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: 04-17 (64), 04-12 (63), 04-14 (63), 04-15 (63), 04-16 (63) — by astronomy; check the weather when the night is within four days.

2043-03-21astronomy score per night — click a bar for that night2043-04-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-03-21 Sat	36	—	unknown	03:20–04:50 (good, 1.5 h)	87.2° 09:25	8.68	87%	116.3°
2043-03-22 Sun	36	—	unknown	03:15–04:50 (good, 1.58 h)	87.2° 09:20	8.62	93%	119.0°
2043-03-23 Mon	36	—	unknown	03:15–04:45 (good, 1.5 h)	87.2° 09:15	8.57	97%	120.2°
2043-03-24 Tue	36	—	unknown	03:10–04:45 (good, 1.58 h)	87.2° 09:10	8.52	100%	119.8°
2043-03-25 Wed	36	—	unknown	03:05–04:45 (good, 1.67 h)	87.2° 09:05	8.47	100%	117.9°
2043-03-26 Thu	35	—	unknown	03:05–04:40 (good, 1.58 h)	87.2° 09:05	8.41	98%	114.8°
2043-03-27 Fri	35	—	unknown	03:05–04:40 (good, 1.58 h)	87.2° 09:00	8.36	95%	110.6°
2043-03-28 Sat	33	—	unknown	04:00–05:35 (good, 1.58 h)	87.2° 09:55	8.31	90%	105.7°
2043-03-29 Sun	34	—	unknown	03:55–05:35 (good, 1.67 h)	87.2° 09:50	8.25	84%	100.3°
2043-03-30 Mon	35	—	unknown	03:55–05:35 (good, 1.67 h)	87.2° 09:45	8.2	76%	94.5°
2043-03-31 Tue	35	—	unknown	03:45–05:30 (good, 1.75 h)	87.2° 09:45	8.14	68%	88.5°
2043-04-01 Wed	38	—	unknown	03:40–05:30 (good, 1.83 h)	87.2° 09:40	8.09	58%	82.5°
2043-04-02 Thu	42	—	unknown	03:20–05:30 (good, 2.17 h)	87.2° 09:35	8.03	49%	76.6°
2043-04-03 Fri	48	—	unknown	03:15–05:25 (good, 2.17 h)	87.2° 09:30	7.98	38%	71.1°
2043-04-04 Sat	52	—	unknown	03:10–05:25 (good, 2.25 h)	87.2° 09:30	7.92	29%	66.3°
2043-04-05 Sun	54	—	unknown	03:10–05:20 (good, 2.17 h)	87.2° 09:25	7.87	19%	62.5°
2043-04-06 Mon	56	—	unknown	03:05–05:20 (good, 2.25 h)	87.2° 09:20	7.81	11%	60.2°
2043-04-07 Tue	58	—	unknown	03:00–05:20 (good, 2.33 h)	87.2° 09:15	7.76	5%	59.9°
2043-04-08 Wed	58	—	unknown	02:55–05:15 (good, 2.33 h)	87.2° 09:10	7.7	1%	61.7°
2043-04-09 Thu	59	—	unknown	02:55–05:15 (good, 2.33 h)	87.2° 09:10	7.64	0%	65.5°
2043-04-10 Fri	59	—	unknown	02:50–05:10 (good, 2.33 h)	87.2° 09:05	7.59	2%	71.0°
2043-04-11 Sat	61	—	unknown	02:45–05:10 (good, 2.42 h)	87.2° 09:00	7.53	7%	77.6°
2043-04-12 Sun	63	—	unknown	02:40–05:10 (good, 2.5 h)	87.2° 08:55	7.47	14%	84.9°
2043-04-13 Mon	62	—	unknown	02:35–05:05 (good, 2.5 h)	87.2° 08:50	7.41	23%	92.2°
2043-04-14 Tue	63	—	unknown	02:35–05:05 (good, 2.5 h)	87.2° 08:50	7.36	34%	99.2°
2043-04-15 Wed	63	—	unknown	02:35–05:00 (good, 2.42 h)	87.2° 08:45	7.3	45%	105.6°
2043-04-16 Thu	63	—	unknown	02:35–05:00 (good, 2.42 h)	87.2° 08:40	7.24	55%	111.1°
2043-04-17 Fri	64	—	unknown	02:30–05:00 (good, 2.5 h)	87.2° 08:35	7.18	66%	115.5°
2043-04-18 Sat	63	—	unknown	02:25–04:55 (good, 2.5 h)	87.2° 08:30	7.13	75%	118.5°
2043-04-19 Sun	58	—	unknown	02:25–04:55 (good, 2.5 h)	87.2° 08:30	7.07	83%	120.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-03-21&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.