2023e1 20230720 dbarlett

My Last Images from July Shows Fading Tail; Comet C/2023 E1 (ATLAS) 2023-07-20/21.  Actually a superbly clear and tranquil night imaging C/2023 E1 (ATLAS).  Due to the apparent speed picking up  as this comet closes in on August 18th (Earth's MOID), I had to reduce the exposure time from 120 seconds to 90s.  Even thought I reduced the time for individual subs the stacked total still exceeded 1.5 hr of integration time under near ideal sky conditions.  The easily seen anti-solar tail, for individual subs from last week,  has been absent over the past few nights.  Also, may be a bit of a "stretch", nonscientific-ally the coma feels larger than a week ago. 
 
A word about the comet's color... can't make this stuff up... the coma appears to me to be quite bluish vs greenish as others have pointed out.  This image has been color calibrated using the procedures outlined in PixInsight's comet notes (seen here).  I took the liberty to saturate the calibrated hue as issued.
Dan
 
 
 Observational details:
Backyard setup
scope: C14 D = 356mm; fl =729mm; F# 2
camera: asi 2600mcP
exposure: 63 x90 sec
Seeing: 4/5
Transparency: 9/10
Observer: DEBartlett
Location: June Lake, California, USA
 
 
Image details:
Projection ............... Gnomonic
Projection origin ........ [730.141024 1458.984220] px -> [RA: 19 32 32.240  Dec: +76 04 46.39]
Resolution ............... 2.128 arcsec/px
Rotation ................. -4.192 deg
Reference system ......... ICRS
Observation start time ... 2023-07-21 05:23:50 UTC
Observation end time ..... 2023-07-21 05:25:20 UTC
Geodetic coordinates ..... 119 04 46 W  37 46 30 N  2357 m
Focal distance ........... 728.88 mm
Pixel size ............... 7.52 um
Field of view ............ 51' 47.0" x 1d 43' 29.8"
Image center ............. RA: 19 32 32.289  Dec: +76 04 46.36  ex: +0.000141 px  ey: -0.000091 px
Image bounds:
   top-left .............. RA: 19 39 02.488  Dec: +76 57 55.13  ex: -0.000182 px  ey: +0.000066 px
   top-right ............. RA: 19 23 49.870  Dec: +76 53 53.00  ex: +0.000464 px  ey: -0.000407 px
   bottom-left ........... RA: 19 40 17.126  Dec: +75 14 38.87  ex: -0.000750 px  ey: +0.000346 px
   bottom-right .......... RA: 19 26 48.240  Dec: +75 11 05.08  ex: +0.002444 px  ey: -0.000689 px