Astrophotography Observation Plan

Target Acquisition & Imaging Protocol | Date: 2026-07-25

Site & Rig Configuration

Location: Palm Beach Gardens, FL (Bortle 6)
Coordinates: Lat: 26.832° N, Lon: -80.128° W
Optics: Celestron XLT 150 + 0.9x Reducer (f/4.5, 675mm FL)
Camera: ZWO ASI2600MM Pro (APS-C Mono, 1.99° x 1.33° FOV)
Hardware: Electronic Auto-Focuser (EAF) & LRGB Filter Wheel

Atmospheric & Lunar Forecast

Sky Quality: Recommended / Good (34% avg. cloud cover)
Transparency: Above Average (71% average humidity)
Seeing: Poor (Turbulent atmosphere, soft details, high twinkle)
Wind: Calm (5 mph avg) – Zero tracking vibration risk
Moon: Waxing Gibbous (83% illumination – Strong impact)

LUNAR MITIGATION STRATEGY: With an 83% illuminated Moon, broadband Luminance imaging will suffer severe gradient contamination. The poor atmospheric seeing will also bloat star profiles. Tonight’s strategy prioritizes Red/RGB filters to cut through the skyglow, utilizing the EAF to maintain tight focus amid thermal shifts, and targeting high-emission regions.

Target Acquisition & Exposure Profiles

1. M8 – Lagoon Nebula (Emission Nebula)

RA 18.0600 / Dec -24.3800

Filters & Optical Settings:

Primary Filter: Red (acting as pseudo-H-alpha to combat 83% Moon glow).
Color Strategy: Run R-G-B sequence. Skip Luminance entirely tonight.
Autofocus: EAF trigger on Red filter. Re-run focus every 45 minutes or 1.2°C temperature change.

Exposure & Camera Settings:

Sub-Exposures: Red: 120s, Green/Blue: 90s (Gain 100, Offset 50, cooled to -10°C).
Total Integration: 2.5 Hours (50x120s Red, 25x90s Green, 25x90s Blue).
Calibration: 30x Darks, 30x Flats per active filter, 50x Bias.

Guiding, Focusing & Framing: Fits comfortably within the 1.99° x 1.33° FOV, leaving ample space for the surrounding nebulosity. Frame in landscape orientation to capture the eastern dust lanes. Due to poor seeing, set guide camera exposure to 2.5 seconds to avoid “chasing the seeing.”

2. M24 – Sagittarius Star Cloud (Milky Way Patch)

RA 18.2800 / Dec -18.4200

Filters & Optical Settings:

Primary Filter: Red, Green, Blue (Broadband).
Moon Mitigation: Avoid Luminance. Rely purely on RGB to preserve star color against the bright sky background.
Autofocus: EAF focus run using the Luminance filter (as a reference point) before swapping to RGB.

Exposure & Camera Settings:

Sub-Exposures: R/G/B: 60s (Gain 100, Offset 50, -10°C). Short subs prevent moon glow saturation.
Total Integration: 1.5 Hours (30x60s per filter channel).
Calibration: Standard Dark/Flat/Bias sets are critical to clean up gradients.

Guiding, Focusing & Framing: At 1.5° wide, M24 occupies almost the entire width of your sensor. Center the frame on the dense star clusters. Multistar guiding is highly recommended here; the dense star field will provide excellent guide stars despite the turbulent atmospheric seeing.

3. M16 – Eagle Nebula (Emission Nebula)

RA 18.3100 / Dec -13.8100

Filters & Optical Settings:

Primary Filter: Red (for the central Pillars of Creation).
Color Strategy: Focus heavily on Red, with shorter Green and Blue runs to map the outer structures.
Autofocus: Run EAF focus routine every 40 minutes. Thermal drop in Florida’s humid air can cause rapid focus drift.

Exposure & Camera Settings:

Sub-Exposures: Red: 180s, G/B: 120s (Gain 100, Offset 50, -10°C).
Total Integration: 3.0 Hours (40x180s Red, 25x120s Green, 25x120s Blue).
Calibration: High-quality flat frames are mandatory to correct for any dew on the reducer.

Guiding, Focusing & Framing: The Eagle Nebula spans 0.58° and will sit comfortably in the center of your 1.99° x 1.33° frame. Center the “Pillars of Creation” precisely. Keep guiding aggression low (around 45-50% on both axes) to prevent overcorrecting in the turbulent, poor-seeing conditions.

4. NGC 6820 – Vulpecula Pillar (Emission Nebula & Cluster)

RA 19.7100 / Dec +23.1800

Filters & Optical Settings:

Primary Filter: Red (targeting the delicate dusty pillars and shock fronts).
Color Strategy: Standard RGB. Limit Luminance to mitigate moonwash.
Autofocus: Force an EAF run immediately prior to starting this target, as it lies in a completely different part of the sky.

Exposure & Camera Settings:

Sub-Exposures: Red: 180s, G/B: 120s (Gain 100, Offset 50, -10°C).
Total Integration: 3.0 Hours (40x180s Red, 25x120s Green, 25x120s Blue).
Calibration: Standard darks and flats are required to extract the faint pillar edges.

Guiding, Focusing & Framing: NGC 6820 is 0.67° in size. Frame the central open cluster NGC 6823 in the center, ensuring the dark pillar structure to the east is well-positioned. Guiding will be stable, but keep an eye on the dew heater settings as Vulpecula rises high into the humid night sky.

Tonight’s Imaging Sequence

To maximize data quality under a 83% Waxing Gibbous Moon and turbulent seeing, the sequence is designed to capture the broadband star cloud target (M24) first while the moon is lower on the horizon, transitioning to the emission nebulae as they reach transit. Finally, we swing north to NGC 6820 to maximize angular separation from the southern moon.

21:15 – 22:30 | M24 Sagittarius Star Cloud (1.25 Hours)

Capture this broadband target immediately at astronomical dusk. Keep exposures short (60s RGB) to avoid saturation from the rising moon. M24 transits at 22:00, providing the best atmospheric transparency.

22:30 – 01:00 | M8 Lagoon Nebula (2.5 Hours)

Imaged during and immediately following its transit window. Prioritize the Red filter channel during this period to isolate the H-alpha emission from the bright background moonlight.

01:00 – 03:30 | M16 Eagle Nebula (2.5 Hours)

As M16 moves past transit, capture the high-contrast structures of the Pillars. Atmospheric seeing will remain soft, so prioritize the Red channel to maintain structure and control star bloat.

03:30 – 05:00 | NGC 6820 Vulpecula Pillar (1.5 Hours)

Swing north to Vulpecula. At Dec +23°, this target offers maximum angular separation from the setting moon in the southwest. Collect high-contrast Red and RGB data until astronomical dawn begins.