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: 05-11 (89), 05-12 (77), 05-26 (63), 05-27 (63), 05-28 (62) — by astronomy; check the weather when the night is within four days.

2035-05-11astronomy score per night — click a bar for that night2035-06-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-05-11 Fri	89	—	unknown	22:25–02:25 (good, 4.0 h)	50.2° 22:35	5.81	23%	78.0°
2035-05-12 Sat	77	—	unknown	22:25–02:20 (good, 3.92 h)	50.2° 22:30	5.75	33%	63.7°
2035-05-13 Sun	60	—	unknown	22:30–02:20 (good, 3.83 h)	50.2° 22:25	5.7	44%	49.8°
2035-05-14 Mon	43	—	unknown	22:30–01:45 (good, 3.25 h)	50.2° 22:20	5.64	55%	36.2°
2035-05-15 Tue	31	—	unknown	22:30–02:35 (marginal, 4.08 h)	50.2° 22:20	5.59	66%	23.0°
2035-05-16 Wed	23	—	unknown	22:35–02:25 (marginal, 3.83 h)	50.2° 22:15	5.53	75%	10.3°
2035-05-17 Thu	17	—	unknown	22:35–02:10 (marginal, 3.58 h)	50.2° 22:10	5.48	83%	3.9°
2035-05-18 Fri	14	—	unknown	22:35–01:55 (marginal, 3.33 h)	50.2° 22:05	5.43	90%	15.5°
2035-05-19 Sat	12	—	unknown	22:40–01:35 (marginal, 2.92 h)	50.2° 22:05	5.38	95%	27.7°
2035-05-20 Sun	16	—	unknown	22:40–01:40 (marginal, 3.0 h)	50.2° 22:00	5.33	98%	39.8°
2035-05-21 Mon	22	—	unknown	22:40–01:50 (marginal, 3.17 h)	50.2° 21:55	5.28	100%	51.8°
2035-05-22 Tue	29	—	unknown	22:45–01:55 (marginal, 3.17 h)	50.2° 21:50	5.23	99%	63.7°
2035-05-23 Wed	37	—	unknown	22:45–00:05 (good, 1.33 h)	50.2° 21:45	5.18	97%	75.6°
2035-05-24 Thu	46	—	unknown	22:45–01:05 (good, 2.33 h)	50.2° 21:45	5.14	93%	87.4°
2035-05-25 Fri	61	—	unknown	22:50–01:15 (good, 2.42 h)	50.2° 21:40	5.09	88%	99.2°
2035-05-26 Sat	63	—	unknown	22:50–01:15 (good, 2.42 h)	50.2° 21:35	5.05	81%	111.1°
2035-05-27 Sun	63	—	unknown	22:50–01:15 (good, 2.42 h)	50.2° 21:30	5.0	73%	123.1°
2035-05-28 Mon	62	—	unknown	22:50–01:20 (good, 2.5 h)	50.2° 21:25	4.96	64%	135.2°
2035-05-29 Tue	60	—	unknown	22:55–01:15 (good, 2.33 h)	50.2° 21:25	4.92	54%	147.6°
2035-05-30 Wed	58	—	unknown	22:55–01:10 (good, 2.25 h)	50.2° 21:20	4.88	44%	160.3°
2035-05-31 Thu	56	—	unknown	22:55–01:05 (good, 2.17 h)	50.2° 21:15	4.84	33%	173.1°
2035-06-01 Fri	55	—	unknown	22:55–01:05 (good, 2.17 h)	50.2° 21:10	4.8	24%	172.3°
2035-06-02 Sat	52	—	unknown	23:00–01:00 (good, 2.0 h)	50.2° 21:10	4.77	15%	158.5°
2035-06-03 Sun	50	—	unknown	23:00–00:55 (good, 1.92 h)	50.2° 21:05	4.73	7%	144.1°
2035-06-04 Mon	49	—	unknown	23:00–00:50 (good, 1.83 h)	50.2° 21:00	4.7	2%	129.2°
2035-06-05 Tue	47	—	unknown	23:00–00:50 (good, 1.83 h)	50.2° 20:55	4.67	0%	114.0°
2035-06-06 Wed	44	—	unknown	23:05–00:45 (good, 1.67 h)	50.2° 20:50	4.64	1%	98.8°
2035-06-07 Thu	43	—	unknown	23:05–00:40 (good, 1.58 h)	50.2° 20:50	4.61	5%	83.7°
2035-06-08 Fri	41	—	unknown	23:05–00:35 (good, 1.5 h)	50.2° 20:45	4.59	12%	68.8°
2035-06-09 Sat	35	—	unknown	23:05–00:30 (good, 1.42 h)	50.2° 20:40	4.56	20%	54.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-05-11&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.