1. What is Field of View?

Field of View (FOV) is the angular extent of the observable world that is seen at any given moment through an optical instrument like a telescope or camera. It determines how much of the sky you can see through your equipment.

2. How Does the Calculator Work?

The calculator uses the FOV formula:

Where:

• \( FOV \) — Field of View in degrees
• \( d \) — Sensor size (mm)
• \( f \) — Focal length (mm)

Explanation: The formula calculates the angle based on the ratio between the sensor size and the focal length of the optical system.

3. Importance of FOV Calculation

Details: Knowing your FOV helps in planning astronomical observations, framing celestial objects correctly, and understanding what will fit in your camera's frame.

4. Using the Calculator

Tips: Enter the sensor size (typically the diagonal measurement) in millimeters and the focal length of your telescope or lens in millimeters. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical FOV for astronomical telescopes?
A: It varies widely, from about 0.5° for long focal length telescopes to 5° or more for wide-field instruments.

Q2: How does sensor size affect FOV?
A: Larger sensors with the same focal length will show a wider field of view.

Q3: What's the relationship between magnification and FOV?
A: Higher magnification typically means narrower FOV, as you're zooming in on a smaller portion of the sky.

Q4: Should I use horizontal or diagonal sensor measurement?
A: Diagonal measurement is most common as it represents the full extent of the sensor.

Q5: How does this relate to apparent FOV of eyepieces?
A: The eyepiece's apparent FOV combines with the telescope's magnification to determine the true FOV.