How to read A/B codes
Quick start (3 steps)
- Set location, date, and timezone.
- Select a planet and define visibility constraints.
- Compute to view rise/set/transit, best window, chart bands, and CSV.
Inputs
Summary
Altitude chart
Ephemeris table
| Local time | Planet alt (deg) | Planet az (deg) | Sun alt (deg) | Moon alt (deg) | Mag | Diameter (") | Elongation (deg) | Good |
|---|
Definitions & notes
- Azimuth uses north=0°, east=90°, south=180°, west=270°.
- Altitude uses horizon=0° and zenith=+90°.
- Best window uses the longest contiguous interval where both dark-sky and altitude conditions are true.
- CSV column order is fixed for workflow compatibility.
- Magnitude, apparent diameter, and constellation are planning-grade approximations.
How to use this calculator effectively
This guide helps you use Planet Observation Planner in a repeatable way: define a baseline, change one variable at a time, and interpret outputs with explicit assumptions before you share or act on results.
How it works
The page applies deterministic logic to your inputs and shows rounded output for readability. Treat it as a comparison workflow: run one baseline case, adjust a single parameter, and measure both absolute and percentage deltas. If a result seems off, verify units, time basis, and sign conventions before drawing conclusions. This approach keeps your analysis reproducible across teammates and sessions.
When to use
Use this page when you need a fast estimate, a classroom check, or a practical what-if comparison. It works best for planning and prioritization steps where you need direction and magnitude quickly before investing in deeper modeling, manual spreadsheets, or formal external review.
Common mistakes to avoid
- Changing multiple parameters at once, which hides the true cause of output movement.
- Mixing units (percent vs decimal, monthly vs yearly, gross vs net) across scenarios.
- Comparing with another tool without aligning defaults, constants, and rounding rules.
- Using rounded display values as exact downstream inputs without re-checking precision.
Interpretation and worked example
Run a baseline scenario and keep that result visible. Next, modify one assumption to reflect your realistic alternative and compare direction plus size of change. If the direction matches your domain expectation and the size is plausible, your setup is usually coherent. If not, check hidden defaults, boundary conditions, and interpretation notes before deciding which scenario to adopt.
See also
FAQ
How is the best window selected?
The tool samples the full local day at the chosen step, extracts contiguous intervals that satisfy all conditions, then selects the longest interval. If lengths tie, the earliest start is selected.
Why can rise or set be unavailable?
At high latitudes or specific seasons, a planet may not cross the horizon threshold during the local day. The planner keeps this explicit and still returns the rest of the timeline safely.
Can I reproduce the same setup later?
Yes. Input state is encoded in URL query parameters, so opening the same link restores the same configuration.
What should I do first on this page?
Start with the minimum required inputs or the first action shown near the primary button. Keep optional settings at defaults for a baseline run, then change one setting at a time so you can explain what caused each output change.
Why does this page differ from another tool?
Different pages often use different defaults, units, rounding rules, or assumptions. Align those settings before comparing outputs. If differences remain, compare each intermediate step rather than only the final number.