Questions related to Optical Astronomy
I am wondering if it is possible to measure mode-locked laser stability (timing jitter, Noise) with an oscilloscope if the pulse duration is in the femtoseconds regime (lets say 150fs). If so, what type of measurement on an oscilloscope would quantify laser stability. What should be the bandwidth of the photodetector and oscilloscope?
Can any one help me how to find a detailed information about several radio telescopes: VLA, VLBA etc? I am interested mainly in spacial resolution, working frequency and sensitivity - minimum detectable values in Jy.
What are the advantages of using the michelson interferometer ?
What are the disadvantages of using other interferometers ?
What are the trade-offs ?
The energy of a CMB photon when released is given by Planck constant times frequency; and also at arrival. Therefore, as frequency decreases with expansion, the energy at reception is S times lower, being S the space expansion since then. As S is around 1000, the CMB photons arrive with an energy that is only 1/1000 of their original energy; where is this huge missing energy?
Reasoning in a different way, the energy density of a black body radiation is proportional to the 4th power of temperature, which shifts inversely to space expansion; so the energy density decreases with the 4th power but space expansion only accounts for the 3rd power decrease.
What happens here? Is this a problem of missing energy? Or is this evidence that there is no conservation of energy over time?
Energy conservation is a property of mechanical interactions that was assumed as a fundamental law; truly, we only have evidences of this law in interactions, but not through time with the accuracy required for applying it at cosmic scale.
Conservation laws presume and imply an invariant, static, universe; but the universe is not static.
What do you think? Is energy missing in cosmic radiation or the validity of conservation laws over time needs to be analyzed?
I am trying to study the IR spectrum of hot water in the waveno. range 4000 to 400 cm (inverse). If any published data is available, that will help me a lot! This is in turn an attempt to study the hot water spectrums obtained from the sun (sunspots).
I am currently writing software to control a small refractor (125 mm). Drive motors are brushed DC, encoders are 10 000 ppr mounted on the motors, gearbox has 1:8000 ratio. The German equatorial mount is well built and solid. The observer's software has a GUI and writes directly to Excel spreadsheet using dynamic data exchange (DDE). Another program communicates with the servo drives, and receives pointing information and other instructions from the GUI, via Excel spreadsheet. So both the GUI and servo control software can exchange data via DDE and both can read and write to Excel spreadsheets, allowing data plots, simple statistics etc. Currently the software has a fair number of GUI accessible functions. What would you expect a telescope control program to have as a must, and what would you like if you could choose features?