I’m writing this blog entry whilst still on holiday and not having any means of transferring my digicam pics to my smartphone, so I’ll present the text first and images later.
A holiday to the Scottish Highlands presented itself with an opportunity to take advantage of (potentially) clear dark skies as I usually have to put up with light-polluted skies at home.
I hadn’t really tried out my new Canon SX20IS digicam for some astrophotography, preferring to continue to use my ageing S2IS with CHDK. However the SX20IS really offered a number of advantages over the S2IS such as better ISO capabilities (ISO 800 to 3200) and better resolution. So over a couple of nights, whilst dodging some broken cloud, I managed to obtain some impressive (in my eyes and with my limited photographic ability) images that kicked the S2’s images on the first night into a cocked hat.
As a comparison, on the first night I mainly used the S2IS with CHDK and took a number of exposures 20-32sec in length, ISO400. A lot of noise was picked up and only the brightest stars were picked up. However I was able to save these as RAW images so I may be able to obtain more detail once I get back to my laptop. I took a couple of disappointing shots with the SX20 which only picked up the very brightest stars in Cassiopeia.
However the next night I decided to use the SX20 and after making some aperture changes and setting the ISO value to 1600, this really opened up the quality of the images. Once the broken cloud had nearly completely cleared, I set the camera up on a wooden table on top of the tripod (there were trees all around so I couldn’t get any horizon shots) and started snapping again and Cassiopeia. With the ISO set to 1600, aperture F2.8, manual focus and time 15″, the images taken had substantially less noise than from the S2IS and more stars were picked up by the SX20’s CCD.
As I took more shots and applied the zoom slightly to M31 (Andromeda Galaxy) which I managed to pick up in the image, the aperture adjusted automatically to F4.0. However because I couldn’t see M31 in the viewfinder, it was hit-and-miss (more miss actually) aand couldn’t get a closer image of the object. Even though ISO has more image noise, I’ve been very impressed with the SX20’s ability to take low light shots – and I haven’t even tried the ISO3200 mode yet!
Posted by Wordmobi