How long your trails will be, how many frames the session takes, and whether the gap between them will turn the trails into dotted lines. Free, no sign-up.
All the free tools
Every tool fastast serves, each on its own page. No account, no e-mail, nothing stored — open one, use it, close the tab.
Every tool here does one thing, on one page, and asks nothing of you: no account, no e-mail address, no cookie banner to dismiss before you can work. Type what you need, read the answer, close the tab. Nothing you enter is kept.
Each tool has its own address, so a link to one is a link to that tool alone. The list below is the whole set, and the search box filters it by name or by what a tool does.
NPF rule calculator: how long you can expose the night sky before stars trail, from your sensor, lens and where you point, not focal length alone.
Which nights of the next year the Milky Way core is visible from your location: dark sky, no Moon, core high enough, grouped into runs. Free.
Moon phase calendar for your city: every night's phase, illumination, moonrise and moonset, distance and size, and how big it is on your lens.