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: 01-23 (18), 01-24 (16), 02-21 (16), 01-25 (15), 02-19 (15) — by astronomy; check the weather when the night is within four days.

2041-01-23astronomy score per night — click a bar for that night2041-02-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-01-23 Wed	18	—	unknown	19:05–19:30 (good, 0.42 h)	87.2° 13:10	11.02	65%	112.5°
2041-01-24 Thu	16	—	unknown	19:05–19:25 (good, 0.33 h)	87.2° 13:05	10.99	55%	108.5°
2041-01-25 Fri	15	—	unknown	19:05–19:20 (good, 0.25 h)	87.2° 13:00	10.96	45%	103.5°
2041-01-26 Sat	13	—	unknown	19:10–19:15 (good, 0.08 h)	87.2° 12:55	10.93	34%	97.8°
2041-01-27 Sun	12	—	unknown	19:10–19:15 (good, 0.08 h)	87.2° 12:55	10.9	24%	91.5°
2041-01-28 Mon	12	—	unknown	18:35–19:45 (marginal, 1.17 h)	87.2° 12:50	10.87	15%	84.9°
2041-01-29 Tue	11	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.84	8%	78.4°
2041-01-30 Wed	10	—	unknown	19:10–19:35 (marginal, 0.42 h)	87.2° 12:40	10.81	3%	72.4°
2041-01-31 Thu	9	—	unknown	19:15–19:30 (marginal, 0.25 h)	87.2° 12:35	10.78	0%	67.3°
2041-02-01 Fri	9	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.2° 12:35	10.75	1%	63.8°
2041-02-02 Sat	9	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.2° 12:30	10.71	5%	62.3°
2041-02-03 Sun	9	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.2° 12:25	10.68	11%	62.8°
2041-02-04 Mon	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.64	19%	65.1°
2041-02-05 Tue	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.61	29%	69.0°
2041-02-06 Wed	9	—	unknown	05:20–06:25 (marginal, 1.08 h)	87.2° 12:15	10.57	39%	73.8°
2041-02-07 Thu	10	—	unknown	05:50–05:55 (good, 0.08 h)	87.2° 12:10	10.54	50%	79.3°
2041-02-08 Fri	10	—	unknown	05:45–05:50 (good, 0.08 h)	87.2° 12:05	10.5	60%	85.0°
2041-02-09 Sat	11	—	unknown	05:45–05:50 (good, 0.08 h)	87.2° 12:00	10.46	69%	90.8°
2041-02-10 Sun	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.2° 11:55	10.43	78%	96.4°
2041-02-11 Mon	12	—	unknown	05:35–05:50 (good, 0.25 h)	87.2° 11:50	10.39	85%	101.8°
2041-02-12 Tue	11	—	unknown	05:45–05:50 (good, 0.08 h)	87.2° 11:45	10.35	91%	106.6°
2041-02-13 Wed	11	—	unknown	05:40–05:45 (good, 0.08 h)	87.2° 11:40	10.31	96%	110.8°
2041-02-14 Thu	11	—	unknown	05:40–05:45 (good, 0.08 h)	87.2° 11:40	10.27	99%	114.2°
2041-02-15 Fri	12	—	unknown	05:35–05:45 (good, 0.17 h)	87.2° 11:35	10.23	100%	116.6°
2041-02-16 Sat	13	—	unknown	05:30–05:45 (good, 0.25 h)	87.2° 11:30	10.19	99%	117.8°
2041-02-17 Sun	13	—	unknown	05:25–05:40 (good, 0.25 h)	87.2° 11:25	10.15	97%	117.7°
2041-02-18 Mon	14	—	unknown	05:25–05:40 (good, 0.25 h)	87.2° 11:20	10.11	93%	116.2°
2041-02-19 Tue	15	—	unknown	05:20–05:40 (good, 0.33 h)	87.2° 11:20	10.07	87%	113.6°
2041-02-20 Wed	15	—	unknown	05:15–05:40 (good, 0.42 h)	87.2° 11:15	10.03	80%	109.8°
2041-02-21 Thu	16	—	unknown	05:15–05:35 (good, 0.33 h)	87.2° 11:10	9.98	71%	105.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-01-23&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.