| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| Vman | "Thank you so much for the idea on using heatshrink material as a material for making the slit. This is better than paper or cardboard because it di..." | Read more » | over 7 years ago | |||
| cfastie | "I don't know whether you could see a clear projected image of the spectrum. I think you could, but it would rather small and dim. I also don't know..." | Read more » | about 10 years ago | |||
| wizard | "Wow... excellent information... thanks. I am a newbie, and my questions will be indicative of that.... I see now that I may assemble two spectrome..." | Read more » | about 10 years ago | |||
| Tom_H | "The basic grating equation works for transmission as well as reflection. The sign conventions can throw you though. One purpose of the collimatin..." | Read more » | almost 12 years ago | |||
| liz | "This is amazing! I also like Dan Beavers graphic :) " | Read more » | almost 12 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 » | almost 12 years ago | |||
| danbeavers | " I hope this illustrates what I mean. " | Read more » | almost 12 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 » | almost 12 years ago | |||
| danbeavers | "Chris, I am referring to the rotational alignment between the slit axis and the grating's ruling. What is the effect when the angles are rotated? " | Read more » | almost 12 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 » | almost 12 years ago | |||
| Tom_H | "Great job! An optical bench from Legos --- super! Yes there are a lot of variables at work here. If you want to bend your mind a bit, read some of..." | Read more » | almost 12 years ago | |||
| danbeavers | "Great investigation! Another question is slit to grating angle. What effect does that have? What are the symptoms of misalignment? " | Read more » | almost 12 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 » | almost 12 years ago | |||
| warren | "Oh, almost forgot my other question! Do the camera lens and aperture make any difference at all? You didn't use a camera for this... could you try ..." | Read more » | almost 12 years ago | |||
| warren | "Amazing. Two questions: does the distance between the camera and the grating affect focus? if we assume that for the design of a compact/useful s..." | Read more » | almost 12 years ago | |||
| straylight | "wow, what a useful research note, thanks for taking the time to post it and explain what you did. Interesting to be able to compare the ocean opti..." | Read more » | almost 12 years ago | |||
| cfastie | "That's a challenge if smartphone cameras are not very sensitive to low light. More tests are called for, but I think the cheap diffraction grating..." | Read more » | almost 12 years ago | |||
| warren | "I think maybe you mean 0.2mm and 0.4mm, mathew? Good to know, both of you -- i'm getting the desktop kit slits cut today!! Thanks. " | Read more » | almost 12 years ago | |||
| mathew | "Chris-- When I was doing the spectrometer tests I found that 2mm was too dim to reliably read the spectra with a cell phone camera and settled on 4..." | Read more » | almost 12 years ago | |||
| warren | "For the short term, it will prompt you to take a photo, and will allow you to upload it. Once we start on the native app, it will work just like th..." | Read more » | almost 12 years ago | |||
| cfastie | "Alex - That's an good point that some smart phones do HDR. To improve the chances of great results, users of the smart phone spectrometer could tak..." | Read more » | almost 12 years ago | |||
| warren | "I'm very impressed that the foldable spectrometer can get such good resolution. Partially, of course, that's the DSLR, but I'm glad that folks with..." | Read more » | almost 12 years ago | |||
| cavazos | "Chris Thanks for sharing your views. I believe the exposure issue can be fixed by using High Dynamic Range or HDR technique. I'm not a photography..." | Read more » | almost 12 years ago | |||
| cfastie | "Hi Alex, I haven't experimented much with webcams yet, so I don't know the answer. I do know that a narrow slit is critical for precisely identif..." | Read more » | almost 12 years ago |