- Making a tachometer for a grinding / polishing machine for telescope mirrors
- Massive scalability when querying metrics stored in Graphite
- multifactor authentication for distributed VPN mesh - part 3, VPN mesh
- multifactor authentication for distributed VPN mesh - part 2, token configuration, local OTP
- multifactor authentication for distributed VPN mesh - part 1, server and client configuration, cloud OTP
- Easy multifactor authentication for SSH using YubiKey NEO tokens
- Monitoring for the cloud, part 2 - architecture
- Monitoring for the cloud, part 1 - tools and techniques
- 150 mm f/8 mirror (25 mm Pyrex) Polishing and figuring log
- How to see Sirius B
When making a telescope mirror on the machine, two parameters are important: the rotation speed of the mirror, and the rotation speed of the overarm eccentric. Other environmental parameters also matter: temperature and humidity are foremost here. To more easily monitor and display these variables, I've built an electronic device that collects this data and shows it on the control panel. This is how to build the device.
Just a quick link to the polishing log for the 150 mm parabolic mirror:
Sirius is the brightest star in the night sky, visible anywhere on Earth except the far North. If you live in the northern hemisphere at a temperate latitude, Sirius is that very bright white star due south every winter in the evening. But did you know that Sirius is also a double star? The companion, Sirius B, also known as The Pup, is a very small star orbiting the primary, and can be seen using amateur telescopes, even small ones. It's not an easy observation to make, but it can be done if you follow certain guidelines. Here's how to do it.
So, we did a "science project" today, the kids and me. We made a scale model of the Solar System, out on the street, to get a visual impression of its true size. It was pretty amazing. It's a very easy project to do, takes a couple hours, and it's a lot of fun.