How to add comets in stellarium

With Comet C/2019 Y4 (Atlas) approaching peak brightness (estimated around magnitude -5) next month, it’s very much on the minds of a lot of astronomers, amateur and professional alike. It’s predicted that C/2019 Y4 will become very much a naked eye comet, and is being hailed as one of THE astronomical events of 2020. And in the current lockdown climate due to the worldwide CV-19 pandemic, it’s a great idea to have something else to focus our energies on right now.

In the meantime though, C/2019 Y4 remains a dim magnitude 8, which makes it difficult to locate. So how do we find it? There are many online resources that can help you get in the right area, including The Sky Live, which plots the position of the comet and gives a whole host of relevant information.

Another method is to use the astronomy software you may already have installed on your computer or laptop, namely Stellarium. As you may know, I’ve become a bit of a fan of Stellarium in recent months, but it does have it’s limitations, one of which is that it doesn’t automatically update newly discovered comets, asteroids etc. So you need to do this manually. But how?

In all reality, although it might sound complicated to update astronomical software, in this case it’s really quite simple.

Open Stellarium and go to the “Configuration” window (or press F2.) From there go to the “Plugins” tab and scroll down to “Solar System Editor.” Click “Configure” and then go to the “Solar System” tab. At the bottom, click “Import orbital elements in MPC format.” On the following “Lists” tab, select the “Comets” radio button. For the source, make sure you have selected “Download a list of objects from the internet” and in the dropdown we select “MPC’s list of observable comets”, and then press “Get orbital elements.” From there I usually select the “Overwrite existing objects” radio button and “Update only the orbital elements.” Tick “Mark All” and then “Add objects.”

Et voila! You can now search for the comet within Stellarium and tell your telescope to go to it if you’re setup for that. If not, and you’d like to know how to set it up, then I’ve covered that in a previous walkthrough. Just please bear in mind that walkthrough only covers getting APT and Stellarium working together.