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: 01-18 (100), 01-19 (100), 01-20 (100), 01-21 (100), 01-22 (100) — by astronomy; check the weather when the night is within four days.

2034-01-18astronomy score per night — click a bar for that night2034-02-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-01-18 Wed	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:15	11.16	3%	138.1°
2034-01-19 Thu	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.5° 20:15	11.13	0%	125.1°
2034-01-20 Fri	100	—	unknown	19:00–01:20 (good, 6.33 h)	72.5° 20:10	11.11	0%	111.8°
2034-01-21 Sat	100	—	unknown	19:00–01:15 (good, 6.25 h)	72.5° 20:05	11.08	3%	98.2°
2034-01-22 Sun	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.5° 20:00	11.05	8%	84.4°
2034-01-23 Mon	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.5° 19:55	11.03	15%	70.5°
2034-01-24 Tue	98	—	unknown	19:05–01:05 (good, 6.0 h)	72.5° 19:55	11.0	24%	56.5°
2034-01-25 Wed	89	—	unknown	19:05–01:00 (good, 5.92 h)	72.5° 19:50	10.97	34%	42.6°
2034-01-26 Thu	77	—	unknown	19:10–00:55 (good, 5.75 h)	72.5° 19:45	10.94	45%	28.9°
2034-01-27 Fri	59	—	unknown	20:45–23:20 (good, 2.58 h)	72.5° 19:40	10.91	57%	15.9°
2034-01-28 Sat	40	—	unknown	19:10–01:05 (marginal, 5.92 h)	72.5° 19:35	10.88	68%	8.3°
2034-01-29 Sun	26	—	unknown	19:10–00:50 (marginal, 5.67 h)	72.5° 19:35	10.85	78%	16.5°
2034-01-30 Mon	20	—	unknown	19:10–00:20 (marginal, 5.17 h)	72.5° 19:30	10.82	86%	29.3°
2034-01-31 Tue	24	—	unknown	19:15–00:15 (marginal, 5.0 h)	72.5° 19:25	10.79	93%	42.6°
2034-02-01 Wed	34	—	unknown	19:15–00:20 (marginal, 5.08 h)	72.5° 19:20	10.76	97%	55.9°
2034-02-02 Thu	48	—	unknown	19:15–20:05 (good, 0.83 h)	72.5° 19:20	10.72	100%	69.0°
2034-02-03 Fri	65	—	unknown	19:15–22:10 (good, 2.92 h)	72.5° 19:15	10.69	100%	81.9°
2034-02-04 Sat	83	—	unknown	19:20–23:25 (good, 4.08 h)	72.5° 19:10	10.65	98%	94.6°
2034-02-05 Sun	100	—	unknown	19:20–23:55 (good, 4.58 h)	72.5° 19:05	10.62	94%	107.0°
2034-02-06 Mon	100	—	unknown	19:20–00:05 (good, 4.75 h)	72.5° 19:00	10.58	88%	119.2°
2034-02-07 Tue	100	—	unknown	19:20–00:00 (good, 4.67 h)	72.5° 19:00	10.55	81%	131.1°
2034-02-08 Wed	100	—	unknown	19:20–00:00 (good, 4.67 h)	72.5° 18:55	10.51	73%	142.7°
2034-02-09 Thu	100	—	unknown	19:25–00:00 (good, 4.58 h)	72.5° 18:50	10.47	64%	154.1°
2034-02-10 Fri	100	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:45	10.44	55%	164.8°
2034-02-11 Sat	100	—	unknown	19:25–23:55 (good, 4.5 h)	72.5° 18:40	10.4	46%	171.6°
2034-02-12 Sun	100	—	unknown	19:25–23:50 (good, 4.42 h)	72.5° 18:40	10.36	36%	166.0°
2034-02-13 Mon	100	—	unknown	19:30–23:45 (good, 4.25 h)	72.5° 18:35	10.32	27%	155.1°
2034-02-14 Tue	100	—	unknown	19:30–23:40 (good, 4.17 h)	72.5° 18:30	10.28	18%	143.0°
2034-02-15 Wed	100	—	unknown	19:30–23:35 (good, 4.08 h)	72.5° 18:25	10.24	11%	130.3°
2034-02-16 Thu	100	—	unknown	19:30–23:35 (good, 4.08 h)	72.5° 18:25	10.2	5%	117.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-01-18&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.