CrazyNeutrino said:
Lockheed Martin shrinks the telescope
After 400 years, the original telescope design is getting a major upgrade. Part of a DARPA funded project, Lockheed Martin’s Segmented Planar Imaging Detector for Electro-optical Reconnaissance (SPIDER) telescope replaces the large primary lenses used in refracting telescopes with an array of tiny ones that allow the instruments to shrink by a factor of 10 to 100.
more…
> such telescopes have been hampered by the fact that in order to make a refracting telescope more powerful, the front or primary lens needs to be larger and therefore heavier.
I’ve said it before. Fresnel lenses don’t have this problem. When combined with mirrors, the Gascoigne (and similar) correcting lenses used on telescopes like Pan-Starrs also don’t have this problem.
> an array of tiny ones. SPIDER replaces the primary lens with a thin array of tiny lenses like the eye of an insect. Each of these lenses feeds light to a silicon-chip photonic integrated circuits (PIC)
Many sensors (CCD and CMOS) already have an array of tiny lenses in front, one per pixel, the purpose is to make the approaching photon travel more perpendicularly to the pixel, thus improving the output at larger approach angles.
> The clever bit is that SPIDER operates on the principle of interferometry. Normally, this is used by astronomers as a way of turning a number of optical or radio telescopes distributed across an area into one gigantic telescope. It does this by combining the images from these telescopes so they interfere with one another. By analyzing the amplitude and phase of the interference patterns, scientists can turn them into a new image of much higher resolution. “What’s new is the ability to build interferometer arrays that have the same number of channels as a digital camera. They can take a snapshot, process it and there’s your image. It’s basically treating interferometer arrays like a point-and-shoot camera.”
I’ll say that’s new, that’s brilliant if it works. The interferometry is done in hardware behind the chip, which means massively huge numbers of microscale electrical connections.
> a SPIDER telescope doesn’t have to be a tube.
The purpose of the tube is rejection of bright light (such as that from the Sun and Moon). Some such baffle system would still be needed – except for Earth observation during the day of course.
> Probably wanted one on their SR-72…….
The video shows one proposal where it’s attached to a cruise missile.