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.