Maand: april 2013

Remote control your GoTo telescope mount using a Raspberry Pi and SkySafari

SkySafari is a great astronomy app for smart devices like the iPhone, iPad and Android.
The SkySafari Plus and Pro versions add the possibility to remote control your GoTo telescope mount using the special SkyFi adapter.
This adapter sends serial (RS-232) commands, received with a wireless connection, to the handset of the GoTo mount.
Using SkySafari in combination with SkyFi increases the number of objects you can observe and current events in the sky (like comet PANSTARRS at the moment) are found easily this way.

I was wondering if it would be possible to create something like SkyFi using the Raspberry Pi.
And yes, it is possible. Quite easy actually!

What do you need?

  • Raspberry Pi configured with a working network connection (wifi preferred, of course).
  • USB to Serial cable.
  • GoTo telescope mount
  • PC Serial to GoTo handset cable. Shipped with your GoTo mount.
  • SkySafari Plus or Pro
  • Basic Linux knowledge

Now how are we to receive the commands from SkySafari?
This is done by the Serial To Network Proxy (ser2net).

Install ser2net:

sudo apt-get install ser2net

Add the following line, using your favorite text editor, at the end of the ser2net configuration file (/etc/ser2net.conf) which contains the port where ser2net is listening on:

4000:raw:0:/dev/ttyUSB0:9600 NONE 1STOPBIT 8DATABITS

In this case, I chose port 4000. You may choose another port but be sure it is between 1024 and 65535 and does not conflict with any other daemons listening on the same port.

Restart the ser2net service with the new configuration:

sudo /etc/init.d/ser2net restart

Next, configure your telescope in SkySafari.
My setup has a SkyWatcher SynScan GoTo on a EQ3-2 equatorial mount.
Be sure to enter your setup and don’t copy my settings bluntly 😉

skyfi_settings

The IP address in the picture above corresponds with my Raspberry Pi. Of course, you should enter the IP address of your Raspberry Pi.
Same goes for the listening port. I’m using port 4000.
If you configured a different one for ser2net, enter that one.

After that is done, you should try to connect SkySafari with your mount in the Scope menu and you’re off to go!

Light pollution Cinema

I admit, looking at images made by the ISS crew or time lapse movies made by orbiting satellites of our planet at night can be quite beautiful and stunning.
Back on Earth, that beauty is nothing more than pollution. Light pollution.

Light pollution is becoming a real issue. Astronomers are not the only ones trying to alarm the government because of the disappearing dark skies (when was the last time you saw the Milky Way when you looked up?) but also biologists and people involved with health care blowing the whistle for people to get aware.

A great documentary about light pollution and the search for darkness is The City Dark.
After watching this documentary, I was quite shocked about the impact light pollution has on human health and the habitat of wild animals.

Not a documentary but, as they call it, a public service announcement about the problems and solutions of Light Pollution is Losing the Dark.

Made by the International Dark-Sky Association and Loch Ness Productions, which can watched and downloaded for free on the internet.
Special dome versions (for displaying in a planetarium or observatory) are available too.