Best practices for focusing on sun

[Seldom]

Using BYE will FWHM work?  If not, just focus on the disk image by eye?

[admin]

Use the SdDev focus metric instead of FWHM.  If there is a sun spot focus on the that, otherwise you need to focus on the edge of the sun and this is hit and miss

Regards.

[astroman133]

No, FWHM will not work.

Options are 1) focus by eye while looking at the limn; 2) hope for a sunspot to focus on; 3) set up while still dark and focus like normal on a bright star.

[Seldom]

How bad would it be focusing on a terrestrial object several miles away?

[astroman133]

It might get you close, depending on how far away the object is and what focal length you are shooting at.