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: 08-18 (70), 08-17 (67), 08-16 (65), 08-15 (63), 08-14 (59) — by astronomy; check the weather when the night is within four days.

2037-07-20astronomy score per night — click a bar for that night2037-08-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-07-20 Mon	9	—	unknown	03:40–04:55 (marginal, 1.25 h)	72.5° 09:10	5.24	63%	161.4°
2037-07-21 Tue	11	—	unknown	04:00–04:10 (good, 0.17 h)	72.5° 09:10	5.29	73%	170.9°
2037-07-22 Wed	12	—	unknown	04:00–04:10 (good, 0.17 h)	72.5° 09:05	5.34	82%	166.5°
2037-07-23 Thu	14	—	unknown	03:55–04:10 (good, 0.25 h)	72.5° 09:00	5.39	90%	155.1°
2037-07-24 Fri	15	—	unknown	04:00–04:15 (good, 0.25 h)	72.5° 08:55	5.44	95%	142.8°
2037-07-25 Sat	16	—	unknown	03:55–04:15 (good, 0.33 h)	72.5° 08:55	5.49	98%	130.4°
2037-07-26 Sun	16	—	unknown	03:55–04:15 (good, 0.33 h)	72.5° 08:50	5.54	100%	118.2°
2037-07-27 Mon	16	—	unknown	03:55–04:20 (good, 0.42 h)	72.5° 08:45	5.6	99%	106.0°
2037-07-28 Tue	14	—	unknown	04:05–04:20 (good, 0.25 h)	72.5° 08:40	5.65	97%	94.0°
2037-07-29 Wed	12	—	unknown	03:10–04:20 (marginal, 1.17 h)	72.5° 08:35	5.7	93%	82.2°
2037-07-30 Thu	11	—	unknown	03:10–04:25 (marginal, 1.25 h)	72.5° 08:35	5.76	87%	70.5°
2037-07-31 Fri	11	—	unknown	03:10–04:25 (marginal, 1.25 h)	72.5° 08:30	5.81	80%	58.8°
2037-08-01 Sat	11	—	unknown	03:05–04:25 (marginal, 1.33 h)	72.5° 08:25	5.87	72%	47.2°
2037-08-02 Sun	12	—	unknown	03:00–04:30 (marginal, 1.5 h)	72.5° 08:20	5.92	63%	35.6°
2037-08-03 Mon	15	—	unknown	02:50–04:30 (marginal, 1.67 h)	72.5° 08:15	5.98	54%	24.1°
2037-08-04 Tue	20	—	unknown	03:45–04:30 (good, 0.75 h)	72.5° 08:15	6.03	44%	13.4°
2037-08-05 Wed	25	—	unknown	03:20–04:30 (good, 1.17 h)	72.5° 08:10	6.09	34%	8.9°
2037-08-06 Thu	32	—	unknown	03:10–04:35 (good, 1.42 h)	72.5° 08:05	6.15	25%	17.5°
2037-08-07 Fri	37	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.2	16%	29.8°
2037-08-08 Sat	43	—	unknown	02:50–04:35 (good, 1.75 h)	72.5° 08:00	6.26	9%	43.3°
2037-08-09 Sun	49	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:55	6.32	3%	57.3°
2037-08-10 Mon	51	—	unknown	02:45–04:40 (good, 1.92 h)	72.5° 07:50	6.37	0%	71.7°
2037-08-11 Tue	53	—	unknown	02:40–04:40 (good, 2.0 h)	72.5° 07:45	6.43	0%	86.5°
2037-08-12 Wed	56	—	unknown	02:35–04:45 (good, 2.17 h)	72.5° 07:40	6.49	3%	101.4°
2037-08-13 Thu	57	—	unknown	02:30–04:45 (good, 2.25 h)	72.5° 07:40	6.55	9%	116.2°
2037-08-14 Fri	59	—	unknown	02:30–04:45 (good, 2.25 h)	72.5° 07:35	6.6	17%	130.7°
2037-08-15 Sat	63	—	unknown	02:25–04:50 (good, 2.42 h)	72.5° 07:30	6.66	27%	144.9°
2037-08-16 Sun	65	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:25	6.72	38%	158.3°
2037-08-17 Mon	67	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.78	49%	169.4°
2037-08-18 Tue	70	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:20	6.83	60%	168.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-07-20&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.