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: 05-10 (93), 05-11 (93), 05-12 (93), 05-13 (92), 05-14 (90) — by astronomy; check the weather when the night is within four days.

2029-05-10astronomy score per night — click a bar for that night2029-06-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-05-10 Thu	93	—	unknown	22:25–02:30 (good, 4.08 h)	50.2° 22:35	5.83	6%	161.7°
2029-05-11 Fri	93	—	unknown	22:25–02:25 (good, 4.0 h)	50.2° 22:30	5.78	3%	151.0°
2029-05-12 Sat	93	—	unknown	22:30–02:20 (good, 3.83 h)	50.2° 22:30	5.72	0%	139.6°
2029-05-13 Sun	92	—	unknown	22:30–02:15 (good, 3.75 h)	50.2° 22:25	5.67	0%	127.9°
2029-05-14 Mon	90	—	unknown	22:30–02:10 (good, 3.67 h)	50.2° 22:20	5.62	2%	116.0°
2029-05-15 Tue	87	—	unknown	22:35–02:10 (good, 3.58 h)	50.2° 22:15	5.56	5%	103.8°
2029-05-16 Wed	83	—	unknown	22:35–02:05 (good, 3.5 h)	50.2° 22:15	5.51	11%	91.4°
2029-05-17 Thu	78	—	unknown	22:35–02:00 (good, 3.42 h)	50.2° 22:10	5.46	18%	78.8°
2029-05-18 Fri	69	—	unknown	22:40–01:55 (good, 3.25 h)	50.2° 22:05	5.41	26%	66.0°
2029-05-19 Sat	60	—	unknown	22:40–01:55 (good, 3.25 h)	50.2° 22:00	5.36	36%	53.0°
2029-05-20 Sun	45	—	unknown	22:40–01:30 (good, 2.83 h)	50.2° 21:55	5.31	47%	39.9°
2029-05-21 Mon	33	—	unknown	22:40–02:15 (marginal, 3.58 h)	50.2° 21:55	5.26	58%	26.7°
2029-05-22 Tue	25	—	unknown	22:45–02:05 (marginal, 3.33 h)	50.2° 21:50	5.21	70%	14.6°
2029-05-23 Wed	19	—	unknown	22:45–01:50 (marginal, 3.08 h)	50.2° 21:45	5.16	80%	10.7°
2029-05-24 Thu	15	—	unknown	22:45–01:40 (marginal, 2.92 h)	50.2° 21:40	5.11	88%	20.9°
2029-05-25 Fri	14	—	unknown	22:50–01:30 (marginal, 2.67 h)	50.2° 21:35	5.07	95%	34.7°
2029-05-26 Sat	19	—	unknown	22:50–01:30 (marginal, 2.67 h)	50.2° 21:35	5.03	99%	49.0°
2029-05-27 Sun	26	—	unknown	22:50–01:35 (marginal, 2.75 h)	50.2° 21:30	4.98	100%	63.5°
2029-05-28 Mon	33	—	unknown	22:55–00:10 (good, 1.25 h)	50.2° 21:25	4.94	98%	77.7°
2029-05-29 Tue	41	—	unknown	22:55–00:50 (good, 1.92 h)	50.2° 21:20	4.9	94%	91.7°
2029-05-30 Wed	53	—	unknown	22:55–00:55 (good, 2.0 h)	50.2° 21:15	4.86	88%	105.2°
2029-05-31 Thu	54	—	unknown	22:55–01:00 (good, 2.08 h)	50.2° 21:15	4.82	80%	118.3°
2029-06-01 Fri	52	—	unknown	23:00–00:55 (good, 1.92 h)	50.2° 21:10	4.79	70%	130.9°
2029-06-02 Sat	51	—	unknown	23:00–01:00 (good, 2.0 h)	50.2° 21:05	4.75	61%	143.0°
2029-06-03 Sun	49	—	unknown	23:00–00:55 (good, 1.92 h)	50.2° 21:00	4.72	51%	154.5°
2029-06-04 Mon	48	—	unknown	23:00–00:50 (good, 1.83 h)	50.2° 21:00	4.68	42%	164.7°
2029-06-05 Tue	45	—	unknown	23:05–00:45 (good, 1.67 h)	50.2° 20:55	4.65	32%	170.0°
2029-06-06 Wed	44	—	unknown	23:05–00:40 (good, 1.58 h)	50.2° 20:50	4.63	24%	164.3°
2029-06-07 Thu	42	—	unknown	23:05–00:40 (good, 1.58 h)	50.2° 20:45	4.6	16%	154.1°
2029-06-08 Fri	40	—	unknown	23:05–00:35 (good, 1.5 h)	50.2° 20:40	4.57	10%	142.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-05-10&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.