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: 09-13 (100), 09-14 (100), 09-15 (100), 09-16 (100), 09-17 (100) — by astronomy; check the weather when the night is within four days.

2036-09-13astronomy score per night — click a bar for that night2036-10-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-09-13 Sat	100	—	unknown	21:10–02:50 (good, 5.67 h)	71.1° 21:50	8.3	44%	127.3°
2036-09-14 Sun	100	—	unknown	21:10–02:50 (good, 5.67 h)	71.1° 21:45	8.35	34%	134.1°
2036-09-15 Mon	100	—	unknown	21:05–02:45 (good, 5.67 h)	71.1° 21:40	8.4	23%	138.1°
2036-09-16 Tue	100	—	unknown	21:05–02:45 (good, 5.67 h)	71.1° 21:40	8.45	14%	138.3°
2036-09-17 Wed	100	—	unknown	21:05–02:40 (good, 5.58 h)	71.1° 21:35	8.51	7%	134.4°
2036-09-18 Thu	100	—	unknown	21:00–02:35 (good, 5.58 h)	71.1° 21:30	8.56	2%	127.2°
2036-09-19 Fri	100	—	unknown	21:00–02:35 (good, 5.58 h)	71.1° 21:25	8.61	0%	118.0°
2036-09-20 Sat	100	—	unknown	20:55–02:30 (good, 5.58 h)	71.1° 21:20	8.66	1%	107.8°
2036-09-21 Sun	100	—	unknown	20:55–02:25 (good, 5.5 h)	71.1° 21:20	8.71	5%	97.1°
2036-09-22 Mon	100	—	unknown	20:55–02:20 (good, 5.42 h)	71.1° 21:15	8.76	11%	86.6°
2036-09-23 Tue	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.1° 21:10	8.81	19%	76.5°
2036-09-24 Wed	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.1° 21:05	8.86	27%	67.1°
2036-09-25 Thu	100	—	unknown	20:50–02:10 (good, 5.33 h)	71.1° 21:05	8.91	37%	58.6°
2036-09-26 Fri	94	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 21:00	8.96	47%	51.3°
2036-09-27 Sat	88	—	unknown	20:45–02:00 (good, 5.25 h)	71.1° 20:55	9.01	56%	45.7°
2036-09-28 Sun	82	—	unknown	20:40–01:55 (good, 5.25 h)	71.1° 20:50	9.06	66%	42.2°
2036-09-29 Mon	53	—	unknown	20:40–23:20 (good, 2.67 h)	71.1° 20:45	9.11	74%	41.4°
2036-09-30 Tue	44	—	unknown	20:40–02:10 (marginal, 5.5 h)	71.1° 20:45	9.16	82%	43.2°
2036-10-01 Wed	41	—	unknown	20:35–02:00 (marginal, 5.42 h)	71.1° 20:40	9.21	89%	47.5°
2036-10-02 Thu	41	—	unknown	20:35–01:50 (marginal, 5.25 h)	71.1° 20:35	9.25	94%	53.7°
2036-10-03 Fri	45	—	unknown	20:35–20:55 (good, 0.33 h)	71.1° 20:30	9.3	98%	61.2°
2036-10-04 Sat	52	—	unknown	20:30–22:15 (good, 1.75 h)	71.1° 20:25	9.35	100%	69.6°
2036-10-05 Sun	61	—	unknown	20:30–23:05 (good, 2.58 h)	71.1° 20:25	9.4	100%	78.7°
2036-10-06 Mon	73	—	unknown	20:30–23:55 (good, 3.42 h)	71.1° 20:20	9.44	98%	88.1°
2036-10-07 Tue	85	—	unknown	20:25–00:50 (good, 4.42 h)	71.1° 20:15	9.49	93%	97.8°
2036-10-08 Wed	100	—	unknown	20:25–01:00 (good, 4.58 h)	71.1° 20:10	9.53	87%	107.4°
2036-10-09 Thu	100	—	unknown	20:25–01:05 (good, 4.67 h)	71.1° 20:10	9.58	79%	116.7°
2036-10-10 Fri	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:05	9.63	70%	125.3°
2036-10-11 Sat	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 20:00	9.67	59%	132.4°
2036-10-12 Sun	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 19:55	9.71	48%	137.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-09-13&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.