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: 04-01 (93), 04-02 (93), 04-14 (93), 04-15 (93), 04-16 (93) — by astronomy; check the weather when the night is within four days.

2036-04-01astronomy score per night — click a bar for that night2036-04-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-04-01 Tue	93	—	unknown	21:25–05:00 (good, 7.58 h)	50.2° 01:10	8.05	27%	110.3°
2036-04-02 Wed	93	—	unknown	21:30–04:55 (good, 7.42 h)	50.2° 01:05	8.0	38%	96.4°
2036-04-03 Thu	90	—	unknown	21:35–04:55 (good, 7.33 h)	50.2° 01:00	7.94	49%	82.4°
2036-04-04 Fri	84	—	unknown	22:25–04:50 (good, 6.42 h)	50.2° 00:55	7.88	61%	68.2°
2036-04-05 Sat	75	—	unknown	01:00–04:45 (good, 3.75 h)	50.2° 00:55	7.83	72%	54.0°
2036-04-06 Sun	47	—	unknown	21:30–05:10 (marginal, 7.67 h)	50.2° 00:50	7.77	81%	39.7°
2036-04-07 Mon	29	—	unknown	22:45–04:50 (marginal, 6.08 h)	50.2° 00:45	7.72	89%	25.4°
2036-04-08 Tue	22	—	unknown	00:35–04:30 (marginal, 3.92 h)	50.2° 00:40	7.66	95%	11.3°
2036-04-09 Wed	19	—	unknown	02:05–04:15 (marginal, 2.17 h)	50.2° 00:35	7.6	99%	3.2°
2036-04-10 Thu	23	—	unknown	21:40–02:05 (marginal, 4.42 h)	50.2° 00:35	7.55	100%	16.8°
2036-04-11 Fri	31	—	unknown	21:40–03:55 (marginal, 6.25 h)	50.2° 00:30	7.49	98%	30.3°
2036-04-12 Sat	76	—	unknown	21:40–21:55 (good, 0.25 h)	50.2° 00:25	7.43	95%	43.5°
2036-04-13 Sun	90	—	unknown	21:40–00:50 (good, 3.17 h)	50.2° 00:20	7.38	89%	56.4°
2036-04-14 Mon	93	—	unknown	21:45–02:45 (good, 5.0 h)	50.2° 00:20	7.32	82%	68.9°
2036-04-15 Tue	93	—	unknown	21:45–03:40 (good, 5.92 h)	50.2° 00:15	7.26	74%	81.2°
2036-04-16 Wed	93	—	unknown	21:45–03:45 (good, 6.0 h)	50.2° 00:10	7.2	66%	93.3°
2036-04-17 Thu	93	—	unknown	21:50–03:50 (good, 6.0 h)	50.2° 00:05	7.14	56%	105.2°
2036-04-18 Fri	93	—	unknown	21:50–03:50 (good, 6.0 h)	50.2° 00:00	7.09	47%	117.0°
2036-04-19 Sat	93	—	unknown	21:50–03:45 (good, 5.92 h)	50.2° 00:00	7.03	37%	128.9°
2036-04-20 Sun	93	—	unknown	21:55–03:45 (good, 5.83 h)	50.2° 23:55	6.97	28%	140.8°
2036-04-21 Mon	93	—	unknown	21:55–03:40 (good, 5.75 h)	50.2° 23:50	6.91	20%	153.0°
2036-04-22 Tue	93	—	unknown	21:55–03:40 (good, 5.75 h)	50.2° 23:45	6.85	13%	165.3°
2036-04-23 Wed	93	—	unknown	22:00–03:35 (good, 5.58 h)	50.2° 23:40	6.8	7%	177.6°
2036-04-24 Thu	93	—	unknown	22:00–03:30 (good, 5.5 h)	50.2° 23:40	6.74	3%	168.9°
2036-04-25 Fri	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.2° 23:35	6.68	0%	155.6°
2036-04-26 Sat	93	—	unknown	22:00–03:20 (good, 5.33 h)	50.2° 23:30	6.62	0%	142.0°
2036-04-27 Sun	93	—	unknown	22:05–03:20 (good, 5.25 h)	50.2° 23:25	6.56	3%	128.1°
2036-04-28 Mon	93	—	unknown	22:05–03:15 (good, 5.17 h)	50.2° 23:20	6.5	8%	114.1°
2036-04-29 Tue	93	—	unknown	22:05–03:10 (good, 5.08 h)	50.2° 23:20	6.45	15%	99.9°
2036-04-30 Wed	91	—	unknown	22:10–03:05 (good, 4.92 h)	50.2° 23:15	6.39	25%	85.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-04-01&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.