I've added some code to the graphing function of the radio telescope that puts a green R and S at the approximate time of the start(R) and end (S) of astronomical twilight. On the dates where no R or S are visible (during part of the summer) the sun is not more than 18 degrees below the horizon here in Calgary. On the dates where only one letter is visible, the times are virtually identical. In other news, I'm trying to figure out why the software that runs the 'scope keeps quiting seemingly at random. I may just use a cron job to restart the program if it's not running. Kludgy but it works...
