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: 05-05 (78), 05-18 (77), 05-19 (77), 05-20 (77), 05-21 (76) — by astronomy; check the weather when the night is within four days.

2033-05-05astronomy score per night — click a bar for that night2033-06-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-05-05 Thu	78	—	unknown	22:15–02:50 (good, 4.58 h)	50.2° 22:55	6.12	46%	54.9°
2033-05-06 Fri	56	—	unknown	22:20–02:20 (good, 4.0 h)	50.2° 22:50	6.06	56%	42.9°
2033-05-07 Sat	39	—	unknown	22:20–03:10 (marginal, 4.83 h)	50.2° 22:50	6.0	66%	31.1°
2033-05-08 Sun	30	—	unknown	22:20–03:00 (marginal, 4.67 h)	50.2° 22:45	5.95	74%	19.7°
2033-05-09 Mon	23	—	unknown	22:25–02:45 (marginal, 4.33 h)	50.2° 22:40	5.89	82%	9.2°
2033-05-10 Tue	18	—	unknown	22:25–02:30 (marginal, 4.08 h)	50.2° 22:35	5.83	89%	7.9°
2033-05-11 Wed	15	—	unknown	22:25–02:15 (marginal, 3.83 h)	50.2° 22:30	5.78	94%	18.0°
2033-05-12 Thu	15	—	unknown	22:30–02:00 (marginal, 3.5 h)	50.2° 22:30	5.72	98%	29.6°
2033-05-13 Fri	21	—	unknown	22:30–02:10 (marginal, 3.67 h)	50.2° 22:25	5.67	100%	41.6°
2033-05-14 Sat	30	—	unknown	22:30–02:15 (marginal, 3.75 h)	50.2° 22:20	5.62	100%	54.0°
2033-05-15 Sun	40	—	unknown	22:35–23:35 (good, 1.0 h)	50.2° 22:15	5.56	98%	66.5°
2033-05-16 Mon	52	—	unknown	22:35–01:00 (good, 2.42 h)	50.2° 22:15	5.51	94%	79.3°
2033-05-17 Tue	74	—	unknown	22:35–01:40 (good, 3.08 h)	50.2° 22:10	5.46	87%	92.3°
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°

Download: CSV · JSON

💡 API

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