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 3C 273: 02-13 (93), 02-14 (93), 02-15 (93), 02-16 (93), 02-17 (93) — by astronomy; check the weather when the night is within four days.

2043-02-13astronomy score per night — click a bar for that night2043-03-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-02-13 Fri	93	—	unknown	23:30–05:45 (good, 6.25 h)	50.1° 03:15	10.33	20%	166.1°
2043-02-14 Sat	93	—	unknown	23:30–05:45 (good, 6.25 h)	50.1° 03:15	10.29	30%	152.2°
2043-02-15 Sun	93	—	unknown	23:25–05:45 (good, 6.33 h)	50.1° 03:10	10.25	41%	138.1°
2043-02-16 Mon	93	—	unknown	23:25–05:45 (good, 6.33 h)	50.1° 03:05	10.21	53%	124.1°
2043-02-17 Tue	93	—	unknown	23:25–05:40 (good, 6.25 h)	50.1° 03:00	10.17	64%	110.2°
2043-02-18 Wed	91	—	unknown	23:35–05:40 (good, 6.08 h)	50.1° 02:55	10.13	74%	96.4°
2043-02-19 Thu	85	—	unknown	00:40–05:40 (good, 5.0 h)	50.1° 02:55	10.09	83%	82.8°
2043-02-20 Fri	63	—	unknown	02:55–05:40 (good, 2.75 h)	50.1° 02:50	10.05	90%	69.4°
2043-02-21 Sat	44	—	unknown	23:15–05:35 (marginal, 6.33 h)	50.1° 02:45	10.0	96%	56.1°
2043-02-22 Sun	30	—	unknown	00:50–05:35 (marginal, 4.75 h)	50.1° 02:40	9.96	99%	43.1°
2043-02-23 Mon	19	—	unknown	03:20–05:35 (marginal, 2.25 h)	50.1° 02:35	9.92	100%	30.4°
2043-02-24 Tue	19	—	unknown	03:25–05:35 (marginal, 2.17 h)	50.1° 02:35	9.88	99%	18.0°
2043-02-25 Wed	22	—	unknown	23:00–05:30 (marginal, 6.5 h)	50.1° 02:30	9.83	96%	6.7°
2043-02-26 Thu	28	—	unknown	22:35–05:30 (marginal, 6.92 h)	50.1° 02:25	9.79	91%	8.4°
2043-02-27 Fri	39	—	unknown	22:15–05:30 (marginal, 7.25 h)	50.1° 02:20	9.74	85%	19.7°
2043-02-28 Sat	80	—	unknown	22:30–23:05 (good, 0.58 h)	50.1° 02:20	9.7	78%	31.4°
2043-03-01 Sun	87	—	unknown	22:25–03:25 (good, 5.0 h)	50.1° 02:15	9.65	70%	43.1°
2043-03-02 Mon	92	—	unknown	22:25–05:20 (good, 6.92 h)	50.1° 02:10	9.61	60%	54.9°
2043-03-03 Tue	93	—	unknown	22:20–05:20 (good, 7.0 h)	50.1° 02:05	9.56	51%	66.8°
2043-03-04 Wed	93	—	unknown	22:15–05:20 (good, 7.08 h)	50.1° 02:00	9.51	41%	78.8°
2043-03-05 Thu	93	—	unknown	22:10–05:20 (good, 7.17 h)	50.1° 02:00	9.47	32%	91.1°
2043-03-06 Fri	93	—	unknown	22:05–05:15 (good, 7.17 h)	50.1° 01:55	9.42	23%	103.8°
2043-03-07 Sat	93	—	unknown	22:05–05:15 (good, 7.17 h)	50.1° 01:50	9.37	15%	116.9°
2043-03-08 Sun	93	—	unknown	22:00–05:15 (good, 7.25 h)	50.1° 01:45	9.33	8%	130.3°
2043-03-09 Mon	93	—	unknown	21:55–05:10 (good, 7.25 h)	50.1° 01:40	9.28	3%	144.2°
2043-03-10 Tue	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:40	9.23	0%	158.3°
2043-03-11 Wed	93	—	unknown	21:50–05:10 (good, 7.33 h)	50.1° 01:35	9.18	0%	172.0°
2043-03-12 Thu	93	—	unknown	21:45–05:05 (good, 7.33 h)	50.1° 01:30	9.13	3%	170.7°
2043-03-13 Fri	93	—	unknown	21:40–05:05 (good, 7.42 h)	50.1° 01:25	9.08	9%	156.7°
2043-03-14 Sat	93	—	unknown	21:35–05:05 (good, 7.5 h)	50.1° 01:20	9.03	17%	142.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-02-13&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.