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 Vega: 01-30 (41), 01-31 (41), 01-29 (40), 01-28 (39), 01-27 (38) — by astronomy; check the weather when the night is within four days.

2042-01-05astronomy score per night — click a bar for that night2042-02-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-01-05 Sun	9	—	unknown	05:30–06:10 (marginal, 0.67 h)	87.1° 11:55	11.4	100%	113.5°
2042-01-06 Mon	10	—	unknown	05:25–06:10 (marginal, 0.75 h)	87.1° 11:50	11.39	100%	113.0°
2042-01-07 Tue	10	—	unknown	05:20–06:45 (marginal, 1.42 h)	87.1° 11:45	11.37	97%	111.4°
2042-01-08 Wed	11	—	unknown	05:15–06:45 (marginal, 1.5 h)	87.1° 11:45	11.36	93%	108.7°
2042-01-09 Thu	11	—	unknown	05:15–06:45 (marginal, 1.5 h)	87.1° 11:40	11.34	88%	105.3°
2042-01-10 Fri	12	—	unknown	06:05–06:10 (good, 0.08 h)	87.1° 11:35	11.32	81%	101.4°
2042-01-11 Sat	13	—	unknown	06:00–06:10 (good, 0.17 h)	87.1° 11:30	11.3	73%	97.0°
2042-01-12 Sun	14	—	unknown	05:55–06:10 (good, 0.25 h)	87.1° 11:25	11.28	64%	92.3°
2042-01-13 Mon	15	—	unknown	05:50–06:10 (good, 0.33 h)	87.1° 11:25	11.26	55%	87.6°
2042-01-14 Tue	17	—	unknown	05:40–06:10 (good, 0.5 h)	87.1° 11:20	11.24	46%	82.9°
2042-01-15 Wed	19	—	unknown	05:35–06:10 (good, 0.58 h)	87.1° 11:15	11.22	36%	78.4°
2042-01-16 Thu	21	—	unknown	05:25–06:10 (good, 0.75 h)	87.1° 11:10	11.2	27%	74.3°
2042-01-17 Fri	24	—	unknown	05:20–06:10 (good, 0.83 h)	87.1° 11:10	11.18	18%	70.8°
2042-01-18 Sat	26	—	unknown	05:10–06:10 (good, 1.0 h)	87.1° 11:05	11.15	11%	68.2°
2042-01-19 Sun	29	—	unknown	05:05–06:10 (good, 1.08 h)	87.1° 11:00	11.13	5%	66.7°
2042-01-20 Mon	30	—	unknown	05:00–06:10 (good, 1.17 h)	87.1° 10:55	11.1	1%	66.6°
2042-01-21 Tue	31	—	unknown	05:00–06:05 (good, 1.08 h)	87.1° 10:50	11.08	0%	68.1°
2042-01-22 Wed	32	—	unknown	04:55–06:05 (good, 1.17 h)	87.1° 10:50	11.05	2%	71.1°
2042-01-23 Thu	33	—	unknown	04:50–06:05 (good, 1.25 h)	87.1° 10:45	11.03	6%	75.2°
2042-01-24 Fri	34	—	unknown	04:45–06:05 (good, 1.33 h)	87.1° 10:40	11.0	13%	80.3°
2042-01-25 Sat	36	—	unknown	04:40–06:05 (good, 1.42 h)	87.1° 10:35	10.97	22%	85.9°
2042-01-26 Sun	37	—	unknown	04:40–06:05 (good, 1.42 h)	87.1° 10:30	10.94	32%	91.6°
2042-01-27 Mon	38	—	unknown	04:35–06:05 (good, 1.5 h)	87.1° 10:30	10.91	43%	97.2°
2042-01-28 Tue	39	—	unknown	04:30–06:05 (good, 1.58 h)	87.1° 10:25	10.88	55%	102.2°
2042-01-29 Wed	40	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:20	10.85	65%	106.5°
2042-01-30 Thu	41	—	unknown	04:20–06:00 (good, 1.67 h)	87.1° 10:15	10.82	75%	109.9°
2042-01-31 Fri	41	—	unknown	04:30–06:00 (good, 1.5 h)	87.1° 10:15	10.79	83%	112.2°
2042-02-01 Sat	36	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:10	10.75	90%	113.4°
2042-02-02 Sun	35	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:05	10.72	95%	113.3°
2042-02-03 Mon	34	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:00	10.69	98%	112.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-01-05&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.