Astronomy Session Planner

How to read A/B codes

Quick start (3 steps)

Set location, date/timezone, and one shared condition set.
Add targets manually, by paste, or by preset catalog.
Compute ranking and timeline, then open selected targets in Observability time plotter (A7).

Inputs

Latitude (deg) Longitude (deg, east +) Elevation (m) Date

Step (min) Time zone mode IANA time zone Coordinated Universal Time (UTC) offset override (min)

Min altitude (deg) Sun altitude max (deg) Max air mass

Moon constraints (optional)

Moon altitude max (deg) Moon illumination max (0-1) Moon separation min (deg)

Target list

Target ID RA Dec

RA unit Dec unit

Preset

Paste list (ID,RA,Dec or ID RA Dec)

Paste RA unit Paste Dec unit

ID	RA	Dec	Remove

Summary

Targets—

Observable (>0)—

Longest best window—

Top score—

Ranking

Sort Min best-window length (min) Show only observable targets

Target	Score	Best window	Total	Max alt	Min air mass	Min moon separation	Observability time plotter (A7)

Timeline (Top 20)

Selected target

Target—

Best window—

Total observable—

Score—

Deep linkOpen Observability time plotter (A7)

Definitions & notes

Azimuth convention is fixed to north=0°, east=90°.
All calculations run on UTC internally after local+TZ parsing.
The default moon constraints are effectively non-limiting (90°, 1, 0°).
Best-window times are shown in local clock time.

How to use Session Planner Pro effectively

Use this page after you already have a shortlist of targets and want one ranking view for tonight. It is the right tool when the question is not “is this one target visible?” but “which targets deserve time first under the same site, weather, and moon constraints?”

Best workflow

Set site, local time range, altitude floor, and any moon or sky-brightness limits once.
Paste several targets or open them from Catalog Resolver Pro so every candidate is scored against the same rules.
Review the timeline, best window, and score, then open the highest-value targets in Observability, Mosaic Planner Pro, or Finder Chart Pro.

Use another page when

You need the exact window for just one target: use Observability time plotter.
You still have not resolved the target list: use Catalog Resolver Pro first.
You already chose the target and now need panel geometry: use Mosaic Planner Pro.

FAQ

What should I enter first?

Start with the observing site, local date/time, and one clean target list. Keep moon and scoring defaults for the first pass so you can see the natural ranking before tightening filters.

How should I interpret the score?

The score is a planning aid, not an astrophysical truth. Use it to compare targets under one shared setup, then confirm the shortlisted targets in the dedicated timing or chart tools before observing.

When should I open another astronomy tool?

Open Observability time plotter for the exact one-target window, Mosaic Planner Pro for panel layout, Finder Chart Pro for a star chart, and Catalog Resolver Pro when the target IDs still need cleanup.

Can I share the same plan with teammates?

Yes. The share link preserves the current site, filters, and target list so another observer can review the same session assumptions in the browser.

Next steps

Observability time plotter
Validate the single-target window after Session Planner Pro tells you which target is worth checking first.
Catalog Resolver Pro
Clean target names and aliases before you rank a larger observing list.
Mosaic Planner Pro
Move from shortlist to panel geometry when a wide target wins the night.
Finder Chart Pro
Produce a practical chart after you commit to a specific target and time window.