FITS Header, EXIF, And Astrometry Metadata

The read-only table exposes stored FITS records directly. This solved example contains a celestial WCS but no accepted SIP coefficient set.

Astrometry Info interprets the active image's solution in reader-friendly fields; SIP distortion: None records the selected file's actual metadata state.

Purpose, audience, prerequisites, and expected result

These three read-only tools inspect different layers of the active image's in-memory metadata:

• FITS Header shows parsed FITS cards as keyword, value, and comment rows.
• EXIF Viewer shows camera-oriented EXIF tags that AfterNight retained for display.
• Astrometry Info interprets celestial WCS and SIP cards as a compact solution summary.

Use them to diagnose acquisition metadata, check a plate-solve handoff, or inspect a reopened output. You need an active image; FITS Header and EXIF Viewer also require the image to carry at least one card of the corresponding kind. The expected result is an inspection window only. None of these tools edits pixels, metadata, history, files, or the pending-save state.

Image and Sequence Summary owns the fixed common image/file/ sequence report. Image Statistics and Histogram Analysis own pixel measurements. This page does not reproduce those field inventories, and Astrometry Overlays owns overlay rendering and catalog behavior.

Reachability and availability

Item	Current behavior
Path	Image > Information > FITS Header, EXIF Viewer, or Astrometry Info. Standard image-view toolbars expose the same three labels. Focused-view shortcuts are Ctrl+Shift+H, Ctrl+Shift+X, and Ctrl+Shift+P.
Enabled/visible when	FITS Header requires at least one FITS card among the image's header cards. EXIF Viewer requires at least one EXIF field the window shows a row for: an Exif. field of a JPEG, TIFF, PNG or camera-RAW file that the window does not hide. A container's own entries alone, such as a PNG's bit depth or a JPEG comment, do not enable it. When the view refreshes its actions while an edit holds the image, both are disabled until the next update. Main-menu Astrometry Info requires any active image and can show an unsolved state. Toolbar Astrometry Info is visible only for stills and enabled only when the view has parsed WCS; it is hidden for sequences.
Supported inputs/state	Still images and the current decoded frame of a sequence. FITS-style metadata can also originate from XISF or processing; availability does not prove the current file extension. Masks, selections, display channel, zoom, autostretch, overlays, and pixel statistics do not affect the metadata shown.
Outputs/side effects	Modeless read-only dialogs. FITS/EXIF allow one selected row; Astrometry labels allow mouse text selection. There is no report file, table export, table copy action, metadata edit, or history entry.
Persistence	None. Window geometry, column widths, selection, and scroll position are dialog-local and are not stored.
External dependencies	None at inspection time: the engine's FITS (CFITSIO), XISF and EXIF (Exiv2) readers stored the cards when the file was opened, and the solution is read by the engine's own WCS card reader. Opening these panels uses no network, catalog, solver, or external executable.

The menu and toolbar gates are independent. In particular, the main-menu Astrometry action deliberately remains enabled for an unsolved active image so the panel can report No astrometric solution, while its image-toolbar action requires parsed WCS.

Before you start

• Activate the exact view or pause on the exact sequence frame to inspect. FITS and EXIF dialogs stay attached to their originating view. Astrometry Info follows the application's active image while it remains open.
• Reopen a saved output before treating these panels as file verification. They read current in-memory metadata and do not reread the file on every refresh.
• Treat camera, observer, object, location, and time fields as potentially private and as claims from the source file, not independently measured facts.
• For WCS interpretation, distinguish the image-center sky coordinate from the WCS reference coordinate. They need not be equal.

Procedure

1. Activate the target view. If it is a sequence, pause on the frame whose metadata you want to inspect.
2. Open Image and Sequence Summary first when you need common dimensions, pixel type, file identity, frame count, or FPS. It is intentionally not a full metadata dump.
3. Open Image > Information > FITS Header. Confirm the title names the intended view, then inspect the original row order and the Key, Value, and Comment columns. Resize columns or scroll as needed.
4. For a solved image, locate CTYPE1/2, CRPIX1/2, CRVAL1/2, the CD or PC/CDELT matrix, and any A/B or AP/BP SIP cards. Then open Astrometry Info and compare its interpreted fields with those raw cards.
5. Open EXIF Viewer when enabled. Read Tag, Value, and Key together; the Key column is the field's full EXIF key, such as Exif.Photo.ExposureTime. The table is for reading, not a machine-readable export.
6. If the image changes, wait for the normal image load/update notification. The panels refresh automatically; there is no Refresh button. A rename updates each window title.
7. To verify preservation, save in the intended format, reopen the output, and inspect again. Use Saving And Exporting and File Formats for the authoritative format-specific preservation contract.

Complete control and action reference

UI label/action	Type and unit	Default	Valid values/constraints	Effect	Enabled, hidden, or ignored rules	Trade-off or side effect	Scope	Persistence
Image > Information > FITS Header	Main-menu action	Disabled	Click	Opens FITS Header for the active view.	Enabled only when the current image has at least one FITS card. Opening a dialog disables this main-menu action for that originating active view until a FITS dialog closes.	Inspection only.	Active image/current frame	None
FITS Header	Standard-view toolbar action	Disabled without FITS cards	Click	Opens the same FITS dialog for that view.	Standard view only; follows that view's current image metadata. The local toolbar action is not disabled by an already-open dialog.	More than one FITS dialog can be opened for one view.	Originating view	None
Ctrl+Shift+H	Focused-view shortcut	Advertised by FITS toolbar tooltip	Key press	Opens FITS Header.	The reviewed shortcut calls the dialog directly and does not check the action's enabled state.	On metadata without FITS cards it can open an empty dialog; repeated use can open duplicates.	Focused standard view	None
Key / Value / Comment	Read-only three-column table	Source order; no selection	The image's FITS cards	Displays the keyword, the stored value text - a string value with its quotes - and the comment text of every FITS card the image was read with - a FITS file's, or the FITS keywords an XISF file carries. A string continued over CONTINUE cards is one row holding the whole value.	All rows are presented; the viewer does not group HDUs. A file with no FITS card shows an empty table.	Values/comments can be long; row order may include structural and repeated cards.	Originating image/current frame	Dialog lifetime
FITS row selection	Single whole-row selection	None	One row	Highlights one row for visual comparison.	Cell editing is disabled.	There is no built-in table copy/export command.	FITS table	Dialog lifetime
FITS column resize/scroll	Header drag and scroll gestures	Interactive columns; last column stretches	Normal platform table interaction	Reveals long values and navigates rows.	Sorting is not enabled; clicking a heading does not reorder rows.	Presentation only.	FITS table	Dialog lifetime
FITS automatic refresh	Image listener action	Initial calculation on open	Image loaded/updated	Clears and rebuilds rows from the originating view's current image, an empty table when it states no FITS card.	No manual refresh control. Asked while an edit holds the image, the window keeps what it shows and rebuilds at the next update; it never waits for the edit.	None.	Originating view	None
FITS title refresh	Image listener action	FITS Header Viewer <view>	View rename	Updates only the window title.	Does not reread a file.	None.	Dialog title	None
FITS Close	Default primary button/window close	Available	Click, Enter, or close window	Closes the dialog and re-enables the originating view's main-menu FITS action.	Always available.	If duplicate dialogs exist, closing either can re-enable the main action while another remains open.	This dialog	None
Image > Information > EXIF Viewer	Main-menu action	Disabled	Click	Opens EXIF Viewer for the active view.	Enabled only when the current image carries at least one EXIF field the window shows, from a JPEG, TIFF, PNG or camera-RAW file - the rule the window's rows read. Opening disables this main-menu action for the originating active view until an EXIF dialog closes.	Inspection only.	Active image/current frame	None
EXIF Viewer	Standard-view toolbar action	Disabled without EXIF entries	Click	Opens the same EXIF dialog for that view.	Standard view only. The local toolbar action is not disabled by an already-open dialog.	More than one EXIF dialog can be opened for one view.	Originating view	None
Ctrl+Shift+X	Focused-view shortcut	Advertised by EXIF toolbar tooltip	Key press	Opens EXIF Viewer.	The reviewed shortcut does not check the action's enabled state.	On metadata without EXIF it can open an empty dialog; repeated use can open duplicates.	Focused standard view	None
Tag / Value / Key	Read-only three-column table	The order the file stated the fields in; no selection	The image's EXIF fields	Shows the field's name - the last part of its key - its value as the EXIF library renders it, and its full key. A value longer than one stored card is shown whole.	Fields of a JPEG, TIFF, PNG or camera-RAW file. The maker note, the interoperability fields, the strip offsets, the subfile type, the embedded XMP, IPTC and Photoshop blocks, the colour profile and the thumbnail are omitted; an embedded XMP packet is not even read.	This is a human-readable view, not a lossless EXIF serializer.	Originating image/current frame	Dialog lifetime
EXIF row selection	Single whole-row selection	None	One row	Highlights one row.	Cell editing is disabled.	There is no built-in table copy/export command.	EXIF table	Dialog lifetime
EXIF column resize/scroll	Header drag and scroll gestures	Interactive columns; last column stretches	Normal platform table interaction	Reveals long values and navigates rows.	Sorting is not enabled. Rows follow the order the file stated its fields in, not alphabetical order of the Tag label.	Presentation only.	EXIF table	Dialog lifetime
EXIF automatic refresh	Image listener action	Initial calculation on open	Image loaded/updated	Clears and rebuilds the rows from the originating view's current image, an empty table when it states no EXIF field.	No manual refresh control. Asked while an edit holds the image, the window keeps what it shows and rebuilds at the next update; it never waits for the edit.	Current-frame changes replace the table.	Originating view	None
EXIF title refresh	Image listener action	EXIF Header Viewer <view>	View rename	Updates only the window title.	Does not reread a file.	None.	Dialog title	None
EXIF Close	Default primary button/window close	Available	Click, Enter, or close window	Closes the dialog and re-enables the originating view's main-menu EXIF action.	Always available.	Duplicate-dialog re-enable limitation matches FITS.	This dialog	None
Image > Information > Astrometry Info	Main-menu action	Disabled without active image	Click	Opens the astrometric summary for the active image.	WCS is optional; an unsolved image shows an explicit unsolved state. Main-menu source permits a sequence current frame.	Inspection only.	Active image/current frame	None
Astrometry Info	Standard-view toolbar action	Visible but disabled for unsolved still	Click	Opens or raises the originating view's existing Astrometry panel.	Hidden for sequences; enabled only when that still has parsed WCS.	The open panel then follows active-view changes rather than remaining fixed to the launch image.	Current active image	None
Ctrl+Shift+P	Focused-view shortcut	Advertised by Astrometry tooltip	Key press	Opens/raises Astrometry Info.	Honors the toolbar action's visible and enabled state.	No effect on an unsolved still or sequence toolbar context.	Focused standard view	None
Status	Read-only message	No active image, No astrometric solution, or Astrometric solution available	Derived state	Distinguishes absent image, failed/no celestial WCS, and parsed WCS.	Does not expose the card reader's detailed refusal.	A valid status does not certify solve accuracy.	Active image	Runtime
Field center RA	Selectable read-only angle	-	Sexagesimal hours HH:MM:SS.ss	Converts the geometric image-center pixel through WCS; RA is normalized to 24 hours.	Requires valid celestial WCS and a projectable center.	Can differ from CRVAL RA.	Active image	Runtime
Field center Dec	Selectable read-only angle	-	Signed sexagesimal degrees ±DD:MM:SS.s	Converts the geometric image-center pixel through WCS.	Requires valid celestial WCS and a projectable center.	Can differ from CRVAL Dec.	Active image	Runtime
CRVAL RA	Selectable read-only angle	-	Sexagesimal hours HH:MM:SS.ss	Formats the right ascension of the solution's reference point.	Requires valid celestial WCS/reference axes.	It is the world coordinate at the reference pixel, not necessarily field center.	Active image	Runtime
CRVAL Dec	Selectable read-only angle	-	Signed sexagesimal degrees ±DD:MM:SS.s	Formats the declination of the solution's reference point.	Requires valid celestial WCS/reference axes.	It is not necessarily field center.	Active image	Runtime
Image scale	Selectable read-only scale	-	Arcseconds/pixel, three decimals	The side of a square pixel covering the same solid angle as the solution's pixel, from its CD matrix or the PC/CDELT equivalent.	Requires valid WCS and positive finite scale.	One displayed scalar does not describe anisotropic/skewed scale on both axes.	Active image WCS	Runtime
Rotation	Selectable read-only angle	-	Degrees, one decimal, N through E	The solution's orientation: the direction of celestial north, measured from increasing y toward decreasing x.	Requires valid WCS and finite result.	Does not report uncertainty or parity separately.	Active image WCS	Runtime
Field of view	Selectable read-only angular size	-	Arcminutes, two decimals, width x height	The solution's field of view across the image's width and height.	Requires positive finite derived dimensions.	Rectangular scale estimate, not a sampled spherical footprint or overlay viewport.	Whole active image	Runtime
Projection	Selectable read-only text	-	RA---TAN / DEC--TAN, with -SIP when the solution carries a polynomial	The projection the solution is written with.	Requires a valid solution.	Describes the solution as read, not the stored strings.	Active image metadata	Runtime
Equinox	Selectable read-only FITS text	-	Numeric value formatted as Jyyyy.y, otherwise sanitized text; the reference frame when no equinox is stated	Shows EQUINOX, or RADESYS - ICRS for a solution AfterNight wrote - when the header states no equinox.	Can appear without valid complete WCS.	Does not transform coordinates to another epoch.	Active image metadata	Runtime
SIP distortion	Selectable read-only model summary	None	Forward A/B, inverse AP/BP, polynomial orders, and count of coefficients whose magnitude exceeds 1e-12	Summarizes the solution's SIP model, tied to its reference pixel.	Read with the solution: the projection codes carry -SIP exactly when polynomial cards are present, A and B (or AP and BP) come in pairs, every order is from 2 through 6 and every coefficient a number within its order; a missing coefficient is zero. A header that breaks any of these shows no solution at all.	Reports model presence/order/count, not maximum distortion, solve residual, or correction quality.	Active image WCS	Runtime
Solver	Selectable read-only FITS text	Unknown	Sanitized PLTSOLVR value	Identifies the writer recorded by AfterNight's plate-solve path.	Can appear without a valid complete WCS; external solved files often omit this project-specific card.	Unknown does not mean unsolved.	Active image metadata	Runtime
Astrometry automatic refresh/retarget	App/image listener action	Launch image	Active view change; image load/update	Reattaches to the current active view, updates title/status, reparses metadata, and replaces all fields.	No manual refresh button. Rename changes the title. While an edit holds the image, Equinox and Solver read as unknown until its next update.	The inspected target can change simply by focusing another image.	Current active view	None
Astrometry Close	Secondary button/window close	Available	Click or close window	Closes the panel.	The panel belongs to the view it was opened from, so repeat launch through that same view raises it. After focus moves, the open panel retargets, but launch through the newly active view can create a second panel, which belongs to that view.	No metadata change.	This dialog	None

Behavior and state model

FITS rows and EXIF rows

A FITS read keeps the header cards of the image it decodes - the first image HDU, empty primary HDUs and tables skipped - with the primary header's cards that an image extension inherits. The viewer lists them in that order, without sorting or HDU separators. Each row holds the keyword, the value text as stored and the comment; blank cards are not shown, a string continued over CONTINUE cards is one row holding the whole value, and HISTORY and COMMENT cards are ordinary rows. It is not a byte-for-byte 80-character card display. Processing can also create or update FITS-style cards, and XISF can supply compatible FITS keywords, so the panel's gate is metadata presence rather than filename type. The processing-state cards AfterNight writes are quoted FITS strings, with a later duplicate of a keyword removed; a long colour-calibration value continues over CONTINUE cards and appears as one whole row.

EXIF load uses Exiv2. The engine keeps each field as the text the library renders, under its fully qualified EXIF key and in the order the file states the fields, with the field's EXIF type beside it; a field longer than one stored card continues in the next, and the viewer shows it whole. The viewer shows the key's last part as the tag, the value and the full key; it does not show the library's description of a field, which the engine does not keep. MakerNote, interoperability, strip-offset, XML/IPTC/resource/profile entries and the thumbnail are hidden. An embedded XMP packet (Exif.Image.XMLPacket) is removed before the EXIF library reads the record, so it is never shown and a later raster save does not carry it. The other fields are written back by a later raster save when Embed EXIF is on; the table itself is not that serializer.

Both table dialogs listen for image-load and image-update events on their originating view and rebuild on the GUI thread, reading the image under a lease that never waits; asked while an edit holds the image they keep what they show until the next update. Sequence playback can therefore replace rows with the current frame's metadata. They do not follow the globally active view. Astrometry Info instead listens for active-view changes and reattaches its image listener, so its fields can change when focus moves. Ownership does not move with the displayed target: each panel belongs to the view it was opened from. Consequently, a panel launched from view A can follow focus to view B while a new launch through B creates another panel. Repeating the launch through either owner raises only that owner's panel.

WCS and SIP interpretation

Astrometry Info shows the solution the view read from the image's FITS cards through one card reader - the same one the overlays and Plate Solve use - with EQUINOX (or the reference frame) and PLTSOLVR text beside it. The reader takes a header that states the J2000 equinox and no frame - what astrometry.net and ASTAP write - as the ICRS, and refuses FK5 or any other frame. No astrometric solution means the cards state no solution the reader accepts; it does not reveal which card was missing or invalid. A solution AfterNight writes states RADESYS = 'ICRS' and no EQUINOX, every number as the shortest decimal that reads back as itself, the solver's name as PLTSOLVR and none of the solver's comments, so Equinox shows ICRS for it.

For a valid solution, field center is the projection of the image's center, (width / 2, height / 2) measured with the first pixel's center at (0.5, 0.5). CRVAL is the solution's reference point. Scale, rotation, and field of view are the solution's own figures, derived from its CD matrix (or its PC/CDELT equivalent) rather than stored fields. A coordinate is rounded once and the rounding carries into every field: a field centre of 10h 29m 59.996s shows as 10:30:00.00, never as sixty seconds.

The SIP summary is intentionally compact. The polynomial is read with the solution: orders from 2 through 6, A with B and AP with BP, projection codes ending in -SIP exactly when polynomial cards are present, and every coefficient a number within its order; a missing coefficient is zero. The summary counts nonzero coefficients for display. None means no model accepted by this parser, not proof that the raw header has no distortion-related text. See Astrometry Overlays for the forward-model requirement of the distortion-map layer and Plate Solving for how a solution is created.

Refresh and metadata preservation

All three tools are observers: opening, selecting, resizing, scrolling, or closing them never mutates metadata. Image > Actions > Duplicate takes a snapshot of the image - its samples and every metadata object, the header cards and EXIF fields among them - into a new image that has never been a file; focused tests verify that the WCS, solver and projection survive two such duplicate generations. An image a combination makes - a blend, LRGB or channel combination - carries the exposure once, as the sum, with the sources' EXPOSURE/EXPTIME cards dropped, and keeps the observation start, the airmass, a shared filter and every other card only when every source states it.

That in-memory rule is not a universal file-format guarantee. A FITS save writes the image's cards with the structural cards generated from the output and the solution written as the engine's card bridge writes it; XISF carries FITS-style keywords. JPEG/TIFF/PNG EXIF embedding is optional and format-filtered, and an EXIF field the metadata library cannot write is skipped while the others are written. Geometry-changing operations adjust or strip the solution as their own implementation requires. Therefore, use Saving And Exporting and File Formats as the authority, then reopen the actual output for verification.

Inputs, outputs, and metadata

Tool	Input	Visible output	Source modification	Durable output
FITS Header	Current image/frame's FITS header cards	Read-only keyword/value/comment table	None	None
EXIF Viewer	Current image/frame's EXIF fields from a JPEG, TIFF, PNG or camera-RAW file, after load-time and viewer filters	Read-only tag/value/key table	None	None
Astrometry Info	Current active image/frame's FITS cards, read by the engine's WCS card reader with its SIP polynomial	Status plus 11 selectable summary values	None	None

The panels do not display pixel statistics, processing history as a structured timeline, Image Summary's filesystem/sequence fields, XMP/IPTC as separate tables, or astrometry overlay/catalog state. A FITS HISTORY card may appear as an ordinary header row; that is not the same surface as Image History.

Performance and responsiveness

FITS and EXIF refresh work is proportional to the number of retained metadata entries and rebuilds the table on the UI thread. Astrometry refresh formats the solution the view already read and a fixed 11-field report. None of the panels scans pixels, iterates an entire sequence, queries catalogs, or uses the network.

Pause fast sequence playback if repeated current-frame metadata rebuilds are unhelpful. Very large EXIF/FITS collections can make table rebuilding or layout slower; close the dialog when not inspecting it. An image holds at most 8,192 metadata cards of at most 4,096 bytes each; a longer EXIF value is carried over several cards and shown whole.

Worked example

• Evidence mode: Source-and-test-derived.
• Starting state, actions, settings, checkpoints, result, and limitations: The focused formatter fixture builds 640 x 480 metadata with RA---TAN-SIP / DEC--TAN-SIP, CRVAL 187.5 / -45.5, a 0.0005 degree/pixel CD scale, EQUINOX=2000.0, PLTSOLVR='ASTAP', order-2 forward SIP, and two nonzero coefficients. The expected panel reports Astrometric solution available, CRVAL 12:30:00.00 / -45:30:00.0, projection without FITS quotes, J2000.0, an arcsec/pixel scale, field-of-view and rotation units, ASTAP, and A/B 2/2, 2 coeffs; the figures are the solution's own: 1.800 arcsec/px, a rotation of 0.0° and a field of view starting 19.20′. The unsolved fixture reports No astrometric solution. A two-generation duplicate fixture - two snapshots in turn - retains the solution, solver, and projection. This predicts deterministic fields; the source-derived example does not claim a live astronomical solve, table layout, clipboard round trip, or solve accuracy.

Warnings and limitations

• Metadata is descriptive, not trusted validation. A source can contain stale, inconsistent, private, or incorrect cards/tags.
• FITS Header shows the decoded image's cards, with the primary header's inherited ones, without an HDU-name/index column and does not show exact raw 80-character card bytes.
• EXIF Viewer deliberately omits large/binary/resource records and shows each field's tag - the last part of its key - beside the full key, not the EXIF library's description.
• FITS/EXIF tables have no sorting, search, filter, copy, export, or manual refresh action. Selecting a row does not create clipboard text.
• Their focused-view shortcuts do not honor availability or already-open state; empty or duplicate dialogs are possible. Astrometry's shortcut does honor its toolbar gate.
• An open Astrometry panel follows focus, but ownership remains with the view that launched it. Launching from another active view can therefore create a second panel already showing the same current image.
• An image that states no FITS card or EXIF field empties the open table; asked while an edit holds the image, the window keeps what it showed until the next update, so a table can briefly describe the image before the edit.
• An image whose only EXIF fields are ones the window hides - the maker note, the thumbnail, the colour profile or an embedded XMP, IPTC or Photoshop block - does not enable the EXIF Viewer action, since the window would show no row.
• Astrometry Info exposes no parse diagnostics, residual/error estimate, parity, per-axis scales, or SIP displacement magnitude. A formatted solution is not a quality certificate.
• Field center and CRVAL describe different locations. SIP model presence and an overlay's forward-model usability are also different questions.
• Saving or converting to another format can rewrite, subset, or discard metadata. Reopen important outputs before deleting their source/master.

Troubleshooting

Symptom or exact error	Verified cause/enablement path	Recovery	Evidence source
FITS Header is disabled	The current image carries no FITS card, or the view refreshed its actions while an edit held the image. This is a metadata gate, not an extension check.	Activate an image with retained FITS-style metadata, or wait for the edit; reopen a FITS/XISF output when verifying disk preservation.	ActionStateCoordinator.cpp; ImageViewControl.cpp
EXIF Viewer is disabled	The current image carries no EXIF field the window shows: the source stated no EXIF, only fields the window hides, or only the container's own entries; the source is a camera RAW whose EXIF AfterNight does not read - CR3, CRW, MRW or X3F; or the view refreshed its actions while an edit held the image.	Select a camera-originated image with retained EXIF; inspect the source format contract.	ActionStateCoordinator.cpp; ImageViewControl.cpp; common.h (statesShownExifField); ViewToolsTest.TheExifWindowIsOfferedForAnExifFieldOfEveryRasterContainer; RawOpenTest.ACameraFileOpenedThroughTheFileMenuOffersItsExifWindow
A shortcut opens an empty FITS/EXIF window	Ctrl+Shift+H and Ctrl+Shift+X call their dialogs without checking action availability.	Close it and use the enabled menu/toolbar state as the reliable gate.	ImageViewControl.cpp
Clicking FITS/EXIF column headings does not sort	Sorting is not enabled.	Inspect source order; use an external FITS/EXIF tool when sorting/search/export is required.	FITS/EXIF UI builders and controls
FITS/EXIF rows did not change while an edit ran	The window never waits for an edit; it keeps the rows it showed until the edit lands.	Wait for the edit to finish; the table rebuilds on the image's update.	ImageFITSHeaderViewerControl.cpp; ImageEXIFViewerControl.cpp; ImageInspectorContent.cpp
An expected EXIF tag is absent	It has no tag name, is a structural field the reader skips, is an embedded XMP packet, or is one of the filtered MakerNote/interoperability/offset/XML/IPTC/resource/profile entries.	Use a dedicated metadata utility on the original file; do not infer the tag was never present.	ExifCards.cpp; ImageInspectorContent.cpp
Astrometry menu opens but toolbar action is disabled/missing	Main menu requires any image; toolbar requires WCS and is hidden for sequences.	Use the menu to inspect the unsolved state, or plate-solve a still before using the toolbar action.	ActionStateCoordinator.cpp; ImageViewControl.cpp
No astrometric solution appears although WCS-like cards exist	The card reader refused the header: a missing, malformed or duplicated keyword, SIP cards that disagree with the projection codes, a singular matrix, or a frame other than the ICRS - FK5 stated, or an equinox other than J2000 and no frame.	Inspect CTYPE, CRPIX, CRVAL, RADESYS, EQUINOX, the CD or PC/CDELT cards and the SIP cards in FITS Header; rerun Plate Solve when appropriate.	WcsCards.h; PlateSolveTypes.h; ImageAstrometryInfoFormatter.h
SIP distortion says None although SIP cards are visible	The cards are other polynomial keywords than A, B, AP and BP with their orders; a header whose SIP cards the reader cannot take shows no solution rather than None.	Inspect the raw SIP cards and the projection codes.	WcsCards.h; ImageAstrometryInfoFormatter.h
Solver says Unknown on a solved image	The project-specific PLTSOLVR card is absent or empty.	Treat WCS validity separately; use source provenance or rerun a documented solve if solver identity matters.	ImageAstrometryInfoFormatter.h
Astrometry fields change while the panel stays open	Astrometry Info follows the application's active image.	Refocus the intended view and confirm its name in the panel title.	ImageAstrometryInfoControl.cpp
More than one Astrometry Info panel shows the same active image	Each launching view owns one panel pointer, while every open panel follows the globally active view. Launching through a newly focused view can create another panel.	Close redundant panels; repeat launch through the same owner only raises its existing panel.	ImageViewControl.cpp; ImageAstrometryInfoControl.cpp
Reopened output lost some metadata	The chosen codec/save path does not preserve every metadata family, Embed EXIF was off, or an EXIF field the metadata library could not write was skipped.	Keep the master, consult File Formats, choose FITS/XISF where appropriate, and verify the reopened file.	FITS/metadata codecs; Saving And Exporting

Related workflow steps

• Start with Image and Sequence Summary for identity, dimensions, pixel representation, common acquisition fields, and native sequence totals; use these panels only for detailed metadata.
• Use Plate Solving to create or replace WCS/SIP metadata, then inspect the raw and interpreted handoff here.
• Use Astrometry Overlays to render the coordinate grid, catalogs, detected stars, and forward-SIP map. This page reports the metadata model but does not own overlay state.
• Use Saving And Exporting and File Formats to choose a preservation path; reopen and inspect the output before discarding the source.
• Use Image Statistics and Histogram Analysis for pixel evidence rather than metadata claims.

References and provenance

• The IAU FITS Working Group's FITS Standard 4.0 defines FITS cards, keywords, values, and comments.
• NASA/HEASARC's FITS WCS papers and resources links the approved world/celestial-coordinate papers used to interpret WCS.
• Shupe and Hook's registered SIP convention 1.0 defines the forward A/B and inverse AP/BP distortion families.
• CIPA's Exif standards list identifies the current Exif specification; AfterNight's actual visible subset is governed by its Exiv2 loader and viewer filters, not by every possible Exif tag.
• AfterNight's source and focused tests are authoritative for current reachability, formatting, filtering, refresh, duplicate behavior, codec preservation, and known limitations.