Tweets to Make You Look Up

David Hainlin — Wed, 16 Sep 2009 21:20:52 +0000

As a space junkie, I frequent nasa.gov and astronomy picture of the day sites to marvel at the universe and our attempts to learn and explore it. One of my favorite sites is the venerable Heavens Above created and run by Chris Peat. If you haven’t checked it out, please do so soon as it gives lots of very useful information for observing satellites such as space shuttles, international space station (which is large enough to be seen in the daylight hours), Hubble space telescope and hundreds of others. If you register with the site or plug in your location, you can get lists of dates/times to see things like the space station fly overhead. My kids think I’m a genius because I’ve been known to look down at my watch during dinner and announce that the ISS is about to fly overhead – we all run outside and I start a countdown and poof – right on cue – a big bright star starts a lazy, 5 minute pass overhead. All thanks to Chris Peat’s great web site. You can even get star maps and ground track paths to help you get oriented.

I sometimes forget to check the site so I setup an automatic twitter feed to send me reminders. Was very easy to do …

The toughest thing about Heavens Above is remembering to check it frequently. This got me thinking – “wouldn’t it be nice if I got a text message about 10 minutes prior to a pass?”. After thinking about it and looking around on the heavens above site, I concluded there wasn’t any api or service I could coax to do this, I decided to write a quick and dirty script. I also found an blog describing some work that Paul Mison had done at Hackday London a few years ago. (I rarely have unique ideas…). The gist is this, periodically, check for ISS passes over a particular location (Richardson, Texas in this case) and within about 15 minutes of the event, send an update to twitter listing time and starting location (sky direction). I then could follow this twitter account (with mobile updates on) and now I can get notifications about when to look up and wave to our brave ISS crew (I even saw the ISS through the glare of lights at a high school football game).

The script is written in ruby and is setup to run as a cron job on one of my servers. It uses specific latitude and longitude and time zone to pull visible passes for the ISS from heavens above. It grinds up the html using Hpricot and looks for any passes with a magnitude greater then -1.0 (our seeing is better than that in Richardson but I wanted to limit the number of tweets. To reduce the number of hits on Heavens Above, the script caches the information in a config file and only returns to heavens above when it has tweeted about an event. The specifics of lat/long and twitter account are stored in a config file so this can be used for other locations as well. I’ve posted the hack on github.

If you live in/around Richardson, you can follow the richardsontxiss twitter account and it will send you tweets when you can see the ISS. It doesn’t take weather into account, but we are more likely to have clear weather than not. The next passes aren’t until the 24th so be patient if you do follow this. They do have gaps in time where there are few passes but then there will be a storm of great opportunities within a few short days.

If you are wondering what your latitude and longitude is, there is a nifty hack you can use to get it from a google map. Center the map on your location and enter the following in the browser url line:

javascript:void(prompt('',gApplication.getMap().getCenter()));

This will prompt you with the coordinates of the currently centered location on the map. Cool.

Self As Team » space

Tweets to Make You Look Up