Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Triangulum Pinwheel: 02-13 (63), 02-14 (60), 02-15 (57), 02-16 (55), 02-17 (54) — by astronomy; check the weather when the night is within four days.

2031-02-13astronomy score per night — click a bar for that night2031-03-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-02-13 Thu	63	—	unknown	19:25–21:55 (good, 2.5 h)	79.1° 16:25	10.33	61%	160.4°
2031-02-14 Fri	60	—	unknown	19:30–21:50 (good, 2.33 h)	79.1° 16:20	10.29	50%	151.0°
2031-02-15 Sat	57	—	unknown	19:30–21:45 (good, 2.25 h)	79.1° 16:15	10.25	39%	138.9°
2031-02-16 Sun	55	—	unknown	19:30–21:45 (good, 2.25 h)	79.1° 16:10	10.21	28%	125.8°
2031-02-17 Mon	54	—	unknown	19:30–21:40 (good, 2.17 h)	79.1° 16:05	10.17	18%	112.1°
2031-02-18 Tue	51	—	unknown	19:35–21:35 (good, 2.0 h)	79.1° 16:05	10.13	10%	98.2°
2031-02-19 Wed	49	—	unknown	19:35–21:30 (good, 1.92 h)	79.1° 16:00	10.09	4%	84.2°
2031-02-20 Thu	47	—	unknown	19:35–21:30 (good, 1.92 h)	79.1° 15:55	10.05	1%	70.3°
2031-02-21 Fri	46	—	unknown	19:35–21:25 (good, 1.83 h)	79.1° 15:50	10.01	0%	56.7°
2031-02-22 Sat	42	—	unknown	19:40–21:20 (good, 1.67 h)	79.1° 15:50	9.96	2%	43.7°
2031-02-23 Sun	39	—	unknown	19:40–21:15 (good, 1.58 h)	79.1° 15:45	9.92	7%	31.7°
2031-02-24 Mon	34	—	unknown	19:40–21:05 (good, 1.42 h)	79.1° 15:40	9.88	13%	21.7°
2031-02-25 Tue	29	—	unknown	19:40–21:00 (good, 1.33 h)	79.1° 15:35	9.83	20%	16.9°
2031-02-26 Wed	24	—	unknown	19:40–20:45 (good, 1.08 h)	79.1° 15:30	9.79	29%	20.4°
2031-02-27 Thu	18	—	unknown	19:45–20:25 (good, 0.67 h)	79.1° 15:30	9.75	38%	28.9°
2031-02-28 Fri	14	—	unknown	19:45–21:20 (marginal, 1.58 h)	79.1° 15:25	9.7	48%	39.2°
2031-03-01 Sat	12	—	unknown	19:45–21:15 (marginal, 1.5 h)	79.1° 15:20	9.66	57%	50.0°
2031-03-02 Sun	11	—	unknown	19:45–21:05 (marginal, 1.33 h)	79.1° 15:15	9.61	66%	61.0°
2031-03-03 Mon	11	—	unknown	19:50–21:05 (marginal, 1.25 h)	79.1° 15:10	9.56	75%	72.3°
2031-03-04 Tue	11	—	unknown	19:50–21:00 (marginal, 1.17 h)	79.1° 15:10	9.52	83%	83.7°
2031-03-05 Wed	12	—	unknown	19:50–19:55 (good, 0.08 h)	79.1° 15:05	9.47	89%	95.3°
2031-03-06 Thu	14	—	unknown	19:50–20:10 (good, 0.33 h)	79.1° 15:00	9.42	95%	107.1°
2031-03-07 Fri	15	—	unknown	19:55–20:15 (good, 0.33 h)	79.1° 14:55	9.38	98%	119.0°
2031-03-08 Sat	14	—	unknown	19:55–20:15 (good, 0.33 h)	79.1° 14:55	9.33	100%	131.0°
2031-03-09 Sun	13	—	unknown	19:55–20:10 (good, 0.25 h)	79.1° 14:50	9.28	99%	142.8°
2031-03-10 Mon	14	—	unknown	19:55–20:10 (good, 0.25 h)	79.1° 14:45	9.23	96%	153.8°
2031-03-11 Tue	11	—	unknown	20:00–20:15 (good, 0.25 h)	79.1° 14:40	9.18	91%	161.8°
2031-03-12 Wed	10	—	unknown	20:00–20:10 (good, 0.17 h)	79.1° 14:35	9.14	84%	161.6°
2031-03-13 Thu	9	—	unknown	20:00–20:05 (good, 0.08 h)	79.1° 14:35	9.09	75%	153.3°
2031-03-14 Fri	7	—	unknown	19:30–20:30 (marginal, 1.0 h)	79.1° 14:30	9.04	65%	141.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-02-13&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.