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: 08-15 (62), 08-14 (59), 08-13 (57), 08-12 (52), 08-11 (44) — by astronomy; check the weather when the night is within four days.

2042-07-17astronomy score per night — click a bar for that night2042-08-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-07-17 Thu	5	—	unknown	04:20–04:50 (marginal, 0.5 h)	72.6° 09:25	5.09	1%	63.9°
2042-07-18 Fri	6	—	unknown	04:15–04:50 (marginal, 0.58 h)	72.5° 09:20	5.14	3%	76.7°
2042-07-19 Sat	7	—	unknown	04:10–04:55 (marginal, 0.75 h)	72.5° 09:15	5.18	8%	89.2°
2042-07-20 Sun	8	—	unknown	03:40–04:55 (marginal, 1.25 h)	72.5° 09:15	5.23	14%	101.5°
2042-07-21 Mon	11	—	unknown	04:05–04:10 (good, 0.08 h)	72.5° 09:10	5.28	21%	113.6°
2042-07-22 Tue	12	—	unknown	04:00–04:10 (good, 0.17 h)	72.5° 09:05	5.33	29%	125.6°
2042-07-23 Wed	14	—	unknown	03:55–04:10 (good, 0.25 h)	72.5° 09:00	5.38	38%	137.4°
2042-07-24 Thu	17	—	unknown	03:50–04:15 (good, 0.42 h)	72.5° 09:00	5.43	47%	149.3°
2042-07-25 Fri	19	—	unknown	03:50–04:15 (good, 0.42 h)	72.5° 08:55	5.48	57%	161.2°
2042-07-26 Sat	20	—	unknown	03:45–04:15 (good, 0.5 h)	72.6° 08:50	5.53	66%	173.2°
2042-07-27 Sun	22	—	unknown	03:40–04:20 (good, 0.67 h)	72.5° 08:45	5.58	75%	174.3°
2042-07-28 Mon	24	—	unknown	03:35–04:20 (good, 0.75 h)	72.5° 08:40	5.64	84%	161.7°
2042-07-29 Tue	25	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:40	5.69	90%	148.7°
2042-07-30 Wed	27	—	unknown	03:35–04:25 (good, 0.83 h)	72.5° 08:35	5.74	96%	135.3°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-07-17&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.