If the primary mirror is parabolic, like in Newtonian telescopes, you need to keep things close to the main axis. Parabolic mirrors are aberration free for objects at infinity only when the object and the image are near the axis. Ofsetting the parabolic mirror would introduce aberrations.
If...
Fascinating and very informative article. Thank you!
Looks like I was wrong. Thickness does matter, albeit only for the diffraction figures around stars (it doesn't matter for planetary viewing). I just don't understand why that is. If diffraction is basically an edge phenomenon, why are the...
Consider a Newtonian reflector telescope:
As you can see in the image, the little secondary mirror inside the main tube is supported by an X structure called 'spider'. The four "legs" of the spider, called 'vanes' by astronomers, are actually thin stripes of high-tensile material, usually...
Okay, so planets in the Goldilocks zone are far enough from the star that it's less likely they are tidally locked. But assuming such a thing exists - shouldn't the habitable zone be wider if the planet is tidally locked to its star?
At one extreme, the planet would have an Antarctica-sized...
Classic paraboloidal mirror. Incoming flat wavefront of known wavelength (500 nm, green light), propagating parallel to the major axis of the mirror. The wave hits the mirror and is being sent back towards focus. At the focal plane, there's a flat CCD or some other light detector. Upon hitting...
Why negative ions? I thought it's easier to make positive ions - maybe a hot filament would suffice? (I'm pretty ignorant in this area, so that's why I'm asking)
And if making positive ions is easier, how about heavier ions of elements easy to vaporize (Hg, iodine, noble gases... the list is...
I just realized a Van de Graaf generator around 400...500 kV might be easily doable, by an average amateur working in a garage.
I was also thinking these days about a DYI cyclotron project, which I scrapped because the magnet is just too hard to make and feed. But then I figured the Van de...
Recently, there was a http://www.reddit.com/r/space/comments/96iwv/the_year_is_2035_we_have_a_permanent_base_on_the/" on Reddit titled "The year is 2035. We have a permanent base on the moon and have sent multiple teams to Mars and back. What's next for NASA?"
There were several interesting...
Well, OK, I can renounce the requirement for quick computation. The program doesn't have to run in real time after all.
But I do want some precision even for photons passing pretty close to the event horizon. There's a background image, and a black hole between it and the camera. I want to...
Caveat 1: I'm not sure if this message should be posted here, or in the Programming forum.
Caveat 2: I have a BS in Physics, obtained more than a decade ago, but never actually worked in the field. So I'm a bit rusty. :redface: OK, more than a bit.
I am writing a program to simulate the...