220p 20260814 dbartlett

Project Notes:
 

    Very transparent night with good seeing. 
    Comet is quite colorful showing only its frontal region, despite the three hour integration time. 
    The green coma is much reduced formally surrounding the "bullet" shaped shell envelope. 
    This envelope is very large with a central spine. 
    The comet is spectrophotometricColorCalibrated in PixInsight, representing true white balance of 220P. 
    No hint of blue-plasma observed as in all previous observations I have made of this comet. 
    Heavy dust present in the Cetus starfield. 
    The once dust tail extending beyond the FOV is nearly absent. 
    Photometric measurements using Tycho-Tracker indicates the comet's brightness of mag 8.4. 

 

 
 

 
 

Observational details:
 

    Backyard setup 
    2xscopes Tandem: RASA11 D = 279mm; fl =620mm; F# 2.2 
    camera: asi6200mmP and asi6200mcP 
    Seeing: 3.5/5  
    Transparency: 8/10  
    Observer: DEBartlett 
    Location: June Lake, California, USA 

 

 
 

Image Info:
 

(All images processed solely using PixInsight and Comet Photometry Tycho-Tracker)
 

    Resampled 2x2 
    Acquisition...............62x180sec total 

 

 
 

Wide Field
 

    Resolution ............... 2.503 arcsec/px 
    Rotation ................. -0.195 deg 
    Field of view ............ 3d 8' 58.3" x 1d 58' 43.3" 
    Image center ............. RA: 2 50 51.355 Dec: +9 18 42.80 

 

 
 

Cropped
 

    Resolution ............... 2.504 arcsec/px 
    Rotation ................. -0.101 deg 
    Field of view ............ 2d 1' 45.8" x 1d 18' 52.0" 
    Image center ............. RA: 2 53 07.190 Dec: +9 30 09.24 

 

 
 

220P (McNaught)
 

ICQ line:
 

IIIYYYYMnL YYYY MM DD.DD eM/mm.m:r AAA.ATF/xxxx /dd.ddnDC /t.ttmANG ICQ XX*OBSxxf InT APERTURcamchip SFW C ## u.uu xx.x PIXELSIZE
 

220 2026 08 14.46 C 8.4 AR 28.0T 2E940 6.8 21.6m253 ICQ XX BARaeI a720C 6.76mZCP IMX TYT 0 U9*0.11 9.7 2.5s 2.5 Location: June Lake Overlook (MPC U66); Comment: Comet Alt. 47.9
 

 
 

COD U66
 

OBS
 

CATALOG: ATLAS2 - BAND: r (Sun Mag=-26.93)
 

 
 

 10x10 20x20 30x30 40x40 50x50 60x60 RSR FC COD
 

COMET UTC +/- +/- +/- +/- +/- +/- N FWHM CAT
 

------------ ------------------- ----- ----- ----- ----- ----- ----- ---- ---- ---
 

220P 14/08/2026 11:01:58 12.53 11.65 11.20 10.85 10.60 10.40 83.4 18.8 U66
 

220P 14/08/2026 11:01:58* 0.11 0.11 0.11 0.11 0.11 0.11 33 25.5 ATL
 

 
 

 AFRHO LOG
 

COMET UTC DELTA r AP " MAG RSR CM +/- AFRHO OBS
 

------------ ------------------- ----- ----- ----- ----- --- ----- ---- ----- ---
 

220P 14/08/2026 11:01:58 1.20 1.67 22.96 11.48 83 1543 301 3.188 U66