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: 08-17 (100), 08-18 (100), 08-16 (98), 07-31 (95), 08-01 (95) — by astronomy; check the weather when the night is within four days.

2028-07-20astronomy score per night — click a bar for that night2028-08-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-07-20 Thu	70	—	unknown	01:30–04:10 (good, 2.67 h)	79.1° 07:00	5.25	2%	70.2°
2028-07-21 Fri	72	—	unknown	01:30–04:10 (good, 2.67 h)	79.1° 06:55	5.3	0%	84.3°
2028-07-22 Sat	74	—	unknown	01:25–04:10 (good, 2.75 h)	79.1° 06:50	5.35	1%	98.6°
2028-07-23 Sun	78	—	unknown	01:20–04:10 (good, 2.83 h)	79.1° 06:45	5.4	5%	113.0°
2028-07-24 Mon	81	—	unknown	01:15–04:15 (good, 3.0 h)	79.1° 06:45	5.45	11%	127.2°
2028-07-25 Tue	83	—	unknown	01:10–04:15 (good, 3.08 h)	79.1° 06:40	5.5	20%	141.0°
2028-07-26 Wed	85	—	unknown	01:10–04:15 (good, 3.08 h)	79.1° 06:35	5.55	30%	153.9°
2028-07-27 Thu	89	—	unknown	01:05–04:20 (good, 3.25 h)	79.1° 06:30	5.6	41%	163.8°
2028-07-28 Fri	91	—	unknown	01:00–04:20 (good, 3.33 h)	79.1° 06:25	5.66	52%	164.7°
2028-07-29 Sat	93	—	unknown	00:55–04:20 (good, 3.42 h)	79.1° 06:25	5.71	63%	156.1°
2028-07-30 Sun	94	—	unknown	01:00–04:25 (good, 3.42 h)	79.1° 06:20	5.77	73%	144.7°
2028-07-31 Mon	95	—	unknown	00:55–04:25 (good, 3.5 h)	79.1° 06:15	5.82	82%	132.6°
2028-08-01 Tue	95	—	unknown	00:55–04:25 (good, 3.5 h)	79.1° 06:10	5.88	89%	120.5°
2028-08-02 Wed	91	—	unknown	00:55–04:30 (good, 3.58 h)	79.1° 06:10	5.93	94%	108.4°
2028-08-03 Thu	68	—	unknown	01:00–04:30 (good, 3.5 h)	79.1° 06:05	5.99	98%	96.4°
2028-08-04 Fri	55	—	unknown	01:55–04:30 (good, 2.58 h)	79.1° 06:00	6.04	100%	84.5°
2028-08-05 Sat	44	—	unknown	03:15–04:35 (good, 1.33 h)	79.1° 05:55	6.1	100%	72.8°
2028-08-06 Sun	34	—	unknown	00:15–04:35 (marginal, 4.33 h)	79.1° 05:50	6.16	98%	61.3°
2028-08-07 Mon	27	—	unknown	00:15–04:35 (marginal, 4.33 h)	79.1° 05:50	6.21	94%	50.0°
2028-08-08 Tue	22	—	unknown	00:15–04:35 (marginal, 4.33 h)	79.1° 05:45	6.27	88%	38.9°
2028-08-09 Wed	22	—	unknown	00:05–04:40 (marginal, 4.58 h)	79.1° 05:40	6.33	82%	28.4°
2028-08-10 Thu	29	—	unknown	23:50–04:40 (marginal, 4.83 h)	79.1° 05:35	6.38	74%	19.1°
2028-08-11 Fri	38	—	unknown	23:40–04:40 (marginal, 5.0 h)	79.1° 05:30	6.44	65%	14.3°
2028-08-12 Sat	52	—	unknown	01:10–04:20 (good, 3.17 h)	79.1° 05:30	6.5	56%	18.1°
2028-08-13 Sun	68	—	unknown	00:15–04:45 (good, 4.5 h)	79.1° 05:25	6.56	46%	27.5°
2028-08-14 Mon	82	—	unknown	23:55–04:45 (good, 4.83 h)	79.1° 05:20	6.61	35%	38.9°
2028-08-15 Tue	90	—	unknown	23:50–04:50 (good, 5.0 h)	79.1° 05:15	6.67	26%	51.3°
2028-08-16 Wed	98	—	unknown	23:45–04:50 (good, 5.08 h)	79.1° 05:15	6.73	16%	64.4°
2028-08-17 Thu	100	—	unknown	23:40–04:50 (good, 5.17 h)	79.1° 05:10	6.79	9%	78.1°
2028-08-18 Fri	100	—	unknown	23:35–04:55 (good, 5.33 h)	79.1° 05:05	6.84	3%	92.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-20&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.