Comets
Comet C/2020 F3 (NEOWISE)
13 minutes
Taken on July 13, 2020 between 3:13 a.m. and 3:28 a.m. with Canon 2000Da and Maksutov-Newton. A total of 26 frames with 30 seconds exposure each has been stacked.
Left: Image of Comet
C/2020 F3 (Neowise), taken on July 22/23 around midnight at Hoher
List Observatory with Canon EOS 1100Da and Sigma Telezoom (f = 135 mm); 45 exposures with 14 seconds each. Stacking was done on the comet's head such as to yield a sharp image of the comet. Its motion during the 10.5 minutes is recognized by the short star trails. The comet has moved slightly towards the upper left during the exposure. The surroundings (trees etc.) are blurred, owing to the erath's rotation. One can clearly see the plasma tail with its bluish gleam and its straight extension towards an 11 o'clock direction. Extending this tail in its backward direction points exactly to the location of the sun. The plasma tail originates from the sun light, with its photons removing material from the comet's coma by exerting photon pressure, thereby ionizing this material at the same time (so the plasma tail gleams by itself). The dust tail, however, takes a slightly bent direction and just reflects the sunlight. The bending is caused by the comet's motion (to the upper left).
Below: Time-lapse video of 8 minutes exposure. The rotation of the earth is readily seen. The Comet declines and has disappeared behind the trees soon after. Some satellites flit through the field-of-view.