30s exposures and stacking

[freelander86]

Hi,

I want to have a go at stacking photos to create "star trails". My camera only allows 30s exposures which is fine... I understand I just need lots of 30s images and then stack them together to get the final image.

But two question:

1) People say the imaging chips gets hot which is why its limited to 30s... Could there be any risk If I keep taking images...

2)Has anyone done this? Do I simply keep pressing the shutter release every 30s and try to keep the "gaps" to a few seconds???

[Tinker1947]

I think for Star Trails just put the camera in "Bulb" mode that's should be the next setting from 30s use a remote control and leave it for several minutes only needs the one exposure, i don't think heat is a problem i have as have loads of other people uses 2 minutes or more 10 minutes or more with autoguiding with no damage.

[Bizibilder]

The "heat" is not going to damage your camera! It is generated by the camera and may be just enough to show in the sensor as a slightly bright area. You can safely take DSLR images up to many minutes in duration with no ill effect on the camera.

For star trails you may like to try "startrails" software: Startrails application

[freelander86]

Sorry should have said - Its not an SLR. Its a bridge camera. Thats why it doesnt have a bulb mode just the 30s limit...

[Bizibilder]

Comments still apply - just with a 30 sec limit! You should be fine. Take a 30 sec exposure with the lens cap on (or just block the lens with something so no light gets in) and see if you get any "light" areas on your image - you may need to boost contrast to see anything. Do this for each available ISO setting so you can see what is going on. You are taking a "dark" as we say - usually used to calibrate images suffering from things like amplifier glow (the "heat" mentioned above).