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: 08-05 (100), 08-06 (100), 08-07 (100), 08-08 (100), 08-09 (100) — by astronomy; check the weather when the night is within four days.

2040-07-18astronomy score per night — click a bar for that night2040-08-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-07-18 Wed	65	—	unknown	01:40–04:05 (good, 2.42 h)	79.2° 07:05	5.16	66%	155.6°
2040-07-19 Thu	67	—	unknown	01:40–04:05 (good, 2.42 h)	79.2° 07:05	5.21	77%	147.2°
2040-07-20 Fri	68	—	unknown	01:40–04:10 (good, 2.5 h)	79.2° 07:00	5.25	86%	135.8°
2040-07-21 Sat	68	—	unknown	01:35–04:10 (good, 2.58 h)	79.2° 06:55	5.3	93%	122.8°
2040-07-22 Sun	57	—	unknown	01:40–04:10 (good, 2.5 h)	79.2° 06:50	5.35	98%	109.1°
2040-07-23 Mon	48	—	unknown	01:45–04:10 (good, 2.42 h)	79.2° 06:45	5.4	100%	95.0°
2040-07-24 Tue	39	—	unknown	02:45–04:15 (good, 1.5 h)	79.2° 06:45	5.45	99%	80.8°
2040-07-25 Wed	32	—	unknown	04:05–04:15 (good, 0.17 h)	79.2° 06:40	5.5	95%	67.0°
2040-07-26 Thu	27	—	unknown	00:50–04:15 (marginal, 3.42 h)	79.2° 06:35	5.56	88%	53.7°
2040-07-27 Fri	26	—	unknown	00:45–04:20 (marginal, 3.58 h)	79.2° 06:30	5.61	80%	41.3°
2040-07-28 Sat	28	—	unknown	00:40–04:20 (marginal, 3.67 h)	79.2° 06:30	5.66	70%	30.7°
2040-07-29 Sun	36	—	unknown	04:05–04:10 (good, 0.08 h)	79.2° 06:25	5.72	60%	23.4°
2040-07-30 Mon	47	—	unknown	01:15–04:25 (good, 3.17 h)	79.2° 06:20	5.77	49%	22.0°
2040-07-31 Tue	59	—	unknown	01:05–04:25 (good, 3.33 h)	79.2° 06:15	5.83	39%	27.0°
2040-08-01 Wed	73	—	unknown	00:45–04:25 (good, 3.67 h)	79.2° 06:10	5.88	30%	35.5°
2040-08-02 Thu	87	—	unknown	00:40–04:30 (good, 3.83 h)	79.2° 06:10	5.94	22%	45.4°
2040-08-03 Fri	95	—	unknown	00:35–04:30 (good, 3.92 h)	79.2° 06:05	5.99	14%	55.9°
2040-08-04 Sat	99	—	unknown	00:35–04:30 (good, 3.92 h)	79.2° 06:00	6.05	8%	66.6°
2040-08-05 Sun	100	—	unknown	00:30–04:35 (good, 4.08 h)	79.2° 05:55	6.1	4%	77.5°
2040-08-06 Mon	100	—	unknown	00:25–04:35 (good, 4.17 h)	79.2° 05:50	6.16	1%	88.5°
2040-08-07 Tue	100	—	unknown	00:20–04:35 (good, 4.25 h)	79.2° 05:50	6.22	0%	99.5°
2040-08-08 Wed	100	—	unknown	00:15–04:40 (good, 4.42 h)	79.2° 05:45	6.28	1%	110.6°
2040-08-09 Thu	100	—	unknown	00:15–04:40 (good, 4.42 h)	79.2° 05:40	6.33	4%	121.6°
2040-08-10 Fri	100	—	unknown	00:10–04:40 (good, 4.5 h)	79.2° 05:35	6.39	8%	132.4°
2040-08-11 Sat	100	—	unknown	00:05–04:40 (good, 4.58 h)	79.2° 05:35	6.45	14%	142.7°
2040-08-12 Sun	100	—	unknown	00:00–04:45 (good, 4.75 h)	79.2° 05:30	6.5	22%	151.8°
2040-08-13 Mon	100	—	unknown	23:55–04:45 (good, 4.83 h)	79.2° 05:25	6.56	31%	157.7°
2040-08-14 Tue	100	—	unknown	23:55–04:45 (good, 4.83 h)	79.2° 05:20	6.62	41%	157.3°
2040-08-15 Wed	100	—	unknown	23:55–04:50 (good, 4.92 h)	79.2° 05:15	6.68	52%	150.4°
2040-08-16 Thu	100	—	unknown	23:50–04:50 (good, 5.0 h)	79.2° 05:15	6.73	63%	140.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-07-18&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.