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: 12-19 (70), 12-18 (69), 12-17 (67), 12-16 (65), 12-15 (64) — by astronomy; check the weather when the night is within four days.

2042-11-20astronomy score per night — click a bar for that night2042-12-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-11-20 Thu	20	—	unknown	05:05–05:40 (good, 0.58 h)	50.1° 08:50	11.1	54%	146.9°
2042-11-21 Fri	22	—	unknown	05:00–05:45 (good, 0.75 h)	50.1° 08:45	11.12	64%	160.6°
2042-11-22 Sat	23	—	unknown	04:55–05:45 (good, 0.83 h)	50.1° 08:45	11.15	75%	173.9°
2042-11-23 Sun	25	—	unknown	04:50–05:45 (good, 0.92 h)	50.1° 08:40	11.17	84%	169.5°
2042-11-24 Mon	26	—	unknown	04:55–05:45 (good, 0.83 h)	50.1° 08:35	11.19	92%	155.1°
2042-11-25 Tue	23	—	unknown	04:55–05:45 (good, 0.83 h)	50.1° 08:30	11.22	97%	140.2°
2042-11-26 Wed	24	—	unknown	04:50–05:50 (good, 1.0 h)	50.1° 08:25	11.24	100%	125.2°
2042-11-27 Thu	21	—	unknown	04:55–05:50 (good, 0.92 h)	50.1° 08:25	11.26	99%	110.3°
2042-11-28 Fri	18	—	unknown	05:30–05:50 (good, 0.33 h)	50.1° 08:20	11.28	96%	95.7°
2042-11-29 Sat	14	—	unknown	04:10–05:50 (marginal, 1.67 h)	50.1° 08:15	11.3	90%	81.5°
2042-11-30 Sun	12	—	unknown	04:15–05:50 (marginal, 1.58 h)	50.1° 08:10	11.32	83%	67.7°
2042-12-01 Mon	12	—	unknown	04:10–05:55 (marginal, 1.75 h)	50.1° 08:05	11.33	74%	54.4°
2042-12-02 Tue	13	—	unknown	04:05–05:55 (marginal, 1.83 h)	50.1° 08:05	11.35	64%	41.6°
2042-12-03 Wed	15	—	unknown	03:55–05:55 (marginal, 2.0 h)	50.1° 08:00	11.37	55%	29.2°
2042-12-04 Thu	21	—	unknown	03:45–05:55 (marginal, 2.17 h)	50.1° 07:55	11.38	45%	17.2°
2042-12-05 Fri	27	—	unknown	04:30–05:55 (good, 1.42 h)	50.1° 07:50	11.4	36%	6.1°
2042-12-06 Sat	33	—	unknown	04:15–05:55 (good, 1.67 h)	50.1° 07:50	11.41	27%	8.1°
2042-12-07 Sun	40	—	unknown	04:05–06:00 (good, 1.92 h)	50.1° 07:45	11.42	19%	19.3°
2042-12-08 Mon	46	—	unknown	03:55–06:00 (good, 2.08 h)	50.1° 07:40	11.43	12%	31.0°
2042-12-09 Tue	52	—	unknown	03:50–06:00 (good, 2.17 h)	50.1° 07:35	11.44	7%	42.8°
2042-12-10 Wed	55	—	unknown	03:45–06:00 (good, 2.25 h)	50.1° 07:30	11.45	3%	54.8°
2042-12-11 Thu	56	—	unknown	03:40–06:00 (good, 2.33 h)	50.1° 07:30	11.46	1%	67.0°
2042-12-12 Fri	57	—	unknown	03:40–06:00 (good, 2.33 h)	50.1° 07:25	11.47	0%	79.3°
2042-12-13 Sat	59	—	unknown	03:35–06:00 (good, 2.42 h)	50.1° 07:20	11.48	2%	91.8°
2042-12-14 Sun	62	—	unknown	03:30–06:05 (good, 2.58 h)	50.1° 07:15	11.49	6%	104.6°
2042-12-15 Mon	64	—	unknown	03:25–06:05 (good, 2.67 h)	50.1° 07:10	11.49	11%	117.5°
2042-12-16 Tue	65	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 07:10	11.5	19%	130.6°
2042-12-17 Wed	67	—	unknown	03:20–06:05 (good, 2.75 h)	50.1° 07:05	11.5	28%	143.9°
2042-12-18 Thu	69	—	unknown	03:15–06:05 (good, 2.83 h)	50.1° 07:00	11.5	38%	157.3°
2042-12-19 Fri	70	—	unknown	03:10–06:05 (good, 2.92 h)	50.1° 06:55	11.51	49%	170.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-11-20&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.