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: 12-09 (43), 12-10 (41), 12-11 (37), 12-12 (32), 12-13 (28) — by astronomy; check the weather when the night is within four days.

2045-12-09astronomy score per night — click a bar for that night2046-01-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-12-09 Sat	43	—	unknown	18:35–20:15 (good, 1.67 h)	71.1° 15:10	11.45	2%	54.6°
2045-12-10 Sun	41	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:05	11.46	6%	48.4°
2045-12-11 Mon	37	—	unknown	18:35–20:10 (good, 1.58 h)	71.1° 15:00	11.47	12%	44.2°
2045-12-12 Tue	32	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 14:55	11.47	18%	42.5°
2045-12-13 Wed	28	—	unknown	18:35–19:50 (good, 1.25 h)	71.1° 14:55	11.48	26%	43.6°
2045-12-14 Thu	24	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 14:50	11.49	35%	47.1°
2045-12-15 Fri	20	—	unknown	18:35–19:30 (good, 0.92 h)	71.1° 14:45	11.49	44%	52.5°
2045-12-16 Sat	17	—	unknown	18:35–18:55 (good, 0.33 h)	71.1° 14:40	11.5	54%	59.3°
2045-12-17 Sun	15	—	unknown	18:35–20:05 (marginal, 1.5 h)	71.1° 14:40	11.5	63%	67.2°
2045-12-18 Mon	14	—	unknown	18:35–20:00 (marginal, 1.42 h)	71.1° 14:35	11.5	72%	75.8°
2045-12-19 Tue	14	—	unknown	18:35–20:00 (marginal, 1.42 h)	71.1° 14:30	11.51	81%	85.0°
2045-12-20 Wed	14	—	unknown	18:35–18:50 (good, 0.25 h)	71.1° 14:25	11.51	88%	94.6°
2045-12-21 Thu	15	—	unknown	18:35–19:05 (good, 0.5 h)	71.1° 14:20	11.51	94%	104.3°
2045-12-22 Fri	16	—	unknown	18:35–19:10 (good, 0.58 h)	71.1° 14:20	11.51	98%	114.0°
2045-12-23 Sat	17	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:15	11.5	100%	123.0°
2045-12-24 Sun	16	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:10	11.5	99%	130.6°
2045-12-25 Mon	16	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:05	11.5	95%	135.8°
2045-12-26 Tue	17	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 14:00	11.49	89%	137.5°
2045-12-27 Wed	16	—	unknown	18:40–19:05 (good, 0.42 h)	71.1° 14:00	11.49	80%	135.2°
2045-12-28 Thu	14	—	unknown	18:40–19:00 (good, 0.33 h)	71.1° 13:55	11.48	70%	129.6°
2045-12-29 Fri	12	—	unknown	18:40–18:55 (good, 0.25 h)	71.1° 13:50	11.48	59%	121.8°
2045-12-30 Sat	11	—	unknown	18:40–18:55 (good, 0.25 h)	71.1° 13:45	11.47	48%	112.7°
2045-12-31 Sun	8	—	unknown	18:45–18:50 (good, 0.08 h)	71.1° 13:45	11.46	37%	103.0°
2046-01-01 Mon	7	—	unknown	18:10–19:10 (marginal, 1.0 h)	71.1° 13:40	11.45	27%	93.1°
2046-01-02 Tue	7	—	unknown	18:45–19:10 (marginal, 0.42 h)	71.1° 13:35	11.44	18%	83.3°
2046-01-03 Wed	6	—	unknown	18:45–19:05 (marginal, 0.33 h)	71.1° 13:30	11.43	11%	73.8°
2046-01-04 Thu	4	—	unknown	18:45–19:00 (marginal, 0.25 h)	71.1° 13:25	11.41	5%	64.9°
2046-01-05 Fri	3	—	unknown	18:15–18:30 (marginal, 0.25 h)	71.1° 13:25	11.4	2%	56.8°
2046-01-06 Sat	3	—	unknown	18:15–18:25 (marginal, 0.17 h)	71.1° 13:20	11.39	0%	50.1°
2046-01-07 Sun	2	—	unknown	18:15–18:20 (marginal, 0.08 h)	71.1° 13:15	11.37	1%	45.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-12-09&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.