C/2019 U6 Lemmon
Closest to Sun on 2020 June 18 at 0.91AU
Closest to Earth on 2020 June 29 at 0.83AU
Maximum brightness 5th magnitude in June 2020
Orbital period +9,000 yrs

MPC finally announced on March 25th with CBET4735 that asteroid A/2019 U6 is definitely a comet, and redesignated as C/2019 U6 Lemmon.
The comet has the potential to become faintly visible with the naked eye during June 2020, peaking at magnitude 5.5 late in that month.
Comet Lemmon has shown a very stable light curve with a bright nuclear condensation. These types of comets are more easily predictable.

35S Finder chart for June 2020 evening

On June 1, you will find the magnitude 6.5 comet situated in Canis Major, in the evening sky, about 6 degrees South East of Sirius, however moonlight interferes.
On June 7, the comet lies 45 northwest of planetary nebula NGC2440 in Puppis.
The comet moves into Hydra on the 15th.
On June 23, the comet will be situated very close to Alphard in Hydra.
The comet may then appear at its brightest, magnitude 5.5, easily visible in binoculars and possibly naked eye from a dark site.
Moonlight will start to interfere from June 26


35S Finder chart for July 2020 evening

At the start of July, Comet Lemmon will start to fade as it recedes from both the Earth and Sun.
Hopefully it reached its expected peak of magnitude 5.5, faintly visible to the unaided eye.

On July 1, you will find the magnitude 6.0 comet situated in Sextans, between Beta and Delta Sex, in the early evening sky after sunset, however moonlight will interfere until July 7.
On July 8, the comet now situated in Leo, will be 35 S of 12th mag galaxy NGC 3604.
By July 17, the now magnitude 7.0 comet enters the realm of the Virgo supercluster of galaxies. Astrophotographers take note:
It will be 30S of NGC 4178 on this night. Then on July 19 it is adjacent to NGC 4371.
On July 20 it will be adjacent to M87, then adjacent to M89 on the following night of the 21st. On July 23, it is 27W of NGC 4689.
By August 1, the now magnitude 8 comet will be situated in coma Berenices, only 2 degrees away from magnitude 10.0 comet C/2017 T2 PANSTARRS.
Note that the brighter comet NEOWISE will also be in the same vicinity of sky!


Comet C/2019 U6 (Lemmon) 2020 June 8 at 0900UT, visual estimate = 6.5, through 8x40mm binoculars.
Wide field image using Canon 60Da + Sigma 200mm lens. Note star clusters M46, M47 in Puppis.

Above: C/2019 U6 Lemmon on 2020 May 29, visual estimate through 15x70mm binoculars = 7.0

Above: C/2019 U6 Lemmon rendezvous with star cluster M41 in Canis Major on May 28

C/2019 U6 Lemmon. 2020 May 25 at 09:10UT.
Visual magnitude 7.2 through 15x70mm binoculars. Showing a nice 1 degree ion tail in this image.

Image taken on 2020 May 16 at 9UT. Visual observation of C/2019 U6, m1=7.6, dia=6' dc=5 15x70mm binoculars

Above: C/2019 U6 Lemmon and galaxy NGC 1964 in Lepus on 2020 May 9 at 0900UT.
I visually observed the comet prior to moonrise using a pair of 15x70mm binoculars and estimated it at magnitude 7.8
Well condensed and surprisingly brighter than expected.

By April 16th the comet had brightened to magnitude 10.2 with a 4' coma and DC3

I observed the comet visually on Mar. 14.43 with a 20-cm reflector (70x),
estimating total magnitude 13.0 and finding a poorly condensed coma of diameter 2'.

35S Finder chart for April-May 2020 evening

May 2020
On May 1, you will find the magnitude 8 comet situated in Lepus in the evening sky, about 2 degrees East of Epsilon Lepi,
however moonlight interferes.
Several nice deep sky rendezvous events occur this month where astrophotographers should take note,
or where visual observers can easily go-to galaxy to find the comet.
On May 9, the comet is 20 East of magnitude 11.6 spiral galaxy NGC1964.
Moon free observing period occurs between May 10 to 26.
On May 14, the comet lies adjacent to magnitude 13 galaxy NGC2106.
On May 19, the comet lies 30 north of magnitude 13 galaxy NGC2179.
On the evening of May 21, the comet lies 18 north of the interacting pair of galaxies NGC2207/2163 in Canis Major.
By this time, the comet may have brightened to magnitude 7.0.
On the nights of May 27 and 28, the comet should be a fine site, situated next to M41 star cluster in Canis Major.