Thousands of frames, and only the sharpest kept
A planetary camera works by a method that has no equivalent in ordinary photography: it records thousands of short frames, and software then discards all but the small fraction taken in the moments when the atmosphere happened to be still. The technique is called lucky imaging, and it is why a modest telescope can produce planetary detail that a single exposure could never hold. What follows from the method is which specifications matter. Frame rate comes first, because the whole approach is a numbers game — more frames in the window when the planet is well placed means more usable ones — and the frame rate that counts is the one achieved over the small region of interest the planet occupies, not the full-sensor figure in the headline. Pixel size has to be matched to the focal length of the telescope: pixels too large throw away resolution the optics delivered, pixels too small spread the same light thinner for nothing. The sensor is small by design, since a planet is small. Cooling matters much less here than it does for deep-sky work, because the exposures are measured in milliseconds and thermal noise has no time to build. Read the interface — USB 3 against USB 2 changes the achievable frame rate directly — and read what the camera threads into, and which capture software the maker actually supports. We compare camera type, sensor and pixel size, frame rate, region-of-interest capture, interface, cooling, filter thread, eyepiece fitting and software support.
1.25 in barrel · USB · Moon and planets only, per the maker
A simple USB electronic eyepiece for a 1.25 in focuser, which the maker states outright is for the Moon and planets and not for deep-sky imaging.
Best for: A first attempt at putting the Moon on a laptop screen, at minimum cost
≈ £15 / €25
1.25 in barrel · USB · automatic white balance
A basic USB electronic eyepiece for a 1.25 in focuser with automatic white balance, sold on a listing that repeats its first bullet six times.
Best for: A very cheap first experiment with lunar video capture
≈ £13
4K claimed · 3 in colour display · clamps over eyepieces 22–46 mm
A self-contained electronic eyepiece with a three-inch colour screen that clamps over eyepieces from 22 to 46 mm and records to a card of up to 128 GB.
Best for: Showing the Moon to a group on a screen larger than a phone
≈ €42
3840 × 2160 claimed · 3 in LCD · clamps over eyepieces 22–46 mm
A clamp-on electronic eyepiece with a three-inch colour LCD, adjustable focus and brightness, published at 3840 × 2160 and sold for birdwatching as much as for the sky.
Best for: Daytime wildlife recording through a spotting scope, with the Moon as a secondary use
≈ €50
4 MP sensor · 2 in display · clamps over eyepieces 38–73 mm
A Wi-Fi electronic eyepiece with its own two-inch screen and battery, clamping over eyepieces from 38 to 73 mm, recording 2K video to a card of up to 256 GB.
Best for: Screen-sharing a view in the field, with no laptop and no phone required
≈ €66
4 MP CMOS · 1.47 in display · clamps over eyepieces 30–65 mm
A Wi-Fi camera that clamps around an existing eyepiece rather than replacing it, with a 1.47 in screen, app control and a 32 GB card supplied.
Best for: Recording what an eyepiece already shows, on any instrument that has one
≈ £89 / €99
8 MP · IMX415 colour sensor · 1.25 in barrel · USB 3.0
An electronic eyepiece with an IMX415 colour sensor that replaces a 1.25 in eyepiece and streams live video to a computer over USB 3.0.
Best for: Lunar and planetary video through a 1.25 in focuser, on a Windows or Linux laptop
≈ £84 / €100
Any figure written into the body of this page was true on the day it was written. The amount shown next to each instrument is requested from the retailer as the page loads, and it is that amount, not the text, that stands.
