Acquisition Details
- Dates: Feb. 23–25 2025; Mar. 3–4 2025
- Filters & Exposure:
- Antlia Hα 7 nm 36 mm: 28×300″ (2 h 20 m)
- Antlia V-Pro Blue 36 mm: 30×300″ (2 h 30 m)
- Antlia V-Pro Green 36 mm: 32×300″ (2 h 40 m)
- Antlia V-Pro Luminance 36 mm: 115×300″ (9 h 35 m)
- Antlia V-Pro Red 36 mm: 28×300″ (2 h 20 m)
- Total Integration: 19 h 25 m
- Moon Conditions: Avg. Moon age 17.24 days, phase 18.02%
- Imaging Parameters:
- RA center: 11h 20m 13.2s
- DEC center: +13° 17′ 20″
- Pixel scale: 1.038″/pixel
- Orientation: 69.467°
- Field radius: 0.937°
Object Overview
The Leo Triplet is a trio of galaxies in the constellation Leo, approximately 35 million light-years away. It includes Messier 65 (M65), Messier 66 (M66), and NGC 3628, the “Hamburger Galaxy” with a distinct dust lane and a faint tidal tail.
- M65 reveals tightly wound spiral structure.
- M66’s asymmetric morphology reflects gravitational interactions.
- NGC 3628, seen edge-on, shows both a prominent dust lane and an extended tidal tail.
This group fits elegantly within a medium focal length frame, offering both morphological variety and compositional harmony. This Leo Triplet astrophotography project focuses on M65, M66, and NGC 3628 in the constellation Leo, a famous trio of interacting galaxies.
Processing Notes – Revealing the Tidal Tail of NGC 3628
The Leo Triplet astrophotography challenge lies in balancing galaxy core brightness while revealing faint tidal tails around NGC 3628.
- MultiscaleGradientCorrection (MGC) was applied early to suppress background gradients while preserving faint extended structures. Multiple, conservative iterations ensured retention of real faint signal.
- Stretching was performed in gradual incremental steps rather than all at once, with each adjustment evaluated for preservation of the tidal tail.
- Selective noise reduction was applied to the background, avoiding overly aggressive smoothing that would erase weak features.
- Gradient sample placement was manually refined—automatic models often misclassified the faint halo of NGC 3628 as sky background and subtracted it inadvertently.
Despite nearly 20 hours of integration, the tidal tail remains subtle. Its successful extraction required a refined balance of gradient correction, conservative stretching, and careful noise control. Additional luminance or narrowband (e.g. Ha) data could further enhance this feature in future versions.
FAQ
Q: What focal length is recommended for capturing the Leo Triplet?
A: Between 500 mm and 1000 mm is ideal—it allows inclusion of all three galaxies while preserving detail.
Q: How much integration is needed for the tidal tail?
A: While 4–6 hours suffices for M65/M66, revealing the tidal tail of NGC 3628 benefits significantly from 15+ hours of L data.
Q: Can this target be photographed from light-polluted areas?
A: Yes—M65 and M66 are fairly bright, but detecting the tidal extension requires darker skies or longer integration under suburban conditions.
Extended Insight: Hubble Observations
The Hubble Space Telescope has imaged M66, capturing intricate structures in its spiral arms and star-forming regions during observations from June 2000 (WFPC2) and July 2003 (ACS). These high-resolution views highlighted fine details that ground-based images typically blur, particularly in complex spiral arm areas and dust lanes.