Astrophotography Guide

Night Sky Photography Workflows

Complete step-by-step guides for capturing the night sky: single shots, stacking, timelapses, and long exposures.

Single Astrophotograph

Master the basics of capturing a single sharp night sky image with pinpoint stars.

1. Camera Settings

Manual mode (M)
RAW format for maximum flexibility
Use the Astro Calculator for exposure time
ISO 1600-6400 (camera dependent)
Wide aperture (f/2.8 - f/4)
White balance: Daylight or 4000-5000K

2. Focus Technique

Switch to manual focus
Use Live View, zoom in 10x on a bright star
Adjust focus ring until star is smallest pinprick
Tape the focus ring to prevent shifting
For foreground, take separate focused shots

3. Shooting Technique

Use 2-second timer or remote to avoid shake
Mirror lock-up if available (DSLR)
Shoot during astronomical twilight
Take multiple shots for best selection
Check histogram - expose to the right (ETTR)

💡 Pro Tip:

Use the Astro Calculator to determine your exact maximum exposure time before stars start trailing. This varies by focal length and sensor.

Stacking in Photoshop

Combine multiple exposures to reduce noise and bring out faint details in the night sky.

1. Capture Images

Take 10-50+ identical exposures
Keep settings exactly the same
Include dark frames (lens cap on, same settings)
Include bias frames (fastest shutter, lens cap)
Optional: flat frames (evenly lit surface)

2. Load as Layers

File → Scripts → Load Files into Stack
Check "Attempt to Automatically Align Source Images"
Check "Create Smart Object after Loading Layers"
Click OK and wait for processing

3. Stack & Blend

With Smart Object selected: Layer → Smart Objects → Stack Mode
Choose "Mean" for noise reduction
Or "Median" for removing passing objects (planes, satellites)
Rasterize the Smart Object when satisfied

4. Post-Process

Adjust levels/curves to bring out detail
Increase contrast and clarity
Reduce noise further if needed
Apply color correction

📊 Why Stack:

Stacking 20 images reduces noise by approximately √20 ≈ 4.5x. More images = cleaner final result, but diminishing returns after 30-50 frames.

Creating Timelapses

Capture the motion of stars across the night sky with interval shooting.

1. Interval Setup

Use interval timer mode or app
Interval: exposure time + 1-2 seconds
Example: 20s exposure → 22s interval
Calculate total shots needed (30fps video = 900 shots/min)
Set camera to continuous shooting mode

2. Power Management

Use AC adapter or external battery pack
Disable image review to save battery
Disable image stabilization (on tripod)
Turn off WiFi and Bluetooth
Keep spare batteries warm in cold weather

3. Assembly

Import all images to Lightroom/Photoshop
Apply edits to one, sync to all
Export as JPEG sequence
Import sequence into Premiere/After Effects/Davinci
Set frame rate (24-30fps typical)
Export as video file

⏱️ Quick Math:

For 10 seconds of 30fps video: 10 × 30 = 300 images needed. At 20s intervals, that's 300 × 22s = 110 minutes (1h 50m) of shooting.

Long Exposures (>30s)

Capture extended exposures beyond the 30-second limit using Bulb mode with external control.

1. Camera Setup

Switch to Bulb (B) mode
Manual focus and exposure settings
RAW format for best quality
Disable long exposure noise reduction (can stack later)

2. Remote Control Options

Interval Timer Apps:
• qDSLRDashboard (Android/iOS)
• Cascable (iOS)
• DSLR Controller (Android)
Physical Remotes:
• Wired remote with timer
• Wireless remote + timer attachment
• Intervalometer (dedicated device)

3. Shooting Tips

Use remote to avoid camera shake
Lock mirror up (DSLR) before long exposures
For star trails: 5-30 minute exposures
Watch battery life - use AC adapter
Consider stacking shorter exposures instead

⚠️ Trade-offs:

Very long single exposures (>5 min) increase noise and risk of hot pixels. Stacking many shorter exposures often produces better results with less noise.

Sunrise & Sunset Timelapses

Capture the dramatic transition from day to night (or night to day) with changing light conditions requiring exposure adjustments.

Method 1: Manual Exposure Ramping

Start in manual mode with night sky settings
Set initial: ISO 3200, f/2.8, 20-30s exposure
Check camera every 5-10 minutes
Gradually reduce ISO (3200 → 1600 → 800 → 400)
Then increase aperture (f/2.8 → f/4 → f/5.6)
Finally reduce exposure time (30s → 20s → 15s → 10s)
Use exposure compensation to smooth transitions

⏰ Timing Reference:

Twilight phases:
Astronomical twilight: -18° (darkest)
Nautical twilight: -12°
Civil twilight: -6°
Sunrise/Sunset: 0°

Method 2: Aperture Priority + Auto ISO

Set to A/Av mode
Keep aperture constant (f/2.8 or f/4)
Enable Auto ISO with limits (400-6400)
Set minimum shutter speed (1/30s or slower)
Use exposure compensation (-1 to +1 EV)
Camera adjusts ISO and shutter automatically
Less control but smoother transitions

Method 3: Automated Ramping (Advanced)

Use apps like qDSLRDashboard or LRTimelapse
Create exposure ramping curve ahead of time
App automatically adjusts settings during capture
Most professional method for smooth results
Requires compatible camera and app

🎬 Post-Processing:

Use LRTimelapse or apply deflickering in video editor to smooth out exposure changes between frames. Apply edits consistently across all frames.

Equipment Essentials

Must-Have Gear

Sturdy Tripod: Heavy-duty, no center column extension if possible
Remote Shutter/Intervalometer: Essential for long exposures and timelapses
Wide-Angle Lens: 14-24mm full-frame equivalent preferred
Fast Lens: f/2.8 or faster (f/1.4-1.8 ideal)
Extra Batteries: Cold weather drains batteries faster
Memory Cards: High capacity, fast write speeds (UHS-II recommended)

Nice-to-Have

Star Tracker: Enables longer exposures without trails
Light Pollution Filter: CLS or similar for city shooting
Heater Strip: Prevents lens fogging in cold/humid conditions
Red Headlamp: Preserves night vision while working
Warm Clothing: Essential for long night shoots

Settings Reference Guide

Dark Sky Settings (Bortle 1-3)

ISO: 800-1600
Aperture: f/2.8 - f/4
Exposure: 20-30s (use calculator)
White Balance: 4000-5000K

Suburban Settings (Bortle 4-6)

ISO: 1600-3200
Aperture: f/2.8 (wide open)
Exposure: 15-20s (use calculator)
White Balance: 3500-4500K
Consider light pollution filter

Urban Settings (Bortle 7-9)

ISO: 3200-6400
Aperture: f/2.8 or faster
Exposure: 10-15s max
Focus on bright objects (Moon, planets, constellations)
Light pollution filter highly recommended

🔍 Always Use the Calculator:

Your exact settings depend on focal length, sensor size, and target position. Use the Astro Calculator for precise exposure times.

Best Practices & Common Mistakes

✅ Do This

Shoot during new moon or moonless nights for darkest skies
Use the 500 rule or NPF rule to calculate max exposure
Check weather and cloud forecasts before heading out
Arrive early to scout location and set up in daylight
Bring backup batteries and memory cards
Take dark frames for noise reduction
Compose with interesting foreground elements
Use Live View focus assist (zoom 10x on bright star)
Shoot RAW for maximum editing flexibility
Use interval timer for consistent spacing

❌ Avoid This

Don't use autofocus - always manual focus
Don't shoot during full moon (too bright)
Don't skip the interval between shots in timelapses
Don't touch the camera during exposure
Don't use image stabilization on tripod
Don't use high ISO unnecessarily (adds noise)
Don't forget to check your first few shots
Don't ignore the histogram - expose to the right
Don't use white balance auto (camera gets confused)
Don't forget to disable long exposure NR for stacking

Quick Reference: Exposure Times by Focal Length

Focal Length	500 Rule*	NPF Rule**	Notes
14mm (full-frame)	~35s	~25s	NPF more accurate for modern sensors
24mm (full-frame)	~20s	~15s	Popular wide-angle choice
35mm (full-frame)	~14s	~10s	Good for wider compositions
50mm (full-frame)	~10s	~7s	Standard lens, shorter exposures needed
85mm (full-frame)	~6s	~4s	Telephoto, consider star tracker

*500 Rule: 500 ÷ (focal length × crop factor) = max seconds. Outdated but still used as rough estimate.

**NPF Rule: More accurate, accounts for sensor pixel size. Use the Astro Calculator for precise values based on your exact equipment.

💡 Always use the Astro Calculator for your specific camera and lens combination!