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: 05-14 (93), 05-13 (92), 05-10 (91), 05-11 (91), 05-12 (91) — by astronomy; check the weather when the night is within four days.

2027-04-23astronomy score per night — click a bar for that night2027-05-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-04-23 Fri	45	—	unknown	02:25–04:45 (good, 2.33 h)	87.3° 08:15	6.84	90%	94.0°
2027-04-24 Sat	45	—	unknown	02:20–04:45 (good, 2.42 h)	87.3° 08:10	6.78	84%	87.0°
2027-04-25 Sun	46	—	unknown	02:15–04:45 (good, 2.5 h)	87.3° 08:05	6.73	76%	80.2°
2027-04-26 Mon	49	—	unknown	02:05–04:40 (good, 2.58 h)	87.3° 08:00	6.67	68%	73.8°
2027-04-27 Tue	57	—	unknown	01:40–04:40 (good, 3.0 h)	87.3° 07:55	6.61	59%	67.9°
2027-04-28 Wed	61	—	unknown	01:40–04:35 (good, 2.92 h)	87.3° 07:55	6.55	49%	62.9°
2027-04-29 Thu	67	—	unknown	01:35–04:35 (good, 3.0 h)	87.3° 07:50	6.49	40%	58.9°
2027-04-30 Fri	72	—	unknown	01:30–04:35 (good, 3.08 h)	87.3° 07:45	6.43	31%	56.2°
2027-05-01 Sat	77	—	unknown	01:25–04:30 (good, 3.08 h)	87.3° 07:40	6.38	22%	55.2°
2027-05-02 Sun	81	—	unknown	01:25–04:30 (good, 3.08 h)	87.3° 07:35	6.32	14%	56.1°
2027-05-03 Mon	83	—	unknown	01:20–04:30 (good, 3.17 h)	87.3° 07:35	6.26	8%	58.9°
2027-05-04 Tue	83	—	unknown	01:15–04:25 (good, 3.17 h)	87.3° 07:30	6.2	3%	63.5°
2027-05-05 Wed	85	—	unknown	01:10–04:25 (good, 3.25 h)	87.3° 07:25	6.15	0%	69.5°
2027-05-06 Thu	87	—	unknown	01:05–04:25 (good, 3.33 h)	87.3° 07:20	6.09	0%	76.7°
2027-05-07 Fri	87	—	unknown	01:05–04:20 (good, 3.25 h)	87.3° 07:20	6.03	3%	84.6°
2027-05-08 Sat	88	—	unknown	01:00–04:20 (good, 3.33 h)	87.3° 07:15	5.98	8%	92.8°
2027-05-09 Sun	89	—	unknown	00:55–04:15 (good, 3.33 h)	87.3° 07:10	5.92	16%	100.9°
2027-05-10 Mon	91	—	unknown	00:55–04:15 (good, 3.33 h)	87.3° 07:05	5.86	25%	108.6°
2027-05-11 Tue	91	—	unknown	00:50–04:15 (good, 3.42 h)	87.3° 07:00	5.81	36%	115.2°
2027-05-12 Wed	91	—	unknown	00:50–04:10 (good, 3.33 h)	87.3° 07:00	5.75	47%	120.4°
2027-05-13 Thu	92	—	unknown	00:45–04:10 (good, 3.42 h)	87.3° 06:55	5.7	58%	123.8°
2027-05-14 Fri	93	—	unknown	00:45–04:10 (good, 3.42 h)	87.3° 06:50	5.64	69%	124.9°
2027-05-15 Sat	91	—	unknown	00:40–04:05 (good, 3.42 h)	87.3° 06:45	5.59	79%	123.7°
2027-05-16 Sun	90	—	unknown	00:40–04:05 (good, 3.42 h)	87.3° 06:40	5.54	87%	120.5°
2027-05-17 Mon	81	—	unknown	00:40–04:05 (good, 3.42 h)	87.3° 06:40	5.48	93%	115.8°
2027-05-18 Tue	76	—	unknown	00:40–04:05 (good, 3.42 h)	87.3° 06:35	5.43	97%	109.8°
2027-05-19 Wed	69	—	unknown	00:40–04:00 (good, 3.33 h)	87.3° 06:30	5.38	100%	103.2°
2027-05-20 Thu	64	—	unknown	00:40–04:00 (good, 3.33 h)	87.3° 06:25	5.33	100%	96.2°
2027-05-21 Fri	60	—	unknown	00:40–04:00 (good, 3.33 h)	87.3° 06:25	5.28	98%	89.2°
2027-05-22 Sat	56	—	unknown	00:35–03:55 (good, 3.33 h)	87.3° 06:20	5.23	94%	82.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-04-23&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.