Milky Way position on the sky

  • I'm looking for some sort of boundary data to be able to render the milky way on a star map, as visible from Earth. Something that looks like this:

    star map

    For that, I need something like a collection of RA hours and DEC degrees of the "boundary points" of what's visible from Earth (technically the Galactic Center), possibly with proper motion too. I'm not looking for precise luminosity data or anything like that, just the points of the blob on the sky that most resembles the Milky Way's shape and position from the Earth. It's important that I want to render the sky map for any given surface point on Earth, for any given time (within the last 100 years at least).

    Do you know of a database like that? I've been looking on VizieR but I couldn't find what I was looking for.

    There are a lot of panoramic photographs of the milky way view out there - I wonder if it's worth hand-tracing a few outlines from these and storing RA-Dec for the line segments...

    I guess as long as I know the exact time and place the photograph was taken it's not a bad idea. I'd need to cover the whole surface the the Earth though (at least so that I can calculate the look of the Milky way from anywhere)

    I was thinking these (probably public domain) photos show plenty of stars too, so once you identify the stars it might be possible to use their positions on the photo to identify RA/Dec for the milky way clouds, etc too. (One problem is I don't know if such pics have any distortions caused by the projection method chosen. That would have to be accounted for.)

    By the way here is an interesting method (collecting lots of stars from an Infra Red survey) though it doesn't present the usual cloudy appearance.

    Have you already tried `Sky` within `Google Earth` or some `Sky map` app on the smartphone or tablet to locate the current position of the Milky Way?

  • mtewes

    mtewes Correct answer

    6 years ago

    There is a very nice project called d3-celestial by Olaf Frohn on github. In contains a data file describing the Milky Way as polygons, see here. A demo showing this Milky Way can be found here. And even better, the source for this data is cited, pointing to the Milky Way Outline Catalog by Jose R. Vieira.

    Depending on your project, the json format from d3-celestial might be easier to read than the one from Jose R. Vieira.
    Note that you don't have to worry about these "contours" moving on a time scale of hundred years, but this is another question.

    Cartes du Ciel also appears to use the Vieira outline data.

    The link for Vieira seems to be showing a blank page.

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Content dated before 7/24/2021 11:53 AM