C/2017 K2 (PanSTARRS) is an Oort cloud comet with an inbound hyperbolic orbit, discovered in May 2017 at a distance beyond the orbit of Saturn when it was 16 AU (2.4 billion km) from the Sun.
Astronomers first spotted the comet in 2017 using the
Pan-STARRS survey instrument in Hawaii. At the time, they said it was the
farthest active inbound comet they’d yet seen. It was located between the orbits of Saturn and Uranus when they first saw it.
It had been in the constellation of Draco from July 2007 until August 2020. The comet is record breaking because it is already becoming active at such a distance. Only Comet Hale–Bopp produced such a show from that distance with a similar nucleus.
However, this comet will not be as visible as Hale–Bopp was in 1997 in part because it does not come nearly as close to the Sun.
As it was approaching the Sun at a distance of 16 AU at discovery, a mix of ancient ices on the surface containing oxygen, nitrogen, carbon dioxide and carbon monoxide began to sublimate and shed the dust frozen into it. This material expands into a vast 130,000 km (81,000 mi) wide halo of dust, called a coma, enveloping the solid nucleus.
Research with the Hubble Space Telescope (HST) estimates the nucleus to have a circular equivalent diameter of less than 18 km.
The comet was within 5 AU (750 million km) of Earth by 11 January 2022. Around 6 July 2022, the comet crossed the celestial equator, and then on 14 July 2022, made its closest approach to Earth, it passed 1.8 AU (270 million km) when it was in northern skies and shine around 9.0 magnitude making it a decent binoculars object.
The comet has dropped south out of Scorpius, headed into Lupus and constellations that are accessible to Southern Hemisphere observers. It will reach perihelion on 19 December 2022, close to the orbit of Mars.
JPL Horizons models that C/2017 K2 took millions of years to come from the Oort cloud at a distance of roughly 50,000 AU (0.8 ly).
The heliocentric orbital eccentricity drops below 1 in December 2023.
The outbound orbital period will be around 18000 years.
https://earthsky.org/astronomy-essentials/large-comet-c-2017-k2-panstarrs-summer-2022https://en.wikipedia.org/wiki/C/2017_K2_(PanSTARRS)------------------------------------------------------------------------------
I thought I only had the Neowise folder pending, but I found a folder with this comet and I decided to do it, at least it's from this year.
Maurizio managed to do a small session on Bortle 4 on July 8th, 2022 of this peculiar comet.
Since the frames were so few, I decided to do it differently, reminding myself of the type of work that
Kathy Walker did.
First in DSS a bilinear stack was made to achieve the star base.
At the same time that the stack was made, it was obtained the 24 separate calibrated frames.
Each calibrated frame was then applied 2 arcsinh curve 10 and level and proceeded to obtain the starless version of each frame.
Each frame had a bit of cleaning done on the two stars around the area and a slight noise exterminator/detail applied.
Once all the frames were cleaned, in order to make a starless stack of the comet in that area, a strip of stars corresponding to each frame was applied to the extreme edges of each frame with a mask. This allowed DSS to register the frames and proceed to stack the comet once the position of the first and last frame of the sequence was noted.
Likewise, the same reference frame was also kept noted throughout all the process.
Once the final stack was obtained with the 24 frames under the 'average' modality, the stack result was very clear but by applying level, it was possible to stabilize to a neutral background. The extreme edges stars stacked (showing as mini trails) was cleaned with a clone starless path of the image.
In Ps CamRaw was apply final touches and another light denoise. The final image was combined with the stars base obtained at the beginning and the final starless comet image.
I think this kind of workflow is only recommended when a few frames are made, as it turns out to be a long work, but the result is quite satisfactory despite the little time integration done.
We appreciate your visit and wish you the best of skies!
Processed November 2022
https://twitter.com/AstroOtus/status/1594346975276814345 
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