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: 07-31 (93), 07-30 (92), 07-29 (91), 08-01 (91), 07-28 (89) — by astronomy; check the weather when the night is within four days.

2039-07-11astronomy score per night — click a bar for that night2039-08-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-07-11 Mon	20	—	unknown	01:45–03:55 (marginal, 2.17 h)	79.2° 07:35	4.83	62%	36.7°
2039-07-12 Tue	24	—	unknown	03:05–03:55 (good, 0.83 h)	79.2° 07:35	4.87	52%	28.4°
2039-07-13 Wed	30	—	unknown	02:25–03:55 (good, 1.5 h)	79.2° 07:30	4.91	42%	23.7°
2039-07-14 Thu	37	—	unknown	02:10–04:00 (good, 1.83 h)	79.2° 07:25	4.95	33%	24.4°
2039-07-15 Fri	45	—	unknown	01:55–04:00 (good, 2.08 h)	79.2° 07:20	4.99	24%	29.9°
2039-07-16 Sat	52	—	unknown	01:50–04:00 (good, 2.17 h)	79.2° 07:20	5.03	17%	38.2°
2039-07-17 Sun	57	—	unknown	01:45–04:00 (good, 2.25 h)	79.2° 07:15	5.08	10%	47.8°
2039-07-18 Mon	63	—	unknown	01:40–04:05 (good, 2.42 h)	79.2° 07:10	5.12	5%	58.2°
2039-07-19 Tue	65	—	unknown	01:40–04:05 (good, 2.42 h)	79.2° 07:05	5.17	2%	68.9°
2039-07-20 Wed	68	—	unknown	01:35–04:05 (good, 2.5 h)	79.2° 07:00	5.22	0%	80.0°
2039-07-21 Thu	71	—	unknown	01:30–04:10 (good, 2.67 h)	79.2° 07:00	5.27	0%	91.3°
2039-07-22 Fri	73	—	unknown	01:25–04:10 (good, 2.75 h)	79.2° 06:55	5.31	3%	102.8°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-07-11&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.