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 V1057 Cyg: 05-09 (77), 04-22 (72), 04-23 (72), 04-24 (72), 04-27 (72) — by astronomy; check the weather when the night is within four days.

2045-04-10astronomy score per night — click a bar for that night2045-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-04-10 Mon	53	—	unknown	02:45–05:10 (good, 2.42 h)	87.2° 09:00	7.56	35%	64.2°
2045-04-11 Tue	57	—	unknown	02:45–05:10 (good, 2.42 h)	87.2° 09:00	7.5	26%	60.2°
2045-04-12 Wed	61	—	unknown	02:40–05:05 (good, 2.42 h)	87.3° 08:55	7.44	18%	57.5°
2045-04-13 Thu	63	—	unknown	02:35–05:05 (good, 2.5 h)	87.3° 08:50	7.39	12%	56.3°
2045-04-14 Fri	65	—	unknown	02:30–05:05 (good, 2.58 h)	87.2° 08:45	7.33	6%	56.9°
2045-04-15 Sat	65	—	unknown	02:25–05:00 (good, 2.58 h)	87.2° 08:40	7.27	2%	59.2°
2045-04-16 Sun	66	—	unknown	02:25–05:00 (good, 2.58 h)	87.2° 08:40	7.21	0%	63.2°
2045-04-17 Mon	66	—	unknown	02:20–04:55 (good, 2.58 h)	87.3° 08:35	7.15	1%	68.7°
2045-04-18 Tue	68	—	unknown	02:15–04:55 (good, 2.67 h)	87.3° 08:30	7.1	3%	75.1°
2045-04-19 Wed	69	—	unknown	02:10–04:55 (good, 2.75 h)	87.2° 08:25	7.04	8%	82.4°
2045-04-20 Thu	69	—	unknown	02:10–04:50 (good, 2.67 h)	87.2° 08:25	6.98	15%	90.0°
2045-04-21 Fri	71	—	unknown	02:05–04:50 (good, 2.75 h)	87.2° 08:20	6.92	24%	97.7°
2045-04-22 Sat	72	—	unknown	02:05–04:50 (good, 2.75 h)	87.3° 08:15	6.86	35%	105.2°
2045-04-23 Sun	72	—	unknown	02:00–04:45 (good, 2.75 h)	87.3° 08:10	6.81	46%	111.9°
2045-04-24 Mon	72	—	unknown	02:00–04:45 (good, 2.75 h)	87.2° 08:05	6.75	57%	117.6°
2045-04-25 Tue	71	—	unknown	01:55–04:40 (good, 2.75 h)	87.2° 08:05	6.69	68%	121.6°
2045-04-26 Wed	71	—	unknown	01:55–04:40 (good, 2.75 h)	87.3° 08:00	6.63	78%	123.6°
2045-04-27 Thu	72	—	unknown	01:50–04:40 (good, 2.83 h)	87.3° 07:55	6.57	87%	123.3°
2045-04-28 Fri	65	—	unknown	01:50–04:35 (good, 2.75 h)	87.2° 07:50	6.51	94%	120.8°
2045-04-29 Sat	63	—	unknown	01:50–04:35 (good, 2.75 h)	87.2° 07:45	6.46	98%	116.5°
2045-04-30 Sun	58	—	unknown	01:50–04:30 (good, 2.67 h)	87.2° 07:45	6.4	100%	110.8°
2045-05-01 Mon	55	—	unknown	01:50–04:30 (good, 2.67 h)	87.3° 07:40	6.34	99%	104.3°
2045-05-02 Tue	52	—	unknown	01:45–04:30 (good, 2.75 h)	87.3° 07:35	6.28	97%	97.4°
2045-05-03 Wed	50	—	unknown	01:45–04:25 (good, 2.67 h)	87.2° 07:30	6.22	92%	90.4°
2045-05-04 Thu	49	—	unknown	01:40–04:25 (good, 2.75 h)	87.2° 07:30	6.17	86%	83.5°
2045-05-05 Fri	52	—	unknown	01:35–04:25 (good, 2.83 h)	87.2° 07:25	6.11	78%	76.9°
2045-05-06 Sat	59	—	unknown	01:05–04:20 (good, 3.25 h)	87.3° 07:20	6.05	70%	70.9°
2045-05-07 Sun	65	—	unknown	01:00–04:20 (good, 3.33 h)	87.3° 07:15	6.0	61%	65.6°
2045-05-08 Mon	72	—	unknown	00:55–04:20 (good, 3.42 h)	87.2° 07:10	5.94	52%	61.2°
2045-05-09 Tue	77	—	unknown	00:55–04:15 (good, 3.33 h)	87.2° 07:10	5.88	42%	58.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-04-10&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.