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 North America Nebula: 04-24 (74), 04-27 (74), 04-26 (73), 04-28 (73), 04-22 (72) — by astronomy; check the weather when the night is within four days.

2042-03-30astronomy score per night — click a bar for that night2042-04-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-03-30 Sun	48	—	unknown	03:40–05:35 (good, 1.92 h)	87.2° 09:45	8.18	74%	112.5°
2042-03-31 Mon	44	—	unknown	03:40–05:30 (good, 1.83 h)	87.2° 09:40	8.13	82%	115.8°
2042-04-01 Tue	43	—	unknown	03:35–05:30 (good, 1.92 h)	87.2° 09:40	8.08	88%	118.0°
2042-04-02 Wed	43	—	unknown	03:35–05:25 (good, 1.83 h)	87.2° 09:35	8.02	94%	118.8°
2042-04-03 Thu	43	—	unknown	03:30–05:25 (good, 1.92 h)	87.2° 09:30	7.97	98%	118.3°
2042-04-04 Fri	43	—	unknown	03:30–05:25 (good, 1.92 h)	87.2° 09:25	7.91	100%	116.5°
2042-04-05 Sat	41	—	unknown	03:25–05:20 (good, 1.92 h)	87.2° 09:25	7.85	100%	113.5°
2042-04-06 Sun	40	—	unknown	03:25–05:20 (good, 1.92 h)	87.2° 09:20	7.8	98%	109.6°
2042-04-07 Mon	38	—	unknown	03:25–05:15 (good, 1.83 h)	87.2° 09:15	7.74	95%	104.8°
2042-04-08 Tue	38	—	unknown	03:20–05:15 (good, 1.92 h)	87.2° 09:10	7.69	90%	99.4°
2042-04-09 Wed	39	—	unknown	03:15–05:15 (good, 2.0 h)	87.2° 09:05	7.63	83%	93.6°
2042-04-10 Thu	39	—	unknown	03:10–05:10 (good, 2.0 h)	87.2° 09:05	7.57	75%	87.6°
2042-04-11 Fri	41	—	unknown	03:00–05:10 (good, 2.17 h)	87.2° 09:00	7.52	66%	81.6°
2042-04-12 Sat	48	—	unknown	02:40–05:10 (good, 2.5 h)	87.2° 08:55	7.46	56%	75.8°
2042-04-13 Sun	54	—	unknown	02:35–05:05 (good, 2.5 h)	87.2° 08:50	7.4	45%	70.4°
2042-04-14 Mon	60	—	unknown	02:30–05:05 (good, 2.58 h)	87.2° 08:45	7.34	34%	65.9°
2042-04-15 Tue	64	—	unknown	02:30–05:00 (good, 2.5 h)	87.2° 08:45	7.29	24%	62.7°
2042-04-16 Wed	65	—	unknown	02:25–05:00 (good, 2.58 h)	87.2° 08:40	7.23	14%	61.2°
2042-04-17 Thu	67	—	unknown	02:20–05:00 (good, 2.67 h)	87.2° 08:35	7.17	7%	61.8°
2042-04-18 Fri	68	—	unknown	02:15–04:55 (good, 2.67 h)	87.2° 08:30	7.11	2%	64.5°
2042-04-19 Sat	69	—	unknown	02:10–04:55 (good, 2.75 h)	87.2° 08:30	7.05	0%	68.9°
2042-04-20 Sun	69	—	unknown	02:10–04:50 (good, 2.67 h)	87.2° 08:25	7.0	1%	74.7°
2042-04-21 Mon	71	—	unknown	02:05–04:50 (good, 2.75 h)	87.2° 08:20	6.94	5%	81.2°
2042-04-22 Tue	72	—	unknown	02:00–04:50 (good, 2.83 h)	87.2° 08:15	6.88	11%	88.0°
2042-04-23 Wed	72	—	unknown	01:55–04:45 (good, 2.83 h)	87.2° 08:10	6.82	19%	94.7°
2042-04-24 Thu	74	—	unknown	01:55–04:45 (good, 2.83 h)	87.2° 08:10	6.76	28%	101.0°
2042-04-25 Fri	72	—	unknown	01:55–04:40 (good, 2.75 h)	87.2° 08:05	6.71	38%	106.6°
2042-04-26 Sat	73	—	unknown	01:50–04:40 (good, 2.83 h)	87.2° 08:00	6.65	48%	111.3°
2042-04-27 Sun	74	—	unknown	01:50–04:40 (good, 2.83 h)	87.2° 07:55	6.59	58%	115.0°
2042-04-28 Mon	73	—	unknown	01:45–04:35 (good, 2.83 h)	87.2° 07:50	6.53	68%	117.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-03-30&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.