Finally got the sun and the helioscope together and has a few minutes to play and adjust. Its FAR from a usable instrument. But here are the preliminary results. Here is the actual sunspot imagery from NASA’s hundred million dollar SOHO satellite. It shows two “small” sun spots This represents the best possible images one could hope to achieve.
Archive for June, 2011
Our media services people were cleaning out the musty, dusty recesses of the campus and found a circa 1960′s opaque projector. It was a high quality version with a very nice, huge, projector lens. The lens itself has a whopping 4″ diameter clear aperture, and a 18″ focal length, and is well, but not perfectly, corrected for color. It was designed to take a letter sized paper and project it on a 6 foot screen. The lens forms a pea size image of the sun which basically vaporizes anything in its path. Its not a toy.
I’ll be going out to Provo, Utah for the Novell ( Attachmate? NetIQ? SuSE? ) TTP Conference. I’ve been in the habit of shooting time lapse series in the evenings and free time ( what’s that? ) while I’m out there – as its a very different place from the verdant rolling hills of Eastern Pennsylvania. I normally use a portable AC supply, which is an integrated 12 volt 20 Ah battery + inverter. So while the battery itself provides about 200 watt-hours, it can only power the camera for 12 hours. It weighs about 20# – so not really something you want to carry around or take on a plane. The underlying problem is that the camera needs 8.4vdc, which comes from the AC adapter, which is fed by the inverter, fed by the 12v battery. So there is a lot of waste and inefficiency. The camera itself uses only 4 watts, and the AC adapter uses 20 watts! So already we are at 75% waste. Also the power pack needs to be protected from the elements – and it uses house current, so dangerous when wet. Other than that, its great!
So I built a DC-DC power supply using off the shelf components: 2000 mAh AA NiMH batteries, an 8 AA cell battery holder from Radio Shack, and a DC-DC switching power supply. The DC-DC converter is a very cool. It has a 20-turn potentiometer to adjust the voltage out, and decoupling capacitors on the output so no external caps are necessary. Its about the size of a nickel. And it accepts Vin up to 30 volts! I created a harness so multiple DC-DC modules can be dialed in to the desired voltage and easily swapped out depending on the camera used.