Astrophotography Planner
Plan your astrophotography sessions with precision. Exposure calculators, celestial event tracking, and optimal shooting conditions.
Calculate maximum exposure time before stars trail using NPF Rule, 500 Rule, and more
Most accurate method. Accounts for sensor resolution and aperture.
(35 × A + 30 × P) ÷ F
Classic rule. Often produces slight trailing on modern sensors.
500 ÷ (F × crop)
Conservative. Safer for high-resolution sensors and pixel peeping.
300 ÷ (F × crop)
One frame at 100 percent tells you whether the next hour is worth shooting
A slightly bright frame is easier to darken later than a dark frame is to brighten. Shadows hold the noise. A peak pressed against the left edge needs more ISO, or a longer shutter within the NPF limit above.
Focus and shutter are right.
The shutter is too long for the focal length. Shorten it.
Coma, from the lens. Stop down from f/1.4 toward f/2.0.
Focus. Refocus at 10× on a bright star and tape the ring again.
Plan shoots around the lunar cycle — new moon is ideal for deep sky imaging. Dedicated page: Moon Phase Tonight.
| Phase | Illumination | Deep Sky | Best For |
|---|---|---|---|
| New Moon | 0–5% | Excellent | Milky Way, nebulae, faint DSOs. Darkest skies. |
| Crescent | 5–35% | Good | Deep sky when moon is below horizon. |
| Quarter | 35–65% | Limited | Plan around moonrise/set times. |
| Gibbous | 65–95% | Poor | Star trails, moonlit landscapes. |
| Full Moon | 95–100% | Avoid | Lunar photography, moonlit scenes only. |
Galactic core visibility by month and hemisphere
Four checks before you leave, in this order
The Milky Way and deep sky need astronomical darkness. Nautical darkness is enough for aurora and the moon.
A moon below the horizon while the subject is up is the dark window. A bright moon washes out the Milky Way and faint targets. Aurora, star trails, and a lit foreground can work under it.
For the Milky Way, where the core rises and how high it climbs. For aurora, the Kp your latitude needs, from the Aurora Tracker. For a deep-sky target, the months it is up in the evening, in the Deep Sky Objects finder.
A clear forecast can still be haze. Humidity and thin high cloud wash out the core even when stars show.
If the first two fail, pick another night. If all four pass, scout the foreground in daylight and arrive before dark.
Major annual meteor showers with peak dates and expected rates
| Shower | Peak Date | ZHR | Speed | Moon | Conditions | Radiant |
|---|
The Bortle Dark-Sky Scale for evaluating observation sites
Zodiacal light, gegenschein, and zodiacal band visible. Scorpius and Sagittarius regions cast shadows. Airglow is visible.
Airglow may be faintly visible near horizon. M33 visible with direct vision. Summer Milky Way highly structured.
Light pollution domes visible on horizon. Clouds illuminated near horizon. Milky Way appears complex.
Light pollution domes obvious. Milky Way visible but lacking detail. M31 visible to naked eye.
Milky Way washed out at horizon. Clouds clearly illuminated. Only hints of zodiacal light on best nights.
Milky Way only visible at zenith. Sky background appears grayish-white. M31 barely visible.
Entire sky has vague grayish-white hue. Milky Way invisible. Strong light sources in all directions.
Sky glows white or orange. Only the moon, planets, and a few bright stars visible. Ground brightly lit.
Two faint glows from dark sites. Neither is a town, and neither is aurora.
It is sunlight scattered by dust in the plane of the solar system. It rises from the horizon as a tilted cone along the ecliptic, once twilight is fully gone, or just before dawn begins. From the Northern Hemisphere it is best in the west after dusk from February to April, and in the east before dawn from August to October. From the Southern Hemisphere the months swap. It needs a dark site and no moon.
It is light from the upper atmosphere itself. It shows as faint green or red bands, strongest 10 to 20 degrees above any horizon, at any latitude and any hour. It drifts slowly, where aurora changes in minutes. Leave it in the frame. Pulling it out usually takes the sky color with it.
It sits on one horizon only, as a dome, usually orange. Driving away from it helps. Driving farther does nothing for the other two.
Going from f/4 to f/1.8 more than doubles the starlight you capture in the same 20 seconds.
See mount picks15–25 second exposures: any wobble smears stars into dashes.
View on AmazonWhite light ruins night vision. Red light lets you change cards without flooding the scene.
View on AmazonOptimal settings for different astrophotography subjects
Quick reference for the field
