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: 04-18 (93), 04-19 (93), 04-20 (93), 04-21 (93), 04-22 (93) — by astronomy; check the weather when the night is within four days.

2033-04-18astronomy score per night — click a bar for that night2033-05-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-04-18 Mon	93	—	unknown	21:50–02:30 (good, 4.67 h)	50.2° 00:05	7.1	84%	69.7°
2033-04-19 Tue	93	—	unknown	21:50–03:25 (good, 5.58 h)	50.2° 00:00	7.04	76%	82.4°
2033-04-20 Wed	93	—	unknown	21:50–03:30 (good, 5.67 h)	50.2° 23:55	6.99	67%	95.3°
2033-04-21 Thu	93	—	unknown	21:55–03:35 (good, 5.67 h)	50.2° 23:50	6.93	56%	108.5°
2033-04-22 Fri	93	—	unknown	21:55–03:35 (good, 5.67 h)	50.2° 23:45	6.87	45%	122.1°
2033-04-23 Sat	93	—	unknown	21:55–03:35 (good, 5.67 h)	50.2° 23:45	6.81	34%	135.9°
2033-04-24 Sun	93	—	unknown	22:00–03:30 (good, 5.5 h)	50.2° 23:40	6.75	24%	150.0°
2033-04-25 Mon	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.2° 23:35	6.69	14%	164.1°
2033-04-26 Tue	93	—	unknown	22:00–03:25 (good, 5.42 h)	50.2° 23:30	6.64	7%	173.9°
2033-04-27 Wed	93	—	unknown	22:05–03:20 (good, 5.25 h)	50.2° 23:25	6.58	2%	163.7°
2033-04-28 Thu	93	—	unknown	22:05–03:15 (good, 5.17 h)	50.2° 23:25	6.52	0%	149.4°
2033-04-29 Fri	93	—	unknown	22:05–03:10 (good, 5.08 h)	50.2° 23:20	6.46	1%	134.9°
2033-04-30 Sat	93	—	unknown	22:10–03:05 (good, 4.92 h)	50.2° 23:15	6.4	5%	120.5°
2033-05-01 Sun	93	—	unknown	22:10–03:05 (good, 4.92 h)	50.2° 23:10	6.35	11%	106.6°
2033-05-02 Mon	93	—	unknown	22:10–03:00 (good, 4.83 h)	50.2° 23:10	6.29	18%	93.0°
2033-05-03 Tue	90	—	unknown	22:15–02:55 (good, 4.67 h)	50.2° 23:05	6.23	27%	79.9°
2033-05-04 Wed	86	—	unknown	22:15–02:50 (good, 4.58 h)	50.2° 23:00	6.17	37%	67.3°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-04-18&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.