Building a radio telescope for a school science project

The image above is a picture of  Hydrogen emissions from our galaxy. The cool thing about this picture is it wasn’t taken with millions of dollars worth of equipment; instead, only a few hundred dollars worth of ham radio gear was needed to get a picture of the Milky Way. [Shanni Prutchi], with the help of her dad [David] built this radio telescope in 5th grade, and even gave a presentation on this build at the National Radio Astronomy Observatory.

Instead of a gigantic satellite dish, [Shanni] used a loop yagi antenna to collect radio signals in the 1420 MHz band. These signals are amplified, filtered, and sent to an ICOM IC R-7000 receiver specially modified by [Shanni]’s dad for radio astronomy.

After her telescope saw first light, [Shanni] and [David] decided to use their brand new toy to detect the passage of the sun. At around 10:00 am they pointed the telescope at where the sun would be at 1:30 pm. For the next few hours, the telescope gathered and integrated radio signals to make an awesome graph. Yep, [Shanni]’s scope can detect radio waves coming directly from the sun.

Like a lot of us, [Shanni] was very much influenced by the movie Contact, something we brought up last week in a post on software-defined radio telescopes. This telescope was built in 2005, meaning [Shanni] couldn’t take advantage of any of the new advances in cheap software radios. We’re still waiting for someone to throw a Realtek SDR telescope together, so if you’ve got one send it in

A quick kludge to view the transit of Venus

[Justin] is a bit of an astronomy geek, but that doesn’t mean he’s always prepared for celestial phenomena. When he realized the May 20th annular eclipse was only a few days away, [Justin] dropped everything, built a pinhole solar viewer, and drove three hours for the best view of the eclipse. He learned something watching the eclipse; these sort of things sneak up on you, and you really need to plan ahead if you want to truly enjoy the music of the celestial spheres. After the eclipse, [Justin] set to work building a filter to watch a Venusian eclipse with his telescope.

If [Justin] pointed his 8 inch Schmidt–Cassegrain directly at the sun, he would most likely damage the optics in his ‘scope, burn several retinas, and other very, very bad things. The best way to view the Sun with a telescope is with an expensive Hydrogen alpha or a general solar filter, but these are expensive and the clock was rapidly ticking down to the transit of Venus. After reading that blocking most of the light from coming into the ‘scope, [Justin] built an aperature reducer out of a few bits of foam board, foil, and dark fleece.

How did viewing the transit with a telescope turn out? Well, if you don’t compare [Justin]’s pictures to the multi-million dollar toys NASA and astronomers have, pretty good. It’s a very good job considering the entire foam-core aperture reducer was built in the course of an evening.

While it may be a little early to be planning for the next Venusian transit in the year 2117, there will be a transit of Mercury on May 9, 2016. All [Justin] has to do is remember when it will happen.

Seeing the Venus transit; this is why you should visit your local hackerspace

So I thought about getting a pair of protective glasses so that I could safely stare at the sun during yesterday’s Venus transit. But then it was forecast to be cloudy in the afternoon (the event didn’t start until 5pm here) so I forgot about it and figured I’d try to catch it next time around (which is 105 years from now).

I went about life, ate some dinner, then grabbed my latest project and headed off to the monthly meeting at Sector67, the local Hackerspace in Madison, WI. Lo and behold I arrived to find this sight in the parking lot:

Sure, my priorities may have pushed the viewing to the side. But others made it their mission to see the once or twice in a lifetime event and I got to see it just for being in the same place as them. This is the meat and potatoes of Hackerspaces…. collaboration. A source of new ideas, motivations, and inspirations.

One of the members brought a telescope and went online to figure out how to safely use it for viewing. For about $2.50 he rigged up a funnel covered with a piece of acetate which interfaced with the eyepiece of the scope. The image at the top shows the entire sun, and even though some of the cloud cover can clearly be seen, there’s Venus, plain as day. The cardboard box is just providing a shaded viewing area around the funnel. As with most cosmic experiences, it surprised me by being way cooler than described. See a few extra pictures in the gallery after the break.

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Automated sky tracking to catch UFOs

If you were to try to take a picture of a UFO, how would you do it? Sit by the side of a road in Nevada near Area 51? Pie tin on a string? A French team of UFO enthusiasts put together an automated UFO detection device (Google translate) out of a disco light and CCTV camera so long nights of watching the skies can be automated.

The build uses a disco light with an altitude and azimuth mount to constantly scan the skies on the lookout for strange, unexplained lights. Attached to this swiveling mount is a camcorder and a CCTV camera that streams video to the command and control laptops for image analysis.

In addition to object tracking, there’s also a diffraction grating in front of the CCTV camera. The team behind this project previously used this for some very low tech spectroscopy (translation) to identify emission lines in a light source. Light that have a signature including Oxygen and Nitrogen will probably be ionized air, while less common elements may be the signature of “advanced propulsion.”

While this build is going to detect a lot of satellites and meteors, there’s a definite possibility of capturing an unexplained phenomenon on video.

Two telescope improvements

Despite being a college class everyone regarded as an easy ‘A,’ astronomy is very hard work. Not only do many hours go into capturing a single image, the equipment itself must be constantly monitored well into the freezing cold of night. [Jerry] sent in a few neat projects that have made his nights much more comfortable.

First up is a mod for a focus controller. The focus of a telescope changes constantly with temperature, atmospheric conditions, and especially what filter is being used. The stock USB-nSTEP focuser [Jerry] used required hard-to-find unipolar steppers, so he modded his USB-nSTEM to accept bipolars with a Pololu A4988 driver.

Next up is [Jerry]’s very impressive DIY Off-axis guider that he machined himself. An off-axis guider allows an astronomer to guide the ‘scope without having to deal with a dinky, surprisingly flexible guide scope. We’re really impressed with [Jerry]’s machine skills, but that’s what you get when you’ve got an awesome mill like his.

Photographing near-space objects we’re not supposed to know about

[Thierry Legault] doesn’t just look up at the stars, the uses a motorized telescope base of his own making to track and photograph secret objects orbiting the earth. What do we mean by ‘secret objects’? Spy stuff, of course.

Last month he captured some video of the X-37B, an unmanned and secretive reusable spacecraft (read: spy shuttle) which is operated by the United States Air Force. That was back on the 21st of May but a few nights later he also saw the USA-186, an optical reconnaissance (Keyhole) satellite.

After trying to cope with manual tracking using the RC control seen above [Thierry] set out to upgrade his equipment. He ended up designing his own software package (and then released it as freeware) to automatically track the trajectory of orbiting objects. He uses a second telescope to locate the object, then dials it in with the bigger telescope. Once in frame, the software takes over.

[Wired via Dangerous Prototypes]

Building an oak telescope

You might not think about the finish of your homemade telescope but if it’s build from solid oak you probably should. [Gregory Strike] built this 8″ telescope a few years back but just posted about it a few days ago. The optics are quite expensive but the rest of the build was done dirt cheap and he did a great job of it.That includes taking care to finish the oak boards that make up the octagonal body of the instrument.

This is much more approachable for the average hacker than something like the 22″ binocular build (or going way too far and building your own observatory). [Gregory] developed his design after looking at a couple of others. If you need a bit of a push to get started check out the telescope resource we ran across in our days of Internet infancy.