brainwagon

Ken Boak had mentioned on twitter that someone was creating a blinken-lights front end for the simh simulator of the PDP-8, called the PiDP-8, since you can power the entire thing from a Raspberry Pi. Very cool, but not quite available yet. What was available from Oscar is the Kim-Uno, a simulator for the old […]

Just bookmarking this for now: The NOAA Magnetic Field Calculator This website can accept a latitude longitude (or, conveniently, a Zip code) and will give the you predictions of what the inclination and declination of the magnetic field is. John used this apparently to make predictions about the field near my location.

If you follow me on twitter (@brainwagon) you’ve undoubtedly seen a few mysteriously short tweets about experiments I’ve been performing on magnetometers. It’s hard to give any meaningful context in just 140 characters, so I thought I would dump a short overview of what I’m doing here, in the hope that I’ll turn it into […]

I’ve been having a bit of fun with my DJI quadcopter lately, but there is something that is annoying me and stressing me in the back of my head, and that’s surrounding the legality of flying quadcopters. Basically, it’s impossible to determine with any certainty whether flying your quadcopter in any particular place is legal. […]

If you are going to test your telescope mirror, you will sooner or later need a Ronchi screen. The best Ronchi screens are usually made on glass, with the black lines being formed by metal or chrome deposition. Another way to make a good screen is by film reduction: you print a large screen and […]

For the second week in a row, I carted my body down to the Chabot Science Center and attended the Chabot Telescope Makers workshop. My intention was two-fold: I was going to extract the mirror from a little 6″ telescope that I had found at a garage sale and purchased for a mere $15, and […]

I mentioned that I was searching for my 6″ f/12 that I made years ago. Still have not found it, but I was wondering: how good is a 6″ f/12 sphere? I recall hours of polishing to try to get to a nice, smooth null, but don’t remember if I ever quantitatively figured out how […]

As I mentioned before, I’m trying to get back into telescope making, a hobby that I haven’t been involved with for a few years. The fruits of more than a decade of telescope making are in my garage: I have a bunch of supplies and utilities that i have sort of lost track of. Somewhere, […]

I updated my old 2001 Ronchi test code to support arbitrary conic surfaces, and then uploaded the code to github. My current 12.5″ project is an f/5 paraboloid: If we were interested in making a spherical mirror, we’d have these as patterns: Why bother writing this code? I’m actually interested in trying to acquire images […]

It was a long time since I wrote the code that I used for Ronchi code, and while I had some confidence in it, I wasn’t 100% sure that I had verified it. So, today, I took a copy of Ronchi for Windows 2 (I downloaded it from here) and set it up to predict […]

Since I stopped actively working on building telescopes, there have been numerous bits of technology that are now widely and cheaply available, and that can be used to implement new, interesting functionality. In particular I hadn’t considered that the same kind of sensors which are used to control quadcopters could be used to determine the […]

At the Chabot Telescope Maker’s workshop, we make a lot of use of the Ronchi test. It’s great for figuring out gross defects and problems with your mirror. Back in the day, I wrote a simple program to generate Ronchi patterns for a given parabolic mirror. Here are six Ronchi patterns generated by my code […]

It was a warm and reasonably calm day, so Carmen and I decided to take the Phantom 2 out to Lime Ridge Open Space, where many RC enthusiasts fly. Rather than bore you with 18 minutes of video, I thought I might give you two short video highlights… Without further ado:

LB3RE sent me a link to this awesome HF beacon by Anthony, F4GOH and Christophe, F4GOJ that has many of the same features as my (as yet still in-progress) beacon transmitter does. And, of course, his actually exists, so it’s already infinitely more awesome than my idea. I was particularly interested in his very simple […]

I forgot to mention my chat with Gert, another telescope making regular up at the Chabot Telescope Maker’s Workshop. He’s a skilled astrophotographer and all around interesting guy, and has embarked on a campaign to do some high quality imaging of Jupiter. You can see some of his results here. Pretty nifty stuff. I copied […]