If you really can't get AF to latch onto anything, then switch it to MF and if your lens has a physical display/ruler showing the focus distance then rotate your focus-ring until it's set it to the infinity mark, or if it doesn't have one then fine, go and squint through your camera at the night sky and rotate your focus ring back an forth until the stars look as sharp as you can. After it's managed to *beep* and latch onto something with AF, then take your finger off, find the Manual Focus (MF) switch (usually on the side of your lens) and switch your lens to MF and then you're good to go - now just remember not to bump that autofocus ring (or the zoom ring either as on some lenses changing zoom affects focus, so it might be best to set how wide you want to zoom first). It helps to set your camera to use only its centre auto-focus point so you can precisely select what to focus on. Yes you usually can actually Auto Focus (AF) at night, providing you accurately point at a star that's bright enough, or at something like the moon, or failing these, on a point light source on the horizon somewhere - its all about the same distance away as far as your camera's concerned. Don't let all these ideals dissuade you though, you can still have fun and get some pretty cool shots in your backyard, in town.īefore you get tangled atop tripods, get your focus sorted first. I think the best star trail shots are ones with something interesting framing up the foreground, so perhaps near some impressive trees and an old shed or something. Another point to consider when picking your location is what to have in your foreground. Also it's best to shoot from somewhere where there's less chance of a car, a torch-wielding person, or even a plane accidentally ruining your shot. Of course you need a clear, cloudless night, and ideally a dry (not humid) night too, else condensation may form on your lens (some people literally wrap those little hand-warmers around the lens to keep it warm to prevent this). The moon too adds significant light pollution so shooting during a 'new moon' (no moon) is ideal, or when the moon has set below the horizon, or at the very least, is well out of shot (and won't move in!). Removing the offending trails, cosmic ray strikes, and other artifacts that don’t belong.You really can try this anywhere, but you'll find that if you're too close to town, then the 'light pollution' that emanates from civilisation makes it harder to see the stars, so rather than being nice and black, the background to your stars will become a pale haze instead, and this also means you won't be able to take as long a photo (ie such long trails) before it becomes completely washed out. It continues by computing which pixels are brighter or darker than all the other frames and rejects them. The process works by creating an average of all the pixels in your subframes and compares each pixel. So, the pixels making up the satellite trail magically disappear. When a sample value falls outside the acceptable range, Winsorization does not simply reject it but replaces it with the nearest valid neighbor in the sample. The process is Pixel Rejection, and the pull-down selection is Winsorized Sigma Clipping. It works best if you have 10 subframes or more. But, by far, the easiest is to let the application replace the satellite trail. Some manual methods include PixelMath and d2Seg (which draws a line segment between two x and y points). Once a satellite leaves its trails on your frame, it’s near impossible to remove it after stacking.įortunately, PixInsight and other astrophotography processing software can deal with removing the trails during stacking. No one likes to be photobombed, especially astrophotographers, by the ever-increasing number of satellites.
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