Comet C/2025 Lemmon A6
in the Evening sky
10/25/25

 
 This
            is the last day before the moon will be in the sky to wash out
            this comet, which is also in the west. About an hour of imaging
            is possible at this point before the comet sets, the first 45
            mins or so are mostly out of the horizon haze. But on this night
            I had an additional difficulty - Rolling waves of red and green
            airglow were back again and recorded as moving smears in each
            subframe. Airglow of course is the uppermost atmosphere glowing
            from high levels of solar wind. Most of the time, it is a brownish
            color as the green and red emmisions are overlaid. But on occasion
            they separate into bands and move slowly across the sky. (And
            my subframes!). This is a 3 part mosaic with the RASA 8, with
            each frame roughly 15 minutes long. The camera was rotated such
            that the comets blue gas tail would align with the edge of the
            frame (about 25 degrees) so that a continuous series of subframes
            could be taken and over lap properly and not "stairstep".
            It worked and while it was very challenging to remove the airglow
            banding, I used Graxpert and cleaned it up pretty well.

            
Select an image size for a larger view:

1400 x 1200
            


Lens:  8 f/2 RASA Schmidt
Camera: ASI2600 MC
Platform:  Ioptron GEM45
Exposure:  40 mins
Location:  Payson, Arizona
Elevation:  5150 ft.
Sky:  Seeing  4/10, Transparency 7/10
Outside Temperature:  55F
Processing Tools:  Maxim DL, Photoshop CS2
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