How to Figure Required Telescope Diameter?

In summary, the conversation is about a program that calculates various things related to telescopes, such as resolving power and mirror diameter. However, there seems to be an issue with the results for finding the required mirror size for a given angular diameter. The conversation mentions the use of the Nyquist-Shannon sampling theorem and photon wavelength, but the person is unsure about the accuracy. They are looking for help in reversing the Dawes' limit formula to find the mirror size needed. The suggestion of using Airy discs and diffraction is mentioned as a possible solution.
  • #1
willgtl
5
1
A awhile ago I wrote a program to calculate various things like maximum resolving power of a given telescope's primary mirror, angular diameter of an object of a given size from a given distance and mirror diameter required to see an object of a given angular diameter.

However, I seem to have completely failed on the last part. I just now looked back at that program and got results of tens of kilometers when I know my result should've been mere dozens of meters. Looking at the code, I appear to have involved the Nyquist-Shannon sampling theorem and photon wavelength, with no recollection as to why.

I have a feeling I'm completely off-base. Could someone enlighten me on how to essentially reverse the Dawes' limit formula, and find the mirror size required for a given angular diameter? Thanks!
 
Physics news on Phys.org
  • #2
From wiki:

"A calculation using Airy discs as point spread function shows that at Dawes' limit there is a 5% dip between the two maxima, whereas at Rayleigh's criterion there is a 26.3% dip."

Does this help? No sampling required, but it is based on diffraction.
 

Related to How to Figure Required Telescope Diameter?

1. What is the formula for calculating required telescope diameter?

The formula for calculating required telescope diameter is: D = 2 * (F * A * M), where D is the diameter of the telescope, F is the focal ratio, A is the aperture of the telescope, and M is the magnification desired.

2. How do I determine the focal ratio of a telescope?

The focal ratio of a telescope can be determined by dividing the focal length by the aperture. For example, if a telescope has a focal length of 1000mm and an aperture of 200mm, the focal ratio would be 5 (1000/200 = 5).

3. What is considered a good magnification for a telescope?

A good magnification for a telescope is typically between 50x to 75x per inch of aperture. However, it is important to note that the atmospheric conditions and quality of the telescope's optics can also affect the ideal magnification.

4. How do I measure the aperture of a telescope?

The aperture of a telescope can be measured by the diameter of its primary mirror or lens. This can be done using a ruler or a caliper. It is important to measure the actual opening of the telescope, not just the size of the tube.

5. What factors should I consider when choosing a telescope diameter?

When choosing a telescope diameter, it is important to consider the type of objects you want to observe, the atmospheric conditions in your area, and your budget. Larger telescope diameters generally provide better image quality, but they can be more expensive and require more storage space.

Similar threads

Can the Hubble telescope measure the diameter of Betelgeuse?
    • Introductory Physics Homework Help
Replies
4
Views
1K
Stargazing Documenting the setup of my new telescope
    • Astronomy and Astrophysics
2
Replies
49
Views
2K
I Calculating the Raleigh Criterion constant to 99 significant figures
    • Optics
Replies
3
Views
1K
I How Does Angular Diameter Distance Apply to the Last Scattering Surface?
    • Astronomy and Astrophysics
Replies
2
Views
2K
Stargazing Is this a realistic design for a kilometer wide telescope?
    • Astronomy and Astrophysics
Replies
14
Views
3K
Black hole calculations, the "Event Horizon Telescope"
    • Introductory Physics Homework Help
Replies
1
Views
2K
Hubble Space Telescope Diffraction Limit
    • Introductory Physics Homework Help
Replies
1
Views
2K
Angular Magnification of a telescope,
    • Introductory Physics Homework Help
Replies
1
Views
2K
Energy requirement for melting through five klicks of ice?
    • General Engineering
Replies
14
Views
2K
Rayleigh Criterion or Resolving Power?
    • Introductory Physics Homework Help
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top