Randy's Bench

A repository for projects past and present

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1970’s Astronomical Scrapbook

Here’s few snippets from a scrapbook I kept back when. It primarily comprised newspaper clippings I thought of interest at the time ~1973 to 1980. Hope you enjoy a trip to the past…

Mariner 10


Pioneer 10

To be continued…


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We have touchdown!

As the image below depicts Viking 1 on the Martian surface after it’s successful landing on July 20th of 1977, so have I finally landed back on the bench.


The above clipping is from a astronomy themed scrapbook I maintained during the ’70’s.
(I think I’ll do a post on this scrapbook in the future…lot’s of Pioneer probe, Viking and other stuff.

While I wait for a parts shipment to arrive (In part to finish off Lily, our chess computer still waiting patiently in the wings, I thought I’d revisit the Z80-based SBC I put together back a few years. As a preparation for that I’m going to revisit a favorite text I picked up at a used book store back in 1983. As pictured, this is the Art of Electronics Laboratory Manual 1st Edition which has a few nice Z80-based experiments including an experiment involving a couple of DAC chips used to output a programmed sequence to an oscilloscope.

LabCover 1981

With that in mind I picked up a few more breadboards, gathered up some chips and and began…Breadboard


Here’s a short video of the fun in process…

I’ll add some schematics as things progress. As always, thanks for viewing! …Randy

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A Compact Solar Spectrograph

Back in 2003 I designed and built a grating based spectrograph primarily used for casual solar spectral studies as well as gaining an appreciation of the beauty and elegance of it’s spectral lines.

This served reasonably well for many years of on and off again operation, but always had a few niggles I never quite worked out. The grating turret was a bit wonky and would sometimes get hung up. Additionally it would slightly wobble during rotation causing a shift in spectrum placement on the camera sensor or viewing eyepiece

Another source of occasional frustration was the adjusting mechanism on the entrance slit which did work…just not very well. The final aspect was it’s rather cumbersome size for it’s purpose…With those things in mind I’m endeavoring to reduce it’s overall dimensions, simplify the problem areas and create a friendlier instrument in practice.

To begin I’ve looked at a rather simple arrangement which offers somewhat less flexibility (in my own implementation) but in return gains solidity, portability and simplification of operation (at least, that’s my wish).

Here’s my proposed layout diagram based on a German spectroscopy forum’s Minispec design by author Danial Sablowski:

And here’s a few pieces and parts I’ve got at this point… First a pair of cheap Walmart Pencil sharpeners I purchased for a whopping 47 cents each:

And the parts we need from the sharpeners (blades for our entrance slit)

And the completed (for the most part) spectrograph slit assembly:

Next in order, to properly determine optimal part configuration, I found a suitable cardboard box of roughly similar dimensions to act as a flexible test bed to this end. As shown, I placed the entrance slit assembly and 35mm collimator lens to better gage focal length adjustments. The slit assembly tube(s) allow two points of adjustability, which were set at midway.The collimator lens was set roughly at its correct focal length. A small hole was cut out in line with the slit/collimator positioning to permit a finder scope, set at infinity focus, in order to make the necessary adjustments to bring the slit into sharp focus. Those readings were jotted down in my project notebook.

The final enclosure will also have a 20mm hole bored to ensure the collimator lens has good focus on the slit jaws.

That’s the story so far…back when I’ve further progress to report…..Thanks for looking

“To invent, you need a good imagination and a pile of junk.”
-Thomas A. Edison

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Documenting a Stellar Journey – Notebook one

Presented is the initial journal offering of my time spent exploring Amateur Spectroscopy. This first notebook covers the time period of October 1995 to November 1996. There’s several additional journals I’ll upload over time…

Thanks for watching!



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Documenting a Stellar Journey Part one

Since I appear to be engaged a bit less (read, alot less) in bench projects currently I thought it would be an opportune time to gather my experiences, both unfruitful detours and modest successes, with an amateurs endeavors into Spectroscopy.

With that in mind I present the first in a line of videos primarily to document my story with which I spent a great deal of time in the past. Along with my observations and ensuing results (Parts 1 & 2), I plan to additionally document my Journals kept during what was an exciting time for me…

So I present to you part 1 of this series.

And here’s a link to my YouTube channel…

Subscribe if you like…Thanks and  best regards


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A strange thing happened on the way back to the Bench…

Well here I was finally crawling back to the bench after an extended leave and was distracted yet again…..dam those PC’s! Gaming coupled with my enjoyment with all things Star Trek again caught my attention. So I present to you a few videos I uploaded to my YouTube channel recently…please enjoy!



Oh and here’s my YouTube channel link..


Subscribe if you like…Thanks and  regards (I’ll be back)