161p 20260910 dbartlett

161P_Hartley_IRAS_TandemRASA11s_asi6200mmP_asi6200mcP_64x90sec_20260910_040504_local_JuneLake_California_USA_DEBartlett
 

 
 

Moving at a Good Clip, Comet 161P Hartley-IRAS Picks Up Speed in the Constellation of Cetus, Sept10 2026
 

 
 

ASTROBIN-Full Resolution, animation and other Goodies:
 

https://app.astrobin.com/i/ocfo2r?r=0
 

 
 

Project Notes:
 

    My first go at 161P/Hartley-IRAS with a measured brightness at mag 13.0. 
    A faint nuclear region fan-shape expansion towards the 3 o’clock position (starless closeup) 
    Looking forward to this one as it heads to Oct 2 earth MOID and peak projected brightness. 
    Dusty region making observations and processing a chore. 
    As usual, color calibration was performed with PixInsight's SpectrometricColorCalibration process using a white balance of the spectral class of our sun as reference.  

 

 
 

Observational details:
 

    Backyard setup 
    2xscopes Tandem: RASA11 D = 279mm; fl =620mm; F# 2.2 
    camera: asi6200mmP and asi6200mcP 
    Seeing: 4/5  
    Transparency: 9/10 some moonlight 
    Observer: DEBartlett 
    Location: June Lake, California, USA 

 

 
 

Image Info:
 

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

    Resampled 2x2 
    Acquisition...............64x90sec total 

 

Widefield
 

    Resolution ............... 2.501 arcsec/px 
    Rotation ................. 0.177 deg 
    Field of view ............ 2d 49' 4.9" x 2d 0' 8.5" 
    Image center ............. RA: 2 18 50.502 Dec: -17 11 28.15 

 

Closeup
 

    Resolution ............... 2.500 arcsec/px 
    Rotation ................. 0.183 deg 
    Field of view ............ 1d 1' 22.3" x 45' 17.3" 
    Image center ............. RA: 2 18 42.891 Dec: -17 12 13.67 

 

 
 

161P (Hartley-IRAS)
 

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
 

161 2026 09 10.45 C 13.0 AG 28.0T 2B880 5.1 ICQ XX BARaeI a180C 5.09mZCP IMX TYT 0 U9*0.15 13.2 2.5s 2.5 Location: June Lake Overlook (MPC U66); Comment: Comet Alt. 35.2
 

 
 

COD U66
 

OBS
 

CATALOG: ATLAS2 - BAND: g (Sun Mag=-26.46)
 

 
 

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

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

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

161P 10/09/2026 10:53:21 17.41 16.36 15.91 15.61 15.41 15.22 43.6 18.6 U66
 

161P 10/09/2026 10:53:21* 0.15 0.15 0.15 0.15 0.15 0.15 32 34.2 ATL
 

 
 

 AFRHO LOG
 

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

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

161P 10/09/2026 10:53:21 0.79 1.65 35.13 15.77 44 19 5 1.283 U66