CHDK is a firmware enhancement that operates on a number of Canon Cameras. In particular our older A540 model is one of those and in the last few years we have mainly used the CHDK firmware to increase the maximum exposure time of our camera from 15 seconds to 64 seconds.
For those of us Digital SLR challenged (ie we don’t have one), this is a godsend!

I updated both of our cameras (A540 and A495) Saturday with the latest and greatest versions of the CHDK. To my surprise, it seemed to indicate that it could now expose even longer than 64 seconds!

I had to try this out, so after returning from the Public Observing Session last night, I went out and tried a simple short series of exposures: 15, 64, 128 and 161 seconds. For each of these the camera exposes a light image and then a same time dark frame, so even these 4 images took 10 minutes.

It worked! And the new maximum exposure seems to be 2048 seconds (or just over 34 minutes)!!!
Wow. If it really can expose that long we will need an external 3.15vdc power source as well.

I shot just below Cassiopeia at Perseus to minimize the star trails, but as you can see in the longer exposures, they become significant. We will bring along our barn door tracker next time and try it out!

OK.. Here are the results

15 sec exposure

64 second exposure

128 second exposure

161 second exposure