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: 12-04 (43), 12-03 (42), 12-02 (40), 12-01 (39), 12-05 (39) — by astronomy; check the weather when the night is within four days.

2041-11-06astronomy score per night — click a bar for that night2041-12-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-11-06 Wed	1	—	unknown	—	50.1° 09:45	10.69	98%	157.9°
2041-11-07 Thu	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.1° 09:40	10.72	100%	143.4°
2041-11-08 Fri	3	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.1° 09:35	10.76	99%	129.1°
2041-11-09 Sat	3	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.1° 09:35	10.79	96%	115.1°
2041-11-10 Sun	3	—	unknown	05:15–05:30 (marginal, 0.25 h)	50.1° 09:30	10.82	91%	101.6°
2041-11-11 Mon	3	—	unknown	05:15–05:35 (marginal, 0.33 h)	50.1° 09:25	10.85	84%	88.4°
2041-11-12 Tue	3	—	unknown	05:15–05:35 (marginal, 0.33 h)	50.1° 09:20	10.88	76%	75.6°
2041-11-13 Wed	4	—	unknown	05:15–05:35 (marginal, 0.33 h)	50.1° 09:15	10.91	67%	63.2°
2041-11-14 Thu	4	—	unknown	05:05–05:35 (marginal, 0.5 h)	50.1° 09:15	10.94	57%	51.0°
2041-11-15 Fri	6	—	unknown	05:00–05:40 (marginal, 0.67 h)	50.1° 09:10	10.97	48%	39.1°
2041-11-16 Sat	7	—	unknown	04:50–05:40 (marginal, 0.83 h)	50.1° 09:05	11.0	38%	27.3°
2041-11-17 Sun	10	—	unknown	05:35–05:40 (good, 0.08 h)	50.1° 09:00	11.03	29%	15.5°
2041-11-18 Mon	13	—	unknown	05:25–05:40 (good, 0.25 h)	50.1° 09:00	11.05	21%	4.1°
2041-11-19 Tue	16	—	unknown	05:15–05:40 (good, 0.42 h)	50.1° 08:55	11.08	14%	8.8°
2041-11-20 Wed	19	—	unknown	05:05–05:45 (good, 0.67 h)	50.1° 08:50	11.1	8%	20.8°
2041-11-21 Thu	22	—	unknown	05:00–05:45 (good, 0.75 h)	50.1° 08:45	11.13	3%	33.2°
2041-11-22 Fri	24	—	unknown	04:55–05:45 (good, 0.83 h)	50.1° 08:40	11.15	1%	45.9°
2041-11-23 Sat	25	—	unknown	04:50–05:45 (good, 0.92 h)	50.1° 08:40	11.18	0%	58.8°
2041-11-24 Sun	27	—	unknown	04:45–05:45 (good, 1.0 h)	50.1° 08:35	11.2	2%	71.9°
2041-11-25 Mon	29	—	unknown	04:45–05:50 (good, 1.08 h)	50.1° 08:30	11.22	6%	85.3°
2041-11-26 Tue	30	—	unknown	04:40–05:50 (good, 1.17 h)	50.1° 08:25	11.24	12%	98.9°
2041-11-27 Wed	32	—	unknown	04:35–05:50 (good, 1.25 h)	50.1° 08:20	11.26	20%	112.7°
2041-11-28 Thu	33	—	unknown	04:30–05:50 (good, 1.33 h)	50.1° 08:20	11.28	29%	126.5°
2041-11-29 Fri	35	—	unknown	04:30–05:50 (good, 1.33 h)	50.1° 08:15	11.3	40%	140.5°
2041-11-30 Sat	36	—	unknown	04:25–05:50 (good, 1.42 h)	50.1° 08:10	11.32	51%	154.6°
2041-12-01 Sun	39	—	unknown	04:20–05:55 (good, 1.58 h)	50.1° 08:05	11.34	62%	168.6°
2041-12-02 Mon	40	—	unknown	04:15–05:55 (good, 1.67 h)	50.1° 08:05	11.35	73%	176.3°
2041-12-03 Tue	42	—	unknown	04:10–05:55 (good, 1.75 h)	50.1° 08:00	11.37	83%	162.6°
2041-12-04 Wed	43	—	unknown	04:15–05:55 (good, 1.67 h)	50.1° 07:55	11.38	90%	148.5°
2041-12-05 Thu	39	—	unknown	04:15–05:55 (good, 1.67 h)	50.1° 07:50	11.4	96%	134.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-11-06&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.