Astrophotography exposure time

This piece of code compute exposure time according 4 differents methodes :

• NPF: (35 x Aperture +30 x Pixel Pitch) / Focal Length​​
• NPF full: Accuracy x (16.9 x Aperture + 0.10 x Focal Length + 13.7 x Pixel Pitch) / (Focal Length x cos(declinaison))
• 4Crop: 100 x (4−crop​) / Focal Length
• Rule500: 500 / Crop-Factor x Focal Length

Best accuracy of exposure time is given by NPF full rule

For details please see:

• The 500 Rule
• Règle NPF – calcul du temps de pose sans filé d’étoiles

Setup and running

• Add your own technical specification in config.yml file (some technical parameters can be find on Digital Camera Database
• go run main.go
• As a result :

NPF Simple    :  temps de pause de 50.6 sec.
NPF Complet   :  temps de pause de 23.6 sec.
4 Crops       :  temps de pause de 46.7 sec.
Règle des 500 :  temps de pause de 60.5 sec.

Help needed

Is there a way to calculate Pixel Pitch and Crop Factor?