DIY Solar Scintillation Seeing Monitor

[IanL]

Inspired by this thread on the SolarChat forum, I built my own Solar Scintillation Seeing Monitor (SSSM).  I've written up a detailed build guide here to help those less electronically inclined to build their own: http://www.blackwaterskies.co.uk/2017/06/diy-solar-scintillation-seeing-monitor-sssm/

What is an SSSM?  It's a simple device designed by E. J. Seykora at the Department of Physics, East Carolina University which uses a photo diode, amplifier and an Arduino-type board to monitor solar seeing conditions. (Note: This device is not suitable for monitoring night-time seeing).  Commercially built and supported models are made by Airylab in France and sold through various distributors at a cost of around £240 at the time of writing; the DIY version costs less than a tenth of this to make and is functionally identical as far as I can tell.

Why would you want to monitor solar seeing conditions? Apart from scientific interest and perhaps comparing the quality of seeing conditions between locations, the main reason is to use Joachim Stehle's free FireCapture plugin (here).  The plugin will continuously monitor seeing and automatically start capturing images/video when they exceed a user-defined quality threshold.  This means you can set up your solar imaging rig and leave it to its own devices rather than having to fill up your hard disk with gigabytes of videos that you then have to sort through manually later.

I have made a couple of small improvements in my version of the build, specifically refactoring the Arduino sketch to make it more readable and more modular, plus I've added support for graphical display of seeing quality over time by adding a cheap OLED display and supporting code.  (OLED modules can be had for less than £5.00 on eBay).

Hopefully you'll find this an interesting project for the summer months!

 

Edited June 24, 2017 by IanL

[descott12]

Hi Ian,

Thanks for the great post. After seeing it, I built my own.

https://www.cloudynights.com/topic/749771-homemade-solar-scintillation-monitor-warningthis-is-pretty-geeky-stuff/

I am having a problem with it and I was hoping you could help. It seems to display a seeing value of around 11 most of the time. It responds appropriately to shade vs full sun and I keep the input voltage very close to 1.0. I have checked all the internal voltage levels and the ones that should be at 2.5 are ok.  The seeing value never goes below about 10 unless I increase the input voltage but that is the denominator in the equation so that is just a result of the math on not the actual conditions. Measuring over a shingle roof vs a grassy field doesn't seem to change anything. Any thoughts? My local seeing  is around 2.5. to 3 usually and that is about 1/4 of what is being reported. I noticed that the firmware has a multiplier of 4.46 which is a little suspicious but access to the orignal Seykora paper is no longer possible so I wasn't sure what the factor was for. Anyway, thanks again in advance for any advice you may have.

Dave

[GreatAttractor]

Dave, the original article (with all derivations) can be found here: http://adsabs.harvard.edu/full/1993SoPh..145..389S

I tried to figure out the 4.46 value in this post and I think it checks out.

[JamesF]

I think I might have to have a go at making one of these myself.

James