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: 03-18 (95), 03-17 (94), 03-16 (88), 03-15 (78), 02-27 (75) — by astronomy; check the weather when the night is within four days.

2042-02-17astronomy score per night — click a bar for that night2042-03-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-02-17 Mon	63	—	unknown	03:10–05:40 (good, 2.5 h)	87.1° 09:05	10.16	8%	67.4°
2042-02-18 Tue	65	—	unknown	03:10–05:40 (good, 2.5 h)	87.1° 09:00	10.12	3%	69.6°
2042-02-19 Wed	66	—	unknown	03:05–05:40 (good, 2.58 h)	87.1° 09:00	10.08	0%	73.2°
2042-02-20 Thu	67	—	unknown	03:00–05:40 (good, 2.67 h)	87.1° 08:55	10.04	1%	78.0°
2042-02-21 Fri	67	—	unknown	02:55–05:35 (good, 2.67 h)	87.1° 08:50	9.99	4%	83.6°
2042-02-22 Sat	69	—	unknown	02:50–05:35 (good, 2.75 h)	87.1° 08:45	9.95	10%	89.4°
2042-02-23 Sun	71	—	unknown	02:50–05:35 (good, 2.75 h)	87.1° 08:40	9.91	18%	95.2°
2042-02-24 Mon	71	—	unknown	02:45–05:30 (good, 2.75 h)	87.1° 08:40	9.86	28%	100.6°
2042-02-25 Tue	72	—	unknown	02:40–05:30 (good, 2.83 h)	87.1° 08:35	9.82	39%	105.3°
2042-02-26 Wed	74	—	unknown	02:35–05:30 (good, 2.92 h)	87.1° 08:30	9.78	50%	109.0°
2042-02-27 Thu	75	—	unknown	02:40–05:30 (good, 2.83 h)	87.1° 08:25	9.73	60%	111.6°
2042-02-28 Fri	73	—	unknown	02:35–05:25 (good, 2.83 h)	87.1° 08:25	9.69	70%	113.0°
2042-03-01 Sat	71	—	unknown	02:35–05:25 (good, 2.83 h)	87.1° 08:20	9.64	79%	113.2°
2042-03-02 Sun	64	—	unknown	02:35–05:25 (good, 2.83 h)	87.1° 08:15	9.6	86%	112.3°
2042-03-03 Mon	60	—	unknown	02:35–05:20 (good, 2.75 h)	87.1° 08:10	9.55	92%	110.3°
2042-03-04 Tue	57	—	unknown	02:35–05:20 (good, 2.75 h)	87.1° 08:05	9.5	97%	107.4°
2042-03-05 Wed	54	—	unknown	02:35–05:20 (good, 2.75 h)	87.1° 08:05	9.46	99%	103.8°
2042-03-06 Thu	50	—	unknown	02:45–05:15 (good, 2.5 h)	87.1° 08:00	9.41	100%	99.7°
2042-03-07 Fri	47	—	unknown	03:00–05:15 (good, 2.25 h)	87.1° 07:55	9.36	99%	95.3°
2042-03-08 Sat	46	—	unknown	03:10–05:15 (good, 2.08 h)	87.1° 07:50	9.31	96%	90.7°
2042-03-09 Sun	45	—	unknown	03:10–05:10 (good, 2.0 h)	87.1° 07:45	9.27	92%	86.0°
2042-03-10 Mon	46	—	unknown	02:55–05:10 (good, 2.25 h)	87.1° 07:45	9.22	86%	81.5°
2042-03-11 Tue	49	—	unknown	02:20–05:10 (good, 2.83 h)	87.1° 07:40	9.17	78%	77.3°
2042-03-12 Wed	52	—	unknown	02:05–05:05 (good, 3.0 h)	87.1° 07:35	9.12	70%	73.5°
2042-03-13 Thu	59	—	unknown	01:55–05:05 (good, 3.17 h)	87.1° 07:30	9.07	60%	70.4°
2042-03-14 Fri	68	—	unknown	01:35–05:05 (good, 3.5 h)	87.1° 07:30	9.02	50%	68.1°
2042-03-15 Sat	78	—	unknown	01:30–05:00 (good, 3.5 h)	87.1° 07:25	8.97	40%	66.9°
2042-03-16 Sun	88	—	unknown	01:25–05:00 (good, 3.58 h)	87.1° 07:20	8.92	30%	67.0°
2042-03-17 Mon	94	—	unknown	01:20–04:55 (good, 3.58 h)	87.1° 07:15	8.87	20%	68.6°
2042-03-18 Tue	95	—	unknown	01:20–04:55 (good, 3.58 h)	87.1° 07:10	8.82	11%	71.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-02-17&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.