Safe Solar Viewer

This is a 3D printed version of the Safe Solar Viewer described by [T.R.Richardson of the College of Charleston 
Department of Physics and Astronomy](http://richardsont.people.cofc.edu/safe_solar_folder/index.html).

It is a safe way to present an image of the sun without risk to anyone's eyes, and is an excellent way to show the sun's image to children.

**Never look directly at the sun with binoculars or a telescope as the result will be instant blindness**.

It has been designed with the objective lens I had in my drawer - a 400mm focal length lens with a 49mm thread that was intended to be used for macro photography when screwed to the front of a camera lens. A smaller lens will also work very well, but don't go bigger. The Barlow lens came from [SurplusShed](https://www.surplusshed.com/) as described in the original designer's web page: mine was a 28mm diameter lens with a focal length of -20 (ref: L1829). USA buyers will find that buying this lens is easy, but as a UK residen