Comet C/2020 F3 (NEOWISE)

By  Christian Buil

The comet C/2020 F3 (NEOWISE) is observed with various categories of spectrograph from my personal observatory in Antibes Saint-Jean. First, some images wide field images taken in the evening ...

Comet C/2020 F3 NEOWISE the July 16.8, 2020 (Sony A7s + Samyang 135 mm f/2, 2 sec. exposure).

UVEX (UtraViolet EXplored spectrograph) session. 10-inch f/8 GSO Ritchey-Chretien on a 10Micron GM2000 equatorial mount. ZWO ASI183MM camera for the acquisition.

Any question about UVEX project, see here:

Up, the comet image on the 35 microns wide UVEX spectrograph entrance slit. Left, the image of the spectrum on the acquisition computer.

Colored 2D image of the comet UVEX spectrum, the July 9, 2020 (‘morning). Note the very intense yellow sodium doublet (Na D).

The same after sky-background removed.Colored 2D image of the comet UVEX spectrum, the July 9, 2020 (‘morning). Note the very intense yellow sodium doublet (Na D).

Contrast enhanced version. The ultraviolet CN band is at the left.

The extracted low resolution spectral profile (two contrast). The Na D line is impressive, because the comet is near the sun and this metallic atom is very exited :

The July 13, 2020 with the « Nice People » group member’s, an eShel session (high resolution R = 11000).

Note the low elevation of the telescope (Newton 250-mm f/4.5) . Left, hand guiding on the coma image (Pierre Dubreuil).

The telescope head with the fiber interface.

The fiber scrambler.

The eShel spectrograp in the wine cellar for very good temperature regulation and low temperature. The camera used is the ASI620MM (ZWO) model equipped with the new IMX455 sensor (24 x 36 format).

The échelle 2D spectrum of C/2020 F3 (NEOWISE) the July 15.8, 2020. Note for example the well resolved C2 bands, the sodium doublet just up to the center of the image and the cyanogen bands (CN) in the extreme bottom. Thanks too the IMX455 large format.

Global high resolution (R=11000) spectrum taken the July 15.8, 2020 (6 x 180 secondes exposure).

Detail of 4700 A C2 band. 

Detail of 5100 A C2 band. 

The [OIII] oxygen line. 

Ultraviolet CN band profile from a spectrum taken the July 16.8, 2020.  

During the July 15.8 , 2020 observation. 

Valérie Desnoux, Christian Buil and C/2020 F3 (Credit Manuel Antuna).