Observer: John C.H. Tsai (Aether Gear)
Date & Time: April 3rd,2025
Location: El Camino College, Torrance, California
Telescope: Celestron C11 (f/10, 2800mm focal length)
Target: Messier 81 (NGC 3031), “Bode’s Galaxy”
1. Target Overview
Messier 81, commonly known as Bode’s Galaxy, is a grand design spiral galaxy located in the constellation Ursa Major. It lies approximately 12 million light-years away and is one of the brightest galaxies visible from Earth. M81 features a prominent central bulge and well-defined spiral arms, making it a favorite for both amateur and professional astrophotographers.
2. Imaging Conditions
- Sky Quality: Urban/Suburban (Bortle 7–8)
- Seeing: Fair, with some visible atmospheric softening
- Moonlight: Not specified, likely present given overall sky brightness
- Light Pollution: High; image shows significant skyglow and color cast
3. Imaging Results
Framing & Composition:
- The galaxy is well-centered with minimal field rotation.
- Adequate surrounding star field provides context for the deep sky target.
Focus:
- Star profiles are slightly soft, but round—focus was close to optimal.
Exposure Quality:
- Galaxy core is clearly defined.
- Faint halo and spiral arms are present but subdued due to sky brightness.
- High sky background indicates short exposure or lack of filtering.
Color & Balance:
- Strong bluish background hue from light pollution or atmospheric scatter.
- Color corrected during post-processing for better balance.
Post-Processing Enhancements:
- Contrast enhancement to boost galaxy core visibility
- Sharpening to define surrounding stars and core structure
- Color balancing to reduce blue bias and recover neutral tones
4. Equipment Feedback
Optics:
- Celestron C11 provides excellent resolution at f/10, but benefits from a focal reducer or image stacking in high light-pollution areas.
Tracking:
- Stars appear well tracked with minimal drift or elongation
- No severe motion artifacts observed, suggesting solid mount performance
Filters:
- No narrowband or broadband light pollution filters were applied
- Recommended for future sessions: Optolong L-Pro or Baader Moon & Skyglow
5. Improvement Suggestions
- Use longer total integration time (e.g., 30+ stacked exposures)
- Implement light pollution filters to improve background contrast
- Capture with dithering and calibration frames (bias, dark, flat)
- Apply background extraction and gradient removal in software like PixInsight or Siril
- Consider focal reduction to increase FOV and reduce required exposure time
6. Overall Assessment
This capture of M81 demonstrates solid acquisition technique under challenging urban skies. Despite light pollution and single-frame limitations, the core structure of the galaxy is well resolved and identifiable. With additional exposure time and calibration, this data has potential to yield an impressive final image.
Rating: ★★★★ (4/5 for single-frame capture under urban conditions)
Prepared by: Osiris
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