At last, a naked-eye comet

After a fairly lengthy time of "comet starvation" we finally had an appearance of a comet which, while not super-bright, was visible to the naked eye. Comet Hale-Bopp in 1997 was the last one to be so visible. Using binoculars brought out a pretty impressive view of this "new" comet  (NEOWISE C/2020 F3), even in the light-polluted sky in our part of the city. Without the coved-19 pandemic in progress, the RASC would have held many public astronomy meetings; now this can only be approximated virtually (i.e. Zoom, and similar applications).

NEOWISE C/2020 F3 was discovered on March 27, 2020 by NASA's "Wide-field Infrared Survey Explorer" space telescope, which has been in orbit for about 11 years. You can see the source of the comet's name. This is a very productive telescope, which has discovered thousands of astronomical objects. Look up details in WIKIPEDIA under its name. 

At the time of discovery Neowise was a faint blob of magnitude 18, at twice the Earth's distance away from the sun. From position measurements made of Neowise C/2020 F3's orbital positions as it moved towards the Sun, a 4,400 year long orbit was calculated. By now, Neowise has been moving away from the Sun for some time, and is well past its closest approach to Earth on July 22. That means that its brightness is diminishing. The close approach to the Sun resulted in a change in the comet's orbital shape. The orbit is now longer and the comet has been recalculated to return in about 6700 years, or so (I won't wait for it).

Comet Neowise C2020 F3

This picture was taken on July 19, around 10:30 PDT with a Canon 60Da camera from our lawn next to the house. It's a 10-second exposure (f8, ISO 800). A slightly enhanced image, it is meant to show the comet better from our severely light-polluted area. It was easy to see with the naked eye. 

As the comet gets fainter, more and more telescope power will be needed to view it directly; photography, and the Hubble space telescope will be able to follow it for a longer time. By the third of August, the comet had faded to about magnitude 7, it was a faint hazy patch in my 10x50 binoculars, and I could not discern a tail. It was definitely no longer a naked-eye object. The Moon was almost full, and, in addition, the sky was somewhat hazy. Added to the light pollution in our area, this made viewing the comet less than ideal. 

 

Under similar conditions, Neowise was still visible in my 15x50 Canon stabilized binoculars in the evening (around 11pm PDT) of Aug. 9, between stars 70Virginis and 71Virginis. Directly looking at it showed a very faint, fuzzy, barely noticeable patch. Averted vision made it more readily perceived. The difficulty seeing it made for more fun to search for and trying to find it. Neowises's apparent motion is now relatively small, due to the relationship of the Earth's and the comet's respective orbits. It's like we were passed by a train, and we can see it down the track, getting smaller and smaller, but not moving sideways much.