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: 05-20 (100), 05-21 (100), 05-22 (100), 05-23 (100), 05-24 (100) — by astronomy; check the weather when the night is within four days.

2028-05-01astronomy score per night — click a bar for that night2028-05-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-05-01 Mon	80	—	unknown	01:30–04:30 (good, 3.0 h)	87.3° 07:40	6.33	48%	119.0°
2028-05-02 Tue	81	—	unknown	01:25–04:30 (good, 3.08 h)	87.3° 07:35	6.28	59%	123.6°
2028-05-03 Wed	80	—	unknown	01:25–04:25 (good, 3.0 h)	87.3° 07:30	6.22	70%	125.9°
2028-05-04 Thu	80	—	unknown	01:20–04:25 (good, 3.08 h)	87.3° 07:25	6.16	80%	125.8°
2028-05-05 Fri	80	—	unknown	01:20–04:25 (good, 3.08 h)	87.3° 07:25	6.1	89%	123.0°
2028-05-06 Sat	71	—	unknown	01:20–04:20 (good, 3.0 h)	87.3° 07:20	6.05	95%	118.1°
2028-05-07 Sun	66	—	unknown	01:20–04:20 (good, 3.0 h)	87.3° 07:15	5.99	99%	111.6°
2028-05-08 Mon	61	—	unknown	01:20–04:20 (good, 3.0 h)	87.3° 07:10	5.93	100%	104.1°
2028-05-09 Tue	56	—	unknown	01:20–04:15 (good, 2.92 h)	87.3° 07:05	5.88	98%	96.2°
2028-05-10 Wed	53	—	unknown	01:20–04:15 (good, 2.92 h)	87.3° 07:05	5.82	95%	88.2°
2028-05-11 Thu	51	—	unknown	01:15–04:15 (good, 3.0 h)	87.3° 07:00	5.77	89%	80.6°
2028-05-12 Fri	52	—	unknown	01:10–04:10 (good, 3.0 h)	87.3° 06:55	5.71	82%	73.4°
2028-05-13 Sat	61	—	unknown	00:35–04:10 (good, 3.58 h)	87.3° 06:50	5.66	73%	67.0°
2028-05-14 Sun	67	—	unknown	00:35–04:10 (good, 3.58 h)	87.3° 06:45	5.6	64%	61.6°
2028-05-15 Mon	74	—	unknown	00:30–04:05 (good, 3.58 h)	87.3° 06:45	5.55	55%	57.4°
2028-05-16 Tue	81	—	unknown	00:25–04:05 (good, 3.67 h)	87.3° 06:40	5.5	46%	54.7°
2028-05-17 Wed	88	—	unknown	00:20–04:05 (good, 3.75 h)	87.3° 06:35	5.45	36%	53.7°
2028-05-18 Thu	93	—	unknown	00:15–04:00 (good, 3.75 h)	87.3° 06:30	5.39	27%	54.5°
2028-05-19 Fri	98	—	unknown	00:15–04:00 (good, 3.75 h)	87.3° 06:30	5.34	19%	57.0°
2028-05-20 Sat	100	—	unknown	00:10–04:00 (good, 3.83 h)	87.3° 06:25	5.29	12%	61.1°
2028-05-21 Sun	100	—	unknown	00:05–03:55 (good, 3.83 h)	87.3° 06:20	5.24	6%	66.6°
2028-05-22 Mon	100	—	unknown	00:00–03:55 (good, 3.92 h)	87.3° 06:15	5.2	2%	73.1°
2028-05-23 Tue	100	—	unknown	23:55–03:55 (good, 4.0 h)	87.3° 06:10	5.15	0%	80.4°
2028-05-24 Wed	100	—	unknown	23:55–03:55 (good, 4.0 h)	87.3° 06:10	5.1	0%	88.2°
2028-05-25 Thu	100	—	unknown	23:50–03:50 (good, 4.0 h)	87.3° 06:05	5.06	3%	96.2°
2028-05-26 Fri	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.3° 06:00	5.01	8%	104.1°
2028-05-27 Sat	100	—	unknown	23:45–03:50 (good, 4.08 h)	87.3° 05:55	4.97	15%	111.5°
2028-05-28 Sun	100	—	unknown	23:40–03:50 (good, 4.17 h)	87.3° 05:50	4.93	24%	118.0°
2028-05-29 Mon	100	—	unknown	23:35–03:50 (good, 4.25 h)	87.3° 05:50	4.89	34%	122.9°
2028-05-30 Tue	100	—	unknown	23:35–03:45 (good, 4.17 h)	87.3° 05:45	4.85	46%	125.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-05-01&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.