Adey Baker said:
Incidentally, on a straight note, the set-up by the bloke in 1935 involved mounting the camera without the lens (so not quite the fore-runner to digiscoping).
Digiscoping is afocal coupling with a digital camera. Afocal coupling is about as old as optics and cameras. Using the eyepiece and no camera lens as Adey mentions above is called eyepiece projection.
So yes, digiscoping isn't some new technological breakthrough. But when the first people repeated the same thing that has been done through the years with various scopes and cameras, some of them noticed a significantly better result. We happen to live in a time when a lot of the things that made this type of photography impractical has been improved very significantly.
Lens coatings make prictical the stack of the many optical surfaces found in the scope objective, eyepiece and zoom camera lens digiscoping combo. Without these advanced coatings, I suspect the image would be extremely low in contrast.
The small CCD found in digicams results in small camera lenses which have entrance pupils that can fall within the eye relief of the scope. This combined with relatively long eye relief eye pieces (common because scope manufacturers are being more sensitive to the needs of people wearing glasses) lets many more camera and eyepiece combination work well.
And finally, high power spotting scopes for birding have really advanced in quality over the past few decades.
When you combine these elements (and probably others like autoexposure and autofocus) with the near instantaneous feedback and the super low cost per shot of a digital camera, an approach that used to typically yield poor results becomes quite viable and practical.
So at a fundamental level, it is true that digiscoping isn't new. But at a practical level, there is a good reason it is perceived by many as a "new breaktrough". Without the relatively new developement of the digital camera and the refinement of other related technologies, digiscoping would not be a very viable technique.
