Make Your Own Telescope, Right Down To The Glass

Telescopes are great tools for observing the heavens, or even surrounding landscapes if you have the right vantage point. You don’t have to be a professional to build one though; you can make all kinds of telescopes as an amateur, as this guide from the Springfield Telesfcope Makers demonstrates.

The guide is remarkably deep and rich; no surprise given that the Springfield Telescope Makers club dates back to the early 20th century. It starts out with the basics—how to select a telescope, and how to decide whether to make or buy your desired instrument. It also explains in good detail why you might want to start with a simple Newtonian reflector setup on Dobsonian mounts if you’re crafting your first telescope, in no small part because mirrors are so much easier to craft than lenses for the amateur. From there, the guide gets into the nitty gritty of mirror production, right down to grinding and polishing techniques, as well as how to test your optical components and assemble your final telescope.

It’s hard to imagine a better place to start than here as an amateur telescope builder. It’s a rich mine of experience and practical advice that should give you the best possible chance of success. You might also like to peruse some of the other telescope projects we’ve covered previously. And, if you succeed, you can always tell us of your tales on the tipsline!

The Constant Monitoring And Work That Goes Into JWST’s Optics

The James Webb Space Telescope’s array of eighteen hexagonal mirrors went through an intricate (and lengthy) alignment and calibration process before it could begin its mission — but the process is far from being a one-and-done. Keeping the telescope aligned and performing optimally requires constant work from its own team dedicated to the purpose.

Alignment of the optical elements in JWST are so fine, and the tool is so sensitive, that even small temperature variations have an effect on results. For about twenty minutes every other day, the monitoring program uses a set of lenses that intentionally de-focus images of stars by a known amount. These distortions contain measurable features that the team uses to build a profile of changes over time. Each of the mirror segments is also checked by being imaged selfie-style every three months.

This work and maintenance plan pays off. The team has made over 25 corrections since its mission began, and JWST’s optics continue to exceed specifications. The increased performance has direct payoffs in that better data can be gathered from faint celestial objects.

JWST was fantastically ambitious and is extremely successful, and as a science instrument it is jam-packed with amazing bits, not least of which are the actuators responsible for adjusting the mirrors.

Laser Surgery: Expanding The Bed Of A Cheap Chinese Laser Cutter

Don’t you just hate it when you spend less than $400 on a 40-watt laser cutter and it turns out to have a work area the size of a sheet of copy paper? [Kostas Filosofou] sure did, but rather than stick with that limited work envelope, he modified his cheap K40 laser cutter so it has almost five times the original space.

The K40 doesn’t make any pretenses — it’s a cheap laser cutter and engraver from China. But with new units going for $344 on eBay now, it’s almost a no-brainer. Even with its limitations, you’re still getting a 40-watt CO2 laser and decent motion control hardware to play with. [Kostas] began the embiggening by removing the high-voltage power supply from its original space-hogging home to the right of the work area. With that living in a new outboard enclosure, a new X-Y gantry of extruded aluminum rails and 3D-printed parts was built, and a better exhaust fan was installed. Custom mirror assemblies were turned, better fans were added to the radiator, and oh yeah — he added a Z-axis to the bed too.

We’re sure [Kostas] ran the tab up a little on this build, but when you’re spending so little to start with, it’s easy to get carried away. Speaking of which, if you feel the need for an even bigger cutter, an enormous 100-watt unit might be more your style.

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