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 Great Orion Nebula: 02-06 (89), 02-07 (89), 02-08 (89), 02-09 (89), 02-10 (89) — by astronomy; check the weather when the night is within four days.

2034-02-04astronomy score per night — click a bar for that night2034-03-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-02-04 Sat	50	—	unknown	19:20–20:55 (good, 1.58 h)	42.9° 21:00	10.65	98%	72.3°
2034-02-05 Sun	81	—	unknown	19:20–22:50 (good, 3.5 h)	42.9° 20:55	10.62	94%	83.8°
2034-02-06 Mon	89	—	unknown	19:20–23:40 (good, 4.33 h)	42.9° 20:50	10.58	88%	95.0°
2034-02-07 Tue	89	—	unknown	19:20–23:50 (good, 4.5 h)	42.9° 20:45	10.55	81%	106.1°
2034-02-08 Wed	89	—	unknown	19:20–23:55 (good, 4.58 h)	42.9° 20:40	10.51	73%	116.9°
2034-02-09 Thu	89	—	unknown	19:25–23:55 (good, 4.5 h)	42.9° 20:40	10.47	64%	127.3°
2034-02-10 Fri	89	—	unknown	19:25–23:55 (good, 4.5 h)	42.9° 20:35	10.44	55%	137.2°
2034-02-11 Sat	89	—	unknown	19:25–23:50 (good, 4.42 h)	42.9° 20:30	10.4	46%	146.3°
2034-02-12 Sun	89	—	unknown	19:25–23:45 (good, 4.33 h)	42.9° 20:25	10.36	36%	153.3°
2034-02-13 Mon	89	—	unknown	19:30–23:40 (good, 4.17 h)	42.9° 20:25	10.32	27%	156.4°
2034-02-14 Tue	89	—	unknown	19:30–23:40 (good, 4.17 h)	42.9° 20:20	10.28	18%	153.6°
2034-02-15 Wed	88	—	unknown	19:30–23:35 (good, 4.08 h)	42.9° 20:15	10.24	11%	146.1°
2034-02-16 Thu	86	—	unknown	19:30–23:30 (good, 4.0 h)	42.9° 20:10	10.2	5%	135.8°
2034-02-17 Fri	85	—	unknown	19:30–23:25 (good, 3.92 h)	42.9° 20:05	10.16	2%	124.1°
2034-02-18 Sat	83	—	unknown	19:35–23:20 (good, 3.75 h)	42.9° 20:05	10.12	0%	111.5°
2034-02-19 Sun	82	—	unknown	19:35–23:20 (good, 3.75 h)	42.9° 20:00	10.08	1%	98.4°
2034-02-20 Mon	80	—	unknown	19:35–23:15 (good, 3.67 h)	42.9° 19:55	10.04	5%	85.0°
2034-02-21 Tue	75	—	unknown	19:35–23:10 (good, 3.58 h)	42.9° 19:50	10.0	12%	71.7°
2034-02-22 Wed	65	—	unknown	19:40–23:05 (good, 3.42 h)	42.9° 19:45	9.95	20%	58.6°
2034-02-23 Thu	54	—	unknown	19:40–22:50 (good, 3.17 h)	42.9° 19:45	9.91	30%	46.2°
2034-02-24 Fri	40	—	unknown	19:40–22:30 (good, 2.83 h)	42.9° 19:40	9.87	42%	35.0°
2034-02-25 Sat	28	—	unknown	19:40–23:20 (marginal, 3.67 h)	42.9° 19:35	9.82	53%	26.6°
2034-02-26 Sun	19	—	unknown	19:45–23:05 (marginal, 3.33 h)	42.9° 19:30	9.78	64%	23.5°
2034-02-27 Mon	13	—	unknown	19:45–22:40 (marginal, 2.92 h)	42.9° 19:30	9.73	74%	27.4°
2034-02-28 Tue	11	—	unknown	19:45–22:20 (marginal, 2.58 h)	42.9° 19:25	9.69	83%	35.9°
2034-03-01 Wed	13	—	unknown	19:45–22:20 (marginal, 2.58 h)	42.9° 19:20	9.64	90%	46.2°
2034-03-02 Thu	16	—	unknown	19:45–22:25 (marginal, 2.67 h)	42.9° 19:15	9.6	95%	57.3°
2034-03-03 Fri	21	—	unknown	19:50–22:35 (marginal, 2.75 h)	42.9° 19:10	9.55	99%	68.7°
2034-03-04 Sat	28	—	unknown	19:50–20:10 (good, 0.33 h)	42.9° 19:10	9.51	100%	80.1°
2034-03-05 Sun	34	—	unknown	19:50–21:35 (good, 1.75 h)	42.9° 19:05	9.46	99%	91.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-02-04&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.