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 Seven Sisters: 08-26 (89), 08-27 (89), 08-25 (87), 08-28 (87), 08-24 (85) — by astronomy; check the weather when the night is within four days.

2042-07-31astronomy score per night — click a bar for that night2042-08-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-07-31 Thu	25	—	unknown	03:35–04:25 (good, 0.83 h)	72.6° 08:30	5.8	99%	121.6°
2042-08-01 Fri	22	—	unknown	03:35–04:25 (good, 0.83 h)	72.5° 08:25	5.85	100%	107.5°
2042-08-02 Sat	18	—	unknown	03:50–04:25 (good, 0.58 h)	72.5° 08:20	5.91	98%	93.2°
2042-08-03 Sun	15	—	unknown	02:50–04:30 (marginal, 1.67 h)	72.5° 08:20	5.97	93%	78.7°
2042-08-04 Mon	13	—	unknown	02:55–04:30 (marginal, 1.58 h)	72.5° 08:15	6.02	86%	64.1°
2042-08-05 Tue	12	—	unknown	02:55–04:30 (marginal, 1.58 h)	72.6° 08:10	6.08	77%	49.6°
2042-08-06 Wed	12	—	unknown	02:50–04:35 (marginal, 1.75 h)	72.5° 08:05	6.13	67%	35.2°
2042-08-07 Thu	16	—	unknown	02:35–04:35 (marginal, 2.0 h)	72.5° 08:05	6.19	56%	21.0°
2042-08-08 Fri	22	—	unknown	03:55–04:35 (good, 0.67 h)	72.5° 08:00	6.25	44%	7.0°
2042-08-09 Sat	30	—	unknown	03:05–04:40 (good, 1.58 h)	72.6° 07:55	6.3	34%	7.0°
2042-08-10 Sun	38	—	unknown	02:55–04:40 (good, 1.75 h)	72.5° 07:50	6.36	24%	20.5°
2042-08-11 Mon	44	—	unknown	02:45–04:40 (good, 1.92 h)	72.5° 07:45	6.42	15%	33.9°
2042-08-12 Tue	52	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:45	6.48	8%	47.1°
2042-08-13 Wed	57	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:40	6.53	4%	60.0°
2042-08-14 Thu	59	—	unknown	02:30–04:45 (good, 2.25 h)	72.6° 07:35	6.59	1%	72.8°
2042-08-15 Fri	62	—	unknown	02:25–04:50 (good, 2.42 h)	72.5° 07:30	6.65	0%	85.3°
2042-08-16 Sat	65	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:25	6.71	2%	97.7°
2042-08-17 Sun	67	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:25	6.76	5%	109.8°
2042-08-18 Mon	69	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.82	9%	121.8°
2042-08-19 Tue	72	—	unknown	02:10–04:55 (good, 2.75 h)	72.6° 07:15	6.88	16%	133.7°
2042-08-20 Wed	74	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:10	6.94	23%	145.5°
2042-08-21 Thu	76	—	unknown	02:00–04:55 (good, 2.92 h)	72.5° 07:10	6.99	32%	157.4°
2042-08-22 Fri	80	—	unknown	02:00–05:00 (good, 3.0 h)	72.5° 07:05	7.05	41%	169.3°
2042-08-23 Sat	82	—	unknown	01:55–05:00 (good, 3.08 h)	72.6° 07:00	7.11	50%	178.5°
2042-08-24 Sun	85	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 06:55	7.17	60%	166.3°
2042-08-25 Mon	87	—	unknown	01:45–05:00 (good, 3.25 h)	72.5° 06:50	7.22	70%	153.7°
2042-08-26 Tue	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.5° 06:50	7.28	79%	140.7°
2042-08-27 Wed	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.5° 06:45	7.34	87%	127.3°
2042-08-28 Thu	87	—	unknown	01:45–05:05 (good, 3.33 h)	72.6° 06:40	7.39	94%	113.4°
2042-08-29 Fri	66	—	unknown	01:55–05:10 (good, 3.25 h)	72.5° 06:35	7.45	98%	99.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-07-31&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.