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: 08-10 (49), 08-09 (48), 08-08 (45), 08-07 (43), 08-06 (41) — by astronomy; check the weather when the night is within four days.

2027-07-12astronomy score per night — click a bar for that night2027-08-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-07-12 Mon	2	—	unknown	04:40–04:45 (marginal, 0.08 h)	72.5° 09:45	4.87	72%	166.6°
2027-07-13 Tue	2	—	unknown	04:35–04:45 (marginal, 0.17 h)	72.5° 09:40	4.9	80%	178.8°
2027-07-14 Wed	2	—	unknown	04:30–04:45 (marginal, 0.25 h)	72.5° 09:40	4.95	88%	168.5°
2027-07-15 Thu	3	—	unknown	04:30–04:50 (marginal, 0.33 h)	72.5° 09:35	4.99	93%	156.4°
2027-07-16 Fri	3	—	unknown	04:25–04:50 (marginal, 0.42 h)	72.5° 09:30	5.03	97%	144.4°
2027-07-17 Sat	3	—	unknown	04:30–04:50 (marginal, 0.33 h)	72.5° 09:25	5.07	100%	132.5°
2027-07-18 Sun	5	—	unknown	04:25–04:50 (marginal, 0.42 h)	72.5° 09:20	5.12	100%	120.7°
2027-07-19 Mon	5	—	unknown	03:45–04:05 (marginal, 0.33 h)	72.5° 09:20	5.17	98%	108.8°
2027-07-20 Tue	5	—	unknown	03:40–04:05 (marginal, 0.42 h)	72.5° 09:15	5.21	95%	97.0°
2027-07-21 Wed	5	—	unknown	03:40–04:10 (marginal, 0.5 h)	72.5° 09:10	5.26	91%	85.1°
2027-07-22 Thu	5	—	unknown	03:40–04:10 (marginal, 0.5 h)	72.5° 09:05	5.31	84%	73.1°
2027-07-23 Fri	5	—	unknown	03:40–04:10 (marginal, 0.5 h)	72.5° 09:00	5.36	77%	61.0°
2027-07-24 Sat	6	—	unknown	03:35–04:15 (marginal, 0.67 h)	72.5° 09:00	5.41	68%	48.7°
2027-07-25 Sun	7	—	unknown	03:30–04:15 (marginal, 0.75 h)	72.5° 08:55	5.46	58%	36.1°
2027-07-26 Mon	9	—	unknown	03:20–04:15 (marginal, 0.92 h)	72.5° 08:50	5.51	48%	23.2°
2027-07-27 Tue	12	—	unknown	04:05–04:15 (good, 0.17 h)	72.5° 08:45	5.56	37%	9.9°
2027-07-28 Wed	17	—	unknown	03:50–04:20 (good, 0.5 h)	72.5° 08:40	5.62	27%	4.0°
2027-07-29 Thu	21	—	unknown	03:40–04:20 (good, 0.67 h)	72.5° 08:40	5.67	17%	18.1°
2027-07-30 Fri	25	—	unknown	03:30–04:20 (good, 0.83 h)	72.5° 08:35	5.72	9%	32.7°
2027-07-31 Sat	29	—	unknown	03:25–04:25 (good, 1.0 h)	72.5° 08:30	5.78	3%	47.6°
2027-08-01 Sun	31	—	unknown	03:20–04:25 (good, 1.08 h)	72.5° 08:25	5.83	0%	62.8°
2027-08-02 Mon	32	—	unknown	03:15–04:25 (good, 1.17 h)	72.5° 08:25	5.89	0%	78.0°
2027-08-03 Tue	35	—	unknown	03:15–04:30 (good, 1.25 h)	72.5° 08:20	5.94	4%	93.2°
2027-08-04 Wed	37	—	unknown	03:10–04:30 (good, 1.33 h)	72.5° 08:15	6.0	9%	108.0°
2027-08-05 Thu	38	—	unknown	03:05–04:30 (good, 1.42 h)	72.5° 08:10	6.06	17%	122.5°
2027-08-06 Fri	41	—	unknown	03:00–04:35 (good, 1.58 h)	72.5° 08:05	6.11	26%	136.5°
2027-08-07 Sat	43	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:05	6.17	37%	150.1°
2027-08-08 Sun	45	—	unknown	02:55–04:35 (good, 1.67 h)	72.5° 08:00	6.23	47%	163.2°
2027-08-09 Mon	48	—	unknown	02:50–04:40 (good, 1.83 h)	72.5° 07:55	6.28	57%	175.8°
2027-08-10 Tue	49	—	unknown	02:45–04:40 (good, 1.92 h)	72.5° 07:50	6.34	67%	171.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-07-12&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.