Moving thing


http://legacysurvey.org//viewer/?ra=187.4273&dec=11.4104&layer=sdss2&zoom=15
Could this be a comet? I have no idea where and how to find known comet trajectories for a given timescale and position.
Here’s an animation of the object for all the different bands it was visible (r, i, z, g, respectively):

In 4m12s it moved 2.97 arc seconds.

Edit: Maybe I have some parameters wrong here, but I think I have checked all the variables… It’s either 63000 hits with a gigantic deviation in ra/dec (single pass with no mag limit) or 0 hits (two-pass with mag limit).

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“Beach-balls” in SDSS are very likely to be asteroids.

Maybe broaden the RA search box size (or use center/radius search)?

And make sure your time zone etc conversion is correct? I presume you did something like use the “Data” link in the viewer to find out which exposure it is in (looks like 3063/1/50), and then looked up the date (somehow) and converted (somehow) it to whatever timezone – are you sure you got that right?

For the viewer’s JPL Horizons query, we use a center + size search, with query “w0 0 45” (45 arcsec, I guess), no mag limit, mag_required = yes, two_pass = yes.

I guess I could try adding a JPL link for the SDSS layer…

cheers,
–dustin

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Thanks for the reply! Yes, I checked the exposure date from the original FITS files and converted the timezone in the search to match it.

I tried center+size searches too but only up to “w0 0 30”. But with that big search radius the server timeouts with two-pass enabled. (Error 504)

It would be great if you could do that, because those “beach-balls” are much easier to spot in SDSS than other surveys. Thank you! :slight_smile:

Oooh, a JPL link for SDSS would be great!!!