Comments

Author Comment Last activity Moderation
cfastie "Dan, paste this embedding code into the note. We might have to adjust the height and width values. [open angle bracket]iframe src="http://www.giga..." | Read more » about 11 years ago
cfastie "Jeff, the critical angle seems to be the grating angle in relation to the light path from the slit. For 1000 lines/mm grating film, this angle is a..." | Read more » about 11 years ago
cfastie "That looks beautiful. Also very clever. Will there be any provision to alter the geometry among the slit, the grating and the camera lens? Assumi..." | Read more » about 11 years ago
cfastie "I guess that's 148 megapixels. So get a free account at gigapan.com, download the free uploader, upload your jpg, and click on embed to get the emb..." | Read more » about 11 years ago
cfastie "ICE is free and easy and worth having: http://research.microsoft.com/en-us/UM/redmond/groups/IVM/ICE/ You can get a free account at Photosynth: ht..." | Read more » about 11 years ago
cfastie "Dan, How many pixels does is have? If you cut it into three generously overlapping pieces, then stitch them back together in Microsoft ICE, you can..." | Read more » about 11 years ago
cfastie "Required viewing for Spectronic 20 owners: Thanks to Nadya for discovering this one. " | Read more » about 11 years ago
cfastie "Yes, now I have it. When the entrance slit is rotated the rectangular spectral image turns into a parallelogram. It seems to get compressed vertic..." | Read more » about 11 years ago
cfastie "Tom, The Jobin Yvon tutorial describes reflection gratings, and I don't know enough to apply those rules to our transmission grating setups. The ma..." | Read more » about 11 years ago
cfastie "Dan, I don't know what you mean by slit to grating angle. Angle g? Tom, I am reading now! " | Read more » about 11 years ago
cfastie "Jeff, Really good questions. I don’t think I can answer any of them from first principles. Focusing the image of the spectrum is one of the inscru..." | Read more » about 11 years ago
cfastie "Adam, You must be right that some protocols for identifying substances require knowledge of the absolute intensity of spectral peaks. I am not fam..." | Read more » about 11 years ago
cfastie "Adam, That's right, a narrower entrance slit allows emission or absorption lines to be resolved better. So you can know more precisely the wavelen..." | Read more » about 11 years ago
cfastie "Andres, I think when you do some things to a spectrum, like re-extract, rotate image, or set sample line, the calibration is reset to null. So it m..." | Read more » over 11 years ago
cfastie "Hi Jan, Thanks for this post. It is really good to see data on the effect of the blue LED. Your spectrograph makes it clear that most people will..." | Read more » over 11 years ago
cfastie "It looks like 3° of change in the angle is not enough, and maybe 6° is needed for center the visible spectrum in the photo image. But I am a little..." | Read more » over 11 years ago
cfastie "The only relevant waste stream I know of is under my desk where several one inch squares of the stuff are somewhere. I keep dropping them and litt..." | Read more » over 11 years ago
cfastie "Pat this is cool. Obviously there are no overhead utility lines in your neighborhood. Hooray for suburban planning. " | Read more » over 11 years ago
cfastie "Instructions for using the Public Lab spectrometers are here: http://publiclaboratory.org/wiki/spectral-workbench-usage The key instruction for yo..." | Read more » over 11 years ago
cfastie "Babu, You might be right that the blue channel is more sensitive to NIR, based on the fact that the healthy foliage in your super blue photo has a..." | Read more » over 11 years ago
cfastie "Babu, The new camera is going to be very fun to use. It would be interesting to see a histogram for each channel from an image like that one. We c..." | Read more » over 11 years ago
cfastie "Brent, It might be that you need to adjust the alignment of the camera. The relationship among the slit, the grating, and the camera is critical ..." | Read more » over 11 years ago
cfastie "Babu, Here is a paper about getting separate NIR and red bands by doing what Ned suggested – subtracting one band from another: http://cigr.ageng20..." | Read more » over 11 years ago
cfastie "Hi Babu, My limited experience with these techniques leads me to suggest that it will be quite difficult to separate the red and near infrared ban..." | Read more » over 11 years ago