Field of View
Will this target fit in my camera?
Frame a target and calculate the exact angular sensor field.
- Key result
- Horizontal field · Vertical field · Pixel scale
- Model
- Exact geometry
Calculator and quantity index
What do you need to work out?
Search in the language you use at the telescope. Results explain what each calculator answers, which inputs it needs and how certain its model is.
23 calculators found
Optics & framing
Reducer & Barlow
What does this reducer or Barlow do to my telescope?
Calculate how an ordered modifier train changes focal length and focal ratio.
- Key result
- Effective focal length · Effective focal ratio
- Model
- Exact geometry
Back-focus Spacing
Which spacer thickness do I need?
Balance adapters, filters and camera depth against required back-focus.
- Key result
- Spacer required · Back-focus error
- Model
- Exact geometry
Plate-solving Scale
What scale should I give my plate solver?
Derive solver scale bounds and sensor field from the imaging train.
- Key result
- Pixel scale · Solver scale range · Image field
- Model
- Exact geometry
Mosaic Planning
How many panels does this mosaic need?
Tile a target extent with controlled field overlap.
- Key result
- Mosaic panel count · Mosaic grid · Total mosaic integration
- Model
- Exact geometry
Image quality
Resolution & Sampling
Am I over- or under-sampled?
Compare diffraction, seeing and camera sampling.
- Key result
- Pixel scale · Airy disc · Pixels per seeing FWHM
- Model
- Exact geometry
Sensor Tilt
How much is my sensor tilted?
Translate focus differences across a sensor into plane tilt.
- Key result
- Combined plane tilt · Corner focus spread
- Model
- Measured model
Drizzle Planner
Should I use 2× or 3× drizzle?
Forecast drizzle output size, memory and sampling support.
- Key result
- Drizzle output dimensions · Drizzle working memory · Samples per output pixel
- Model
- Heuristic
Autofocus Planning
What autofocus step size and range should I use?
Relate optical depth of focus to focuser steps and sweep size.
- Key result
- Critical focus zone · Autofocus step spacing · Autofocus sweep
- Model
- Planning estimate
Acquisition
Exposure & SNR
What SNR will this imaging plan produce?
Estimate calibrated signal-to-noise for a stack.
- Key result
- Stack signal-to-noise · Single-frame SNR · Sky/read variance ratio
- Model
- Measured model
Optimal Sub-exposure
How long should each subframe be?
Balance read-noise swamping against highlight saturation.
- Key result
- Minimum useful exposure · Saturation ceiling · Recommended sub-exposure
- Model
- Measured model
Integration Planner
How many frames must I capture?
Turn a desired accepted integration into a capture count and rejection allowance.
- Key result
- Frames to capture · Remaining integration · Relative SNR gain
- Model
- Planning estimate
Filter Exposure Planner
How should I divide time between filters?
Allocate integration among three filters using priority and throughput.
- Key result
- Channel integration · Channel frame count
- Model
- Planning estimate
Star Saturation
Will bright stars saturate in this exposure?
Predict when a bright-star pixel reaches usable full well.
- Key result
- Saturation-limited exposure · Well used · Predicted peak
- Model
- Measured model
Mount & guiding
Guiding Ratio
Is my guide setup sufficiently precise?
Compare guide-camera and imaging-camera angular scales.
- Key result
- Guiding ratio · Guide image scale
- Model
- Exact geometry
Polar Alignment
How far out is my polar alignment?
Estimate polar-axis error from measured stellar drift.
- Key result
- Polar alignment error · Drift rate
- Model
- Measured model
Guiding Exposure
How long should my guide-camera exposure be?
Find a guide exposure that measures the star before mount motion becomes excessive.
- Key result
- Recommended guide exposure · Motion-limited maximum
- Model
- Measured model
Field Rotation
How long can I expose on an alt-az mount?
Convert an alt-az field-rotation rate into edge trailing and exposure limits.
- Key result
- Field-rotation exposure limit · Edge trail
- Model
- Planning estimate
Sky & environment
Imaging Window
How long can I image this target tonight?
Intersect a target altitude interval with available darkness.
- Key result
- Usable imaging window · Time above altitude
- Model
- Planning estimate
Atmospheric Extinction
How much signal will the atmosphere remove?
Estimate pressure-adjusted airmass and transmission loss.
- Key result
- Airmass · Atmospheric extinction · Transmission
- Model
- Planning estimate
Dew & Heater
How much dew-heater power do I need?
Estimate dew point, optic margin and heater demand.
- Key result
- Dew point · Heater power · Heater current
- Model
- Planning estimate
Session planning
Calibration Frames
How many darks, flats and bias frames do I need?
Plan master-frame noise, counts and storage.
- Key result
- Calibration frame count · Master random noise · Calibration storage
- Model
- Heuristic
Storage Volume
How much disk space will tonight require?
Convert sensor format and cadence into a session data budget.
- Key result
- Frame size · Session storage · Sustained write rate
- Model
- Planning estimate
Quantity index
Jump from the name used in a manual or imaging application to the calculator that produces it.
- Airmass (X)Atmospheric Extinction
- Airy disc (θA)Resolution & Sampling
- Atmospheric extinction (Δm)Atmospheric Extinction
- Autofocus step spacingAutofocus Planning
- Autofocus sweepAutofocus Planning
- Back-focus errorBack-focus Spacing
- Calibration frame countCalibration Frames
- Calibration storageCalibration Frames
- Channel frame countFilter Exposure Planner
- Channel integrationFilter Exposure Planner
- Combined plane tilt (α)Sensor Tilt
- Corner focus spreadSensor Tilt
- Critical focus zone (CFZ)Autofocus Planning
- Dew pointDew & Heater
- Drift ratePolar Alignment
- Drizzle output dimensionsDrizzle Planner
- Drizzle working memoryDrizzle Planner
- Edge trailField Rotation
- Effective focal length (f)Reducer & Barlow
- Effective focal ratio (N)Reducer & Barlow
- Field-rotation exposure limitField Rotation
- Frame sizeStorage Volume
- Frames to captureIntegration Planner
- Guide image scaleGuiding Ratio
- Guiding ratio (q)Guiding Ratio
- Heater currentDew & Heater
- Heater powerDew & Heater
- Horizontal field (θₕ)Field of View
- Image fieldPlate-solving Scale
- Master random noiseCalibration Frames
- Minimum useful exposure (tmin)Optimal Sub-exposure
- Mosaic gridMosaic Planning
- Mosaic panel countMosaic Planning
- Motion-limited maximumGuiding Exposure
- Pixel scale (s)Field of View
- Pixel scale (s)Resolution & Sampling
- Pixel scale (s)Plate-solving Scale
- Pixels per seeing FWHMResolution & Sampling
- Polar alignment error (ε)Polar Alignment
- Predicted peakStar Saturation
- Recommended guide exposureGuiding Exposure
- Recommended sub-exposureOptimal Sub-exposure
- Relative SNR gainIntegration Planner
- Remaining integrationIntegration Planner
- Samples per output pixelDrizzle Planner
- Saturation ceiling (tsat)Optimal Sub-exposure
- Saturation-limited exposureStar Saturation
- Session storageStorage Volume
- Single-frame SNRExposure & SNR
- Sky/read variance ratioExposure & SNR
- Solver scale rangePlate-solving Scale
- Spacer required (e)Back-focus Spacing
- Stack signal-to-noise (SNR)Exposure & SNR
- Sustained write rateStorage Volume
- Time above altitudeImaging Window
- Total mosaic integrationMosaic Planning
- TransmissionAtmospheric Extinction
- Usable imaging windowImaging Window
- Vertical field (θᵥ)Field of View
- Well usedStar Saturation