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: 07-20 (68), 07-19 (67), 07-18 (65), 07-17 (63), 07-16 (59) — by astronomy; check the weather when the night is within four days.

2040-06-21astronomy score per night — click a bar for that night2040-07-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-06-21 Thu	14	—	unknown	03:30–03:40 (good, 0.17 h)	79.2° 08:55	4.42	88%	152.9°
2040-06-22 Fri	13	—	unknown	03:30–03:40 (good, 0.17 h)	79.2° 08:50	4.43	95%	142.7°
2040-06-23 Sat	14	—	unknown	03:25–03:40 (good, 0.25 h)	79.2° 08:45	4.43	99%	130.3°
2040-06-24 Sun	15	—	unknown	03:25–03:40 (good, 0.25 h)	79.2° 08:40	4.44	100%	116.8°
2040-06-25 Mon	14	—	unknown	03:30–03:40 (good, 0.17 h)	79.2° 08:35	4.45	98%	102.8°
2040-06-26 Tue	13	—	unknown	03:35–03:40 (good, 0.08 h)	79.2° 08:35	4.46	93%	88.8°
2040-06-27 Wed	12	—	unknown	02:35–03:40 (marginal, 1.08 h)	79.2° 08:30	4.48	86%	75.0°
2040-06-28 Thu	12	—	unknown	02:35–03:40 (marginal, 1.08 h)	79.2° 08:25	4.49	76%	61.7°
2040-06-29 Fri	13	—	unknown	02:30–03:45 (marginal, 1.25 h)	79.2° 08:20	4.51	66%	49.2°
2040-06-30 Sat	15	—	unknown	02:20–03:45 (marginal, 1.42 h)	79.2° 08:20	4.53	55%	37.7°
2040-07-01 Sun	18	—	unknown	03:10–03:45 (good, 0.58 h)	79.2° 08:15	4.55	45%	28.2°
2040-07-02 Mon	21	—	unknown	03:00–03:45 (good, 0.75 h)	79.2° 08:10	4.57	34%	22.5°
2040-07-03 Tue	26	—	unknown	02:50–03:45 (good, 0.92 h)	79.2° 08:05	4.6	25%	23.0°
2040-07-04 Wed	31	—	unknown	02:35–03:45 (good, 1.17 h)	79.2° 08:00	4.63	17%	29.1°
2040-07-05 Thu	36	—	unknown	02:30–03:50 (good, 1.33 h)	79.2° 08:00	4.66	10%	38.0°
2040-07-06 Fri	39	—	unknown	02:25–03:50 (good, 1.42 h)	79.2° 07:55	4.69	5%	48.0°
2040-07-07 Sat	41	—	unknown	02:25–03:50 (good, 1.42 h)	79.2° 07:50	4.72	2%	58.5°
2040-07-08 Sun	42	—	unknown	02:20–03:50 (good, 1.5 h)	79.2° 07:45	4.75	0%	69.3°
2040-07-09 Mon	46	—	unknown	02:15–03:55 (good, 1.67 h)	79.2° 07:40	4.79	0%	80.2°
2040-07-10 Tue	48	—	unknown	02:10–03:55 (good, 1.75 h)	79.2° 07:40	4.82	2%	91.2°
2040-07-11 Wed	49	—	unknown	02:05–03:55 (good, 1.83 h)	79.2° 07:35	4.86	6%	102.2°
2040-07-12 Thu	51	—	unknown	02:05–03:55 (good, 1.83 h)	79.2° 07:30	4.9	11%	113.2°
2040-07-13 Fri	54	—	unknown	02:00–04:00 (good, 2.0 h)	79.2° 07:25	4.94	18%	124.1°
2040-07-14 Sat	56	—	unknown	01:55–04:00 (good, 2.08 h)	79.2° 07:25	4.98	26%	134.8°
2040-07-15 Sun	58	—	unknown	01:50–04:00 (good, 2.17 h)	79.2° 07:20	5.02	35%	144.9°
2040-07-16 Mon	59	—	unknown	01:45–04:00 (good, 2.25 h)	79.2° 07:15	5.07	45%	153.5°
2040-07-17 Tue	63	—	unknown	01:45–04:05 (good, 2.33 h)	79.2° 07:10	5.11	56%	158.1°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-06-21&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.