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: 05-18 (77), 05-19 (77), 05-20 (77), 05-21 (76), 05-22 (73) — by astronomy; check the weather when the night is within four days.

2033-05-18astronomy score per night — click a bar for that night2033-06-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-05-18 Wed	77	—	unknown	22:40–01:45 (good, 3.08 h)	50.2° 22:05	5.41	80%	105.5°
2033-05-19 Thu	77	—	unknown	22:40–01:45 (good, 3.08 h)	50.2° 22:00	5.35	70%	118.9°
2033-05-20 Fri	77	—	unknown	22:40–01:45 (good, 3.08 h)	50.2° 21:55	5.3	60%	132.5°
2033-05-21 Sat	76	—	unknown	22:40–01:45 (good, 3.08 h)	50.2° 21:55	5.26	48%	146.3°
2033-05-22 Sun	73	—	unknown	22:45–01:40 (good, 2.92 h)	50.2° 21:50	5.21	37%	160.0°
2033-05-23 Mon	71	—	unknown	22:45–01:35 (good, 2.83 h)	50.2° 21:45	5.16	26%	172.3°
2033-05-24 Tue	69	—	unknown	22:45–01:35 (good, 2.83 h)	50.2° 21:40	5.11	16%	168.5°
2033-05-25 Wed	66	—	unknown	22:50–01:30 (good, 2.67 h)	50.2° 21:35	5.07	9%	155.0°
2033-05-26 Thu	65	—	unknown	22:50–01:25 (good, 2.58 h)	50.2° 21:35	5.02	3%	140.7°
2033-05-27 Fri	63	—	unknown	22:50–01:20 (good, 2.5 h)	50.2° 21:30	4.98	0%	126.5°
2033-05-28 Sat	60	—	unknown	22:55–01:15 (good, 2.33 h)	50.2° 21:25	4.94	0%	112.3°
2033-05-29 Sun	58	—	unknown	22:55–01:15 (good, 2.33 h)	50.2° 21:20	4.9	3%	98.5°
2033-05-30 Mon	57	—	unknown	22:55–01:10 (good, 2.25 h)	50.2° 21:20	4.86	8%	85.1°
2033-05-31 Tue	54	—	unknown	22:55–01:05 (good, 2.17 h)	50.2° 21:15	4.82	14%	72.0°
2033-06-01 Wed	47	—	unknown	23:00–01:00 (good, 2.0 h)	50.2° 21:10	4.79	22%	59.3°
2033-06-02 Thu	40	—	unknown	23:00–01:00 (good, 2.0 h)	50.2° 21:05	4.75	31%	46.9°
2033-06-03 Fri	32	—	unknown	23:00–00:35 (good, 1.58 h)	50.2° 21:00	4.72	40%	34.9°
2033-06-04 Sat	25	—	unknown	23:00–00:20 (good, 1.33 h)	50.2° 21:00	4.68	50%	23.2°
2033-06-05 Sun	20	—	unknown	23:05–01:10 (marginal, 2.08 h)	50.2° 20:55	4.65	59%	12.1°
2033-06-06 Mon	15	—	unknown	23:05–01:00 (marginal, 1.92 h)	50.2° 20:50	4.63	68%	6.1°
2033-06-07 Tue	12	—	unknown	23:05–00:50 (marginal, 1.75 h)	50.2° 20:45	4.6	76%	14.4°
2033-06-08 Wed	9	—	unknown	23:05–00:35 (marginal, 1.5 h)	50.2° 20:40	4.57	84%	25.9°
2033-06-09 Thu	9	—	unknown	23:05–00:30 (marginal, 1.42 h)	50.2° 20:40	4.55	91%	37.8°
2033-06-10 Fri	10	—	unknown	23:05–00:30 (marginal, 1.42 h)	50.2° 20:35	4.53	96%	50.1°
2033-06-11 Sat	12	—	unknown	23:10–00:35 (marginal, 1.42 h)	50.2° 20:30	4.51	99%	62.7°
2033-06-12 Sun	15	—	unknown	23:10–00:40 (marginal, 1.5 h)	50.2° 20:25	4.49	100%	75.6°
2033-06-13 Mon	19	—	unknown	23:10–23:40 (good, 0.5 h)	50.2° 20:25	4.48	99%	88.7°
2033-06-14 Tue	22	—	unknown	23:10–23:50 (good, 0.67 h)	50.2° 20:20	4.46	95%	102.1°
2033-06-15 Wed	25	—	unknown	23:10–23:55 (good, 0.75 h)	50.2° 20:15	4.45	90%	115.7°
2033-06-16 Thu	27	—	unknown	23:10–23:55 (good, 0.75 h)	50.2° 20:10	4.44	82%	129.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-05-18&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.