Cheap USB Control for your Telescope

There’s many complex systems for automatically pointing a telescope at an object in the sky, but most of them are too expensive for the amateur astronomer. [Kevin]’s Arduino ST4 interface lets you connect your PC to a reasonably priced motorized telescope mount, without ripping it apart.

The ST4 port is a very basic interface. There’s one pin per direction that the mount can move, and a common pin. This port can be added to just about any motorized mount with some modification to the controller. To connect to an Arduino, a TLP521-4 quad optoisolator is used. This keeps the Arduino and PC fully isolated from the motor circuits. but lets the Arduino take control of the mount.

With the hardware in place, [Kevin] cranked out some software which is available on Google Code. A simple Arduino sketch provides the USB interface, and a custom driver allows the ASCOM Platform to control the mount. Since many astronomy software tools support ASCOM, this allows the mount to be controlled by existing software.

With the interface in place, the mount can be used to find objects (GOTO) and automatically follow them with high accuracy (autoguiding). You can watch the telescope move on its own after the break.

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THP Entry: Making Amateur Astronomy Easy

explrad With the advent of electronics in everything, amateur astronomy has never been easier. Telescope mounts that point in the direction of any astronomical object automatically have been around for decades, and the Telrad – a device that paints 0.5, 2, and 4 degree diameter circles in your finder scope’s field of view are available if you’re just too cool for letting a robot do your job. [Christoph]’s explorad takes the concept of a Telrad and adds a somewhat more electronic twist: it still displays the field of view circles, but adds highlighting of interesting astronomical objects from a custom telescope mount, a huge database, and a few sensors.

By far the biggest challenge to any homebrew finder of astronomical objects is figuring out where the observer is. Not only does [Cristoph] need to take into account the location on Earth (GPS helps with that), but also where North is (electronic compass), where the telescope is pointing (optical encoders on a two axis mount), but also the universal time and current sidereal time. Living on a rotating planet that orbits a sun makes for a lot of code.

The current progress on the star finder to beat all star finders is a bit of code that draws the ‘telrad circles’ and displays placeholders for each patch of sky with a small triangle. Tilting the device or turning the azimuth pot moves these triangles and loads new ones on the fly. Now the name of the game is a sky object database for all the astronomical objects [Cristoph] wants to view.

Open Source Telescope Control


Telescope mounts connected to computers and stepper motors have been available to the amateur astronomer for a long time, and for good reason, too. With just the press of a button, any telescope can pan over to the outer planets, nebula, or comets. Even if a goto command isn’t your thing, a simple clock drive is a wonderful thing to have. As with any piece of professional equipment, hackers will want to make their own version, and thus the openDrive project was born. It’s a project to make an open source telescope controller.

Right now, the project is modular, with power supply boards, a display board, motor driver, an IO board (for dew heaters and the like), and a hand-held controller. There’s an openDrive forum that’s fairly active covering both hardware and software. If you’re looking for a project to help you peer into the heavens, this is the one for you. If telescope upgrades aren’t enough to quench your astronomical thirst you could go full out with a backyard observatory build.

Danke [Håken] for the tip.

DIY PC to telescope interface cable

If you’re serious about astronomy these days, you want to have a computer controlled telescope. Although you can easily purchase a pre-made cable that connects the two devices, where’s the fun in that? [Charles], being an avid Maker, has created a nice step by step guide so you can build your own.

This is a great weekend project, and one that even a novice electronics hobbyist should be able to tackle. It’s straight forward, rather quick, and very easy. Strip some insulation off both ends of the cable, then cut off the unneeded wires. (You’ll only be working with three of them.) Prep everything with heat shrink tubing. Crimp one end of the wires into an RJ10 plug, then solder the other end of the wires into a DB9 connector. Secure the heat shrink tubing in place, attach the housings, and you can call it finished!

[Charles] said the whole procedure only took him around 15 minutes. Total cost? Less than $17 in parts.

Print your own adjustable lenses

3d-printed-eyeglass-lenses[Christopher] is really going the distance with his liquid-filled 3D printed lens project. The idea is to create a bladder out of two pieces of clear plastic. It can then be filled with liquid at a variable level of pressure to curve the plastic and create an adjustable lens. He was inspired by the TED talk (which we swear we already covered but couldn’t find the post) given by [Josh Silver] on adjustable eyeglass lenses.

Don’t miss the video after the break. [Christopher] shows off the assembly process for one lens. Two 3D printed frames are pressure fit together to hold one piece of plastic wrap. Two of those assemblies are then joined with JB weld and some 3D printed clips that help to hold it. A piece of shrink tubing is used as a hose to connect a syringe to the bladder. By filling the lens assembly with water he’s able to adjust how it refracts light.

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Simple iPhone telescope mount


This cheap and easy hack will let you use your old smart phone to take pictures and videos of the view through a telescope. [Xobmo] built the connector for just 55 cents. Apart from our concerns about scratching the lens when inserting the phone in the bracket we love the idea.

He was given the Celestron Powerseeker 70AZ as a gift from his wife last Christmas. He looked around the Internet and saw that there are already some solutions for recording video using an iPhone 3GS. This design on Thingiverse would be perfect, but he doesn’t have access to a 3D printer and ordering it form a service would cost almost $50. But when he got to thinking about it, all he needed was a ring to fit on the telescope and a way to connected the iPhone to it. He headed down to the hardware store and picked up a PVC coupler. After working with a hack saw and drill he ended up with a slot with two wings on it. Just slip the phone in and slide the ring on the eyepiece. You can see some action shots, and get a look at the mount itself, in the clip after the break.

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Another great backyard observatory build

With a little help from their friends [Jeff Fisher] and his dad built this observatory in their back yard. Their use of simple building materials and techniques show that you can create a respectable home observatory without breaking the bank.

It starts with a footing for the telescope mount. This is completely separated from the building that surrounds it so there will be no issue with vibrations affecting the images it is capturing. From there a foundation made of cinder blocks was laid before placing joists and installing a sub floor. It was during this process that they trenched and placed conduit to run power to the building. With the floor in place the walls were stick built and a carefully crafted dome was assembled and hefted in place by this septet of gentlemen.

Four months was all it took to get to this point, but [Jeff] and his dad are still working on a deck to go around the observatory. They’re using a very nice telescope that they purchased, but it is also possible to build one of those yourself.

[via Reddit]