Selected by you

M 33

RGB · 1 observing sessions in the archive

RGB · 2 h 09 min · 43 Lights

M 33
Full-resolution image
Illustrative foreground layers · no catalogue-distance anchors for this display.Illustrative effect · not a physical depth measurement.
Field guide · not available for this image

No saved catalogue overlay is qualified for this exact image; your image and science remain available.

Available results · 3 / 5 modules

Each module is checked separately. An unavailable module does not invalidate the saved master; a complete list is not scientific certification.

Selected input exposures

Image quality at a glance

Selected inputs against your whole archive · RGB and DNB remain separate.

RGB · all contributing sessions

Star width / FWHM
2.74 sensor pixels
Current archive average3.00 sensor pixels
Difference -0.26
43/43 selected · archive 865/865 exposures · 11 sessions · 8 objects
Star shape / eccentricity
0.48 dimensionless
Current archive average0.45 dimensionless
Difference +0.03
43/43 selected · archive 865/865 exposures · 11 sessions · 8 objects
Background
746.51 ADU
Current archive average749.61 ADU
Difference -3.10
43/43 selected · archive 865/865 exposures · 11 sessions · 8 objects
Background scatter
34.18 ADU
Current archive average34.26 ADU
Difference -0.07
43/43 selected · archive 865/865 exposures · 11 sessions · 8 objects
Stellar model SNR
123.15 dimensionless
Current archive average138.73 dimensionless
Difference -15.59
43/43 selected · archive 865/865 exposures · 11 sessions · 8 objects
Stellar model estimate · different fields
Star width / FWHM
Selected exposure values · whole-archive RGB mean · physical sessions separated.
Star shape / eccentricity
Star shape / eccentricity
Selected exposure values · whole-archive RGB mean · physical sessions separated.
Background
Background
Selected exposure values · whole-archive RGB mean · physical sessions separated.
Background scatter
Background scatter
Selected exposure values · whole-archive RGB mean · physical sessions separated.
Stellar model SNR
Stellar model SNR
Selected exposure values · whole-archive RGB mean · physical sessions separated.
How this archive average is calculated

Each unique original exposure contributes once per valid saved metric. Arithmetic mean across all objects; RGB and DNB separate. Missing or invalid values are excluded, never zero. This descriptive reference includes the selected exposures and later nights.

Exposure, camera settings, field brightness, sampling and stellar populations may differ. Background and stellar model SNR are not normalized measures of sky quality, master SNR or detection sensitivity. A difference is not a grade.

Stored per-frame medians of stellar fits are averaged; stars are not pooled. SNR requires a positive recorded effective gain and at least five stellar estimates. Units remain separate. Unknown method versions are recorded, not invented. Small, undersampled stars may bias shape measurements.

Archive version ab3717b4ec376ea87d5261c94fe6dbbd42a97237e09422490b5844921d286006

Matched acquisition settings · original session-weighted comparison

Selected input exposures

Image quality at a glance

Measurements of the selected input exposures, not the finished master.

RGB · 180.0 s · 43 Lights

Acquisition settings & contributing sessions

180.0 s · Gain 100.0 · Archive snapshot 2026-11-09T03:24:34.927460+00:00

Recorded focal length: 611.0 mm · separate header/settings cohorts, not additional observing sessions.

RGB Session 1 · 2026-11-07

Execution version was not saved: this comparison is limited to the same observing session.

Star width (FWHM)
2.74 sensor pixels
Current archive average2.74 sensor pixels
Difference 0.00 sensor pixels
43/43 frames · archive: 1 Sessions
Star shape
0.48 dimensionless
Current archive average0.48 dimensionless
Difference 0.00 dimensionless
43/43 frames · archive: 1 Sessions
Eccentricity of stellar model fits
Background
746.51 ADU
Current archive average746.51 ADU
Difference 0.00 ADU
43/43 frames · archive: 1 Sessions
Background scatter
34.18 ADU
Current archive average34.18 ADU
Difference 0.00 ADU
43/43 frames · archive: 1 Sessions
Stellar SNR
123.15 dimensionless
Current archive average123.15 dimensionless
Difference 0.00 dimensionless
43/43 frames · archive: 1 Sessions
Model estimate · same target field
Star width (FWHM) over time
Star width (FWHM) · saved per-exposure values and current archive average. Sessions are separate; gaps are not joined.
Star shape · Trend
Star shape over time
Star shape · saved per-exposure values and current archive average. Sessions are separate; gaps are not joined.
Background · Trend
Background over time
Background · saved per-exposure values and current archive average. Sessions are separate; gaps are not joined.
Background scatter · Trend
Background scatter over time
Background scatter · saved per-exposure values and current archive average. Sessions are separate; gaps are not joined.
Stellar SNR · Trend
Stellar SNR over time
Stellar SNR · saved per-exposure values and current archive average. Sessions are separate; gaps are not joined.

Provisional star fits · stellar SNR is a model estimate, not master SNR.

Reading these values

Provisional stellar models: undersampled stars can bias the measurements. Differences are not quality grades. Stellar SNR is not nebular or master-image SNR.

Previously selected image · retained
Previously selected image
Preview image · up to 2560 px

RGB · 2 h 09 min · 43 Lights

Observing sessions

More exposure time · conditional SNR planning

Planning · model estimate

What would more exposure time bring?

Based on the actual inputs of this selected master. RGB and DNB are modelled separately.

Current relative SNR = 1.00×. This is a reference level, not a measured master SNR. There is no universal “good” SNR target: it depends on the feature, aperture or region, noise definition and intended use.

RGB

2 h 09 min · 43 selected Lights. Sub-exposures: 180 s

1.00×1.50×2.00×SNR / current SNR · conditional modelNow0.0 h2.1 h4.3 h6.5 hAdditional integration · same mode

One more comparable hour: about 21.0% higher SNR relative to now. Each following hour adds less relative benefit; it does not become useless.

Examples, not recommended thresholds
Relative SNR goalAdditional timeTotal time
1.25×1 h 12 min 34 s3 h 21 min 34 s
1.50×2 h 41 min 15 s4 h 50 min 15 s
2.00×6 h 27 min8 h 36 min

Detail visibility is not angular resolution. More integration can reveal fainter structures. Seeing, optics, sampling, focus and guiding limit sharpness; this curve does not predict smaller or rounder stars.

Model assumptions and exact scope

Same target region, filter, camera, sub-exposure mix, throughput and sky conditions; independent random noise and comparable stacking weights. Fixed-pattern noise, calibration errors, gradients, correlated noise, changing conditions and rejected data can reduce the realised gain. Total exposure is not an effective per-pixel weight or an HDR-core coverage map.

Relative SNR = √((current time + additional time) / current time). Required extra time = current time × (goal² − 1). No numerical floor or absolute master SNR has been fitted; no per-frame star-SNR median is substituted.

Time means usable integration in the stack, excluding overheads, rejected frames and nights with unsuitable conditions. The curve is a planning scenario, not a measured progress history.

Signal and noise · Siril documentation

Explore stars in the image

Image geometry is not sufficiently verified, or the exact catalogue is not yet saved.

Science & measurements

Experimental photometry · no confirmed transit. 0 unresolved technical review items.

Histograms, light curves & event evidence

Intensity histograms

RGB · 43/43 original exposures measured.

RGB · Raw pixel values

ADU · decoded digital value · Pixel count per bin; not a wavelength spectrum.

-0.56.554e+042.786e+08BG1G2R

All saved bins, including negative values.

Exact counts and measured valuesWerte und Darstellungsbins · Complete unchanged bins (NPZ)

Current display image

8-bit display values · nonlinear · Pixel count per bin; not a wavelength spectrum.

-0.5255.58.015e+05BGR

All saved bins, including negative values.

Exact counts and measured valuesWerte und Darstellungsbins · Complete unchanged bins (NPZ)

Events · technical review

Not measured

0 unresolved technical review items · 0 Gaia IDs searched · 0 tested windows. Windows are not independent events.

No confirmed transit. Short artifact clusters and time-correlated errors can pass this screening. Real periodic search: insufficient coverage; no globally calibrated false-alarm probability is available.

Saved event evidenceTest windows, supporting exposures and limitations
Photometry precision and sampling · experimental

Photometry & transit readiness

Not measured for this scope. Use the manual Review → Measure action once native exposures, calibration and geometry are qualified.

Comparison-star evidence · experimental
Stack input review · 0 exclusions

Input image review

0 excluded from this imaging stack · 0 flagged for inspection · 43 original exposures retained.

Exclusions affect this image stack only. Raw measurements and calibrated scientific images remain available. A satellite-like line alone does not reject an entire exposure.

Typical reference exposureReference raw frame and representative star crops
Method and all inputs

Median/MAD comparisons stay within the same session, exposure, recorded setup and orientation. At least 12 valid frames and 75% coverage are required. Only simultaneous strong width and elongation outliers with at least 20 fitted stars can be excluded automatically. These are engineering thresholds, not a validated defect classifier. Entire-night defects and satellite trails may escape these metrics; pixel rejection remains a separate stack operation.

ExposureImaging decisionReason
Input 079576373b77retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 9d05797d6052retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input dd75da83a1ffretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input b42ab7770e15retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 1044602d77a3retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input a406f98b6c80retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 7f622d9076b8retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 458d27fd9487retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 06b81a6c3ff2retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 56e6c925b77cretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 80ea476ff3ccretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input d8b6f95ff454retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 833561e5df18retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input c36d1cfabc29retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 835f1fadb177retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 208b1fabb7adretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input c95775266b6bretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input f453a9b23b9cretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input cbcc2bf1f427retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 67b52b047d58retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input e13905911332retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 54ca6afbf91fretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 61d426d994adretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 08c0c2cfaebcretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 366703f542b2retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 595e402b5ae3retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input bb2a4fb56689retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input fb7fb0ee576bretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 931e55593816retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input f23608239de9retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 840c3fa64642retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 2ae722aa63acretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input afa973867e75retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 4acb73f02da1retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 94c3b093f4efretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 47c81091325aretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 12607c403df4retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 6dbfaa107b88retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 55f66f1e9ac5retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input af93b55501cbretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 73ec235166faretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input bd10694749a2retain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier
Input 681964a15a8dretain · weights R/G/B 1.000 / 1.000 / 1.000no_supported_outlier

Stack contribution weights

Equal contribution retained after weighting review

Compared with an equal-weight control using the exact same exposures, crop, normalization and pixel rejection. Star width and shape are reviewed separately.

No supported texture improvement without a worse channel

Matched stars: 64 · background-texture ratio R/G/B: 1.000 / 1.000 / 0.993. Ratios compare weighted / equal; they are not a calibrated SNR.

Per-exposure weights and method

Weights are proportional to inverse background variance after Siril additive-scale normalization, independently in R, G and B, normalized to mean one. Displayed native values are reconstructed from rounded saved statistics. A weight is not a universal quality grade.

Input IDR / G / B contribution
1044602d77a31.0000 / 1.0000 / 1.0000
079576373b771.0000 / 1.0000 / 1.0000
458d27fd94871.0000 / 1.0000 / 1.0000
a406f98b6c801.0000 / 1.0000 / 1.0000
c95775266b6b1.0000 / 1.0000 / 1.0000
94c3b093f4ef1.0000 / 1.0000 / 1.0000
d8b6f95ff4541.0000 / 1.0000 / 1.0000
bd10694749a21.0000 / 1.0000 / 1.0000
2ae722aa63ac1.0000 / 1.0000 / 1.0000
06b81a6c3ff21.0000 / 1.0000 / 1.0000
208b1fabb7ad1.0000 / 1.0000 / 1.0000
b42ab7770e151.0000 / 1.0000 / 1.0000
cbcc2bf1f4271.0000 / 1.0000 / 1.0000
afa973867e751.0000 / 1.0000 / 1.0000
73ec235166fa1.0000 / 1.0000 / 1.0000
f23608239de91.0000 / 1.0000 / 1.0000
fb7fb0ee576b1.0000 / 1.0000 / 1.0000
12607c403df41.0000 / 1.0000 / 1.0000
61d426d994ad1.0000 / 1.0000 / 1.0000
f453a9b23b9c1.0000 / 1.0000 / 1.0000
af93b55501cb1.0000 / 1.0000 / 1.0000
08c0c2cfaebc1.0000 / 1.0000 / 1.0000
9d05797d60521.0000 / 1.0000 / 1.0000
595e402b5ae31.0000 / 1.0000 / 1.0000
80ea476ff3cc1.0000 / 1.0000 / 1.0000
7f622d9076b81.0000 / 1.0000 / 1.0000
835f1fadb1771.0000 / 1.0000 / 1.0000
833561e5df181.0000 / 1.0000 / 1.0000
840c3fa646421.0000 / 1.0000 / 1.0000
56e6c925b77c1.0000 / 1.0000 / 1.0000
366703f542b21.0000 / 1.0000 / 1.0000
c36d1cfabc291.0000 / 1.0000 / 1.0000
47c81091325a1.0000 / 1.0000 / 1.0000
67b52b047d581.0000 / 1.0000 / 1.0000
55f66f1e9ac51.0000 / 1.0000 / 1.0000
6dbfaa107b881.0000 / 1.0000 / 1.0000
54ca6afbf91f1.0000 / 1.0000 / 1.0000
681964a15a8d1.0000 / 1.0000 / 1.0000
dd75da83a1ff1.0000 / 1.0000 / 1.0000
bb2a4fb566891.0000 / 1.0000 / 1.0000
e139059113321.0000 / 1.0000 / 1.0000
4acb73f02da11.0000 / 1.0000 / 1.0000
931e555938161.0000 / 1.0000 / 1.0000

Correlated noise, shared calibration errors and local pixel rejection are not represented by these frame-level weights. Individual-exposure photometry is unchanged.

Appendix · measurement methods & observing conditions
Observing nights and Moon

RGB

2026-11-07 19:52:31 CET (UTC+0100) → 2026-11-07 22:16:26 CET (UTC+0100)

2.3% Moon illumination · saved calculation

Altitude -53.1°Target separation —

Mitte des Aufnahmezeitraums

Original saved observation note

Time assumption: DATE-OBS interpreted as UTC because TIMESYS is missing. Astronomical context is provisional.

Original saved observation note

Moon altitude is approximate; local Earth-orientation data may be incomplete.

Original saved observation note

Geometric Moon altitude, without terrain or refraction; site elevation assumed to be 0 m.

Saved time assumptions are unchanged. Site and weather are shown on the session pages.

Explain this comparison

Comparison with your current archive: each physical observing session has equal weight. Valid per-exposure values are first averaged within each session, then the session means are averaged. Later sessions and the exposures shown here may be included. This is neither an independent test nor a formal quality grade.

Selected data use the exact input IDs of this product. RGB and DNB, methods, units, sampling and recorded acquisition settings remain separate. Unknown setup metadata do not establish physical compatibility. A few sessions form only a small descriptive reference. Missing values do not count as zero.

FWHM and star shape are saved medians of the stellar fits in each exposure; the display averages these per-exposure values. Stellar SNR is the saved median of model estimates from at least five stars per exposure. Model: source Poisson noise, background variance and uncertainty in the mean local sky. Circular aperture radius 3, sky annulus 5–7 sampling pixels, 3σ clipping. EGAIN in electrons/ADU is required. Different star selections remain a limitation even within the same field.

Background and scatter are raw green-grid ADU under compatible acquisition conditions. Field emission, gradients and stellar populations limit comparison. These are not measurements of pure seeing, nebular SNR or transit sensitivity. The previous grading rule requiring eight other nights has not changed.

RGB · Background: 43/43 valid selected exposures; archive 43/43 frames, 1 Sessions. Unknown properties: device_id, readout_mode, optical_configuration, filter, execution_method_version.

RGB · Star shape: 43/43 valid selected exposures; archive 43/43 frames, 1 Sessions. Unknown properties: device_id, readout_mode, optical_configuration, filter, execution_method_version.

RGB · Star width (FWHM): 43/43 valid selected exposures; archive 43/43 frames, 1 Sessions. Unknown properties: device_id, readout_mode, optical_configuration, filter, execution_method_version.

RGB · Stellar SNR: 43/43 valid selected exposures; archive 43/43 frames, 1 Sessions. Unknown properties: device_id, readout_mode, optical_configuration, filter, execution_method_version.

RGB · Background scatter: 43/43 valid selected exposures; archive 43/43 frames, 1 Sessions. Unknown properties: device_id, readout_mode, optical_configuration, filter, execution_method_version.

Archive version ab3717b4ec376ea87d5261c94fe6dbbd42a97237e09422490b5844921d286006. This export is a frozen snapshot; it does not update without a new export.

All measurements and frozen archive comparison

Individual-frame quality review · advisory

Image-quality assistant

0 selected frames worth reviewing · 43/43 inputs have enough same-session support. All frames remain selected exactly as before.

Separate raw measurements, compared with the median of the same session and recorded setup. No overall score, automatic rejection or diagnosis.

Method, coverage and limitations

Review distance = (value − session median) / (1.4826 × MAD). The threshold 3.5 is an advisory rule, not statistical significance. At least 12 valid frames and 75% coverage are required; zero MAD is unavailable. SNR requires the existing gain and star-count checks. Background changes are flagged in either direction.

Shared tracking/focus problems can affect an entire night without producing an outlier. No independent validation labels exist yet. Raw-green sampling and changing star populations limit interpretation. RGB/DNB, exposure, method and recorded orientation remain separate; unknown metadata do not establish compatibility.

RGB · 180.0 s · session acq_a9287c7f: Background level 43/43; Background scatter 43/43; Detected sources 0/43: too few valid session frames; Star eccentricity 43/43; Star width (FWHM) 43/43; Stellar SNR estimate 43/43. Unknown: device_id, filter, optical_configuration, readout_mode, recorded_orientation_deg.

Method session-quality-assistant-1. Saved measurements and existing archive comparisons are unchanged.