Astrophotography Observation Plan
Nordland AI Observatory Control • Eagle Lake Observatory, MN
Planned Targets & Acquisition Strategy
1. NGC 5907 Splinter Galaxy
Type: Galaxy • Angular Size: 0.21° • RA 15.2600 / Dec 56.3200- Filter: UV/IR Cut Filter (Slot 1).
- Broadband Warning: Waning Gibbous moon (96%) will introduce significant gradients. Keep exposures short.
- Auto-Focuser: Trigger EAF auto-focus routine every 45 minutes or upon a 1.0°C temperature delta.
- Sub-Exposure: 90 seconds (protects background from moonlight saturation).
- Gain / Offset: Gain 100 / Offset 70 (Unit Gain).
- Cooling: Sensor cooled to -10°C.
- Target Integration: 1.5 Hours (~60 frames).
At 0.21°, NGC 5907 will appear as a crisp, ultra-thin needle framed inside the wide 2.59° FOV of the Redcat 51. Center the core precisely. Utilize dither every 3 frames to control sensor walking noise. Focus must be locked on a bright field star before starting the sequence.
2. NGC 7380 Wizard Nebula
Type: Emission Nebula • Angular Size: 0.42° • RA 22.9500 / Dec 58.1000- Filter: Dual Narrowband (Ha + OIII) (Slot 2).
- Moon Immunity: Excellent target under 96% moonlight; narrow bandpasses cut directly through skyglow.
- Auto-Focuser: Run EAF auto-focus immediately upon switching to dual-band filter.
- Sub-Exposure: 300 seconds (5 minutes).
- Gain / Offset: Gain 100 / Offset 70 (or Gain 300 HCG for higher SNR).
- Cooling: Sensor cooled to -10°C.
- Target Integration: 3.5 Hours (~42 frames).
The Wizard Nebula (0.42°) frames exceptionally well within the 2.59° wide field, leaving ample sky for surrounding Ha emission structure. Multi-star auto-guiding is essential due to 300s sub-exposures. Ensure RMS guide error remains below 1.0 arcsec.
3. NGC 7023 Iris Nebula
Type: Reflection Nebula • Angular Size: 0.30° • RA 21.0300 / Dec 68.1700- Filter: UV/IR Cut Filter (Slot 1).
- Moon Sensitivity: Reflection dust is susceptible to lunar wash-out. Focus acquisition on the bright central core.
- Auto-Focuser: Refocus every 45 minutes or 1.0°C delta.
- Sub-Exposure: 60 to 90 seconds (prevents washing out subtle dust reflections).
- Gain / Offset: Gain 100 / Offset 70.
- Cooling: Sensor cooled to -10°C.
- Target Integration: 1.5 Hours (~60-90 frames).
Frame the central star HD 200775 at the focal center. The 2.59° field will capture the outer dark dust clouds, though contrast will be lower due to the 96% moon. Dither aggressively (every 2-3 subs) to enable effective rejection of sky glow gradients during stacking.
Sequencing Recommendation & Chronological Timeline
Tonight’s strategy balances target transit altitudes, filter mechanics, and the overpowering 96% Waning Gibbous moon. Broadband targets are prioritized earlier in the evening when moon altitude/glare allows, while the central hours of the night are dedicated to narrowband emission imaging.
Power on mount, ASI533MC Pro cooling to -10°C, and engage dew heaters immediately (RH 90%). Perform polar alignment, auto-focus on a bright star with UV/IR Cut filter, and run initial guide calibration.
Image NGC 5907 during its peak transit at 45° altitude. Use 90s sub-exposures with the UV/IR Cut filter. Galaxy imaging is best handled early before moonlight saturation reaches peak sky brightness.
Slew to the Iris Nebula at high northern altitude. Maintain UV/IR Cut filter. Collect 60-90s sub-exposures. Re-run EAF focus routine at 00:15 or upon 1.0°C temperature drop.
Switch filter wheel to Dual Narrowband (Ha+OIII). Auto-focus immediately. Capture long 300s sub-exposures for 3.5 hours. The narrowband filter cuts cleanly through the 96% moonlight, maximizing SNR during prime late-night hours.
Park mount, capture 30x Dark frames (if needed) and 30x Flat frames per filter used (UV/IR Cut and Dual Narrowband). Park scope and safely turn off camera cooling.