How do you calculate aliasing?
A simple rule to predict this aliased frequency is: decrement fo by fs enough times to get within the observable frequency range of [−fN , fN ]. The absolute value of this result is the aliased frequency. Sampling at 5.5kHz gives a time step of 0.182 milliseconds.
How is fold over frequency calculated?
(Also called Nyquist frequency.) The highest frequency that can be measured using discretely sampled data. It is given by nf (rad s-1) = π/Δt, where nf is the Nyquist frequency and t is the time increment between observations.
How do you find the pixel scale?
The pixel scale is just 206 * (pixel size) / (focal length). Assuming your 30 mm guide scope is f/4 that would be a focal length of 120mm. Using a common guide camera such as the ASI120MM which has a pixel size of 3.8u, the pixel scale is 206 * 3.8 / 130 = 6.0 arcseconds/pixel.
What effect is caused by undersampling?
The aliasing effect due to the undersampling technique can be used for our advantage. When a signal is sampled at a rate less than twice its maximum frequency, the aliased signal appears at Fs – Fin, where Fs is the sampling frequency and Fin in the input signal frequency.
Why does aliasing occur?
Aliasing occurs when you sample a signal (anything which repeats a cycle over time) too slowly (at a frequency comparable to or smaller than the signal being measured), and obtain an incorrect frequency and/or amplitude as a result.
Can I use a telescope as a telephoto lens?
Instead of changing magnification by moving internal lens elements as a zoom lens does, the magnification of a telescope is changed by switching eyepieces. So technically, no, you can’t use a telescope as a zoom lens.
What is a good resolution for telescope?
about 0.05 arcsecs
Resolution of the telescope The Hubble Space Telescope has a best resolution of about 0.05 arcsecs. That’s about the apparent thickness of the unfolded paper clip almost 2 miles away.
What is a fold over?
To crease something so that one part of it is positioned on top of another part.
What is folding of a signal?
Folding transforms an operation from a unit-time processing to N unit-times processing where N is called folding factor. Therefore, multiple same operations (less than N) used in original system could be replaced with a signal operation block in transformed system.
What is the pixel scale?
Pixel scale is a measurement of how much of the sky is covered by one pixel. Image Scale (arc-seconds) = 206 * Pixel Size (microns) / Focal Length (mm).
