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: 02-23 (88), 02-24 (88), 02-25 (87), 02-22 (86), 02-26 (85) — by astronomy; check the weather when the night is within four days.

2027-02-14astronomy score per night — click a bar for that night2027-03-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-02-14 Sun	38	—	unknown	19:30–00:05 (marginal, 4.58 h)	72.5° 18:30	10.3	57%	4.2°
2027-02-15 Mon	25	—	unknown	19:30–23:45 (marginal, 4.25 h)	72.5° 18:25	10.26	68%	18.1°
2027-02-16 Tue	18	—	unknown	19:30–23:25 (marginal, 3.92 h)	72.5° 18:25	10.22	78%	32.5°
2027-02-17 Wed	20	—	unknown	19:30–23:20 (marginal, 3.83 h)	72.5° 18:20	10.18	87%	47.2°
2027-02-18 Thu	27	—	unknown	19:35–23:25 (marginal, 3.83 h)	72.5° 18:15	10.13	94%	62.1°
2027-02-19 Fri	38	—	unknown	19:35–20:30 (good, 0.92 h)	72.5° 18:10	10.09	98%	77.1°
2027-02-20 Sat	53	—	unknown	19:35–22:00 (good, 2.42 h)	72.5° 18:10	10.05	100%	91.9°
2027-02-21 Sun	68	—	unknown	19:35–22:55 (good, 3.33 h)	72.5° 18:05	10.01	99%	106.6°
2027-02-22 Mon	86	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 18:00	9.97	95%	120.9°
2027-02-23 Tue	88	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:55	9.92	89%	134.8°
2027-02-24 Wed	88	—	unknown	19:40–22:55 (good, 3.25 h)	72.5° 17:50	9.88	81%	148.2°
2027-02-25 Thu	87	—	unknown	19:40–23:00 (good, 3.33 h)	72.5° 17:50	9.84	72%	161.2°
2027-02-26 Fri	85	—	unknown	19:40–22:55 (good, 3.25 h)	72.5° 17:45	9.79	62%	173.8°
2027-02-27 Sat	82	—	unknown	19:45–22:50 (good, 3.08 h)	72.5° 17:40	9.75	53%	173.7°
2027-02-28 Sun	80	—	unknown	19:45–22:45 (good, 3.0 h)	72.5° 17:35	9.7	43%	161.7°
2027-03-01 Mon	77	—	unknown	19:45–22:45 (good, 3.0 h)	72.5° 17:30	9.66	34%	149.9°
2027-03-02 Tue	74	—	unknown	19:45–22:40 (good, 2.92 h)	72.5° 17:30	9.61	25%	138.0°
2027-03-03 Wed	72	—	unknown	19:50–22:35 (good, 2.75 h)	72.5° 17:25	9.57	18%	126.2°
2027-03-04 Thu	70	—	unknown	19:50–22:30 (good, 2.67 h)	72.5° 17:20	9.52	11%	114.3°
2027-03-05 Fri	67	—	unknown	19:50–22:25 (good, 2.58 h)	72.5° 17:15	9.47	6%	102.3°
2027-03-06 Sat	65	—	unknown	19:50–22:25 (good, 2.58 h)	72.5° 17:15	9.43	2%	90.2°
2027-03-07 Sun	61	—	unknown	19:55–22:20 (good, 2.42 h)	72.5° 17:10	9.38	0%	77.8°
2027-03-08 Mon	60	—	unknown	19:55–22:15 (good, 2.33 h)	72.5° 17:05	9.33	0%	65.2°
2027-03-09 Tue	57	—	unknown	19:55–22:10 (good, 2.25 h)	72.5° 17:00	9.28	3%	52.4°
2027-03-10 Wed	53	—	unknown	19:55–22:10 (good, 2.25 h)	72.5° 16:55	9.23	7%	39.4°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-02-14&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.