WHAPOS Sky Aperture Calculator
Enter the telescope aperture to calculate the resulting sky aperture for WHAPOS Spectrograph.
Example: 0.8 m, 80 cm or 800 mm
Please enter a telescope aperture greater than 0.
Sky aperture
2.26 arcsec
Calculation based on WHAPOS with 35 µm fiber diameter and F/4 fiber input.
Formula
θsky = dfiber Dtelescope × F/#fiber × k
- dfiber
- 35 µm fiber diameter
- F/#fiber
- 4 fiber focal ratio
- Dtelescope
- telescope aperture in metres
- k
- 4.85 µm / (arcsec × m)
The factor k converts one arcsecond on the sky into micrometres in the telescope focal plane per metre of focal length.