Exposure Time Calculator

Observing Setup

Site Telescope

Telescope parameters

Primary Mirror Diameter m Secondary Mirror Diameter m Focal Length m Optical Throughput %

Camera

Camera parameters

Pixel Pitch µm Quantum Efficiency % Dark Current Rate e-/s/pix Readout Noise e-/pix Full Well Capacity e-

Filter

Filter parameters

Central Wavelength nm Filter Bandwidth nm Filter Transmission %

System

Throughput Correction %

Coordinates (J2000, decimal degrees)

Right Ascension deg Declination deg

Morphology

Brightness

Brightness System

Apparent Magnitude mag

Zero Point Flux erg/s/cm²/Å

Spectral Energy Distribution (SED)

SED Model

Spatial Spreading (FWHM, arcsec)

Seeing Diffraction

Optical Tracking

Atmosphere & Background

Add moonlight to sky background Dark Sky Brightness (mu_dark, baseline) mag/arcsec² Extinction Coefficient mag/airmass

Observatory Location

Latitude deg Longitude deg Elevation m

Exposure Strategy

Single Exposure Time s Calculation Goal

Number of Exposures

When

Sweep time range

Observation Time (local)

Photometry — aperture and sky annulus

Aperture Factor (k_ap) Sky Annulus (k_in – k_out) Sky Estimator