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: 11-20 (20), 11-19 (19), 11-18 (18), 11-21 (18), 11-17 (16) — by astronomy; check the weather when the night is within four days.

2037-10-23astronomy score per night — click a bar for that night2037-11-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-10-23 Fri	0	—	unknown	—	50.2° 11:40	10.17	100%	158.1°
2037-10-24 Sat	0	—	unknown	—	50.2° 10:35	10.21	99%	146.1°
2037-10-25 Sun	0	—	unknown	—	50.1° 10:30	10.25	97%	133.9°
2037-10-26 Mon	0	—	unknown	—	50.1° 10:30	10.29	93%	121.5°
2037-10-27 Tue	0	—	unknown	—	50.1° 10:25	10.33	87%	109.0°
2037-10-28 Wed	0	—	unknown	—	50.2° 10:20	10.37	79%	96.3°
2037-10-29 Thu	0	—	unknown	—	50.1° 10:15	10.4	70%	83.3°
2037-10-30 Fri	0	—	unknown	—	50.1° 10:10	10.44	60%	70.1°
2037-10-31 Sat	0	—	unknown	—	50.1° 10:10	10.48	50%	56.5°
2037-11-01 Sun	0	—	unknown	—	50.2° 10:05	10.51	38%	42.7°
2037-11-02 Mon	0	—	unknown	—	50.2° 10:00	10.55	28%	28.5°
2037-11-03 Tue	1	—	unknown	—	50.1° 09:55	10.58	18%	13.9°
2037-11-04 Wed	1	—	unknown	—	50.1° 09:55	10.62	10%	0.9°
2037-11-05 Thu	1	—	unknown	—	50.1° 09:50	10.65	4%	15.8°
2037-11-06 Fri	1	—	unknown	—	50.2° 09:45	10.69	1%	30.7°
2037-11-07 Sat	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.2° 09:40	10.72	0%	45.5°
2037-11-08 Sun	3	—	unknown	05:50–06:05 (marginal, 0.25 h)	50.1° 09:35	10.75	3%	60.1°
2037-11-09 Mon	4	—	unknown	05:45–06:05 (marginal, 0.33 h)	50.1° 09:35	10.79	8%	74.3°
2037-11-10 Tue	5	—	unknown	05:40–06:05 (marginal, 0.42 h)	50.1° 09:30	10.82	15%	88.1°
2037-11-11 Wed	6	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.2° 09:25	10.85	23%	101.4°
2037-11-12 Thu	7	—	unknown	05:05–06:05 (marginal, 1.0 h)	50.1° 09:20	10.88	32%	114.2°
2037-11-13 Fri	9	—	unknown	05:30–05:35 (good, 0.08 h)	50.1° 09:15	10.91	42%	126.7°
2037-11-14 Sat	10	—	unknown	05:25–05:35 (good, 0.17 h)	50.1° 09:15	10.94	52%	138.9°
2037-11-15 Sun	11	—	unknown	05:20–05:35 (good, 0.25 h)	50.2° 09:10	10.97	61%	150.9°
2037-11-16 Mon	14	—	unknown	05:20–05:40 (good, 0.33 h)	50.2° 09:05	11.0	70%	162.8°
2037-11-17 Tue	16	—	unknown	05:15–05:40 (good, 0.42 h)	50.1° 09:00	11.02	78%	174.6°
2037-11-18 Wed	18	—	unknown	05:10–05:40 (good, 0.5 h)	50.1° 08:55	11.05	86%	173.5°
2037-11-19 Thu	19	—	unknown	05:05–05:40 (good, 0.58 h)	50.1° 08:55	11.08	92%	161.6°
2037-11-20 Fri	20	—	unknown	05:10–05:45 (good, 0.58 h)	50.2° 08:50	11.1	96%	149.5°
2037-11-21 Sat	18	—	unknown	05:10–05:45 (good, 0.58 h)	50.1° 08:45	11.13	99%	137.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-10-23&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.