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Dark energy spectroscopic instrument creates largest 3D map of the cosmos (lbl.gov)
49 points by layer8 14 days ago | hide | past | favorite | 5 comments

What causes the dark radial stripes? Blocked by something in the sky? Downtime?

I know Elite Dangerous has similar artifacts showing small radial areas of the galaxy that our telescopes have surveyed (but it's lines of stars rather than lines of darkness)

My best guess is that those are near very bright foreground stars, which cause artifacts in the corresponding imaging survey. DESI Legacy Imaging Surveys is used to pre-select targets for spectroscopic observations. If you go to legacysurvey.org/viewer you can see some of the bright stars and the kinds of issues they can cause.

Things in the way. I'd guess it's opaque dust clouds in our galaxy. Could also be bright stars (as jwuphysics suggested).

For deep background, Michael S. Turner just published a nice review of the past 50 years of cosmology, from when the "errors were in the exponents" ;)

The Road to Precision Cosmology


DESI is just one of the super-mapping scopes to come online in late 2010s-early 2020s. There GAIA about 3/4 through its program to map the positions and movement of 2 billion stars (2%) in the Milky Way. And the Roman telescope will rephotograph much of sky at least once a week, looking objects that change brightness or position- about 10,000,000 expected a night. These could be new asteroids, Planet X, super novea, etc.

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