Scores are estimated from moon phase, moonlight interference and dark-window timing for Matsu. This first version does not include cloud cover, so always check weather.
馃寣 Sep is a good window for the Milky Way core over Matsu: it climbs to a shootable altitude around 19:23, sinks back down near 22:13, and peaks around 19:23 at roughly 32掳 in the South. Avoid moonlight and face that direction to catch the bright galactic center.
| Date | Score | Tonight's Moon | Dark window |
|---|---|---|---|
| 2026-09-07 | 92 路 Good | Waning Crescent 19% | 19:33-04:23 |
| 2026-09-08 | 92 路 Good | Waning Crescent 11% | 19:31-04:24 |
| 2026-09-09 | 92 路 Good | Waning Crescent 5% | 19:30-04:24 |
| 2026-09-10 | 92 路 Good | Waning Crescent 1% | 19:29-04:25 |
| 2026-09-11 | 92 路 Good | New Moon 0% | 19:28-04:25 |
| Date | Score | Tonight's Moon | Moonrise | Moonset | Dark window |
|---|---|---|---|---|---|
| 2026-09-01 | 52 路 Fair | Waning Gibbous 83% | 20:39 | 09:17 | 19:40-04:20 |
| 2026-09-02 | 52 路 Fair | Waning Gibbous 74% | 21:20 | 10:20 | 19:39-04:20 |
| 2026-09-03 | 64 路 Fair | Waning Gibbous 63% | 22:07 | 11:26 | 19:38-04:21 |
| 2026-09-04 | 74 路 Fair | Last Quarter 52% | 23:03 | 12:33 | 19:36-04:21 |
| 2026-09-05 | 74 路 Fair | Waning Crescent 40% | -- | 13:39 | 19:35-04:22 |
| 2026-09-06 | 84 路 Good | Waning Crescent 29% | 00:05 | 14:39 | 19:34-04:23 |
| 2026-09-07 | 92 路 Good | Waning Crescent 19% | 01:12 | 15:32 | 19:33-04:23 |
| 2026-09-08 | 92 路 Good | Waning Crescent 11% | 02:21 | 16:19 | 19:31-04:24 |
| 2026-09-09 | 92 路 Good | Waning Crescent 5% | 03:28 | 16:59 | 19:30-04:24 |
| 2026-09-10 | 92 路 Good | Waning Crescent 1% | 04:33 | 17:35 | 19:29-04:25 |
| 2026-09-11 | 92 路 Good | New Moon 0% | 05:34 | 18:08 | 19:28-04:25 |
| 2026-09-12 | 92 路 Good | Waxing Crescent 1% | 06:34 | 18:40 | 19:27-04:26 |
| 2026-09-13 | 92 路 Good | Waxing Crescent 5% | 07:32 | 19:13 | 19:25-04:26 |
| 2026-09-14 | 92 路 Good | Waxing Crescent 10% | 08:30 | 19:46 | 19:24-04:27 |
| 2026-09-15 | 92 路 Good | Waxing Crescent 17% | 09:27 | 20:23 | 19:23-04:27 |
| 2026-09-16 | 84 路 Good | Waxing Crescent 25% | 10:25 | 21:03 | 19:22-04:27 |
| 2026-09-17 | 84 路 Good | Waxing Crescent 34% | 11:22 | 21:47 | 19:20-04:28 |
| 2026-09-18 | 74 路 Fair | Waxing Crescent 43% | 12:17 | 22:36 | 19:19-04:28 |
| 2026-09-19 | 64 路 Fair | First Quarter 53% | 13:09 | 23:29 | 19:18-04:29 |
| 2026-09-20 | 74 路 Fair | Waxing Gibbous 62% | 13:56 | -- | 19:17-04:29 |
| 2026-09-21 | 62 路 Fair | Waxing Gibbous 71% | 14:39 | 00:24 | 19:16-04:30 |
| 2026-09-22 | 52 路 Fair | Waxing Gibbous 80% | 15:18 | 01:21 | 19:14-04:30 |
| 2026-09-23 | 40 路 Poor | Waxing Gibbous 87% | 15:53 | 02:17 | 19:13-04:31 |
| 2026-09-24 | 40 路 Poor | Waxing Gibbous 93% | 16:26 | 03:14 | 19:12-04:31 |
| 2026-09-25 | 40 路 Poor | Waxing Gibbous 97% | 16:58 | 04:11 | 19:11-04:32 |
| 2026-09-26 | 40 路 Poor | Waxing Gibbous 100% | 17:29 | 05:08 | 19:10-04:32 |
| 2026-09-27 | 40 路 Poor | Full Moon 100% | 18:02 | 06:06 | 19:08-04:32 |
| 2026-09-28 | 40 路 Poor | Waning Gibbous 97% | 18:38 | 07:07 | 19:07-04:33 |
| 2026-09-29 | 40 路 Poor | Waning Gibbous 92% | 19:18 | 08:11 | 19:06-04:33 |
| 2026-09-30 | 40 路 Poor | Waning Gibbous 85% | 20:05 | 09:17 | 19:05-04:34 |
The Matsu calendar combines Moon phase, dark windows, and short-range conditions, but the score still needs local context and light pollution checks.
Score
High scores mean friendlier moonlight and night windows, and short-range views can include cloud and transparency. Local fog, patchy cloud, and nearby lights can still change the outcome.
Moonlight
Full-moon periods light the landscape but reduce faint-star and Milky Way contrast. For the Milky Way, meteors, or deep-sky targets, new-moon periods are usually better.
Dark window
Dark outside is not always dark enough. The dark window considers twilight ending, Moon rise and set, and the length of usable night.
After choosing a good date, confirm location, direction, and hourly weather for the night.
Short range
Moon phase can be planned months ahead, but cloud needs a short-range forecast. For the actual night, use hourly stargazing index and on-site observation.
Place
High elevation may help with low cloud, but nearby lights can still wash out the sky. Use the dark-sky map to remove weak candidates first.
Direction
A site may only work for certain horizons. Use the sky map to check the galactic center, Moon, and constellations before facing sea, mountains, or city lights.
Related tools: Stargazing & Moon Viewing Score 路 This month鈥檚 Moon phase calendar 路 Astro Events 路 Meteor Showers