Outlier magnitudes in the Solar System First Look MPC Reported Detections

Thanks for the notebooks to parse the First Look Solar System detections reported to the Minor Planet Center (MPC). I’m finally get a chance to poke at the Solar System data products/released data while on the plane to the RCW.

I think this likely a question for @mjuric . I’ve been parsing through the First LOOK MPC data. I’ve found a few very deviant photometric points with huge error bar (4 out of 343760 photometric measurements that jump out because they are well beyond the expected limiting magnitude). I was wondering if it’s known what happened with the observations? Bad observing conditions or something going on with the calibration? The photometric quality of this dataset is fantastic, so I’m really asking more out of curiosity because I would take a look at the images if this was in DP1.

Here’s all the apparent mags report in all filters (roughly characterized by orbit) in the First Look reported observations in a box/whisker.

I looked at which objects those belong to and plotted the light curve - Here’s 3 of the 4:



Thanks!

I should have labeled axes - looks like it didn’t save (bottom is magnitude versus mjd )

Hi Meg, not sure if its related but I had been looking into this for DP1 and also noticed the occasional significantly outlying photometric measurement. Here’s a notebook with some examples.

Looks like most of the outliers had flags for dipoleFitAttempted and/or shape_flag. I also tried looking at the difference in apFlux, psfFlux, trailFlux and found that the aperture measurement had the greatest photometric outliers. I had started looking at a couple of these sources and they did appear to be slightly trailed and/or faint and fuzzy. So I wonder if this means that not all the flux is fully captured for these sources, especially for an aperture measurement?

@jrob93 Thanks for the suggestions. I believe trailed source photometry was submitted to the MPC.

Hi @mschwamb, sorry for the delay. I’m pinging @mjuric about this and we’ll hopefully have an answer for you soon.

Thanks @mschwamb @jrob93 !

I’m not 100% sure what’s up with these, but I’d start by looking at what the cutouts look for these in the RFL data and whether they’re close to artifacts (or instrumentally affected in some other way). That’s be my guess at what’s going on. I think this is not a SolSys-specific problem, but just general “how often will we get photometric outliers” type of thing. I can’t do it myself right now (we don’t have the tooling ready yet to make this easy), but I’ll put it on the TODO list.

Maybe someone on the image processing side of the DM house (or the CST) can take a look earlier?

Cheers, - M.

Thanks, @mjuric. I’m not sure how I can look at these in the RFL data as all we have is the image viewer of the co-added observation and the video of Solar System discoveries. So whatever you can take a look is fine by me. I wanted to raise in case its an edge case that can be addressed for DP2 processing/prompt products processing. I agree it seems those data points are impacted by something and should be flagged in some way.

Oh, sorry for the poor phrasing! – the “I’d start by looking at…” bit was more for our pixel team if they can get to it sooner than I can :slight_smile: .

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