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: 05-07 (93), 05-08 (93), 05-09 (93), 05-10 (93), 05-11 (91) — by astronomy; check the weather when the night is within four days.

2043-05-07astronomy score per night — click a bar for that night2043-06-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-05-07 Thu	93	—	unknown	22:20–02:40 (good, 4.33 h)	50.1° 22:50	6.03	2%	155.0°
2043-05-08 Fri	93	—	unknown	22:20–02:40 (good, 4.33 h)	50.1° 22:45	5.97	0%	139.9°
2043-05-09 Sat	93	—	unknown	22:20–02:35 (good, 4.25 h)	50.1° 22:40	5.91	1%	124.7°
2043-05-10 Sun	93	—	unknown	22:25–02:30 (good, 4.08 h)	50.1° 22:40	5.86	5%	109.7°
2043-05-11 Mon	91	—	unknown	22:25–02:25 (good, 4.0 h)	50.1° 22:35	5.8	12%	94.9°
2043-05-12 Tue	86	—	unknown	22:25–02:20 (good, 3.92 h)	50.1° 22:30	5.75	20%	80.6°
2043-05-13 Wed	74	—	unknown	22:30–02:20 (good, 3.83 h)	50.1° 22:25	5.69	30%	66.6°
2043-05-14 Thu	61	—	unknown	22:30–02:00 (good, 3.5 h)	50.1° 22:25	5.64	40%	53.2°
2043-05-15 Fri	45	—	unknown	22:30–01:45 (good, 3.25 h)	50.1° 22:20	5.58	50%	40.2°
2043-05-16 Sat	33	—	unknown	22:35–02:35 (marginal, 4.0 h)	50.1° 22:15	5.53	61%	27.6°
2043-05-17 Sun	25	—	unknown	22:35–02:25 (marginal, 3.83 h)	50.1° 22:10	5.48	70%	15.6°
2043-05-18 Mon	20	—	unknown	22:35–02:10 (marginal, 3.58 h)	50.1° 22:05	5.43	79%	5.3°
2043-05-19 Tue	16	—	unknown	22:40–02:00 (marginal, 3.33 h)	50.1° 22:05	5.38	86%	10.4°
2043-05-20 Wed	14	—	unknown	22:40–01:50 (marginal, 3.17 h)	50.1° 22:00	5.33	92%	21.7°
2043-05-21 Thu	15	—	unknown	22:40–01:40 (marginal, 3.0 h)	50.1° 21:55	5.28	96%	33.3°
2043-05-22 Fri	20	—	unknown	22:45–01:45 (marginal, 3.0 h)	50.1° 21:50	5.23	99%	45.1°
2043-05-23 Sat	26	—	unknown	22:45–01:50 (marginal, 3.08 h)	50.1° 21:45	5.18	100%	56.9°
2043-05-24 Sun	34	—	unknown	22:45–23:40 (good, 0.92 h)	50.1° 21:45	5.13	99%	68.7°
2043-05-25 Mon	42	—	unknown	22:50–00:50 (good, 2.0 h)	50.1° 21:40	5.09	96%	80.6°
2043-05-26 Tue	59	—	unknown	22:50–01:05 (good, 2.25 h)	50.1° 21:35	5.04	92%	92.7°
2043-05-27 Wed	61	—	unknown	22:50–01:10 (good, 2.33 h)	50.1° 21:30	5.0	86%	104.9°
2043-05-28 Thu	62	—	unknown	22:50–01:15 (good, 2.42 h)	50.1° 21:30	4.96	78%	117.3°
2043-05-29 Fri	60	—	unknown	22:55–01:15 (good, 2.33 h)	50.1° 21:25	4.92	69%	129.9°
2043-05-30 Sat	58	—	unknown	22:55–01:10 (good, 2.25 h)	50.1° 21:20	4.88	59%	142.8°
2043-05-31 Sun	56	—	unknown	22:55–01:05 (good, 2.17 h)	50.1° 21:15	4.84	49%	155.9°
2043-06-01 Mon	55	—	unknown	22:55–01:05 (good, 2.17 h)	50.1° 21:10	4.8	38%	168.9°
2043-06-02 Tue	52	—	unknown	23:00–01:00 (good, 2.0 h)	50.1° 21:10	4.76	27%	173.8°
2043-06-03 Wed	50	—	unknown	23:00–00:55 (good, 1.92 h)	50.1° 21:05	4.73	17%	160.9°
2043-06-04 Thu	49	—	unknown	23:00–00:50 (good, 1.83 h)	50.1° 21:00	4.7	9%	146.4°
2043-06-05 Fri	47	—	unknown	23:00–00:50 (good, 1.83 h)	50.1° 20:55	4.67	4%	131.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-05-07&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.