Maximum exposure time to avoid star trails

Sensor width:  mm
Sensor height:  mm
Pixels (columns):  px
Pixels (rows):  px
Pixel size:  µm

<< Enter some values or select a camera above to get the table here. >>

Q: I don't understand at all what's going on here?
A: Ok here's some random links...
Q: I have a XYZ fisheye, can you include it in the table?
A: No, I'm too lazy to do projection math just for fisheyes.

Q: Can you include my camera model in the dropdown?
A: No. Put in the values manually or get the Excel from below.

Q: Your calculated time is too short/long/ugly!
A: Probably, these are theoretical numbers and don't take into account things like: Q: When I print this page, all the explanations disappear?!
A: Yes. On purpose. It fits nicely on an A4 paper that way.

Original spreadsheet:
Janne Heinonen

Original JS calc:
This hack by vaizki @ IRCnet