Closest to Sun on 2020 July 3 at 0.29AU

Closest to Earth on 2020 July 22 at 0.69AU

Maximum brightness 1 in early July 2020

Orbital period 6,600+ years


Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE), formerly the WISE earth-orbiting satellite , discovered this comet on 2020 March 27th.

A preliminary orbit showed that this comet was to pass considerably close to the Sun in early July,
then have a favourable pass by Earth a couple of weeks later. This comet had strong potential for naked eye visibility.
It was restricted to northern hemisphere viewers during peak brightness in July before becoming visible to southerners later in July.

I imaged the new comet soon after discovery on 2020 April 2 at 10:10UT, Using a C11 RASA f/2.2 + Canon 60Da.
It displayed a very diffuse but LARGE coma 5’ wide. A rough estimate of magnitude 13.
A follow-up observation on 2020 April 16 gave a magnitude of 12.2.

My observation on 2020 May 29 indicated the comet had brightened rapidly to magnitude 8.1, with a 30' ion tail on a photo.

My final pre-perihelion observation on 2020 June 10 was pushing the limits of comet observing
when the comets solar elongation was 21 degrees and altitude above local horizon was 5 degrees.
approximate visual estimate = 6.8 using 15x70mm binoculars

(see images below of the comets development pre-perihelion)

My forecast for comet C/2020 F3 NEOWISE below was based on my visual observations made between April 25 to June 10.
H0=7.4, n=4.5 graphed using comet for windows, with a peak brightness of magnitude 1.8 on July 3 to magnitude 6.0 on August 1

The comet remained invisible in June until it entered the SOHO C3 CORONAGRAPH
on JUNE 23 at around 10UT, about 5oclock position, then departed the FOV on JUNE 27 at 23UT, about 3oclock position
Download the animation at: https://soho.nascom.nasa.gov/data/Theater/


Comet C/2020 F3 NEOWISE survived its close approach to the Sun, much to everyone’s relief.

It was seen in deep twilight during early July at 1st magnitude and sporting a lovely dust tail 1 degree long.
This had grown to 15 degrees long by mid-July.
It certainly turned into a fine comet (nearly great status) for northerners

Viewing conditions improved during July as the comet moved into the evening sky for northerners.


C/2020 F3 NEOWISE on 2020 July 26 at 04:27UT.
Taken remotely in Sierra Nevada using I-Telescope T24.
This is a stack of 10x60 second images processed with Maxim DL using sharp fft.

Note the corkscrew dust jet emanating from the nucleus and the many fine streamers of ionised gas embedded within a diffuse dust tail

The earliest opportunity for southerners to see the fading comet occurred on the early evening of July 26, very low on the northwestern horizon.
It appeared 4th magnitude and sport a nice dust tail, visible in binoculars and photos.

By August 1, the fading comet had rapidly gained altitude over the north-western evening horizon and from 35S latitude, 15 degrees up at end of astronomical twilight.
The 5th magnitude comet was then situated near the Coma Berenices star cluster Melotte 111, making a terrific photo opportunity for astrophotographers,
especially with NGC4565 and NGC4559 in the vicinity.
On the evening of August 2, it was 1.5 degrees west of magnitude 10 galaxy NGC4725.
On August 4, it was 20’ East of the “Blackeye” galaxy M64.
On August 6, moonlight no longer interfered and the now magnitude 6 comet was 50’ West of globular cluster M53 in Coma Berenices
On August 7, it was 35’ South of magnitude 9 globular cluster NGC5053
On August 11, it was 2.5 degrees west of magnitude 10 comet C/2017 T2 PANSTARRS!
On August 18, the now magnitude 7 comet transited through NGC5363, an 11th magnitude galaxy in Virgo with NGC5317 a little further south!
Moonlight interfered from August 23 and by end of August, the comet has faded to magnitude 8.


View of C/2020 F3 NEOWISE from just outside Swan Hill, Victoria, Australia. Taken on Sunday July 26 at 7pm.
A single 15 second exposure using a Canon 6D and lens at 150mm.
Comet was only 2 degrees above the horizon with some cloud interference. Not naked eye visible due to moonlight interference and low altitude.
Visual estimate of magnitude 4.2 using binoculars


Image below made prior to solar conjunction and was my last pre-perihelion observation of it.


C/2020 F3 (NEOWISE) 2020 June 8th at 08:30UT.
visual estimate = 7.1 through 15x70mm binoculars. Altitude 8 degrees. Solar elongation 23 degrees.
Observation made prior to moonrise. Ion tail >40' in PA147.

Above photo taken on 2020 June 3 at 08:45UT.
Comet was at 12 degrees altitude, with 94% moonlight interference. Coma is 5’ wide and Ion tail is >30’ long in PA140.

C/2020 F3 NEOWISE on 2020 May 29, rapidly approaching the Sun. Visual magnitude was 8.1 at the time

C/2020 F3 NEOWISE + reflection nebula NGC 2170
2020 May 25 at 08:50UT. Visual magnitude 8.5 using 25x100mm binoculars.

2020 May 9 at 0905UT.
I visually observed the comet prior to moonrise using a pair of 25x100mm binoculars and estimated it at magnitude 10.0.
The comet is well on track to reaching naked eye visibility during July.



35S Finder chart for April-May 2020 evening

During May, the comet was seen in the evening sky for southerners, traversing through Lepus and Monoceros.
It ended the month in Orion before disappearing into evening twilight by June 11th

The comet brightened from magnitude 11 to 7 during this period.


Finder chart for August includes the tracks of C/2020 F3 NEOWISE, C/2019 U6 Lemmon and C/2017 T2 PANSTARRS, all in the same vicinity of sky!

The comet faded from magnitude 5 to 8 during this period


My visual observations of the comet: