cmd-plotting

name	cmd-plotting
description	Generate astronomy colour-magnitude diagrams in Python with reproducible plotting choices.
version	1.0.0
author	AstroAgent / AIP
license	MIT
metadata	{"hermes":{"tags":["python","astronomy","plotting","cmd","visualization"],"category":"python","related_skills":["shboost24-cmd","seaborn-paper-plots"]}}

CMD Plotting

When to Use

Use this skill for colour-magnitude diagrams or related astronomy plots in Python.

Procedure

1. Keep only required columns.
2. Use consistent axis labeling and explicit units when available.
3. Prefer density representations for large samples.
4. Save publication-ready PNG outputs by default.

Pitfalls

• Avoid scatter plots for very large datasets when density plots are more appropriate.
• Avoid undocumented axis transformations.
• For a known cluster, anchor member selection to literature values. Set the parallax / proper-motion cuts from the cluster's published distance and mean proper motion — not from whatever maximizes the member count. A count-maximizing selection pulls in field stars, smears the main sequence, and makes the turn-off (and any age read-off) wrong.

Verification

• Plot labels and file outputs match the stated convention.