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: 04-21 (71), 04-22 (71), 04-23 (71), 04-24 (71), 04-20 (70) — by astronomy; check the weather when the night is within four days.

2037-04-03astronomy score per night — click a bar for that night2037-05-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-04-03 Fri	32	—	unknown	03:45–05:25 (good, 1.67 h)	87.2° 09:30	7.95	84%	90.1°
2037-04-04 Sat	33	—	unknown	03:40–05:25 (good, 1.75 h)	87.2° 09:25	7.9	75%	83.4°
2037-04-05 Sun	35	—	unknown	03:30–05:20 (good, 1.83 h)	87.2° 09:20	7.84	65%	77.2°
2037-04-06 Mon	39	—	unknown	03:20–05:20 (good, 2.0 h)	87.2° 09:20	7.79	55%	71.7°
2037-04-07 Tue	43	—	unknown	03:00–05:15 (good, 2.25 h)	87.2° 09:15	7.73	46%	67.1°
2037-04-08 Wed	50	—	unknown	02:55–05:15 (good, 2.33 h)	87.2° 09:10	7.67	36%	63.5°
2037-04-09 Thu	56	—	unknown	02:50–05:15 (good, 2.42 h)	87.2° 09:05	7.62	27%	61.2°
2037-04-10 Fri	60	—	unknown	02:45–05:10 (good, 2.42 h)	87.2° 09:00	7.56	19%	60.1°
2037-04-11 Sat	61	—	unknown	02:45–05:10 (good, 2.42 h)	87.2° 09:00	7.5	12%	60.5°
2037-04-12 Sun	62	—	unknown	02:40–05:05 (good, 2.42 h)	87.2° 08:55	7.45	7%	62.2°
2037-04-13 Mon	63	—	unknown	02:35–05:05 (good, 2.5 h)	87.2° 08:50	7.39	3%	65.2°
2037-04-14 Tue	65	—	unknown	02:30–05:05 (good, 2.58 h)	87.2° 08:45	7.33	1%	69.2°
2037-04-15 Wed	65	—	unknown	02:25–05:00 (good, 2.58 h)	87.2° 08:40	7.27	0%	74.2°
2037-04-16 Thu	66	—	unknown	02:25–05:00 (good, 2.58 h)	87.2° 08:40	7.22	2%	79.8°
2037-04-17 Fri	66	—	unknown	02:20–04:55 (good, 2.58 h)	87.2° 08:35	7.16	5%	85.9°
2037-04-18 Sat	68	—	unknown	02:15–04:55 (good, 2.67 h)	87.2° 08:30	7.1	11%	92.3°
2037-04-19 Sun	69	—	unknown	02:10–04:55 (good, 2.75 h)	87.2° 08:25	7.04	18%	98.7°
2037-04-20 Mon	70	—	unknown	02:05–04:50 (good, 2.75 h)	87.2° 08:25	6.98	27%	104.8°
2037-04-21 Tue	71	—	unknown	02:05–04:50 (good, 2.75 h)	87.2° 08:20	6.93	37%	110.3°
2037-04-22 Wed	71	—	unknown	02:05–04:50 (good, 2.75 h)	87.2° 08:15	6.87	48%	114.9°
2037-04-23 Thu	71	—	unknown	02:05–04:45 (good, 2.67 h)	87.2° 08:10	6.81	59%	118.2°
2037-04-24 Fri	71	—	unknown	02:00–04:45 (good, 2.75 h)	87.2° 08:05	6.75	70%	119.7°
2037-04-25 Sat	64	—	unknown	02:00–04:40 (good, 2.67 h)	87.2° 08:05	6.69	80%	119.2°
2037-04-26 Sun	61	—	unknown	02:00–04:40 (good, 2.67 h)	87.2° 08:00	6.64	89%	116.6°
2037-04-27 Mon	58	—	unknown	02:00–04:40 (good, 2.67 h)	87.2° 07:55	6.58	95%	112.3°
2037-04-28 Tue	53	—	unknown	02:00–04:35 (good, 2.58 h)	87.2° 07:50	6.52	99%	106.6°
2037-04-29 Wed	49	—	unknown	02:05–04:35 (good, 2.5 h)	87.2° 07:45	6.46	100%	100.1°
2037-04-30 Thu	45	—	unknown	02:15–04:35 (good, 2.33 h)	87.2° 07:45	6.4	98%	93.2°
2037-05-01 Fri	43	—	unknown	02:25–04:30 (good, 2.08 h)	87.2° 07:40	6.34	94%	86.3°
2037-05-02 Sat	43	—	unknown	02:10–04:30 (good, 2.33 h)	87.2° 07:35	6.29	88%	79.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-04-03&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.