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: 12-29 (59), 12-30 (59), 12-28 (58), 12-31 (57), 01-01 (55) — by astronomy; check the weather when the night is within four days.

2042-12-26astronomy score per night — click a bar for that night2043-01-24

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-12-26 Fri	41	—	unknown	18:40–20:45 (good, 2.08 h)	87.2° 15:00	11.5	100%	100.4°
2042-12-27 Sat	47	—	unknown	18:40–20:55 (good, 2.25 h)	87.2° 14:55	11.49	98%	106.8°
2042-12-28 Sun	58	—	unknown	18:40–20:55 (good, 2.25 h)	87.2° 14:55	11.48	94%	112.2°
2042-12-29 Mon	59	—	unknown	18:40–21:00 (good, 2.33 h)	87.2° 14:50	11.48	88%	116.3°
2042-12-30 Tue	59	—	unknown	18:40–21:05 (good, 2.42 h)	87.2° 14:45	11.47	80%	118.9°
2042-12-31 Wed	57	—	unknown	18:45–21:00 (good, 2.25 h)	87.2° 14:40	11.46	72%	119.9°
2043-01-01 Thu	55	—	unknown	18:45–20:55 (good, 2.17 h)	87.2° 14:35	11.45	62%	119.4°
2043-01-02 Fri	54	—	unknown	18:45–20:55 (good, 2.17 h)	87.2° 14:35	11.44	53%	117.5°
2043-01-03 Sat	52	—	unknown	18:45–20:50 (good, 2.08 h)	87.2° 14:30	11.43	44%	114.4°
2043-01-04 Sun	50	—	unknown	18:45–20:45 (good, 2.0 h)	87.2° 14:25	11.42	34%	110.3°
2043-01-05 Mon	48	—	unknown	18:45–20:40 (good, 1.92 h)	87.2° 14:20	11.4	26%	105.4°
2043-01-06 Tue	46	—	unknown	18:50–20:40 (good, 1.83 h)	87.2° 14:15	11.39	18%	99.9°
2043-01-07 Wed	44	—	unknown	18:50–20:35 (good, 1.75 h)	87.2° 14:15	11.38	11%	94.0°
2043-01-08 Thu	42	—	unknown	18:50–20:30 (good, 1.67 h)	87.2° 14:10	11.36	6%	87.9°
2043-01-09 Fri	41	—	unknown	18:50–20:25 (good, 1.58 h)	87.2° 14:05	11.34	2%	81.7°
2043-01-10 Sat	39	—	unknown	18:50–20:20 (good, 1.5 h)	87.2° 14:00	11.33	0%	75.6°
2043-01-11 Sun	38	—	unknown	18:50–20:20 (good, 1.5 h)	87.2° 14:00	11.31	1%	70.1°
2043-01-12 Mon	35	—	unknown	18:55–20:15 (good, 1.33 h)	87.2° 13:55	11.29	3%	65.4°
2043-01-13 Tue	33	—	unknown	18:55–20:10 (good, 1.25 h)	87.2° 13:50	11.27	8%	62.0°
2043-01-14 Wed	29	—	unknown	18:55–20:00 (good, 1.08 h)	87.2° 13:45	11.25	15%	60.1°
2043-01-15 Thu	24	—	unknown	18:55–19:50 (good, 0.92 h)	87.2° 13:40	11.23	24%	60.2°
2043-01-16 Fri	21	—	unknown	18:55–19:40 (good, 0.75 h)	87.2° 13:40	11.21	34%	62.1°
2043-01-17 Sat	17	—	unknown	19:00–19:25 (good, 0.42 h)	87.2° 13:35	11.18	45%	65.8°
2043-01-18 Sun	14	—	unknown	19:00–20:25 (marginal, 1.42 h)	87.2° 13:30	11.16	56%	70.9°
2043-01-19 Mon	13	—	unknown	19:00–20:15 (marginal, 1.25 h)	87.2° 13:25	11.14	67%	77.1°
2043-01-20 Tue	12	—	unknown	19:00–20:10 (marginal, 1.17 h)	87.2° 13:20	11.11	78%	83.9°
2043-01-21 Wed	12	—	unknown	19:00–20:10 (marginal, 1.17 h)	87.2° 13:20	11.09	86%	90.9°
2043-01-22 Thu	12	—	unknown	19:05–20:05 (marginal, 1.0 h)	87.2° 13:15	11.06	93%	97.9°
2043-01-23 Fri	12	—	unknown	18:30–20:05 (marginal, 1.58 h)	87.2° 13:10	11.03	98%	104.5°
2043-01-24 Sat	12	—	unknown	18:30–20:00 (marginal, 1.5 h)	87.2° 13:05	11.0	100%	110.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-12-26&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.