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 HD 189733: 02-12 (6), 02-13 (6), 02-10 (4), 02-11 (4), 02-06 (3) — by astronomy; check the weather when the night is within four days.

2034-01-15astronomy score per night — click a bar for that night2034-02-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-01-15 Sun	0	—	unknown	—	71.1° 12:45	11.22	20%	69.5°
2034-01-16 Mon	0	—	unknown	—	71.1° 12:40	11.2	13%	60.5°
2034-01-17 Tue	0	—	unknown	—	71.1° 12:35	11.18	7%	52.0°
2034-01-18 Wed	0	—	unknown	—	71.1° 12:30	11.16	3%	44.7°
2034-01-19 Thu	0	—	unknown	—	71.1° 12:30	11.13	0%	39.6°
2034-01-20 Fri	0	—	unknown	—	71.1° 12:25	11.11	0%	37.9°
2034-01-21 Sat	0	—	unknown	—	71.1° 12:20	11.08	3%	40.3°
2034-01-22 Sun	0	—	unknown	—	71.1° 12:15	11.05	8%	46.2°
2034-01-23 Mon	0	—	unknown	—	71.1° 12:10	11.03	15%	54.6°
2034-01-24 Tue	0	—	unknown	—	71.1° 12:10	11.0	24%	64.5°
2034-01-25 Wed	0	—	unknown	—	71.1° 12:00	10.97	34%	75.2°
2034-01-26 Thu	0	—	unknown	—	71.1° 12:00	10.94	45%	86.3°
2034-01-27 Fri	1	—	unknown	—	71.1° 11:50	10.91	57%	97.4°
2034-01-28 Sat	1	—	unknown	—	71.1° 11:50	10.88	68%	108.3°
2034-01-29 Sun	1	—	unknown	—	71.1° 11:45	10.85	78%	118.6°
2034-01-30 Mon	1	—	unknown	—	71.1° 11:40	10.82	86%	128.0°
2034-01-31 Tue	1	—	unknown	—	71.1° 11:35	10.79	93%	135.6°
2034-02-01 Wed	1	—	unknown	—	71.1° 11:35	10.76	97%	140.6°
2034-02-02 Thu	1	—	unknown	—	71.1° 11:30	10.72	100%	142.0°
2034-02-03 Fri	2	—	unknown	05:55–06:00 (marginal, 0.08 h)	71.1° 11:25	10.69	100%	139.7°
2034-02-04 Sat	2	—	unknown	05:50–05:55 (marginal, 0.08 h)	71.1° 11:20	10.65	98%	134.3°
2034-02-05 Sun	2	—	unknown	05:50–05:55 (marginal, 0.08 h)	71.1° 11:15	10.62	94%	127.0°
2034-02-06 Mon	3	—	unknown	05:45–05:55 (marginal, 0.17 h)	71.1° 11:15	10.58	88%	118.6°
2034-02-07 Tue	3	—	unknown	05:40–05:55 (marginal, 0.25 h)	71.1° 11:10	10.55	81%	109.7°
2034-02-08 Wed	3	—	unknown	05:35–05:55 (marginal, 0.33 h)	71.1° 11:05	10.51	73%	100.5°
2034-02-09 Thu	3	—	unknown	05:35–05:50 (marginal, 0.25 h)	71.1° 11:00	10.47	64%	91.2°
2034-02-10 Fri	4	—	unknown	05:30–05:50 (marginal, 0.33 h)	71.1° 10:55	10.44	55%	81.8°
2034-02-11 Sat	4	—	unknown	05:25–05:50 (marginal, 0.42 h)	71.1° 10:55	10.4	46%	72.6°
2034-02-12 Sun	6	—	unknown	05:20–05:50 (marginal, 0.5 h)	71.1° 10:50	10.36	36%	63.6°
2034-02-13 Mon	6	—	unknown	05:15–05:45 (marginal, 0.5 h)	71.1° 10:45	10.32	27%	55.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-01-15&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.