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Astrophotography & Cameras

Astrophotography Storage Session Planner

Estimate a frame ledger from stored array geometry, use measured per-file sizes, or solve how many additional frames fit after copies, working space and reserve.

Astronomy & Space · model workbench

Turn light and calibration frame counts into an explicit source, archive-copy, working and free-space capacity plan without pretending stored files equal raw sensor bit depth alone.

Private calculations in your browser · explicit inputs and model boundaries
Example preview · Uniform mono sessionMinimum-capacity allocation
Planned capacity · 34.3701419 GiBPrimary source: 11.6858482 GiBAdditional copies: 11.6858482 GiBWorking allowance: 5.84292412 GiBFree-space reserve: 5.15552128 GiBPrimary source · 11.6858482 GiBAdditional copies · 11.6858482 GiBWorking allowance · 5.84292412 GiBFree-space reserve · 5.15552128 GiB

The live bar assigns the solved minimum capacity to the primary source dataset, additional complete copies, processed/working allowance and the free-space reserve. Every segment comes from the current frame ledger and entered retention policy.

  1. 1EnterProvide the known values
  2. 2CalculateResults update automatically
  3. 3VerifyReview the details and units
Try an example

Enter values in px.

Enter values in px.

Enter values in channels.

Use the representation stored in the file, which may differ from the camera ADC depth.

Use 1 for no payload reduction; 2 means the stored payload is half the uncompressed payload.

Enter values in KiB.

Frame groups
1 row
Row 1

Empty rows are ignored until edited. Keep commas and tabs out of individual entries; use the paste view for comma- or tab-separated records.

Enter values in copies.

Enter values in % of source dataset.

Enter values in % of capacity.

Calculation result

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Enter valid values to see the result.

Your entries are calculated in this browser and are not submitted to 365CALCS.COM.

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Understand the relationship

The reasoning behind the result

Stored representation determines the payload model

Bpayload = Nx Ny C b / 8

Array width, height, channel count and stored bits per sample form the uncompressed image payload. Camera ADC depth alone does not determine how a file is represented.

The uniform workflow then applies an entered uncompressed-to-stored payload ratio and adds explicit per-file header/container overhead. It is an estimate rather than a FITS, TIFF, XISF or camera-raw encoder.

Calibration frames remain itemized

Bsource = Σ Ni Bi

Light, dark, flat, bias and other groups retain independent counts in the ledger even when their per-file sizes match.

A frame class does not decide how many calibration files are appropriate or whether a calibration protocol is valid.

Copies and working space are separate

Ballocation = Bsource(c + w)

The complete-copy count c includes the primary dataset. Working allowance w is a fraction of one source dataset rather than another hidden complete copy.

This transparent multiplier can represent processed and temporary products only to the degree chosen by the visitor.

Reserve belongs to the whole capacity

Bcapacity = Ballocation/(1 − r)

Solving capacity from a reserve fraction r leaves exactly that share of the resulting volume free. The inverse protects the same share before fitting additional whole files.

A filesystem, RAID, cloud-object store, backup service or scratch workflow can have further overhead and failure-domain requirements that must be added explicitly.

Binary and decimal units differ

1 MiB = 2²⁰ bytes; 1 MB = 10⁶ bytes

The calculator performs every allocation in bytes, then reports both MiB/GiB and decimal MB/GB. A numeric capacity quoted in GB is not silently treated as GiB.

No throughput or transfer-time promise is derived from capacity alone.

Follow the numbers

Estimate one uniform monochrome archive

  1. Multiply 6,248 × 4,176 pixels by one channel and 16 stored bits, then divide by 8 to obtain the uncompressed payload bytes per frame.
  2. Divide that payload by the entered 1.5 compression ratio and add 64 KiB of entered header/container overhead.
  3. Multiply the stored-file estimate by 120 lights, 40 darks, 100 flats and 100 bias frames while retaining every group in the ledger.
  4. Multiply the complete source dataset by two retained copies and add a 50% working allowance.
  5. Divide that allocation by 0.85 so 15% of the resulting minimum capacity remains free.

The result is a byte-based capacity plan with calibration, copy, working and reserve components that can be audited independently.

Quick guide

How to use this calculator

  1. Use uniform mode when every listed frame shares one stored array and representation, measured mode when actual stored MiB differs by group, or the capacity inverse to solve whole additional files.
  2. Class each row as light, dark, flat, bias or other so the source ledger keeps science and calibration data visible. The class changes reporting only; it does not change file size.
  3. Count every retained complete dataset copy, including the primary. Add a separate working percentage for calibrated, registered, stacked, exported or temporary products you want capacity reserved for.
  4. Keep free-space reserve as a percentage of the whole volume. Compare GiB with operating-system binary capacity and decimal GB with vendor-labelled capacity using the printed unit conversions.

Calculation method

Calculation and interpretation

Turn light and calibration frame counts into an explicit source, archive-copy, working and free-space capacity plan without pretending stored files equal raw sensor bit depth alone.

Uniform stored file = width × height × channels × stored bits / (8 × compression ratio) + per-file overhead; source dataset = Σ(count × stored file); allocation = source × (complete copies + working fraction); minimum capacity = allocation/(1 − reserve fraction); maximum additional files = floor((capacity × (1 − reserve) − fixed allocation)/(new file × allocation multiplier)).

Worked example

Estimate one uniform monochrome archive

The result is a byte-based capacity plan with calibration, copy, working and reserve components that can be audited independently.

Uniform stored file = width × height × channels × stored bits / (8 × compression ratio) + per-file overhead; source dataset = Σ(count × stored file); allocation = source × (complete copies + working fraction); minimum capacity = allocation/(1 − reserve fraction); maximum additional files = floor((capacity × (1 − reserve) − fixed allocation)/(new file × allocation multiplier)).

Supported inputs

Precision and limits

Stored-file estimate

Uniform mode is a payload model. Real FITS, XISF, TIFF, camera raw and other files can add headers, padding, metadata, tiles, previews, checksums or compression behaviour beyond the entered assumptions.

No compression guarantee

Compression ratio is entered explicitly. Actual lossless compression depends on file format, data distribution, noise and encoder settings and may differ across frames.

No calibration prescription

Dark, flat and bias rows are an itemized storage ledger. The page does not prescribe a calibration protocol, frame count, exposure, temperature match or processing method.

Copies are not a backup strategy

A copy count does not verify isolation, integrity, versioning, restore testing, geographic separation or protection from device, user or account failure.

Capacity is not performance

Filesystem overhead, reserved blocks, RAID parity, snapshots, cloud versions, transfer speed, write endurance, cache and application scratch use are not fetched or inferred.

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