GZ32JPL23ring occults 4U 185-75921 on 2017 May 20


Jose L. Ortiz asked the amateurs for an observation of a 800km TNO in the night from Friday to Saturday the 20.May 2017. The star was 13 mag and no problem even for small telescopes. The minor planet has a possible ring similar like Chariklo:

The weather prediction saw a 50% chance for Munich.

The sky became clear after midnight and the conditions were perfect.

It was possible to use 2 telescopes. The 80cm Cassegrain was used with the Watec 120N. The integration was rised to 0,64s to make shure to get a good Signal to Noise Ratio (SNR). Several videos are made.

The biggest video was made between 1:24 and 1:44 UT. The Position im Munich was:
+48:07:18.8 n.B
11:36:25.4 ö.L
at 611m

For the Photometry I used the software Tangra. Inspide of the perfect conditions in Munich there was nothing significant to see.

The additional Meade Schmidt-Cassegrain was used with a Atik 314L. Here was the exposure-time 0,4s. At Bin6 the Atik has a readout-time of 0,25s. So both telescopes have a framerate near 1,6fps. The Photometry of the Atik-pictures was made with the software Miniwin. Also here is nothing to see. The path went some hundret kilometers to the south. Spain an Greece were positive.


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