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: 02-27 (76), 02-26 (74), 02-25 (72), 02-23 (71), 02-24 (71) — by astronomy; check the weather when the night is within four days.

2031-01-29astronomy score per night — click a bar for that night2031-02-27

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-01-29 Wed	40	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:20	10.86	46%	97.2°
2031-01-30 Thu	41	—	unknown	04:25–06:00 (good, 1.58 h)	87.1° 10:20	10.83	56%	103.3°
2031-01-31 Fri	42	—	unknown	04:20–06:00 (good, 1.67 h)	87.1° 10:15	10.8	65%	108.9°
2031-02-01 Sat	43	—	unknown	04:15–06:00 (good, 1.75 h)	87.1° 10:10	10.76	74%	113.7°
2031-02-02 Sun	44	—	unknown	04:20–06:00 (good, 1.67 h)	87.1° 10:05	10.73	82%	117.6°
2031-02-03 Mon	45	—	unknown	04:15–06:00 (good, 1.75 h)	87.1° 10:00	10.7	88%	120.3°
2031-02-04 Tue	44	—	unknown	04:15–05:55 (good, 1.67 h)	87.1° 10:00	10.66	94%	121.7°
2031-02-05 Wed	40	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:55	10.63	97%	121.5°
2031-02-06 Thu	40	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:50	10.59	100%	119.7°
2031-02-07 Fri	39	—	unknown	04:10–05:55 (good, 1.75 h)	87.1° 09:45	10.56	100%	116.5°
2031-02-08 Sat	38	—	unknown	04:05–05:55 (good, 1.83 h)	87.1° 09:40	10.52	98%	112.0°
2031-02-09 Sun	36	—	unknown	04:05–05:50 (good, 1.75 h)	87.1° 09:40	10.48	94%	106.5°
2031-02-10 Mon	34	—	unknown	04:05–05:50 (good, 1.75 h)	87.1° 09:35	10.45	88%	100.2°
2031-02-11 Tue	34	—	unknown	04:05–05:50 (good, 1.75 h)	87.1° 09:30	10.41	81%	93.4°
2031-02-12 Wed	35	—	unknown	04:00–05:50 (good, 1.83 h)	87.1° 09:25	10.37	72%	86.3°
2031-02-13 Thu	37	—	unknown	03:50–05:45 (good, 1.92 h)	87.1° 09:25	10.33	61%	79.3°
2031-02-14 Fri	40	—	unknown	03:40–05:45 (good, 2.08 h)	87.1° 09:20	10.29	50%	72.7°
2031-02-15 Sat	45	—	unknown	03:35–05:45 (good, 2.17 h)	87.1° 09:15	10.25	39%	66.8°
2031-02-16 Sun	52	—	unknown	03:15–05:45 (good, 2.5 h)	87.1° 09:10	10.21	28%	62.0°
2031-02-17 Mon	57	—	unknown	03:15–05:40 (good, 2.42 h)	87.1° 09:05	10.17	18%	59.0°
2031-02-18 Tue	63	—	unknown	03:10–05:40 (good, 2.5 h)	87.1° 09:05	10.13	10%	58.2°
2031-02-19 Wed	65	—	unknown	03:05–05:40 (good, 2.58 h)	87.1° 09:00	10.09	4%	59.6°
2031-02-20 Thu	67	—	unknown	03:00–05:40 (good, 2.67 h)	87.1° 08:55	10.05	1%	63.1°
2031-02-21 Fri	67	—	unknown	02:55–05:35 (good, 2.67 h)	87.1° 08:50	10.01	0%	68.3°
2031-02-22 Sat	69	—	unknown	02:55–05:35 (good, 2.67 h)	87.1° 08:45	9.96	2%	74.5°
2031-02-23 Sun	71	—	unknown	02:50–05:35 (good, 2.75 h)	87.1° 08:45	9.92	7%	81.2°
2031-02-24 Mon	71	—	unknown	02:45–05:35 (good, 2.83 h)	87.1° 08:40	9.88	13%	88.2°
2031-02-25 Tue	72	—	unknown	02:40–05:30 (good, 2.83 h)	87.1° 08:35	9.83	20%	95.0°
2031-02-26 Wed	74	—	unknown	02:35–05:30 (good, 2.92 h)	87.1° 08:30	9.79	29%	101.5°
2031-02-27 Thu	76	—	unknown	02:35–05:30 (good, 2.92 h)	87.1° 08:25	9.75	38%	107.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-01-29&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.