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: 05-22 (73), 05-23 (71), 05-24 (69), 05-25 (66), 05-26 (64) — by astronomy; check the weather when the night is within four days.

2036-05-22astronomy score per night — click a bar for that night2036-06-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-05-22 Thu	73	—	unknown	22:45–01:40 (good, 2.92 h)	50.2° 21:50	5.19	10%	160.8°
2036-05-23 Fri	71	—	unknown	22:45–01:35 (good, 2.83 h)	50.2° 21:45	5.15	5%	147.3°
2036-05-24 Sat	69	—	unknown	22:45–01:30 (good, 2.75 h)	50.2° 21:40	5.1	1%	133.4°
2036-05-25 Sun	66	—	unknown	22:50–01:30 (good, 2.67 h)	50.2° 21:35	5.06	0%	119.2°
2036-05-26 Mon	64	—	unknown	22:50–01:25 (good, 2.58 h)	50.2° 21:30	5.01	2%	104.7°
2036-05-27 Tue	63	—	unknown	22:50–01:20 (good, 2.5 h)	50.2° 21:30	4.97	6%	90.1°
2036-05-28 Wed	58	—	unknown	22:55–01:15 (good, 2.33 h)	50.2° 21:25	4.93	13%	75.4°
2036-05-29 Thu	51	—	unknown	22:55–01:10 (good, 2.25 h)	50.2° 21:20	4.89	22%	60.8°
2036-05-30 Fri	42	—	unknown	22:55–00:55 (good, 2.0 h)	50.2° 21:15	4.85	33%	46.4°
2036-05-31 Sat	32	—	unknown	22:55–00:40 (good, 1.75 h)	50.2° 21:15	4.81	44%	32.2°
2036-06-01 Sun	23	—	unknown	23:00–01:30 (marginal, 2.5 h)	50.2° 21:10	4.78	55%	18.2°
2036-06-02 Mon	17	—	unknown	23:00–01:15 (marginal, 2.25 h)	50.2° 21:05	4.74	66%	4.6°
2036-06-03 Tue	13	—	unknown	23:00–01:05 (marginal, 2.08 h)	50.2° 21:00	4.71	76%	9.1°
2036-06-04 Wed	10	—	unknown	23:00–00:50 (marginal, 1.83 h)	50.2° 20:55	4.68	84%	22.3°
2036-06-05 Thu	9	—	unknown	23:05–00:40 (marginal, 1.58 h)	50.2° 20:55	4.65	91%	35.3°
2036-06-06 Fri	11	—	unknown	23:05–00:40 (marginal, 1.58 h)	50.2° 20:50	4.62	96%	48.1°
2036-06-07 Sat	14	—	unknown	23:05–00:45 (marginal, 1.67 h)	50.2° 20:45	4.59	99%	60.8°
2036-06-08 Sun	17	—	unknown	23:05–00:50 (marginal, 1.75 h)	50.2° 20:40	4.57	100%	73.2°
2036-06-09 Mon	21	—	unknown	23:05–23:45 (good, 0.67 h)	50.2° 20:35	4.54	99%	85.4°
2036-06-10 Tue	25	—	unknown	23:05–00:05 (good, 1.0 h)	50.2° 20:35	4.52	96%	97.5°
2036-06-11 Wed	28	—	unknown	23:10–00:10 (good, 1.0 h)	50.2° 20:30	4.5	91%	109.5°
2036-06-12 Thu	32	—	unknown	23:10–00:10 (good, 1.0 h)	50.2° 20:25	4.49	85%	121.3°
2036-06-13 Fri	31	—	unknown	23:10–00:15 (good, 1.08 h)	50.2° 20:20	4.47	78%	133.2°
2036-06-14 Sat	30	—	unknown	23:10–00:10 (good, 1.0 h)	50.2° 20:20	4.46	70%	145.0°
2036-06-15 Sun	29	—	unknown	23:10–00:05 (good, 0.92 h)	50.2° 20:15	4.45	61%	157.0°
2036-06-16 Mon	27	—	unknown	23:10–00:00 (good, 0.83 h)	50.2° 20:10	4.44	51%	169.1°
2036-06-17 Tue	26	—	unknown	23:10–00:00 (good, 0.83 h)	50.2° 20:05	4.43	41%	178.2°
2036-06-18 Wed	25	—	unknown	23:10–23:55 (good, 0.75 h)	50.2° 20:00	4.43	31%	165.7°
2036-06-19 Thu	24	—	unknown	23:10–23:50 (good, 0.67 h)	50.2° 20:00	4.42	22%	152.6°
2036-06-20 Fri	22	—	unknown	23:15–23:45 (good, 0.5 h)	50.2° 19:55	4.42	14%	139.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-05-22&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.