I’d been hearing lately about some astronomy software for the iPhone/iPad called SkySafari (made by Southern Stars), but not owning either one of those devices myself, I hadn’t really bothered to look into it at all. That all changed when I came across an ad for SkySafari in Sky and Telescope magazine that showed that an Android version was available. Now I became much more interested to see what the fuss was about, so I dropped $14.99 in the Google Play store for the Plus version so I could try it out on my HTC Incredible phone as well as my rooted Barnes and Noble Nook Color. Mostly, I wanted to see if SkySafari would connect to my digital setting circles box via bluetooth. Initial impressions are very good.

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I didn’t find out about last Sunday’s solar eclipse until just a few days prior, and I didn’t have any equipment that I could use to safely view the eclipse. Not wanting to resort to the pinhole projection method for viewing the eclipse, I consulted my 40-year-old copy of Sam Brown’s classic (and extremely informative) book All About Telescopes for some other ideas. The book showed a design that would fit over the front of my 8″ Newtonian telescope, stopping the aperture down to 2″ and using a lens from a welding helmet to knock down the sun’s intensity to a manageable level. All I needed was the welding lens.

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Decent paper maps for backpacking can sometimes be challenging to find. My preferred map has always been the USGS 7.5-minute quad, with a scale of 1-24,000 (1 inch equals 2000 feet). Don’t get me wrong–there are plenty of ways to access the data. The USGS makes the map images available as PDFs online for free from the USGS Store, for example. National Geographic sells their TOPO! State Series software with maps on DVD for $49.95. Or you can go to a web site like Trails.com or AllTrails.com to access maps online (for $49.95/year–a price that I find a little astonishing). The big disadvantage to using any of these sources is that, for the average guy, it’s difficult to print out the map you want in the format you want.

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QRP to the Field is an annual event, held the last weekend in April, when amateur radio operators who have an irresistible case of spring fever pack up their QRP (low-power) ham gear and head for the great outdoors for the purpose of making contacts with other equally-afflicted amateurs. I am, of course, proudly standing in the ranks of those impaired individuals. I usually use QRP to the Field as an excuse to embark on my first backpacking trip of the year.

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If you read any of the tech blogs, you know that the Windows 8 Consumer Preview is now available for anyone to try. What holds most people back from trying pre-release versions of Windows is having someplace to install it that won’t trash your existing OS installation. Often times this is done by creating a new partition on a hard disk and installing the preview OS there. Easier, in my mind at least, is to install the new OS in a virtual machine. That’s what I decided to do this morning. I already use virtual machines for other purposes (for example, I have a virtual machine running Windows XP so I can run some older software that’s not compatible with Windows 7). I use VMWare Player, a free product from VMWare.

It took me a few tries to successfully install the Windows 8 preview, so I thought I’d document what worked for me. Here we go:

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I’ve written a small program called EkBoxTester that you can download to aid in testing your Digital Setting Circles interface board after you’ve constructed it. EkBoxTester requires Microsoft .Net 4.0 to be installed on your computer. EkBoxTester consists of a single executable file (EkBoxTester.exe) that can be run from wherever you want. There is no installer–just download and run it.

The source code for EkBoxTester can be downloaded from here. It was written using Microsoft Visual C# 2010 Express Edition–a free but reasonably complete development environment for writing .Net applications in C#. You can use the source code as an example of how to communicate with an EkBox via the serial port.

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FAR Circuits has just released a kit for a USB version of my Digital Setting Circles project. The USB version relies on the FTDI TTL-232-5V interface cable as shown in a previous post. A complete writeup is now included on my USB Digital Setting Circles page. Here’s the schematic for this new kit:

 

USB Digital Setting Circles Schematic
USB Digital Setting Circles Schematic

 

The kit is much simpler than the serial version–the pull-up resistors were eliminated, the oscillator replaced by a crystal, and a MAX232 chip is no longer needed. The board and encoders are powered by the USB port, too, so no external power supply is needed. The kit includes all the components, including the programmed PIC chip, but does not include the TTL-232-5V cable. The cable must be purchased separately and is readily available from Mouser and Digikey, for about $20 plus shipping.

This kit should work great if you want to run your digital setting circles straight through the USB port of your laptop. However, if your goal is to use a bluetooth connection between your computer/PDA/smartphone and the board, then the serial version of the kit is the one you want to use. Furthermore, this USB version really isn’t adaptable for use with a smartphone or PDA–the TTL-232 USB cable needs to plug in to a PC in order to work.

My Martin OMC-16E guitar has a big strap button to accommodate the 1/4″ jack for its electronics (a Fishman Ellipse Matrix Blend pickup)–too big for the holes in most guitar straps. I’d been wanting to buy myself a nice strap for this guitar but the big strap button was holding me up. My wife and I were planning to visit the Martin Guitar factory in Nazareth, PA as part of an upcoming vacation. Knowing that they had a gift shop and I might be able to buy a strap there, I decided to hold off until our visit.

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One thing that puts people off when they consider building their own digital setting circles is the cost of the two rotary encoders that are needed. Building my DSC circuit is fairly inexpensive (maybe $30 or so), but a pair of high-resolution optical encoders can set you back to the tune of $150 or so. Recently, someone posted information about these capacitive encoders on the Palmastro Yahoo! group. Apparently, they work well in digital setting circles applications, and they appear to be electrically compatible with optical encoders. The spec sheet says they’re accurate to 15 arcmin, which is probably good enough for most users. The best part? You can have a pair for about $50. Digi-Key is supposedly a source of these babies.