3D-Printed Solar Filter for Sunspot Observation

Sun spot activity currently ramping up. Time to take out the telescope and go for some early evening sun spotting from the balcony.

A note of WARNING and DISCLAIMER: only use certified sun filter foil, I am using Seymour Solar Filter, grade ND5, available here. Be responsible and operate on your own risk.

Child looking through a telescope fitted with an orange 3D-printed solar filter

Telescope equipped with 3D printed sun filter, maximum telescope diameter 183mm.

CAD render of the 3D-printed solar filter holder on a telescope tube — Filter assembly, 2 support rings, 2 screw on covers to protect the delicate filter foil (!!safety item!!)

CAD section of the solar filter holder: support rings and filter foil

CAD render of the assembled solar filter holder with mounting screws

That’s the sunspot image as of 2022/06/23, not ours (lacking a camera adapter), curtesy NASA:

nolle.engineering

Sun spot spotting