Module auto 

Everything the arcsec command line decides for the user, as a library.

crate::pipeline::solve_image needs to be told everything: the field size in radians, the binning, the database directory and name, the minimum star size in (binned) pixels. A user — of the CLI, or of an application embedding arcsec — knows less than that and expects the rest to be worked out the way the CLI does it. This module is that working-out, shared by the arcsec binary and the C library so the two cannot drift:

• where catalogues live (default_catalog_dir, default_db_path);
• which star database suits a field (select_db_for_fov);
• how far to bin (choose_binning);
• which pixel scales to try when the scale is not known (ScaleSearch, ladder);
• when to use a blind index, and how (find_arcsec_index, collect_index_files);
• and the whole solve built from those decisions: a SolveRequest becomes a Plan, and Plan::solve runs it.

use arcsec_core::auto::{Plan, SolveRequest};
let mut img = load();
img.normalize_for_detection();
let request = SolveRequest {
    hint: Some((83.82_f64.to_radians(), (-5.39_f64).to_radians())),
    pixel_scale: Some(1.1),
    search_radius: 10.0_f64.to_radians(),
    ..SolveRequest::default()
};
let plan = Plan::new(&request, img.width, img.height)?;
let solved = plan.solve(&img)?;
println!("RA {:.4}°", solved.wcs.ra0.to_degrees());

Structs

Hypothesis

One scale hypothesis: centre × SCALE_STEP^step.

Plan

A SolveRequest with every decision made, for an image of a given size.

SolveRequest

What the caller knows about an image and how it wants it solved, in the caller’s terms. Every field has the CLI’s default (SolveRequest::default).

Solved

A solution from Plan::solve.

Enums

Event

Something Plan::solve_with reports while it runs.

ScaleSearch

When the catalogue search tries other pixel scales.

Constants

ASTAP_EXTS

File extensions of the star database formats, with the number of sky cells each layout has: .1476 and .290 tile the sky, .001 is one all-sky file.

DB_FOV_RANGES

Field-of-view range each ASTAP database is built for, and how much we prefer it when several are eligible (higher = denser, so a better fit).

INACCURATE_SCALE

The fraction by which a solved scale may differ from the one the solve started from before the solution says so (inaccurate_scale_warning), as astap_cli.

LADDER_FIELDS

How far round the hint each hypothesis is searched, in fields of that hypothesis: the hint’s own position and the ring of eight round it. The search at the assumed scale then continues out to -r, as it always has.

MIN_SOLVE_DIM

Smallest image side, in (binned) pixels, that reaches the solver. Detection cannot run on a one-pixel-wide image, and would otherwise panic on it.

SCALE_STEP

Ratio between neighbouring hypotheses: astrometry.net’s index scales step by the same factor.

SOURCES

Databases an index can be built from, deepest first: an index built from an earlier one is preferred when a directory holds several.

UNKNOWN_STEPS

Steps of SCALE_STEP below and above 1″/px searched when nothing gives the scale: 0.25″/px to 64″/px, from a long focal length binned to a camera lens. The blind index searches 0.3–60″/px for the same case.

WRONG_STEPS

Steps either side of a scale that was given (or read from the header) and did not solve, with ScaleSearch::AlsoIfWrong: a quarter to four times it.

Functions

available_dbs

Every database prefix present in db_path, in any supported format, sorted.

choose_binning

The binning factor: requested if given and non-zero, else automatic.

collect_index_files

Collect and rank astrometry.net index files for blind solving.

default_catalog_dir

Where catalogues are kept, in priority order:

default_db_path

The star database directory to use when none is named.

depth_rank

Position of db in SOURCES (deeper is smaller); unknown names sort last.

find_arcsec_index

The arcsec blind index path names: the file itself, or the first *.arcsecix in a directory. None when there is none (the path may still hold Astrometry.net files).

has_star_database

Whether dir holds any of the star databases arcsec knows (D05 … W08), judged by the file each ships for its first cell (d50_0101.1476, w08_0101.001, …).

inaccurate_scale_warning

astap_cli’s warning when the solved scale is not the one it started from: Warning scale was inaccurate! Set FOV=1.00d, scale=1.2", printed after the solution and written to the .ini as WARNING.

index_files

Every arcsec blind index (*.arcsecix) directly in dir, sorted by name. Empty when there are none or dir cannot be read.

ladder

The hypotheses centre × √2^k for k in lo..=hi, most likely first.

preferred_index

The readable arcsec index in dir the solver uses: the one built from the deepest database (by SOURCES), then by file name. None if there is none.

select_db_for_fov

Pick the installed database best suited to a fov_deg field (the longer side, degrees): the densest whose published range contains it, else the nearest. None when db_path holds no star database at all.

wants_installed_index

Whether a search with template’s radius and field is wide enough that an installed index is consulted automatically: more than five fields, and at least 10°.