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: 02-22 (22), 02-20 (21), 02-23 (21), 02-21 (20), 02-27 (20) — by astronomy; check the weather when the night is within four days.

2040-01-30astronomy score per night — click a bar for that night2040-02-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-01-30 Mon	9	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.83	97%	117.0°
2040-01-31 Tue	9	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.2° 12:40	10.8	93%	117.4°
2040-02-01 Wed	8	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.2° 12:35	10.77	88%	116.5°
2040-02-02 Thu	7	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.2° 12:30	10.74	80%	114.1°
2040-02-03 Fri	7	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.2° 12:30	10.7	71%	110.5°
2040-02-04 Sat	7	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.2° 12:25	10.67	61%	105.8°
2040-02-05 Sun	7	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.64	50%	100.2°
2040-02-06 Mon	8	—	unknown	05:20–05:55 (marginal, 0.58 h)	87.2° 12:15	10.6	39%	94.0°
2040-02-07 Tue	9	—	unknown	05:20–05:55 (marginal, 0.58 h)	87.2° 12:15	10.56	28%	87.5°
2040-02-08 Wed	10	—	unknown	05:15–06:25 (marginal, 1.17 h)	87.2° 12:10	10.53	18%	80.9°
2040-02-09 Thu	11	—	unknown	05:45–05:50 (good, 0.08 h)	87.2° 12:05	10.49	10%	74.8°
2040-02-10 Fri	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.2° 12:00	10.45	4%	69.4°
2040-02-11 Sat	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.2° 11:55	10.42	1%	65.4°
2040-02-12 Sun	13	—	unknown	05:35–05:50 (good, 0.25 h)	87.2° 11:50	10.38	0%	63.1°
2040-02-13 Mon	14	—	unknown	05:30–05:50 (good, 0.33 h)	87.2° 11:45	10.34	3%	62.6°
2040-02-14 Tue	14	—	unknown	05:25–05:45 (good, 0.33 h)	87.2° 11:40	10.3	7%	63.9°
2040-02-15 Wed	15	—	unknown	05:20–05:45 (good, 0.42 h)	87.2° 11:35	10.26	14%	66.8°
2040-02-16 Thu	16	—	unknown	05:20–05:45 (good, 0.42 h)	87.2° 11:35	10.22	22%	70.8°
2040-02-17 Fri	18	—	unknown	05:15–05:45 (good, 0.5 h)	87.2° 11:30	10.18	31%	75.5°
2040-02-18 Sat	18	—	unknown	05:10–05:40 (good, 0.5 h)	87.2° 11:25	10.14	41%	80.8°
2040-02-19 Sun	19	—	unknown	05:05–05:40 (good, 0.58 h)	87.2° 11:20	10.1	50%	86.2°
2040-02-20 Mon	21	—	unknown	05:00–05:40 (good, 0.67 h)	87.2° 11:20	10.06	60%	91.7°
2040-02-21 Tue	20	—	unknown	05:00–05:35 (good, 0.58 h)	87.2° 11:15	10.02	69%	97.1°
2040-02-22 Wed	22	—	unknown	04:55–05:35 (good, 0.67 h)	87.2° 11:10	9.97	77%	102.3°
2040-02-23 Thu	21	—	unknown	05:05–05:35 (good, 0.5 h)	87.2° 11:05	9.93	84%	107.0°
2040-02-24 Fri	19	—	unknown	05:00–05:35 (good, 0.58 h)	87.2° 11:00	9.89	91%	111.1°
2040-02-25 Sat	18	—	unknown	04:55–05:30 (good, 0.58 h)	87.2° 11:00	9.84	96%	114.4°
2040-02-26 Sun	19	—	unknown	04:55–05:30 (good, 0.58 h)	87.2° 10:55	9.8	99%	116.6°
2040-02-27 Mon	20	—	unknown	04:50–05:30 (good, 0.67 h)	87.2° 10:50	9.75	100%	117.5°
2040-02-28 Tue	20	—	unknown	04:45–05:25 (good, 0.67 h)	87.2° 10:45	9.71	99%	117.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-01-30&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.