Recent content by Stoyan Petkov

I will attach a graph representing the relative irradiance on the retina. 1,0 represents 100% of the irradiance calculated by the formula Er=pi*Ls*t*de^2/4f^2. The image of the sun on the retina is 159um, so there will be maximum irradiance at the image. The author notes that the formula breaks...

For the sake of correctness the duration is not 0.25 seconds, but 0.6 seconds, my mistake. Not that much of a difference though. This indeed was something to think about, but I think that the damage will appear in the area of highest irradiance. The blurred image around should have lower...

The goal is Retinal irradiance, W/cm^2 because you can then calculate the energy dose J/cm^2 for given duration. In the literature all threshold values for retinal lesions are in J/cm^2. However I started this thread because I couldn't understand how Radiance of the source is calculated when...

I think I have found an answer to what I was looking for. I am not sure about the name of the first document, because I couldn't download it completely. It has something to do with optics geometry, optical design, optical sources etc. Here is quote: Edward F. Zalewski Hughes Danbury Optical...

sophiecentaur, thank you for the reply. The goal of my search is to calculate retinal irradiance (W/cm^2) while measuring irradiance of the sun (which is in fact the corneal irradiance) during the course of the day. Unfortunately I didn't find direct correlation between both, here is quote...

I have to say that the more I search, the more confused I get I found post in this forum, here it is: https://www.physicsforums.com/threads/example-of-calculation-of-radiance.490538/#post-3248682. Actually the post redirects here: http://omlc.org/classroom/ece532/class1/radiance_flashlight.html...

Well, maybe you can see why I'm confused calculating the sun's radiance. That's why I decided to calculate retinal irradiance in a different way. The irradiance of the sun is 1050W/m2. All sources about the power of the sun give this number more or less. The size of the pupil while watching...

I think you're right, but calculating with 7x10^-5 steradians gives approximately 15MW. Otherwise the calculated radiance in Wikipedia is not correct. If we calculate the way you propose the radiance will be multiple times higher

what is the relation between them, quote again "Dividing the irradiance of 1050 W/m2 by the size of the sun's disk in steradians gives an "average radiance of 15.4 MW per square metre per steradian.", I mean how the steradians are calculated is what I don't understand

Hi all, I want to understand how retinal irradiance (Watts per square centimeters) from the sun is calculated. Some sources calculate 11W/cm^2 like this one...