Methodology

• Every data point is a real public page opened by a person, with link, date and one label: Sold (seller marked it sold; if the final price wasn't stated we say so and use the listed price), Asking (listed, not confirmed sold), Dealer demo (dealer used/demo/refurb price), User-reported (sent to us; proof link if any).
• The headline median uses only Sold + Dealer demo points, and only when there are at least 3. Otherwise we show the points and say "not enough sales yet". Asking prices get their own median.
• Variants (tube type, white/green phosphor, sensor/lens, V1/V2) are kept on separate rows, not blended.
• No eBay scraping and no automated forum scraping. We read individual public pages and follow each site's rules.
• US data only; non-US listings are excluded.
• Not an appraisal. Condition, warranty and accessories move real prices.

How specs affect price

Two units with the same model name can be very different devices. These are the specs buyers look at, in plain words. We do not apply price multipliers; we show the specs next to each price so you can compare like with like.

• FOM (figure of merit): a night-vision tube's resolution (lp/mm) multiplied by its signal-to-noise ratio. One number for overall tube quality; higher generally means a clearer, less grainy image. It only means something if it comes from the tube's own spec sheet.
• SNR (signal-to-noise ratio): how clean the image is in very low light. Low SNR looks like "sparkly" static on dark nights.
• Resolution (lp/mm): how much fine detail the tube can show, measured in line pairs per millimetre.
• EBI (equivalent background illumination): the faint glow a tube shows even with no light coming in. Lower is better; high EBI washes out the darkest scenes.
• Blemishes: permanent dark or bright spots in the tube. Their size and zone (zone 1 is the centre, the most noticeable) matter more than the count; spots in the centre bother users most.
• Phosphor, gen, autogating, halo, tube date, spec sheet: white vs green is a preference; Gen 3 vs Gen 2+ is a different tube class; autogating protects the image in changing light; smaller halo around lights is better; a tube date and the original spec sheet let a buyer verify the numbers.
• Sensor resolution and pixel pitch (thermal): more sensor pixels (e.g. 640x480 vs 256x192) mean more detail at distance; pixel pitch with the lens focal length sets magnification and field of view.
• NETD (thermal): how small a temperature difference the sensor can see, in millikelvin. Lower means more contrast in fog, rain or humid air.
• Lens, LRF, firmware: bigger lenses reach farther; a built-in laser rangefinder adds function; firmware version can change features.
• Condition, warranty, hours, accessories: remaining transferable warranty, low use and a complete kit (batteries, mounts, case) are often mentioned by sellers. We record what the listing says and nothing more.