If you’ve been geeking out for a couple decades, chances are you at least saw the Radio Shack ProbeScope at some point in time.

The Radio Shack ProbeScope
The Radio Shack ProbeScope

I bought one back in the late ’90s and found it to be fairly handy for a number of things. Its sampling rate, as I recall, was 4MHz, meaning you could use it to at least detect the presence of RF in a circuit. I also used it to help me debug the code I wrote to emulate serial communications in the microcontroller for my Digital Setting Circles project.

The ProbeScope included a floppy disk with software on it for both DOS and Windows that allowed you to view the waveforms on your PC by connecting the ProbeScope to the PC’s serial port. Alas, the software was written back in the 16-bit days and won’t run on the 64-bit operating systems on most modern PCs. Plus, who has a floppy drive to read that disk anymore? But if you’ve read any of my other blog posts, you know I have a habit of finding ways to revive old but still useful technology that’s long since been left behind.

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This is a little tidbit I stumbled across while reading KE7X’s “The Elecraft KX3 – Portable” manual. I was interested in adding a PTT switch of some sort to go with the lightweight computer headset I intended to use for portable operation with my Elecraft KX3. It’s possible to use the XMIT button on the front panel for PTT, but I wanted something a little more convenient.

A KX3 menu setting, a simple momentary SPST pushbutton switch, and a repurposed ballpoint pen housing ended up doing the trick. I think the picture below is worth a thousand words:

Homebrew PTT switch for the KX3.
Homebrew PTT switch for the KX3.

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Thanks to some help and testing from Pete Eschman, I’ve been able to restore support for Orion telescopes to my ASCOM Driver for Digital Setting Circles. Specifically, Orion Sky Wizard 2 and 3 and Orion Intelliscope platforms should now be working. Please let me know if you have problems using the driver with these platforms.

Orion itself gets no credit for this–they repeatedly ignored my requests for technical support on this issue, despite the fact that the ASCOM driver they published was a slightly-modified version of one of my earlier drivers.

After having not touched the bluetooth-serial interface I built for over a year, I pulled it out of the drawer recently and found it to be dead–specifically, the BT2S module. Seeing that a replacement was going to be $17.95 plus shipping, I began looking for alternatives. I selected the BT2S specifically because it worked at +5V voltage levels. There are a number of similar-looking modules on eBay that sell for much less, but they all use +3.3V supply and logic levels (search for HC-06 on eBay and you’ll see what I’m talking about). Could my circuit be converted to run at 3.3V?

It turns out the answer is yes. I was able to modify the circuit to operate at 3.3V by replacing the MAX232 chip with a MAX3232, the 78L05 voltage regulator with a 78L33 3.3V regulator, and the BT2S with one of the HC-06 bluetooth slave modules available from Amazon, eBay, and several other sources. No changes to the circuit board are needed. I’ve added details on the changes to the project page.

Here’s an image I took with my NexStar 6SE and Canon EOS Digital Rebel XT DSLR of the total lunar eclipse on the evening of 27 Sept 2015, just after the eclipse reached totality. The image was taken with the DSLR mounted at the prime focus of the NexStar 6SE. This is a 1500-mm f/10 setup, with the camera set at ISO 400, 15-sec exposure. Unfortunately, with the long focal length I couldn’t quite fit the entire moon in the frame.

Total lunar eclipse image taken with Canon EOS Digital Rebel XT connected to Celestron NexStar 6SE at prime focus. 1500 mm f/10, ISO 400, 15-sec exposure.
Total lunar eclipse image taken with Canon EOS Digital Rebel XT connected to Celestron NexStar 6SE at prime focus. 1500 mm f/10, ISO 400, 15-sec exposure.

I seem to be getting into the habit of acquiring older gear and then facing the uphill battle of making it work with more modern equipment. Recently, I wandered into the local pawn shop here in Woodland Park and discovered a used Canon EOS Digital Rebel XT (350D) DSLR camera sitting on the shelf. I’d always wanted a DSLR with which to try some astro-imaging but wasn’t willing to shell out the bucks for a new one. So, I laid out the cash and took the 350D home with me to check it out.

Did I mention that we moved from Colorado Springs to Woodland Park this spring? We found ourselves a nice house on an acre with mostly dark skies overhead. You can actually see the Milky Way on moonless nights–completely unlike the washed out urban sky in Colorado Springs. We love it! If you noticed that there haven’t been any additions to the ol’ web site for more than a year, now you know why. It’s a lot of work to get one house ready for sale, sell it, find a new house, buy it, and get moved. I’m pooped. Anyway, let me tell you a little bit about the new camera and what it took to get things up and running.

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One of the things that intrigued me about my new Elecraft KX3 is that it has a built-in serial interface (the ACC1 port). I thought it might be a fun project to see if I could interface it with my Google Nexus 7 Android tablet via bluetooth, reminiscent of my old GOLog project with the Serial Sender. I couldn’t find much in the way of Android apps that would interface to the KX3 in a useful way, but I decided to put together a bluetooth-serial interface and then see if I could write an app of my own that might be handy for, say, SOTA activations and Field Day.

Although I haven’t gotten anywhere yet with writing my own Android app, I did come up with a bluetooth serial interface that works with the KX3. The detailed project description is here. A PC board is available from FAR Circuits, and the project is designed to fit nicely into an enclosure with a built-in 9V battery compartment.

My bluetooth-serial interface
My bluetooth-serial interface

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So, you probably saw the post I put up a day or two ago about having just gotten a Celestron NexStar 6SE telescope. I’ve been having a ball with it so far. My plan last night was to try using my digital camera to take some video of Jupiter and then run it through Registax software to see what came out of it. I followed the instructions posted on this page at Stargazer’s Lounge. I can’t claim to have done anything original here–just followed the cookbook.

My final image of Jupiter, created from video processed by Registax
My final image of Jupiter, created from video processed by Registax

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I’ve never been crazy about my Meade Starfinder 8″ equatorial Newtonian telescope. The optics seem fine, but the mount is heavy, hard to move, and hard to use. Even with my digital setting circles it’s difficult to get the thing pointed exactly where you want it, and a modest breeze can make it almost unusable. Even getting it set up was a chore. So I didn’t really use it much, and I felt bad about that. So, a week ago I decided to buy myself a new telescope, and this time I chose something much more compact–a Celestron NexStar 6SE SCT.

My new Celestron NexStar 6SE on my living room floor just after unboxing
My new Celestron NexStar 6SE on my living room floor just after unboxing

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Who among the backpacking crowd hasn’t wished for a more manageable way to carry a decent camera on the trail? I carried a little pocket digital camera for many years but was never really happy with the pictures I was getting. I really longed for a better quality camera–one with decent optics, versatile optical zoom, capable of taking pictures under various lighting conditions, etc. But it’s a challenge to carry anything bigger than a pocket-sized camera on the trail. Where do you put it so it’s not either always in your hands or bouncing against you at the end of its strap? Continue reading