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.

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 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 resident negotiating the post & packing maze was eventful! However, this was the only supplier I could find for this item, and they went out of their way to help me pay the right amount.

Important note: anyone trying to make this viewer may have different lenses, so it will be necessary to edit the OpenSCAD code - I have tried to make the code as clear as possible. There is also a file called "testPieces.scad" that only prints the size-critical parts - these use very little filament and allows the builder to get dimensions correct before printing the final pieces.

I printed the objective tube to be a tight 'sticking' fit in the objective mount, then sanded the mating surfaces so that they slide together without rattling around. This fit isn't critical, as long as you can slide the tube easily.

Finally, I show the viewer mounted on myhttps://www.printables.com/model/494249 - in reality this wasn't a great idea as this viewer is very sensitive to movement and it is very easy to get it shaking. The original designer's idea, propping it up on blocks, is far more stable.

Apart from the printed items, you will need some 2020 extrusion - I needed 800mm with my lenses - I recommend that you get 1000mm if you're buying new extrusion, just in case. I had a few odd pieces so joined a couple together for this project. OpenSCAD and STL files are included for the simple joiner and the end caps (you might need to adjust sizes to make these fit properly). You will also need some M5 socket cap screws, washers and T-nuts (I'm not sure what the non-metric equivalents would be). If you decide to add the tripod mount you will also need a 1/4-20 UNC nut (the standard thread for cameras) and a length of aluminium strip 20mm wide - the metal strip holds the nut in place and takes the load instead of the plastic. The strip is drilled to match the tripod mount (use the mount as a template).

You will also see that I have used my M3 Screw Knob as the lock screw for the objective - this can be replaced by any suitable M3 screw, but make sure that the end is rounded so that it doesn't dig into the objective tube (it doesn't need to be done up tight).

Print Settings

Printer Brand:

Anycubic

Printer: 

Kossel

Rafts:

No

Supports: 

Yes

Resolution:

0.3

Infill: 

25%

Filament: Assorted PLA Black & white

Notes:

Printed at 60C bed, 200C nozzle

Category: Physics & Astronomy