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: 02-15 (88), 02-16 (86), 02-17 (85), 02-18 (83), 02-19 (82) — by astronomy; check the weather when the night is within four days.

2034-02-15astronomy score per night — click a bar for that night2034-03-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2034-03-06 Mon	48	—	unknown	19:50–21:55 (good, 2.08 h)	42.9° 19:00	9.41	97%	102.5°
2034-03-07 Tue	51	—	unknown	19:55–22:00 (good, 2.08 h)	42.9° 18:55	9.36	93%	113.4°
2034-03-08 Wed	52	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:50	9.32	87%	124.0°
2034-03-09 Thu	51	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:50	9.27	80%	134.2°
2034-03-10 Fri	49	—	unknown	19:55–22:05 (good, 2.17 h)	42.9° 18:45	9.22	72%	143.6°
2034-03-11 Sat	47	—	unknown	20:00–22:00 (good, 2.0 h)	42.9° 18:40	9.17	63%	151.4°
2034-03-12 Sun	45	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.12	53%	156.1°
2034-03-13 Mon	44	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.07	44%	155.4°
2034-03-14 Tue	42	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.02	34%	149.5°
2034-03-15 Wed	40	—	unknown	20:05–21:45 (good, 1.67 h)	42.9° 18:25	8.97	24%	140.3°
2034-03-16 Thu	38	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.92	16%	129.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-02-15&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.