I doubt that they use mirrors with a reflectivity of only 90%. This might be true on large surfaces (meters+), with dust on it, but on smaller surfaces it gets more toward 99%. For instance, simple Al2O3 coating has a reflectivity over 95%. And this is a basic coating, TiO2 can achieve 99%+.
Yes, because photons are energy and all you care about is receiving most of it (actually transform it into a digital signal). The assumptions made are extremely light too (and it should be 20 minutes of integration time leading to a 1.44% ratio). I used the number of the original message. - Same absorption from entrance aperture to the sensor. - Same sensor sensitivity (photon efficiency). - Same sensor Signal To Noise Ratio (SNR). - Same spectral bandwidth. - Same spectral response of the global instrument in the considered spectral range. - and many more...
Surface times Integration time... Keck : 10m^2 and 30 minutes (yes, no need to count the pi/4 ratio as we will make a ratio out of it) Hubble : 2.4m^2 and 5 minutes. Ratio : approx. 1%
Go a little bit further, I prefer a GPU with 1K~2K+ cores running at 800MHz than a single Core at 400GHz for some purpose (simulations, image processing,...). It's not a game on who has the highest clock rate anymore but rather on who is able to fetch data at the fastest speed, who is able prevent algorithm from doing too much branching, instructions replays etc. and generally who is able to maximize throughput...
Sorry but I was indeed writing for deep sky. For coma correcting, you might want to check other-than-Newtons formulae which will have a much better image quality. Seeing usually starts around a 200mm cell if I remember correctly (and depending on your sky humidity level, wind speed, etc.). Problem is that a refractor must have ultra-good quality glass to fight against this nasty chromatism (at least apo, "three folds").
Rule of thumb: Planets=refractor. Deep sky=reflector.
Wow, if you have an unlimited budget to spend, it might be a good idea to have this nice Japanese refractor. But a reflector is still the best ratio of energy collected/dollars. And a nice 8 inch (200mm) F/4 can be a good deep sky telescope for a fifth of the price if not less.
(Sorry for the late answer) No you don't need a stack. The illustration of the stack is just telling you that the PSF is rotating with depth by showing you multiple transverse slices of the EM field during propagation. But imaging particles (=point sources) at different distances from the aperture will produce Dirac's function convoluted by different PSF. This PSF encodes their distance (which is related to the curvature of the input wavefront). As for the phase mask it must be inserted at the aperture (either entrance or exit pupil of the system) such that its plane and the image plane are Fourier conjugates. This is usually feasible and easy.
The result does not impress me too. You can do TRUE 3D through a lens because you can get depth from interferences of the input light field over the finite aperture (\approx lens) size. That requires only A SINGLE IMAGE. One example of this method is the Double Helix Point Spread Function (DHPSF) developed at Univ of Colorado by Pr. Piestun from a specific phase-mask : http://3.bp.blogspot.com/-oX6BL98Bi8Y/TvstLYSp5jI/AAAAAAAABLI/fDKeFKvKWs0/s400/MS+Double-Helix+PSF.JPG If you have the angle, you will have a measure of the depth. This estimation requires only one image. And this is more than ten years older.
So then, why do they write 41MP if they can get only 5MP/8MP images out of the sensor? Because the 41MP cannot be used directly. Oh and look at the PDF of your images too... You start with less SNR than another sensor.
Yeah... but when you do the maths, you find that actually, even under the best case scenario the optics will put a hard limit on performances (the MTF fall-off is *really* significant for their sampling). I am not convinced that this is the optimal point (set of characteristics if you prefer) for the sampling (AKA the optimal point in the trade-off between resolution, MTF fall-off and sensor SNR, "Signal to Noise Ratio").
You're totally right on this... seven years completely wasted as I don't even recall how to write the language name properly... (but, to my discharge, it does sound the same)...
Coming from a different system, I appreciate the fact of not having the choice in the class "I took" AT ALL. I had to learn the same thing as all my other classmates (3 sections of 45 persons each). I think that it helped me because I couldn't feel alone in the storm that way...
Also it was intensive work at this time (12hrs of Maths class/week, about 20Hrs of work by my-self, 1Hr oral examination with one professor per week, 4Hr closed-book-no-calculators-you-have-only-your-brain-and-your-hands exam every two weeks). Then add almost the same in Physics and a little bit of Philosophy, English and Espagnol, and voila!
--- a/Message +++ b/Message - Project costs way more than expected. News at 11. +People are not able to forecast accurately costs of a project (time, money, etc.). News at 11.
Hahahaha, forget that for France... It's not a free country anymore, and there is no political "opposition" party right now : we have a "Nazi" party (Front National), we have a zombie-party (UMP), rulling while the country was involved in selling weapons and DPI technologies to previous Arab dictatorships (just before their revolutions) and also receiving money for their campaigns from these same countries. And a Flanby-party, rulling right now (the name comes from a jelly-like desert, I think that you get the image). As for the citizens : French are morons, they're angry at the government for the same-sex mariage but you won't see them for these (irony)high level things(/irony) such as privacy concerns or human rights. In the 60s, General De Gaulle, got the country out of Otan to emphasize its sovereignty (vs US-UK and USSR). Now all of this has been wiped out as it re-integrated the organization and we are back following US desires... ("yeah, let's buy some more M$ licenses!")
Today : Microsoft listened to customers and removed the "always connected" feature from the XBox, US House wants sustained presence on moon and Mars, Microsoft starts $100k security bug bounty program, Monsanto CTO wins World Food Prize...
April's fool... check. International Joke dat... check. Carnaval... check. SYSTEM FAILURE.
Slashdot Mirror
I doubt that they use mirrors with a reflectivity of only 90%. This might be true on large surfaces (meters+), with dust on it, but on smaller surfaces it gets more toward 99%.
For instance, simple Al2O3 coating has a reflectivity over 95%. And this is a basic coating, TiO2 can achieve 99%+.
Yes, because photons are energy and all you care about is receiving most of it (actually transform it into a digital signal).
The assumptions made are extremely light too (and it should be 20 minutes of integration time leading to a 1.44% ratio). I used the number of the original message.
- Same absorption from entrance aperture to the sensor.
- Same sensor sensitivity (photon efficiency).
- Same sensor Signal To Noise Ratio (SNR).
- Same spectral bandwidth.
- Same spectral response of the global instrument in the considered spectral range.
- and many more...
Surface times Integration time...
Keck : 10m^2 and 30 minutes (yes, no need to count the pi/4 ratio as we will make a ratio out of it)
Hubble : 2.4m^2 and 5 minutes.
Ratio : approx. 1%
What about the spectral range between the two?
Go a little bit further, I prefer a GPU with 1K~2K+ cores running at 800MHz than a single Core at 400GHz for some purpose (simulations, image processing,...). It's not a game on who has the highest clock rate anymore but rather on who is able to fetch data at the fastest speed, who is able prevent algorithm from doing too much branching, instructions replays etc. and generally who is able to maximize throughput...
... they want their GHz war back...
They start making up figures on a market that has not started yet?
Seems like a real great (and useful) idea to me...
Sorry but I was indeed writing for deep sky.
For coma correcting, you might want to check other-than-Newtons formulae which will have a much better image quality.
Seeing usually starts around a 200mm cell if I remember correctly (and depending on your sky humidity level, wind speed, etc.).
Problem is that a refractor must have ultra-good quality glass to fight against this nasty chromatism (at least apo, "three folds").
Rule of thumb: Planets=refractor. Deep sky=reflector.
Wow, if you have an unlimited budget to spend, it might be a good idea to have this nice Japanese refractor. But a reflector is still the best ratio of energy collected/dollars. And a nice 8 inch (200mm) F/4 can be a good deep sky telescope for a fifth of the price if not less.
(Sorry for the late answer)
No you don't need a stack. The illustration of the stack is just telling you that the PSF is rotating with depth by showing you multiple transverse slices of the EM field during propagation. But imaging particles (=point sources) at different distances from the aperture will produce Dirac's function convoluted by different PSF. This PSF encodes their distance (which is related to the curvature of the input wavefront).
As for the phase mask it must be inserted at the aperture (either entrance or exit pupil of the system) such that its plane and the image plane are Fourier conjugates. This is usually feasible and easy.
The result does not impress me too.
You can do TRUE 3D through a lens because you can get depth from interferences of the input light field over the finite aperture (\approx lens) size. That requires only A SINGLE IMAGE.
One example of this method is the Double Helix Point Spread Function (DHPSF) developed at Univ of Colorado by Pr. Piestun from a specific phase-mask :
http://3.bp.blogspot.com/-oX6BL98Bi8Y/TvstLYSp5jI/AAAAAAAABLI/fDKeFKvKWs0/s400/MS+Double-Helix+PSF.JPG
If you have the angle, you will have a measure of the depth. This estimation requires only one image. And this is more than ten years older.
And a WebM/MP4/Downloadable material too, please...
So then, why do they write 41MP if they can get only 5MP/8MP images out of the sensor?
Because the 41MP cannot be used directly. Oh and look at the PDF of your images too... You start with less SNR than another sensor.
Yeah... but when you do the maths, you find that actually, even under the best case scenario the optics will put a hard limit on performances (the MTF fall-off is *really* significant for their sampling). I am not convinced that this is the optimal point (set of characteristics if you prefer) for the sampling (AKA the optimal point in the trade-off between resolution, MTF fall-off and sensor SNR, "Signal to Noise Ratio").
...use 4D light fields...
You're totally right on this... seven years completely wasted as I don't even recall how to write the language name properly... (but, to my discharge, it does sound the same)...
Coming from a different system, I appreciate the fact of not having the choice in the class "I took" AT ALL. I had to learn the same thing as all my other classmates (3 sections of 45 persons each). I think that it helped me because I couldn't feel alone in the storm that way...
Also it was intensive work at this time (12hrs of Maths class/week, about 20Hrs of work by my-self, 1Hr oral examination with one professor per week, 4Hr closed-book-no-calculators-you-have-only-your-brain-and-your-hands exam every two weeks). Then add almost the same in Physics and a little bit of Philosophy, English and Espagnol, and voila!
--- a/Message
+++ b/Message
- Project costs way more than expected. News at 11.
+People are not able to forecast accurately costs of a project (time, money, etc.). News at 11.
Close your Dailymotion account now... Because, sadly, that's the only online service they can spy on...
Hahahaha, forget that for France...
It's not a free country anymore, and there is no political "opposition" party right now : we have a "Nazi" party (Front National), we have a zombie-party (UMP), rulling while the country was involved in selling weapons and DPI technologies to previous Arab dictatorships (just before their revolutions) and also receiving money for their campaigns from these same countries. And a Flanby-party, rulling right now (the name comes from a jelly-like desert, I think that you get the image).
As for the citizens : French are morons, they're angry at the government for the same-sex mariage but you won't see them for these (irony)high level things(/irony) such as privacy concerns or human rights.
In the 60s, General De Gaulle, got the country out of Otan to emphasize its sovereignty (vs US-UK and USSR). Now all of this has been wiped out as it re-integrated the organization and we are back following US desires... ("yeah, let's buy some more M$ licenses!")
C'est le nom d'un quartier de Brest (Lambézelec)...
Si ta base vient d'etre crackée... vient donc faire un tour a Lambé...
Matmatah - Lambé An Dro
4852.6S 12323.6W
We need a waterproof version for R'lyeh!
Let's make every one happy :
D-Wave = \frac{1}{\sqrt{2}} \Psi_{classical computer} + \frac{1}{\sqrt{2}} \Psi_{quantum computer}
But, PLEASE, don't measure it, seriously...
Today : Microsoft listened to customers and removed the "always connected" feature from the XBox, US House wants sustained presence on moon and Mars, Microsoft starts $100k security bug bounty program, Monsanto CTO wins World Food Prize...
April's fool... check.
International Joke dat... check.
Carnaval... check.
SYSTEM FAILURE.
In any case : don't call it Flash Memory... that would be dumb...