From: seawasp@sgeinc.invalid.com   
      
   On 11/24/18 6:24 PM, Jaimie Vandenbergh wrote:   
   > On Sat, 24 Nov 2018 15:01:45 -0800 (PST), lui wolff   
   >  wrote:   
   >   
   >> When dealing with a visible light telescope, if the angular resolution   
   can't resolve the target size as 1 pixel, it's out of range, right?   
   >   
   > Wrong. Pixels aren't one photon wide, they're not just lit or dark. They   
   > will collect photons over time and that is integrated to show the   
   > signal.   
   >   
   > Sensitivity to different EM spectrum ranges is variable, depending on   
   > our ability (and interest) in developing sensors. So there isn't a   
   > universal equation for this part of your spreadsheet, it's very   
   > dependent on technology. Sea Wasp (not sure if he watches here) might   
   > have more info on this, it's his field.   
   >   
      
      
   	Well, there's a lot of people more knowledgeable than me in this. BUT...   
      
   	You're basically correct. Obviously the subtended angle of your target   
   is ONE element. But another very obvious one is the INTENSITY of the   
   target. If you have someone fire a perfectly collimated laser with a   
   spot size of 1/10th your pixel size, you'll still get a pixel activation   
   if that laser dumps in enough photons. SO a really really intense source   
   of heat/light will activate one (or more) of your pixels even if its   
   subtended arc is technically smaller than your receiver.   
      
   	Imagine it like being in a very dark, almost infinitely long cave and   
   someone shining a light at the end of it. You will be able to see the   
   light MUCH farther away than you could have resolved the light's emitter.   
      
   	With Infrared sensors, it's rather different depending on the   
   technology. The most common, microbolometers, work very differently than   
   standard optical imaging sensors (CMOS, usually).   
      
   	Noise floor is another major issue. There's others.   
      
      
   	You can make up for lack of resolution on your sensor in other ways,   
   too. Multiple exposures of the same target taken from properly   
   co-registered locations can be processed to effectively extract more   
   detail than any individual picture would yield.   
      
      
   --   
                         Sea Wasp   
                           /^\   
                           ;;;	   
   Website: http://www.grandcentralarena.com  Blog:   
   http://seawasp.dreamwidth.org   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)