Remote imaging, processing pipeline, and observing plans. Merged from itelescope + astro-pipeline.
laurence
fbd1eb8ec5
astrometry.py solves the deepest master against Gaia and copies the WCS into every master. Asterism matching is invariant to rotation and scale, so camera angle never has to be guessed, but not to a mirror flip, so both parities are tried. Three defects were found and fixed by running it, and each is worth recording because none would have been found by reading the code. Gaia's launch_job_async submits to a job QUEUE and polls. On a query of 600 rows it hung for ten minutes while curl showed both the Gaia and VizieR endpoints answering in under a second. VizieR is now queried first - it serves the identical DR3 catalogue over a plain HTTP request - with Gaia's SYNCHRONOUS endpoint as the fallback. VizieR's row_limit truncates before sorting, so asking for the 600 brightest stars returned 600 arbitrary ones. Asterism matching only works when both lists hold the same bright stars, so this silently produced no match at all. It now fetches generously and picks the brightest locally. The detector deliberately rejects saturated cores, which means the brightest DETECTIONS are not the brightest STARS, while the catalogue's are - so the two top-N lists can barely overlap. A sliding window down the catalogue's magnitude ranking fixed NGC 2030, which matched at catalogue[15:135], skipping the 15 brightest. That is the saturation hypothesis confirmed rather than assumed. NGC 2030 now solves on 243 stars at 0.31 arcsec residual. NGC 2070 and NGC 6744 still do not, and TODO.md records what has already been ruled out - scale, the fetch, truncation - so the next session starts from the remaining candidates rather than repeating the elimination. |
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|---|---|---|
| docs | ||
| itelescope | ||
| observing/eclipse-2026-menorca | ||
| pipeline | ||
| state | ||
| .gitignore | ||
| CLAUDE.md | ||
| README.md | ||
astrophotography
Everything to do with taking, processing and understanding astronomical images: the remote telescopes, the code that turns their frames into pictures and measurements, and the plans for observing in person.
Formed by merging the itelescope and astro-pipeline repositories, with the
history of both preserved.
Layout
| Directory | What it is |
|---|---|
| itelescope/ | The iTelescope.net remote telescope network: a review of every scope, a southern-target guide, the observing plans, and the points drain campaign |
| pipeline/ | The processing and analysis code. Calibration, stacking, plate solving, rendering and the science analyses |
| observing/ | Plans for observing in person. Currently the total solar eclipse of 12 August 2026 from Menorca |
| state/ | Project state under the Default Workflow: objective, current work, decisions, working notes |
| docs/ | The Default Workflow itself: branching, commits, documentation policy, cost control |
Start here
- Planning or reviewing a remote imaging run: itelescope/CAMPAIGN.md and itelescope/TELESCOPES.md
- Processing a session's data: pipeline/README.md
- What is happening right now: state/TODO.md
- Why something was done a particular way: state/DECISIONS.md
Where the image data lives
Not in this repository. A single calibrated frame is 61 MB and a session
runs to several gigabytes, so sessions stay on disk and the code finds them
through the ASTRO_SESSION environment variable:
set ASTRO_SESSION=...\NGC5128\20260721
python pipeline/stack.py
Each session directory carries its own METHODS.md describing what was done to
that data and what was found, written for a reader who was not there. The code
lives here; the pixels and the account of them live with the data.
Things learned the hard way
Recorded because each cost real time or real money, and because each is a requirement for anything built next rather than a curiosity:
- Measure whether a core is saturated before buying time to fix it. A foreground star 69 arcsec from Centaurus A's nucleus was mistaken for the galaxy, and a telescope booking was made to solve a problem that did not exist. Filter the stars out of the measurement first.
- Vet moving-object candidates in detector coordinates. Registration holds the sky still, so it drags sensor defects across the frame on perfectly straight, constant-rate tracks. Hot pixels are better-behaved asteroids than real asteroids. One cut took 141 confident spurious detections to zero.
- Never compare an aperture magnitude against a point-source catalogue without checking the source is a point. A resolved object looks exactly like a 2.8 magnitude outburst.
- Never fit a sky background to a field the target fills. A plane fitted around a large galaxy eats its halo, measured at -17.9 ADU/px. Fit the background and a source model together.
- A photographic ND filter is not a solar filter. It passes the infrared that carries the heat.