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: 02-17 (63), 02-16 (61), 02-15 (54), 02-14 (49), 02-13 (42) — by astronomy; check the weather when the night is within four days.

2042-01-19astronomy score per night — click a bar for that night2042-02-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2042-02-04 Tue	33	—	unknown	04:25–05:55 (good, 1.5 h)	87.1° 09:55	10.65	100%	109.7°
2042-02-05 Wed	32	—	unknown	04:25–05:55 (good, 1.5 h)	87.1° 09:55	10.62	99%	106.5°
2042-02-06 Thu	30	—	unknown	04:25–05:55 (good, 1.5 h)	87.1° 09:50	10.58	97%	102.8°
2042-02-07 Fri	30	—	unknown	04:25–05:55 (good, 1.5 h)	87.1° 09:45	10.55	93%	98.5°
2042-02-08 Sat	30	—	unknown	04:25–05:55 (good, 1.5 h)	87.1° 09:40	10.51	87%	94.0°
2042-02-09 Sun	30	—	unknown	04:15–05:50 (good, 1.58 h)	87.1° 09:35	10.47	80%	89.3°
2042-02-10 Mon	32	—	unknown	04:05–05:50 (good, 1.75 h)	87.1° 09:35	10.44	72%	84.6°
2042-02-11 Tue	35	—	unknown	04:00–05:50 (good, 1.83 h)	87.1° 09:30	10.4	63%	80.1°
2042-02-12 Wed	39	—	unknown	03:50–05:50 (good, 2.0 h)	87.1° 09:25	10.36	54%	75.9°
2042-02-13 Thu	42	—	unknown	03:40–05:45 (good, 2.08 h)	87.1° 09:20	10.32	44%	72.3°
2042-02-14 Fri	49	—	unknown	03:25–05:45 (good, 2.33 h)	87.1° 09:20	10.28	34%	69.3°
2042-02-15 Sat	54	—	unknown	03:20–05:45 (good, 2.42 h)	87.1° 09:15	10.24	24%	67.4°
2042-02-16 Sun	61	—	unknown	03:15–05:45 (good, 2.5 h)	87.1° 09:10	10.2	15%	66.6°
2042-02-17 Mon	63	—	unknown	03:10–05:40 (good, 2.5 h)	87.1° 09:05	10.16	8%	67.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-01-19&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.