C/2020 F3 Neowise

On 27 March 2020 the NEOWISE space-telescope detected a new comet, which would become known as C/2020 F3 Neowise. Initially the comet could only be seen in the early morning, but from 10 July onwards it could be seen in the evening as well.

Its closest approach to the sun was on 3 July 2020, its closest approach to Earth on 23 July at a distance of 0.69AU.

figure 1 is the result of 12 x 1 second subs in LRGB using the SkyWatcher Esprit 150ED and ZWO ASI1600MM Pro Cool, so a total of 48 seconds of data. Processing was done in Deep Sky Stacker (DSS), RGB-combine and luminance was done in PSP.

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On 17 July the sky cleared again, so another attempt was made on C/2020 F3 Neowise. This time the 10Micron GM3000HPS mount was programmed with the orbital parameters of Neowise, so that it could follow the comet unguided. In total 66 subs were taken:

Stacked in DSS, stretched in APP, combined and post-processing in PSP.

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That same night I mounted the ZWO ASI290MC piggy-back on the Esprit and took several series of which this one gave the best result. As imaging lens I used the standard ZWO zoom-lens. It has quite bit of coma at the edges, but through the centre it is not too bad. Exposure time was 3 seconds per frame, while 43 frames were captured, 21 of which made it to the stack. Stacking was done in AutoStakkert with an anchor on the comet. Post-processing in PSP. The image shown here is a crop of the original image.

During the night of 18 to 19 July 2020 the comet C/2020 F3 Neowise had a not so secret meeting with Talitha (iota Ursa Major).

Imaging done with SkyWatcher Esprit 150ED and ZWO ASI1600MM Pro Cool. Lum: 29x 1s (number 30 had a plane in it), 12x 5s R, G and B, so 239 seconds total exposure. Unguided imaging with tracking on the comet using 10Micron GM3000HPS. Stacked in DSS, stretched in APP, RGB combine and post-processing in PSP.

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That same night I imaged the couple afocal with the GTT60 in combination with a ZWO ASI290MC. The view shown here is what a seventeenth century astronomer would have seen. The GTT60 was used with its full aperture (so not stopped down) in combination with a -200mm plano-concave eyepiece. In total 61 frames were captured at 2s exposure time, 30% of which were stacked in AutoStakkert. Post-processing in PSP.

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I then removed the eyepiece and mounted the ZWO ASI290MC colour camera directly focal in the GTT60. Using FireCapture I recorded some data with adjacent image as result. In this way the tail is barely visible, so not representative of what can be seen through the telescope.

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On the night of 20 to 21 July 2020 it was quite heavily clouded, but two gaps were just large enough to focus and image. The imaging session was like before, starting with 30 sub of 2 seconds luminance and followed by 12 x 5 seconds red, green, and blue. However, during the luminance session the sky was not completely clear, so I had to discard those frames. The others were just fine and resulted in this image.

At the time of this image (around 21:50 UTC) Neowise was about halfway in between the feet of Ursa Major.

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On the night of 21 to 22 July 2020 it was again quite heavily clouded, but gaps were large enough to focus and image. The imaging session was like before, starting with 30 sub of 2 seconds luminance and followed by 12 x 5 seconds red, green, and blue.

The subs were captured around 22:25 UTC. The tail now starts to show more detail.

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The night of 29 to 30 July 2020 was reasonable clear with just the odd cloud and some veil cloud cover. Luckily the veil dissolved after midnight, so imaging could commence. As the comet was significantly less bright the imaging session was using 12 x 20 seconds for luminance, red, green, and blue, so 16 minutes of data.

The subs for the image shown here were captured around 22:52 UTC (so just before 1am local time). Due to the longer exposure the star trails are longer than before. Altogether the whole sequence took 18 minutes, which gives a good idea of the speed at which Neowise travels through the sky. The brightest star is HP59558.

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The night of 30 to 31 July 2020 was even better. Nice clear skies, so imaging was no problem. Again C/2020 F3 Neowise was less bright, but for the imaging session again 12 x 20 seconds for luminance, red, green, and blue, was used, so 16 minutes of data.

The subs for the image shown here were captured around 23:10 UTC (so just after 1am local time). This time processing was done in the latest beta version of APP, that now allows comet stacking. The fuzzy object above the core is NGC4314.

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The first August night (1st to the 2nd) there was a very thin cloud cover coming in. Just before it became too thick I managed to run another series. Again the comet was less bright, and again 12 x 20 seconds subs for luminance, red, green, and blue, were taken, so 16 minutes of data.

The subs were captured around 21:27 UTC (so half an hour before midnight local time). Processing was again done using the latest beta version of APP (1.083).

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Still behind a very thin cloud cover C/2020 F3 Neowise was captured for the last time from InFINNity Deck on the night of 2-3 August 2020. Still loosing brightness as expected, a series of 12 x 20 seconds subs for luminance, red, green, and blue, was taken (16 minutes of data).

The subs were captured around 22:10 UTC (so just after midnight local time). Processing was again done using the latest beta version of APP (1.083).

The bright star below C/2020 F3 Neowise is HIP62456.

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