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: 05-26 (63), 05-27 (63), 05-28 (62), 05-25 (61), 05-29 (60) — by astronomy; check the weather when the night is within four days.

2035-05-22astronomy score per night — click a bar for that night2035-06-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2035-06-10 Sun	29	—	unknown	23:05–00:15 (good, 1.17 h)	50.2° 20:35	4.54	30%	40.1°
2035-06-11 Mon	22	—	unknown	23:10–00:05 (good, 0.92 h)	50.2° 20:30	4.52	40%	26.4°
2035-06-12 Tue	17	—	unknown	23:10–00:50 (marginal, 1.67 h)	50.2° 20:30	4.5	51%	13.3°
2035-06-13 Wed	13	—	unknown	23:10–00:40 (marginal, 1.5 h)	50.2° 20:25	4.48	61%	2.5°
2035-06-14 Thu	10	—	unknown	23:10–00:25 (marginal, 1.25 h)	50.2° 20:20	4.47	71%	12.6°
2035-06-15 Fri	7	—	unknown	23:10–00:15 (marginal, 1.08 h)	50.2° 20:15	4.46	79%	24.8°
2035-06-16 Sat	7	—	unknown	23:10–00:05 (marginal, 0.92 h)	50.2° 20:15	4.44	87%	36.9°
2035-06-17 Sun	7	—	unknown	23:10–00:05 (marginal, 0.92 h)	50.2° 20:10	4.44	92%	48.9°
2035-06-18 Mon	9	—	unknown	23:10–00:10 (marginal, 1.0 h)	50.2° 20:05	4.43	97%	60.8°
2035-06-19 Tue	10	—	unknown	23:10–00:10 (marginal, 1.0 h)	50.2° 20:00	4.43	99%	72.6°
2035-06-20 Wed	11	—	unknown	23:15–00:15 (marginal, 1.0 h)	50.2° 19:55	4.42	100%	84.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-05-22&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.