We recently reported on the amateur scientific work of Forrest Mims. Forrest is somewhat unique in being an amateur scientist who has consistently published his work in leading scientific journals. One area of scientific investigation has however attracted amateur scientific contributions of the highest quality almost since its inception, amateur astronomy.
You’ve likely heard of amateur astronomers like David Levy co-discoverer of the Comet Shoemaker–Levy 9 comet, and citizen science projects like galaxy zoo. But the history of amateur astronomy goes back far further than this, in fact as far back as 1781 William Herschel discovered the planet Uranus while employed as a Musician. Another entertainer of sorts, 1930s British comic actor, Will Hay, also made significant contributions discovering a “Great White Spot” on Saturn in-between films roles. Will was an avid amateur astronomer who regularly published his observations.
His belief that astronomy allows us to see humanity’s place in the universe in its true proportion led him to claim “If we were all astronomers there’d be no more war”.
While Will recorded his observations, hand drawn, in a log book. Modern astronomers digitally image the night sky. Digital cameras are of course optimized around the human visual system (as we recently discussed) making them less than ideal for astrophotography. Hackers have therefore made a number of innovations, one of the more audacious being the removal of the Bayer filter:
The Bayer filter is a colored mosaic filter that covers the imaging sensor, splitting light into its Red, Green and Blue components. By removing this filter you effectively triple the camera’s resolution at the cost of its color sensitivity. Somewhat surprisingly the Bayer filter can be removed with a little careful scraping (shown above). While this also removes the microlens which directs light toward the sensor photodiodes, the overall effect is beneficial in many cases.
This is rather drastic, but less destructive modifications are also available. When imaging distant light sources, noise reduction is critical. To remove systematic noise astrophotographers take a “dark image” of a black surface. This background is then subtracted when processing the images. This removes systematic noise in images, which is present is all shots. The remaining noise source is then random. And the most significant source of this random noise is heat. Heat, at the atomic scale, is motion. When charge carriers (electrons) are pushed around by this motion that causes noise. This “Thermal” or Johnson noise causes problems in all kinds of precision applications and there’s really only one way of reducing it: cool things down. For this reason astrophotographers have modified their cameras with active cooling. This often takes the form of a peltier cooler and heatsink, as shown to the right. Commercial digital camera mod kits are also available and the resulting images look great.
Amateurs have often used their advanced optical setups to make significant scientific contributions, like Wayne Jaeschke who recently discovered plumes on Mars. His work, confirmed in collaboration with professional astronomers was published in the journal Nature, and led scientists to dig into their archival images, discovering previous evidence of Martian plumes, of as yet unknown origin.
So far we’ve discussed the use of optical telescopes, but amateurs have also made progress in radio astronomy. While rarely producing the visually appealing images of optical telescopes they are in many ways more technically appealing, relying much more on electronics and signal processing. With the arrival of cheap software defined radio platforms like the RTL-SDR we’ve seen a host of cool radio astronomy projects like pulsar detection, detecting meteors, and capturing noise bursts from Jupiter. The easiest way to get started is probably solar activity monitoring. A good example is the SIDmonitor used to monitor the ionosphere for solar flares. The SIDmonitor is a very simple VLF receiver using a simple opamp. Using this receiver you can detect the sun as it rises and sets, and any peaks caused by unusual solar activity.
It’s hard not to admire the scientific contributions and perseverance of amateur astronomers. Perhaps as Will Hay suggested, if we spent a little more time looking to the sky our cosmic insignificance would be more apparent, and we’d worry a little less about our comparatively small existence.