Taking Data on the Bradford Robotic Scope
Aaron asked me to write up a little something about how I'd gotten the image I did with the Bradford Robotic Telescope in Tenerife. Please feel free to add to, or discuss, this posting. Questions, of course, are always welcome! Especially ones I might be able to answer. :-)
The Bradford Robotic Telescope is an educational robotic scope run by the UK. Its primary missions is to provide telescope time to UK schoolchildren and classrooms for astronomy education. However, wonderfully, the Bradford folks have elected at this point to not restrict the scope's use to just this group.
Obviously, the first thing you need to do is to go to the Bradford scope at http://www.telescope.org (is that just the best URL, or what?) and obtain an account. This will get you credentials to log onto the scope. If I remember correctly, this has to be reviewed so it may take a couple of days.
Once you get an account you can log in. Once logged in you'll find that Bradford has three telescopes for your use. The Galaxy scope, meant for taking images of deep sky objects, takes an image about 24 sq. arc minutes. The Cluster Camera gives you 3 sq. degrees. Finally the constellation camera gives you about 40 sq. degrees. This is the camera we'll be using for our observations of ε Aur.
The Bradford Scope is what I like to call a "batch scope." This means that you submit a job to the scope and then it determines when that job will be done. Beyond putting in the needed parameters, you have no other control of the telescope. This means that Bradford is fine for low time resolution observations. When I say you have no control over when the job will be done, I mean it. I've had jobs that have been completed within 2 hours of submission, and I've had jobs that have taken 2.5 weeks. So, Bradford is fine for our purposes with regard to ε Aur. It would not do for time series observations, or following up on such things as cataclysmic variables, novas, or gamma ray bursts.
Once logged in you'll see a menu on the left side of the screen. The entry of interest will be "Your Menu." This will give you a screen that will have the option to "Submit a Job Request" to the telescope. Select that. You'll be guided through a simple, three step procedure that will have you selecting what you want to image, with what telescope, and then exposure times and filters.
When you select the option to choose what to image you'll find there are several options. You can pick from a menu of IC objects, Messier objects, stars, planets, constellations. I, personally, have never used these, electing the second-to-last option that allows you to input the RA and DEC of the point in the sky you want to image. Going there will allow you, through drop down menues, to input the coordinates of our favorite star. Label what your object is. Save this and then go on to Step 2.
Next you'll be allowed to select the scope you'll want to image from. This is a simple three position radio button. In this case, choose the "Constellation" option. There are some variable stars - most in fact - that would benefit from the "Cluster" camera, but in our case the comparison stars we're using with ε Aur are too far away to get with anything other than the "Constellation" camera. Save this and move on.
The last section will deal with exposure times and filters. Exposure times are done in milliseconds. Remember ε Aur is a bright star (honest!). The image I took had a 2000ms (2 second) exposure time. I have a job in the Bradford queue now that will do a 4 second exposure and I'll report on how that goes. If you do too long of an exposure your stars will overexpose and "bloom." Not only does this make making an estimate difficult, it just looks bad. At this point I recommend an exposure of 2000-3000ms (2-3 seconds).
Filter is next and here you want to choose the 1st option - Clear Filter. I don't think any other filters is really appropriate for our purposes here. The "Constellation" and "Cluster" cameras don't have photometric filters in them (however the Galaxy camera does!), so we'll use the Clear Filter and end up doing our photometric data reduction as "unfiltered with a V zeropoint."
Finally, the site asks you to put in a short comment to remind you of what the image is about. Usually I'll do a quick overview of my options: "EpsAur, Constellation, 2s, Clear" or something like that.
Once the job is submitted you just wait - and by wait I mean log off and get on with your life. Part of your registration process was giving your email address and the Bradford scope uses this to alert you when your job is done. These are amongst the most welcome emails I get.
So, that's how I got the image you saw here last week in this group. I find the Bradford scope to be a valuable adjunct to other methods of data gathering. Its simple, batch system of getting images makes it a valuable educational tool that can also do some good data gathering for science.