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: 08-02 (100), 08-01 (98), 07-31 (96), 07-30 (89), 07-29 (80) — by astronomy; check the weather when the night is within four days.

2027-07-04astronomy score per night — click a bar for that night2027-08-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-07-04 Sun	34	—	unknown	02:35–03:45 (good, 1.17 h)	79.1° 08:05	4.6	1%	80.9°
2027-07-05 Mon	35	—	unknown	02:35–03:45 (good, 1.17 h)	79.1° 08:00	4.63	5%	95.6°
2027-07-06 Tue	38	—	unknown	02:30–03:50 (good, 1.33 h)	79.1° 07:55	4.66	11%	110.1°
2027-07-07 Wed	40	—	unknown	02:25–03:50 (good, 1.42 h)	79.1° 07:55	4.69	20%	124.2°
2027-07-08 Thu	41	—	unknown	02:20–03:50 (good, 1.5 h)	79.1° 07:50	4.72	30%	137.7°
2027-07-09 Fri	43	—	unknown	02:20–03:50 (good, 1.5 h)	79.1° 07:45	4.76	41%	150.2°
2027-07-10 Sat	46	—	unknown	02:15–03:55 (good, 1.67 h)	79.1° 07:40	4.79	52%	160.9°
2027-07-11 Sun	48	—	unknown	02:10–03:55 (good, 1.75 h)	79.1° 07:35	4.83	62%	165.8°
2027-07-12 Mon	50	—	unknown	02:05–03:55 (good, 1.83 h)	79.1° 07:35	4.87	72%	161.0°
2027-07-13 Tue	51	—	unknown	02:00–03:55 (good, 1.92 h)	79.1° 07:30	4.9	80%	151.2°
2027-07-14 Wed	53	—	unknown	02:05–04:00 (good, 1.92 h)	79.1° 07:25	4.95	88%	140.1°
2027-07-15 Thu	54	—	unknown	02:00–04:00 (good, 2.0 h)	79.1° 07:20	4.99	93%	128.7°
2027-07-16 Fri	48	—	unknown	02:00–04:00 (good, 2.0 h)	79.1° 07:15	5.03	97%	117.3°
2027-07-17 Sat	43	—	unknown	02:05–04:00 (good, 1.92 h)	79.1° 07:15	5.07	100%	105.8°
2027-07-18 Sun	37	—	unknown	02:10–04:05 (good, 1.92 h)	79.1° 07:10	5.12	100%	94.3°
2027-07-19 Mon	31	—	unknown	03:05–04:05 (good, 1.0 h)	79.1° 07:05	5.17	98%	82.8°
2027-07-20 Tue	27	—	unknown	01:15–04:05 (marginal, 2.83 h)	79.1° 07:00	5.21	95%	71.3°
2027-07-21 Wed	23	—	unknown	01:15–04:10 (marginal, 2.92 h)	79.1° 07:00	5.26	91%	59.9°
2027-07-22 Thu	20	—	unknown	01:15–04:10 (marginal, 2.92 h)	79.1° 06:55	5.31	84%	48.4°
2027-07-23 Fri	20	—	unknown	01:10–04:10 (marginal, 3.0 h)	79.1° 06:50	5.36	77%	37.2°
2027-07-24 Sat	23	—	unknown	01:00–04:15 (marginal, 3.25 h)	79.1° 06:45	5.41	68%	26.3°
2027-07-25 Sun	31	—	unknown	00:50–04:15 (marginal, 3.42 h)	79.1° 06:40	5.46	58%	17.2°
2027-07-26 Mon	41	—	unknown	01:40–04:15 (good, 2.58 h)	79.1° 06:40	5.51	48%	14.4°
2027-07-27 Tue	52	—	unknown	01:25–04:15 (good, 2.83 h)	79.1° 06:35	5.56	37%	21.5°
2027-07-28 Wed	67	—	unknown	01:05–04:20 (good, 3.25 h)	79.1° 06:30	5.62	27%	33.0°
2027-07-29 Thu	80	—	unknown	01:00–04:20 (good, 3.33 h)	79.1° 06:25	5.67	17%	46.0°
2027-07-30 Fri	89	—	unknown	00:55–04:20 (good, 3.42 h)	79.1° 06:20	5.72	9%	59.9°
2027-07-31 Sat	96	—	unknown	00:50–04:25 (good, 3.58 h)	79.1° 06:20	5.78	3%	74.4°
2027-08-01 Sun	98	—	unknown	00:45–04:25 (good, 3.67 h)	79.1° 06:15	5.83	0%	89.1°
2027-08-02 Mon	100	—	unknown	00:45–04:25 (good, 3.67 h)	79.1° 06:10	5.89	0%	103.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-07-04&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.