Comet C/2025 A6 (Lemmon)
Imaging Session Overview
Comet C/2025 A6 (Lemmon) was observed using non-sidereal tracking with ephemeris data provided by the NASA JPL Horizons System. The imaging system consisted of an Astro-Physics 110GTX refractor telescope paired with an ASI2600MC Pro CMOS camera. Sequence automation and real-time tracking were managed through N.I.N.A. (Nighttime Imaging 'N' Astronomy) software.
- Date: October 4, 2025
- Integration: 30 minutes total (15 × 120-second subs)
- Tracking: Comet (non-sidereal)
- Processing: PixInsight
- Seeing: ~2.3″ FWHM
- Resolution: 1.41"/pixel
Observational Findings
Analysis of the comet-aligned image sequence revealed evidence of a subtle disconnection event within the ion tail. This feature manifested as a faint separation structure visible in the plasma tail region when frames were aligned on the comet nucleus.
Autoguiding performance remained stable throughout the session, with an RMS error of approximately 0.35 arcseconds. The comet alignment procedure in PixInsight successfully isolated the comet's motion, producing a star-free composite with excellent nucleus definition.
Spectral analysis of the tail structure indicated elevated ion activity, evidenced by the cyan spectral bias characteristic of ionized gas emission. A fainter dust component was detected extending toward the southwest position angle. Careful histogram stretching using Generalized Hyperbolic Stretch revealed fine filamentary structures in the tail without saturating the nuclear region.
Data Reduction Workflow
All sub-exposures underwent standard calibration and registration procedures using PixInsight's WeightedBatchPreprocessing script. Following initial preprocessing, two separate integration stacks were generated: one aligned on the comet nucleus and one aligned on the stellar field.
TThe comet-aligned stack was processed to enhance tail morphology and structural detail. Noise suppression was applied using NoiseXTerminator, followed by selective contrast enhancement of the tail region through LocalHistogramEqualization. The final composite image was created by blending the comet stack with a star field reintroduced via PixelMath operations, preserving both the extended tail structure and stellar reference frame.
Final Image
C/2025 A6 (Lemmon) Inverted Image
