[back] C/2025 A6 (Lemmon)

November 11th 2025, f=1050mm

Bigger version / Größere Version (4700 x 3049 pixel)

 (c) 2026 All astro photo images are copyrighted. They may not be used or reproduced without explicit written permission from the authors.

 

300"

 

October 30th 2025, f=135mm

Bigger version / Größere Version (4003 x 5584 pixel)

 (c) 2026 All astro photo images are copyrighted. They may not be used or reproduced without explicit written permission from the authors.

 

0.5°

 

 

 

About this Images / Über dieses Bilder

 

Camera: Upper Image:Moravian C3-PRO-61000 Mono CMOS
Lower Image: , ASI 2600MC pro
Image Type, Orientation: Upper Image: L-RGB composite,  North is at 12:00
Lower Image: RGB OSC image, NORTH is at 12:00
Exposure time/date: Upper Image: November 11th 2025, L: 13x30 sec.,  R,G,B: 7x30s  (0:17h total)
Lower Image: October 30th 2025, 25x60s OSC (0:25h total)
Location: Upper Image: Capella Observatory South at Kiripotib Astro Farm, Namibia
Lower Image: Private mobile observatory of Rainer in his backyard, Heroldsbach/Germany
Filter of upper image: Astronomik Deep-Sky Deep-Sky RGB Filter  plus 6nm SII, Ha, OIII filters on Moravian EFW-3L-9-II External Filter Wheel
Instrument: Upper Image: "Rhea", a PlaneWave DeltaRho 350, 1050mm focal length, 350mm aperture,  f/3 on 10Micron GM2000 HPS II Combi
Lower Image: Samyang 135 mm on  iOptron SkyGuider Pro
Photographer: Rainer Raupach, Josef Pöpsel, Stefan Binnewies, Frank Sackenheim

Remarks:

Comet C/2025 A6 (Lemmon) was discovered in early 2025 and is a long-period comet. It will not return to the inner Solar System for approximately 1,400 years.
The upper image was obtained shortly after perihelion, which occurred on November 8, 2025, at a heliocentric distance of just over 0.5 AU. At that time, the comet had a distance of approximately 1.1 AU from Earth. The lower wide-field image, by contrast, was taken on October 30, shortly before perihelion, when the comet was near its closest approach to Earth (~0.7 AU). This was close to the actual minimum geocentric distance of just under 0.6 AU on October 21, 2025, and coincided with the comet’s peak apparent brightness (magnitude 7.2) [1].
The comet displayed a prominent dust tail as well as a clearly separated plasma tail. While the dust tail appears nearly color-neutral due to reflected sunlight (assuming a G2V white point comparable to the Sun), the plasma tail exhibits a striking bluish hue. The coma, in contrast, shows the characteristic green coloration caused by emission bands of the diatomic carbon (C₂) molecule.
   

Bemerkungen:

Der Komet C/2025 A6 (Lemmon) wurde Anfang 2025 entdeckt und ist ein langperiodischer Komet. Er wird sich erst in etwa 1400 Jahren wieder in Sonnennähe befinden.
Das obere Bild entstand kurz nach dem Perihel, das am 8. November 2025 mit einem Abstand von etwas über 0.5 AE stattfand. Der Abstand zur Erde zu diesem Zeitpunkt betrug dabei ~1.1 AE. Das untere Widefield-Bild wurde hingegen am 30.10., also kurz vor dem Perihel aufgenommen, was mit einem Abstand zur Erde von ~0.7 AE ungefähr der erdnächsten Position (genau am 21.10.2025 mit knapp 0.6 AE) entsprach und das Helligkeitsmaximum (7.2 mag) darstellte [1].
Der Komet zeigte einen deutlichen Staub- sowie einen separierten Plasmaschweif. Während der Staubschweif durch die Reflexion des Sonnenlichts nahezu farbneutral erscheint (beim gewählten Weißpunkt eines G2V-Stern wie der Sonne), leuchtet der Plasmaschweif auffallend bläulich. Die Koma hingegen zeigt die übliche grüne Färbung, verursacht durch Emissionsbanden des Dicarbon-Moleküls (C₂).
References: [1] Orbit data on TheSkyLive: https://theskylive.com/c2025a6-info

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