Interesting object ~again, what am I looking at?

https://www.legacysurvey.org//viewer/?ra=254.8935&dec=41.1044&layer=ls-dr9&zoom=14

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Those are stars in our galaxy. That’s a pretty cool alignment, nice find.

Yeah, neat! If you turn on the Gaia catalog layer (under “Imaging catalogs”), you can see they have similar proper motions (pmRA,Dec) – that’s describing how they’re moving across the sky – and parallax (distance). So they really are nearby each other and moving in the same direction. That applies for both the orange pair and the blue pair (but not the third blue one, it looks like it’s not associated but is very nearly the same brightness!)

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(at first I thought they might be fast-moving stars where we observed them far enough apart in time that they had moved visibly, but nope, actual double stars)

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thank you for explaining the Gaia layer, is it only an archive for stars?

how do you know they are from out galaxy? not challenging what you are saying, I would like to know the steps to know this.

Gaia is a really great European satellite mission that scans the sky and measures the positions and motions of astronomical objects. Anything that it can measure as moving will be inside our galaxy (everything else is just too far away). Gaia measures some galaxies as well as stars, but it will measure the galaxies as stationary :slight_smile:

The resolution of the telescope’s camera isn’t enough to distinguish individual stars in other galaxies. Also, as dstn said, if Gaia can measure its proper motion/parallax, it’s in our galaxy.

thank you, that defines Gaia so much more now

thanks! am I missing something or is this clearly defined somewhere else I should have seen/known?