How long can you expose on a comet?

Enter the comet's apparent motion, your image scale, and how many pixels of trailing you can tolerate to find the max sub length.

Inputs

Comet Motion (arcsec/hour)

Image Scale (arcsec/pixel)

Max Trail (pixels)

Results

Adjust the inputs to see results.

Trail rate = motion / 60 arcsec/min. Max sub = (max trail arcsec / trail rate) × 60 seconds.

All formulas verified by automated tests.