Praxidike, or Jupiter XXVII


Praxidike is a small outer satellite of Jupiter which was not discovered until November 2000, when it was given the temporary designation S/2000 J 7. It was named in August 2003 after Praxidike, the Greek goddess of punishment. The satellite is rather small, only about 7km across, and was magnitude 21.7 when observed. The limiting magnitude of the equipment at Tacande is not much fainter than this! Making the situation worse, the cooler on the camera failed after only 41 minutes into an intended two hour session so the detection is not as emphatic as hoped.

This image was the result of stacking 41 sub-images on the calculated movement of Praxidike, which is why the barely detectable satellite appears circular whereas the background stars are trailed. The artifacts in the background are due to contrast-stretched scattered light from Jupiter.

Image information
Date and times of observation  2021-09-06 22:30 UT
Telescope 0.4m f/6.5 Dilworth-Relay
Camera Starlight Xpress Trius-PRO SX814 CCD
Filter None
Exposure 2460s in 41 subs of 60s each, median-stacked
Centre of image RA 21h53m45.5s  Dec -14°45'14"
Image dimensions 3.8 arcmin × 3.6 arcmin