Bizarre artifact

Not in DECaPS1, but appears in DECaPS2. Very odd shape/colour for an artifact. Unfortunately DECaPS single exposures are broken, so I can’t see if its a strangely masked solar system object.

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Agree, never seen this object before. I’ll forward to @Andrew_Saydjari - who is a member of the DECaPS2 team. It has a planetary-nebula look to it in the g and r bands, this is not the case as it is only visible in DECaPS 2 and nothing else.


@Andrew_Saydjari I can’t find a way to see the single exposures. Do you have access to them? (and do they show anything?)

@dstn Can I use this as reason to ping you on getting the single exposures link working (e.g. Legacy Survey Sky Browser, linking to the faun links the data page does)?

Currently, through the legacysurveyviewer, you can get the single exposures through the data link option (e.g. decaps2 data for RA,Dec (132.1547, -50.8275)). There you get CCDs overlapping the brick. For each exposure, the image link provides a link to our front facing server. I find that to get this link to work I have to go into incognito mode AND refresh the page (@dstn any idea why?) and then the single exposures download. I can also check some of those myself in a few days when I have some more time, but feel free to poke around there (mostly to let me know if that somewhat complicated method for getting the single exposures works).

Very very odd shape/color for an artifact. Solar system object or transient reflection seems most likely… but certainly something fun to run down. Looking at the models… we totally biffed it and deblended it into a bunch of sources :frowning:


Yeah, from the shape I’m guessing this is some kind of glint from a bright source nearby, but since there’s nothing obvious in the static sky nearby, that suggests a transient.

As for the single exposures… for the LS layers, we have all the OOI files on disk, so producing cutouts from them is quick. If you have some way of fetching cutouts directly from faun, that would be great, but short of that… do you really want NERSC copying 700 MB images from faun for each cutout? I don’t :slight_smile: And we’re already short on disk allocation down at DESI HQ, so pulling all the ooi exposures over for DECaPS is going to be a tough sell.


I think I am just advocating having the links point to faun, not the cutouts, which I am happy to have remain broken.

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oh, I see, yes that is doable :slight_smile: