A Guide to Classifying on Backyard Worlds: Planet 9 from the Point of View of a Citizen Scientist


Enjoy this guest post by one of our moderators, Michaela Allen, featuring a video by Guillaume Colin!

Hello newcomers to Backyard Worlds: Planet 9! Or maybe you are a returning citizen scientist to this project… whatever the case, welcome! My goal for this post is to give you a basic beginner’s guide to classifying objects on BW (Backyard Worlds: Planet 9). I am in NO way an expert, but I’d like to share what I have learned so far so that maybe you can learn something too!

A little about me first… My name is Michaela Allen, (@mallen33 on Zooniverse) and I am a current college undergrad student studying physics and astronomy. I’ve been helping classify objects on BW since the project launched, and I’ve learned so much since then! Going into this project I had no idea what it entailed—I was just excited at the prospect of potentially finding something that hadn’t been discovered before!

The first thing I want to share with everyone is a YouTube video made by fellow citizen scientist Guillaume Colin (@karmeliet on Zooniverse) all about his method of analyzing flipbooks on BW. This is a great video where he talks about the basics of BW, SIMBAD, and IRSA. He also goes through the steps of filling out the Think-You’ve-Got-One Form, which can be tricky to find all of the information needed for the form. Seriously, go check it out, and thanks to Guillaume for making this video!

Now, for the rest of this post, we going to look at some of my favorite subjects on BW. So let’s get started!

When you first go on BW, you get to go through a tutorial that shows you all kinds of examples of dipoles, movers, artifacts, etc. You also have a handy field guide on the right of the screen that shows examples of these as well. The tutorial and the field guide are great references to go back and look at– do not forget to use them! I still reference back to them all the time. While those are great examples to get started with, classifying your first subject can still be kind of overwhelming! I’d like to give y’all a few more examples of types of objects and subjects you may encounter while classifying.

In terms of fast movers, I haven’t come across any (yet!). The example in the field guide of Y Dwarf WISE 0855-0714 is what I still go off of. And remember, a true fast mover will appear in all four frames of a subject.

This subject contains a type of artifact called a ghost—it only appears in two frames. These ghosts are not movers and do not need to be submitted to the Think-You’ve-Got-One form.

Other mover “imposters” to look out for is extra noise surrounding the area of declination of the South Atlantic Anomaly. This is in the -25 degrees region of declination, give or take a few arcminutes. This anomaly, which Marc talks more about in his Fast Movers post, tends to cause more noise in the subjects—and the noise can often look a lot like fast movers. For example, take a look at this subject.

There are a few orange dots visible throughout the frames that do look deceivingly like fast movers, but they are just noise. The area of declination and the often sporadic movement of these dots give away that these are not movers.

In terms of dipoles or slow movers, I have seen many! Some are definitely easier to spot than others. A dipole is an object that is moving but in a different way to all of the other objects in the subject. This subject is one of the first subjects I classified on BW, and it has a dipole! See if you can find it.

There it is at RA 151.99, dec 25.51 . I think this one is a great example of a lot of the dipoles I have seen. It isn’t super bright, but it’s not too faint either. It immediately stuck out to me, so I commented on the TALK page and asked for other opinions– don’t forget to comment on the talk pages too! If you’re ever unsure about anything, TALK about it (pun intended)! Sure enough, some people commented back, and I had found my first dipole!

Now, they aren’t all as easy to spot as this one. Faint dipoles take a little more effort. And remember, the fainter a dipole, the better of a chance it has of not being discovered! See if you can find the faint dipole in this subject.

This one is at RA 161.21, dec 13.79— to the right of that artifact. In terms of bigger and brighter dipoles, most of them I have seen have been in SIMBAD and are high proper motion stars. But just because it is bigger and brighter doesn’t mean it is going to be in SIMBAD! Always check to make sure!

Now sometimes you may find multiple objects of interest in a subject, which is great! You have to be careful of misalignment errors sometimes, though. These errors, caused by slight movements of the telescope, make the subjects seem like there are multiple dipoles. We talked about this subject, mentioned by another citizen scientist, @Chrismkemp, in one of the BW hangouts. She had seen seven or eight dipoles in this one subject and was wondering if that was even possible. I’ve come across subjects like these a few times, and they can be pretty tricky to classify. Do you see how the “dipoles” seem to kind of elongate? Marc calls them petals. Unfortunately, they can’t actually be classified as dipoles. If you ever have a subject that seems as if it has multiple dipoles, look for this “petal effect”. There was one real dipole in this subject, though. See if you can spot it!

That real dipole is at RA 349.77 dec -53.63 . This object one doesn’t seem to grow petals like all of the other imposter “dipoles” do in this subject.

The last thing I have to share with y’all is bad frames in some of the subjects. These can range anywhere from stripes across the frame, completely black frames, to half of the frame being cut off like in frame 3 of this subject. While these frames may sometimes look interesting, they do not need to be reported. If you ever come across them, you can always add the #badimage hashtag on the talk page.

Well, I hope that my limited experience has helped some of y’all on classifying objects at Backyard Worlds: Planet 9. Thanks to Marc for letting me share with everyone here! I’ve loved getting to participate in this project, and I’m excited to continue working on it!

See you on TALK, and happy hunting!

-Michaela Allen


1 thought on “A Guide to Classifying on Backyard Worlds: Planet 9 from the Point of View of a Citizen Scientist”

  1. Congrats, Michaela on the guest post and Guillaume on the video! An interesting blog and tutorial in which I picked up a few points and consolidated the way I approached things.

    I’ve been with Backyard Worlds since the very beginning and gradually have evolved towards the procedures demonstrated in this tutorial. Like anyone, there are still a few weaknesses for me to address, which will come with time 🙂


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