Newest observations
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Helsinki, A fireball at night, as bright as a crescent moon
III
28.3.2023 at 22.54 -
Hyvinkää, A fireball at night, brighter than the venus
III
28.3.2023 at 22.54 -
Inari, A fireball in a twilight sky
III
28.3.2023 at 20.15 -
Inari, A fireball in a twilight sky
III
28.3.2023 at 20.15 -
Inari, A fireball in a twilight sky
III
28.3.2023 at 20.15 -
Helsinki, Jollas, Moon
IV
28.3.2023 at 20.03 -
Oulu, One halo form
I
28.3.2023 at 10.30 -
Fregenal de la Sierra, Espanja, Telescopic comet PANSTARRS
II
28.3.2023 at 05.32 -
Kuusamo, Käylä, Moon
III
28.3.2023 at 00.05 -
Kuusamo, Markarian's Chain
27.3.2023 at 23.10 -
Kuusamo, One halo form
I
27.3.2023 at 18.50 -
Vaasa, One halo form
I
27.3.2023 at 16.10
Contact information
Visibility I / V
Jorma Ryske, Etelä-Suomen kosmol. seura
Comet 17P/Holmes had the most massive known comet outburst in 2007 October and its particle remnants are now orbiting the Sun. Different size ejected particles have formulated an hourglass pattern orbits, and the dust trail is brightest at the center of the pattern.
Orekit "Dust Trail Kit -model" was created to model and calculate positions of the dust trail particles, which is described in this scientific publication Evolution of the dust trail of comet 17P/Holmes .
Here is observation of this extremely dim dust trail taken 30/31.10.2022. Two separate three hour exposures were taken during the night having a 4 hour difference in mid-exposures. This allows to use the so-called image subtraction method, which makes this dim dust trail visible in the processed image.
Measured dust trails positions are practically exactly in the positions calculated by the "Dust Trail Kit-model" by Markku Nissinen.
Figure 1: Subtracted image with dust trail movement compensated stacking. Dust trail moved 16"/8px at trails right angle direction during each 3 hour exposure period which was compensated. Extremely dim dark trail is from mid-exposure at 2022-10-30 21:33UT, and light trail is from mid-exposure at 2022-10-31 0136UT
Figure 2: Subtracted image with star registered stacking. Dust trail is spread during the 3h exposures due to trail movement.
Figure 3: Normally star stacked image with 3h30 minute exposure. No sign of dust trail visible. Near the image center is Galaxy PGC 12881 mag15.9. Just outside the image right/west edge is a bright star Mirfak generating some Spider vane diffraction spikes etc.
Figure 4: Observed (round circles around triangles) and Dust Trail Kit model calculated positions (small round markers). Calculation by Markku Nissinen.
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