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 Triangulum Pinwheel: 08-16 (100), 08-17 (100), 08-18 (100), 08-19 (100), 08-20 (100) — by astronomy; check the weather when the night is within four days.

2039-07-23astronomy score per night — click a bar for that night2039-08-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-07-23 Sat	75	—	unknown	01:25–04:10 (good, 2.75 h)	79.2° 06:50	5.36	7%	114.4°
2039-07-24 Sun	79	—	unknown	01:20–04:15 (good, 2.92 h)	79.2° 06:45	5.41	13%	125.9°
2039-07-25 Mon	82	—	unknown	01:15–04:15 (good, 3.0 h)	79.2° 06:40	5.47	21%	137.0°
2039-07-26 Tue	84	—	unknown	01:10–04:15 (good, 3.08 h)	79.2° 06:40	5.52	30%	147.2°
2039-07-27 Wed	85	—	unknown	01:05–04:15 (good, 3.17 h)	79.2° 06:35	5.57	41%	154.8°
2039-07-28 Thu	89	—	unknown	01:05–04:20 (good, 3.25 h)	79.2° 06:30	5.62	52%	156.6°
2039-07-29 Fri	91	—	unknown	01:05–04:20 (good, 3.25 h)	79.2° 06:25	5.68	64%	151.2°
2039-07-30 Sat	92	—	unknown	01:00–04:20 (good, 3.33 h)	79.2° 06:25	5.73	74%	141.2°
2039-07-31 Sun	93	—	unknown	01:00–04:25 (good, 3.42 h)	79.2° 06:20	5.78	84%	129.2°
2039-08-01 Mon	91	—	unknown	01:00–04:25 (good, 3.42 h)	79.2° 06:15	5.84	92%	116.3°
2039-08-02 Tue	73	—	unknown	01:05–04:25 (good, 3.33 h)	79.2° 06:10	5.89	97%	102.9°
2039-08-03 Wed	60	—	unknown	01:25–04:30 (good, 3.08 h)	79.2° 06:05	5.95	100%	89.5°
2039-08-04 Thu	48	—	unknown	02:40–04:30 (good, 1.83 h)	79.2° 06:05	6.01	100%	76.3°
2039-08-05 Fri	37	—	unknown	00:15–04:30 (marginal, 4.25 h)	79.2° 06:00	6.06	97%	63.5°
2039-08-06 Sat	31	—	unknown	00:15–04:35 (marginal, 4.33 h)	79.2° 05:55	6.12	92%	51.4°
2039-08-07 Sun	28	—	unknown	00:10–04:35 (marginal, 4.42 h)	79.2° 05:50	6.18	85%	40.3°
2039-08-08 Mon	29	—	unknown	00:00–04:35 (marginal, 4.58 h)	79.2° 05:45	6.23	77%	30.9°
2039-08-09 Tue	38	—	unknown	23:50–04:40 (marginal, 4.83 h)	79.2° 05:45	6.29	68%	24.5°
2039-08-10 Wed	49	—	unknown	01:25–04:10 (good, 2.75 h)	79.2° 05:40	6.35	58%	23.3°
2039-08-11 Thu	63	—	unknown	00:30–04:40 (good, 4.17 h)	79.2° 05:35	6.4	49%	27.7°
2039-08-12 Fri	82	—	unknown	00:05–04:45 (good, 4.67 h)	79.2° 05:30	6.46	40%	35.4°
2039-08-13 Sat	87	—	unknown	00:00–04:45 (good, 4.75 h)	79.2° 05:30	6.52	30%	44.7°
2039-08-14 Sun	92	—	unknown	23:55–04:45 (good, 4.83 h)	79.2° 05:25	6.58	22%	54.9°
2039-08-15 Mon	99	—	unknown	23:50–04:45 (good, 4.92 h)	79.2° 05:20	6.63	15%	65.6°
2039-08-16 Tue	100	—	unknown	23:50–04:50 (good, 5.0 h)	79.2° 05:15	6.69	9%	76.6°
2039-08-17 Wed	100	—	unknown	23:45–04:50 (good, 5.08 h)	79.2° 05:10	6.75	4%	87.9°
2039-08-18 Thu	100	—	unknown	23:40–04:50 (good, 5.17 h)	79.2° 05:10	6.81	1%	99.4°
2039-08-19 Fri	100	—	unknown	23:35–04:55 (good, 5.33 h)	79.2° 05:05	6.86	0%	111.1°
2039-08-20 Sat	100	—	unknown	23:35–04:55 (good, 5.33 h)	79.2° 05:00	6.92	1%	122.9°
2039-08-21 Sun	100	—	unknown	23:30–04:55 (good, 5.42 h)	79.2° 04:55	6.98	5%	134.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-07-23&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.