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: 03-11 (46), 03-12 (39), 03-13 (31), 03-23 (28), 03-24 (27) — by astronomy; check the weather when the night is within four days.

2027-03-11astronomy score per night — click a bar for that night2027-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-03-11 Thu	46	—	unknown	20:00–22:05 (good, 2.08 h)	72.5° 16:55	9.19	13%	26.2°
2027-03-12 Fri	39	—	unknown	20:00–21:50 (good, 1.83 h)	72.5° 16:50	9.14	21%	12.9°
2027-03-13 Sat	31	—	unknown	20:00–21:40 (good, 1.67 h)	72.5° 16:45	9.09	31%	1.3°
2027-03-14 Sun	23	—	unknown	20:00–20:50 (good, 0.83 h)	72.5° 16:40	9.04	42%	14.6°
2027-03-15 Mon	16	—	unknown	20:00–22:05 (marginal, 2.08 h)	72.5° 16:35	8.99	53%	28.6°
2027-03-16 Tue	13	—	unknown	20:05–21:55 (marginal, 1.83 h)	72.5° 16:35	8.94	64%	42.7°
2027-03-17 Wed	13	—	unknown	20:05–21:50 (marginal, 1.75 h)	72.5° 16:30	8.89	75%	57.1°
2027-03-18 Thu	14	—	unknown	20:05–21:50 (marginal, 1.75 h)	72.5° 16:25	8.84	84%	71.5°
2027-03-19 Fri	17	—	unknown	20:05–21:50 (marginal, 1.75 h)	72.5° 16:20	8.79	92%	86.0°
2027-03-20 Sat	20	—	unknown	20:10–21:00 (good, 0.83 h)	72.5° 16:20	8.73	97%	100.4°
2027-03-21 Sun	24	—	unknown	20:10–21:10 (good, 1.0 h)	72.5° 16:15	8.68	100%	114.7°
2027-03-22 Mon	25	—	unknown	20:10–21:10 (good, 1.0 h)	72.5° 16:10	8.63	100%	128.8°
2027-03-23 Tue	28	—	unknown	20:10–21:10 (good, 1.0 h)	72.5° 16:05	8.58	97%	142.6°
2027-03-24 Wed	27	—	unknown	20:15–21:15 (good, 1.0 h)	72.5° 16:00	8.53	92%	155.9°
2027-03-25 Thu	25	—	unknown	20:15–21:10 (good, 0.92 h)	72.5° 16:00	8.47	86%	168.9°
2027-03-26 Fri	23	—	unknown	20:15–21:05 (good, 0.83 h)	72.5° 15:55	8.42	78%	178.1°
2027-03-27 Sat	22	—	unknown	20:20–21:00 (good, 0.67 h)	72.5° 15:50	8.37	70%	166.0°
2027-03-28 Sun	20	—	unknown	21:20–21:55 (good, 0.58 h)	72.5° 16:45	8.31	60%	153.9°
2027-03-29 Mon	19	—	unknown	21:20–21:55 (good, 0.58 h)	72.5° 16:40	8.26	51%	142.0°
2027-03-30 Tue	17	—	unknown	21:20–21:50 (good, 0.5 h)	72.5° 16:40	8.2	42%	130.1°
2027-03-31 Wed	14	—	unknown	21:25–21:45 (good, 0.33 h)	72.5° 16:35	8.15	32%	118.3°
2027-04-01 Thu	13	—	unknown	21:25–21:40 (good, 0.25 h)	72.5° 16:30	8.1	24%	106.4°
2027-04-02 Fri	11	—	unknown	21:25–21:35 (good, 0.17 h)	72.5° 16:25	8.04	16%	94.3°
2027-04-03 Sat	10	—	unknown	21:25–21:35 (good, 0.17 h)	72.5° 16:20	7.99	10%	82.0°
2027-04-04 Sun	7	—	unknown	20:55–21:55 (marginal, 1.0 h)	72.5° 16:20	7.93	5%	69.4°
2027-04-05 Mon	6	—	unknown	21:30–21:55 (marginal, 0.42 h)	72.5° 16:15	7.87	1%	56.6°
2027-04-06 Tue	5	—	unknown	21:30–21:50 (marginal, 0.33 h)	72.5° 16:10	7.82	0%	43.5°
2027-04-07 Wed	4	—	unknown	20:55–21:20 (marginal, 0.42 h)	72.5° 16:05	7.76	1%	30.1°
2027-04-08 Thu	3	—	unknown	21:00–21:10 (marginal, 0.17 h)	72.5° 16:05	7.71	5%	16.5°
2027-04-09 Fri	2	—	unknown	21:00–21:05 (marginal, 0.08 h)	72.5° 16:00	7.65	10%	2.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-03-11&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.