CBET nr. 4494, issued on 2018, March 16, announces the discovery of an apparently asteroidal object (magnitude ~17) in the course of the "Asteroid Terrestrial-impact Last Alert System" (ATLAS) search program on CCD images obtained with a 0.5-m f/2 Schmidt reflector at Haleakala, Hawaii. Posted on the Minor Planet Center's PCCP webpage, it has been reported as showing cometary activity by CCD astrometrists elsewhere. The new comet has been designated C/2018 E1 (ATLAS).
I performed follow-up measurements of this object, while it was still on the PCCP webpage. Stacking of 5 unfiltered exposures, 60 seconds each, obtained remotely on 2018, March 12.4 from Q62 (iTelescope network) through a 0.70-m f/6.6 reflector + CCD, shows that this object is a comet with a diffuse coma about 5 arcsec in diameter. The FWHM of this object was measured about 20% wider than that of nearby field stars of similar brightness.
My confirmation image (click on it for a bigger version)
"Pre-discovery" Panstarrs observations (2015 & 2016) were identified by R. Weryk. M.P.E.C. 2018-F10 assigns the following elliptical orbital elements to comet C/2018 E1: T 2018 Apr. 17.3; e= 0.95; Peri. = 299.47; q = 2.70; Incl.= 72.48
by Ernesto Guido