Lauren Schatz, XWCL alum here! I flew in from Albuquerque, New Mexico to observe GEO satellites with MagAO-X to see if coronagraphy is possible with an extended source. It sounds simple enough right? “Put dot on top of satellite, done”, but turns out it is more complicated than that.
The first thing you have to do is to actually find the satellite, and we spent some time trying out different methods of determining AZ/EL coordinates. Some were more accurate than others, but all required some noodling around to find the satellite. One thing we tested out was Tiffany’s spiral search code, which worked great!
We had some head scratchers though. Some satellites that should have been visible weren’t! And then we had a real shock, we were trying to see one satellite, but accidentally found a second! (see pic below). Predicting satellite conjunctions is really hard so to stumble upon one accidentally was pretty crazy. The satellites are separated by about 45 arcseconds. Assuming they are at about the same range from Earth, this would be a distance of ~7.8 km. This is a good reminder that space is getting more and more crowded which is why we need the Space Force 🫡 haha. So who is this mysterious second satellite? Aliens? Spies? Direct-TV??? We might never find out. Well I might. Maybe I will tell. Maybe…
Step two of doing coronagraphy on a GEO is to close the AO loop. The sky had other plans however, as the seeing bounced around from 1 arcsec to 2 arcsec and worse. There was a lot of griping about this in the control room, but to me this was excellent seeing compared to Starfire! It was really interesting to see how different AO systems can be and how highly optimized they are for a given site. Average seeing at Starfire is 6 cm r_0 which is about 2.6 arcsec in I-band. The personal best I have ever seen was 11 cm r_0 which is about 1.6 arcsec in I-band. And yet we are able to get meaningful AO correction while tracking LEO satellites screaming across the sky. My personal philosophy is that all problems can be solved with more laser beacons and more AO… so maybe think about LGS-MagAO-X someday…
So I wasn’t able to get the data I needed so this trip ended up being an excuse to binge all my favorite food and shopping I have been missing. It has been really wild to realize I graduated and moved out of Tucson 5 years ago, which is almost as long as I spent living here working on my PhD. Having that context gave me a little bit of an extistential crisis. What have I accomplished in 5 years of my professional career compared to what I did in grad school? Not as much as I would have liked… It is hard to get support when you are a small fish in a big organization so you end up stumbling around trying to get things done by yourself. I have a new appreciation how fast MagAO-X is able to implement new ideas because of the close knit team. Keep on keeping on~
The song of the day is Möbius Chicken Strip by Origami Angel