So, this installment of the series didn’t work out quite like I expected. While, in theory, everything I describe below ought to work, I found problems maintaining the wifi connectivity between the NexStar mount and my laptop. Thus, all I can say is give it a whirl if you want, but I make no guarantees. I’m leaving the instructions up here in case you feel the need to give it a try. If you really want to use your laptop to control your NexStar scope, wired is probably best (although I’ve had some success with bluetooth, too, which I’ll cover in another installment).
In Part 2 of this series we went over the basic setup for connecting your NexStar to a laptop using a wired connection. It works great, but cables between your telescope and laptop can be a real nuisance, because you have to start worrying about the cables wrapping around the telescope as it slews in azimuth (although turning “Cord Wrap” on in the hand controller can mitigate that). In general, cables in the dark seem to me like a recipe for disaster. So in this installment, we’re going to cover connections between telescope and laptop using Wifi. (The next installment of this series will cover using a smartphone or tablet instead of a laptop to connect with the NexStar via wifi.)
In Part 1 of this series, I discussed some of the reasons why you might want to use your laptop or tablet to control your NexStar, and went over some of the options for how you can accomplish that. In this part of the series we’ll get a laptop set up to control your NexStar using the Stellarium software package through a wired connection between the scope and the laptop. With Stellarium, you’ll be able to point and click to easily slew your scope to any object you’d like. Stellarium also is capable of showing a ton of information about that object. It also provides a very pleasing and easy-to-use interface. We’ll go through the process from start to finish. Even if you decide to use a different connection type (WiFi or Bluetooth), the instructions for Stellarium will remain pretty-much the same.
The fundamental requirement for controlling your NexStar with a computer of some sort is, of course, establishing communications between the two. As far as I know, a wired connection can only be done between a computer with a serial port or a USB port and the scope–tablets are not supported for wired connections (but let me know in the comments below if you know of a way).
Having recently gotten myself a new Windows 10 laptop (an Acer Aspire E 15 that I really like), I’ve been going through the process of getting everything set up and installed the way I like (I’m kinda anal retentive about that). That gives me cause to explore new possibilities, like “how can I get my Google contacts and calendar (from my Android phone) to sync up with my installation of MS Outlook on my laptop (which I use for email)?” I’ve asked that question before but never found a decent answer. This time, though, I found a great solution, and it’s free!
GO Contact Sync Mod is a utility I found that runs in the background on my laptop, reaching out to Google’s APIs to keep my Google contacts and calendar sync’d with those in MS Outlook. It has a straightforward user interface where you can define the rules for reconciliation (like “if there is a conflict, the Google contact should overwrite the Outlook contact”). You can tell it how often to perform the sync and it will do so quietly in the background. I’ve been using it for a few weeks now and it works so well that I forget it’s there.
(Why don’t I just use GMail and omit MS Outlook entirely? I have my own domain, including email addresses, so I don’t use a GMail address. And I much prefer MS Outlook’s interface to GMail.)
Since I purchased my Celestron NexStar 6SE a few years ago, I’ve enjoyed dorking around with the different ways I can drive the thing with a computer of one sort or another. Of course, you can use the NexStar SE just fine with only the hand controller, but where’s the fun in that? Truthfully, while it’s certainly usable, the hand controller’s interface is a bit on the clunky side–especially when wading through its menus to find some DSO to which you’d like to slew. I much prefer to be able to use a planetarium app like Stellarium or SkySafari to find and slew to objects of interest.
As I investigated the possibilities, I learned that there are quite a few different ways you can control your NexStar SE with a computer. For starters, the connection between your scope and the computer can be wired (through a serial or USB port), WiFi, or even Bluetooth. Then, once the connection is established, you have quite a few apps from which to choose to do the actual controlling. All of the possible configurations of connection and control have their positives and negatives, and which one might work best for someone depends largely on their own personal preferences.
FAR Circuits is now making available an assembled and tested board for the Bluetooth Digital Setting Circles project described here. The board includes a preprogrammed PIC16F628A chip as well as a fully-configured RN-42 Bluetooth module. You’ll still need to solder a connector for your power source of choice, and you’ll need to obtain your own rotary encoders and connect them through the RJ-45 port included on the board.
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.
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.
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:
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.