As I described in my previous article, I embarked on a “maker” project. I have been experimenting this summer with controlling my telescope with a Raspberry Pi, a small single board computer that I strapped to the scope with Velcro. On the Pi, I am running the Linux planetarium software KStars and its integrated astrophotography suite called Ekos, which is built on the INDI protocol for astronomical equipment control. I have connected my MoonLite Focuser, my Losmandy G11 mount, my Meade DSI guide camera, and my SBIG CCD camera all to the Pi and it manages my entire imaging session. I have been using my laptop to connect with the Raspberry Pi over the wireless network using a computer remote control protocol called VNC and control the entire imaging session from wherever I can connect to wireless. If there is not a wireless network, the Pi can create one.
This new setup has had a number of advantages over my old one. All of the cables between the devices and the computer controlling them (the Pi) can be very short, meaning that there is less degradation of the signal and more rapid response to commands. Due to wireless control, there are no longer any cables required between my laptop and the telescope, which means a reduced tripping hazard at star parties. Also, since I am no longer tethered to the telescope, I can set up my laptop to control it anywhere I want to that is in range, including across the observing field, in an observatory, or even on a couch in front of a TV. Another great benefit is that the Pi is really doing all the work, so once I configure my imaging session and it is automatically executing, I can turn off my power hungry laptop and go do something else. The software (which is free!) is also a lot more capable than my previous software and the developer, Jasem Mutlaq, is extremely receptive to suggestions. He has already incorporated several things that I have recommended and helped me out with issues I was having.
Since I wrote the original article in June I have made great strides of progress. A great deal of that was due to the fact that it was summertime and I had time to work on a big project, but also a lot of credit goes to Jasem Mutlaq, who helped me solve some big issues that I couldn’t figure out. Since my article in June, I got plate solving working extremely well. So well in fact, that I really don’t need that Telrad that I went out and bought in June to do the alignment (duh!). I just tell it to slew to several stars, take short images, the software determines where the scope is pointing each time, and it uses that for the alignment. No more do I need to kneel down on the ground to try to line up a star in the crosshairs and/or press buttons until it is in the center of the CCD. Just click and wait a few seconds. Jasem also solved the memory issue I was having with running KStars/Ekos on a Raspberry Pi. It now has no problems running all of my equipment. I haven’t tested every camera or system, so I don’t know if they would need a more powerful computer, but the Pi seems to work very well for my equipment. I also purchased a 12V USB hub, bought much shorter cables, bought a smaller guide scope, and spent some time cleaning up the equipment on my telescope because the new setup can be much cleaner than the old one.
I have had my telescope out a number of times since I got things working and have taken some really fun images. I have mostly had the scope out in my driveway at home and I have been watching Netflix TV shows while my scope and the Pi are doing all the work. I also set up my scope at Mount Cuba on a couple of occasions and once at the AP Sig meeting at Rick Spencer’s house to test it out in different locations with less light pollution. I have mostly been taking just narrowband Ha and OIII images because they produce good results in a light polluted environment. The system is not perfect yet; some work is still needed. Jasem is currently working on a new autofocus routine and hopes to have that complete in the next couple of weeks. It should make the autofocusing more accurate with faint or misshapen stars. I also have some work to do on my mount because my guiding has not been perfect. I plan to do some maintenance this month.
I also tried out the Raspberry Pi and the new club telescope with my CCD camera in July before I went out west on vacation to see how well that would work. I had some initial issues with my configuration, but after I sorted that out, it worked well with the INDI-Synscan driver. I have taken a few pictures in this manner both then and after I got back in August and September from the comfort of the Mount Cuba Library with the company of Jeff and Jack. The results were promising, but it still needs work. There are actually two drivers that INDI can use to control our club mount and the one I got working is the inferior one that interfaces with the hand controller. Based on some experimentation I did in June, I believe the better driver would work with a direct connection cable rather than what I tried which is called “PC-direct mode.” If we get the cable it should allow us to control the mount using Eqmod/ASCOM on PC and the INDI-Eqmod driver on Mac/Linux. I am also currently working on testing the use of my miniguide scope to guide the club telescope as an experiment and we will see how that works out.
For more information about INDI see: http://www.indilib.org
For more information about KStars see: https://edu.kde.org/kstars/
For more information about Ekos see: http://www.indilib.org/about/ekos.html
For more information about Raspberry Pi see: https://www.raspberrypi.org
Results are shown on the following pages. All of the photos were taken this summer with my SBIG 8300M camera and Paracorr 2 in my new 6-inch f/4 telescope on my Losmandy G11 mount using the software KStars and Ekos running on a Raspberry Pi. All photos were processed in PixInsight and Aperture.
Taken 9/1/2016 in my driveway. Comprised of 10 Ha images with all exposures 5 minutes. Artificially colored red due to monochrome images
North American Nebula
Taken 9/1/2016 in my driveway. Comprised of 9 Ha images and 9 OIII images with all exposures 5 minutes.
Taken 8/27/2016 at Rick Spencer’s house in Elkton Md. Comprised of 10 Ha images and 7 OIII images with all exposures 5 minutes.
Sharpness 184--Pac Man
Taken 8/26/2016 in my driveway. Comprised of 9 Ha images and 9 OIII images with all exposures 5 minutes.
Taken 7/10/2016 in my driveway. Comprised of 15 Ha images and 8 OIII images with all exposures 5 minutes.
Taken 6/8/2016 at the Cheslen Nature Preserve. Comprised of 4 Red, 4 Green, and 4 Blue images with all exposures 5 minutes.
Taken 6/8/2016 at the Cheslen Nature Preserve. Comprised of 4 Red, 4 Green, and 4 Blue Images with all exposures 5 minutes.
Taken 6/10/2016 and 6/29/2016 in my driveway. Comprised of 7 Ha images and 9 OIII images with all exposures 5 minutes. Note: the Ha data in this image was featured in the June Focus. I used the KStars “Load and Slew” feature to load the old image and slew the telescope to the exact same field used for the Ha data so that I could take the OIII data.