer look and shot a few pictures through it. Not too bad for a non-tracking mount and short exposures..






It would have been nice to have spent a little longer there but we thought it wise to retreat from the swarms of mosquitoes that descended upon us after sunset. I still wish I'd brought back the evil insect repellent purchased in Alaska in 1996. It could kill mozzies in an instant but it made me dizzy when I used it..