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: 01-13 (33), 01-14 (32), 01-15 (30), 01-16 (28), 01-17 (27) — by astronomy; check the weather when the night is within four days.

2045-01-13astronomy score per night — click a bar for that night2045-02-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-01-13 Fri	33	—	unknown	18:55–20:10 (good, 1.25 h)	87.2° 13:50	11.26	16%	95.2°
2045-01-14 Sat	32	—	unknown	18:55–20:05 (good, 1.17 h)	87.2° 13:45	11.24	9%	88.6°
2045-01-15 Sun	30	—	unknown	18:55–20:00 (good, 1.08 h)	87.2° 13:40	11.22	5%	82.1°
2045-01-16 Mon	28	—	unknown	19:00–19:55 (good, 0.92 h)	87.2° 13:35	11.19	2%	75.8°
2045-01-17 Tue	27	—	unknown	19:00–19:55 (good, 0.92 h)	87.2° 13:30	11.17	0%	70.1°
2045-01-18 Wed	26	—	unknown	19:00–19:50 (good, 0.83 h)	87.2° 13:30	11.15	0%	65.0°
2045-01-19 Thu	25	—	unknown	19:00–19:45 (good, 0.75 h)	87.2° 13:25	11.12	3%	60.9°
2045-01-20 Fri	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.2° 13:20	11.1	7%	58.0°
2045-01-21 Sat	19	—	unknown	19:05–19:30 (good, 0.42 h)	87.2° 13:15	11.07	12%	56.6°
2045-01-22 Sun	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.2° 13:15	11.05	19%	56.8°
2045-01-23 Mon	14	—	unknown	19:05–19:15 (good, 0.17 h)	87.2° 13:10	11.02	27%	58.8°
2045-01-24 Tue	12	—	unknown	19:05–20:00 (marginal, 0.92 h)	87.2° 13:05	10.99	37%	62.3°
2045-01-25 Wed	10	—	unknown	19:05–19:55 (marginal, 0.83 h)	87.2° 13:00	10.96	47%	67.3°
2045-01-26 Thu	7	—	unknown	19:10–19:50 (marginal, 0.67 h)	87.2° 12:55	10.93	58%	73.5°
2045-01-27 Fri	7	—	unknown	19:10–19:45 (marginal, 0.58 h)	87.2° 12:55	10.9	68%	80.6°
2045-01-28 Sat	7	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:50	10.87	78%	88.3°
2045-01-29 Sun	7	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.2° 12:45	10.84	87%	96.3°
2045-01-30 Mon	7	—	unknown	19:10–19:35 (marginal, 0.42 h)	87.2° 12:40	10.81	94%	104.3°
2045-01-31 Tue	6	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.2° 12:35	10.78	99%	111.6°
2045-02-01 Wed	7	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.2° 12:35	10.74	100%	117.6°
2045-02-02 Thu	7	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.2° 12:30	10.71	98%	121.7°
2045-02-03 Fri	7	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.2° 12:25	10.68	94%	123.5°
2045-02-04 Sat	8	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.64	87%	122.8°
2045-02-05 Sun	8	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.2° 12:20	10.61	78%	119.9°
2045-02-06 Mon	8	—	unknown	05:20–05:55 (marginal, 0.58 h)	87.2° 12:15	10.57	69%	115.4°
2045-02-07 Tue	9	—	unknown	05:15–05:55 (marginal, 0.67 h)	87.2° 12:10	10.54	59%	109.8°
2045-02-08 Wed	9	—	unknown	05:10–05:50 (marginal, 0.67 h)	87.2° 12:05	10.5	48%	103.6°
2045-02-09 Thu	9	—	unknown	05:10–06:25 (marginal, 1.25 h)	87.2° 12:00	10.46	39%	97.0°
2045-02-10 Fri	10	—	unknown	05:45–05:50 (good, 0.08 h)	87.2° 11:55	10.42	30%	90.3°
2045-02-11 Sat	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.2° 11:50	10.39	21%	83.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-01-13&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.