Types of astrophotography compared

The figures are typical ranges, not rules. A good result is possible outside them.

This is the landscape side of astrophotography: a wide, fast lens, a tripod, and a dark foreground under the Milky Way. Because the sky turns, a tripod exposure has to stay short, or the stars become short trails. A common starting point is 15 to 20 seconds at f/2.8 with a 20 mm lens, then you check the stars at full size. The longer the lens, the shorter the exposure you can use. Many people take several frames and stack the sky to cut noise, and shoot the foreground separately.

• Plan it with the Milky Way page: the best months and moon-free dates for your site.
• Use the exposure calculator for the longest exposure before the stars trail.
• A dark site matters more here than anywhere else. A Bortle 4 sky or better shows the core clearly, and a city sky barely shows it.

Wide field means tracked exposures with a short lens or small refractor, so you frame an entire region of sky: Orion, the Heart and Soul nebulae, the Rosette, Andromeda with its neighbors, or a stretch of Milky Way with no foreground. A star tracker lets exposures run for minutes, so far fainter detail appears than on a tripod. Alignment must be reasonably good, but guiding is often skipped.

This is the best bridge into deep sky. You learn tracking, stacking and stretching with forgiving gear. Use the FOV calculator to see which targets fit your lens, and read the calibration frames guide and the processing guide.

Deep-sky imaging uses a telescope to show a single nebula, galaxy or cluster in detail. Targets are faint, so the work is about collecting enough light: long exposures, many of them, over many nights, with a mount that tracks precisely. It has the most equipment, the most steps and the biggest payoff, and it is the most affected by your sky and the Moon. Filters, calibration frames, guiding and a careful stretch all matter.

• Browse the targets and the dark calendar to plan.
• Learn the filters, pixel size and noise and polar alignment pages.
• Expect each target to take several nights. The planner shows which nights are worth setting up for.

Planetary imaging turns the usual rules upside down: very long focal lengths, exposures of milliseconds, video instead of stills, and light pollution that hardly matters. Instead of fighting a faint signal, you fight the shimmer of the atmosphere, and processing is about choosing the best frames and sharpening them. It suits bright skies, a bright Moon and short evenings. Read the photographing planets guide for the details.

• You have a camera and a tripod and want to start tonight: Milky Way wide, if you can reach a dark sky.
• You live under bright skies: planetary and the Moon work from anywhere. Narrowband deep sky is the other route from town.
• You want nebulae without a telescope: wide field on a star tracker.
• You have a telescope and plenty of patience: deep sky.
• You have little time per night: planetary, or wide field with short sessions.
• You like to tweak and process: deep sky has the most to learn. Planetary processing is shorter but fussy.

The types share a lot of the same skills: focusing, reading the histogram, stacking, and learning to read the weather and the Moon. Time spent on one carries over to the others.

1. Start with the Milky Way on a tripod to learn exposure, focus and the sky.
2. Add a star tracker for wide field, which teaches tracking, calibration and stacking.
3. Move to a telescope and an equatorial mount for deep sky, adding guiding and filters as the targets demand.
4. Try planets and the Moon whenever the sky is bright or the Moon is up. They need only the telescope you already have, plus a small camera and a Barlow.

You do not need to follow it in order. Plenty of people never leave one type, and a good picture in any of them is hard to take.