| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| Dongjie | "cool, how do you make the figure like Google streetmap? " | Read more » | over 10 years ago | |||
| nathanathan | "I've started experimenting with phosphorescent paint. Here's a link to a note on what I've done so far. " | Read more » | over 10 years ago | |||
| nathanathan | "I recently ordered a smartphone spectrometer, measuring glow in the dark pigment spectra seems like a fun project to try it out on. I'll give it ..." | Read more » | over 10 years ago | |||
| cfastie | "For some reason it's hard to find spectra of glow-in-the-dark pigments. Really, a thousand Public Lab spectrometers out there and no one has done t..." | Read more » | over 10 years ago | |||
| nathanathan | "I would like to know how glow in the dark paint compares to LEDs. Postcards with glow in the dark rainbows painted on them could be packaged with s..." | Read more » | over 10 years ago | |||
| cfastie | "Would the LED have to be placed outside the entrance slit? Otherwise the grating would form an image of the entire bulb. Standard single color LED..." | Read more » | over 10 years ago | |||
| warren | "I'm interested in something similar for spectrometer exposure calibration -- putting an LED and battery inside each spectrometer, on one side, so y..." | Read more » | over 10 years ago | |||
| cfastie | "The Canon A2200 (refurbished) is on sale today (November 21) for $48.99 (free shipping) with a one year warranty: http://shop.usa.canon.com/shop/e..." | Read more » | over 10 years ago | |||
| mathew | "cool test! this is definitely the most pixels in a research note, as far as I've seen. " | Read more » | over 10 years ago | |||
| mathew | "I think doing calculations based on red and green might be two ways to get to the same result that Chris was seeking in his Oaktober note-- the cha..." | Read more » | over 10 years ago | |||
| warren | "It's weird because we think of green being reflective, but compared to IR, it's very absorbent. " | Read more » | over 10 years ago | |||
| cfastie | "Mathew, That does seem to be a consistent pattern. I think you are right that a green filter might offer the purest visible light channel in a sing..." | Read more » | over 10 years ago | |||
| mathew | "looking at the sensor sensitivity graph for the Nikon D200, its interesting that green is the least sensitive channel in the infrared band, implyin..." | Read more » | over 10 years ago | |||
| cfastie | "Hi Pat, The Wratten 25A is an old standard photographic filter that is still widely available in glass and gel. I think Ned bought a genuine Kodak ..." | Read more » | over 10 years ago | |||
| patcoyle | "Thanks Chris and Ned, this is an encouraging line of inquiry. Remind me on the source for the Wratten 25 filter material, or is it in the prior not..." | Read more » | over 10 years ago | |||
| cfastie | "The aperture mechanism definitely varies among Powershots. By peering into the front of the lens I learned that the high end ones have an actual ir..." | Read more » | over 10 years ago | |||
| timmm063 | "Have you considered watching other sites for cameras that are refurbished? One I would recommend is canonpricewatch.com. It also shows prices for o..." | Read more » | over 10 years ago | |||
| danbeavers | "The filter should have nothing to do with the difference in quality between the center and edge of the image since it is uniform in density. Lense..." | Read more » | over 10 years ago | |||
| cfastie | "I was assuming that the best way to preserve image quality when removing a glass filter would be to replace it with another glass filter. Plastic, ..." | Read more » | over 10 years ago | |||
| warren | "Very interesting line of inquiry. I've always been a bit confused about the role of the filter material itself in focus -- my assumption has been t..." | Read more » | over 10 years ago |