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: 09-26 (100), 09-27 (100), 09-28 (100), 09-29 (100), 09-30 (100) — by astronomy; check the weather when the night is within four days.

2028-09-26astronomy score per night — click a bar for that night2028-10-25

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-09-26 Tue	100	—	unknown	23:45–05:45 (good, 6.0 h)	72.5° 04:45	8.96	64%	129.4°
2028-09-27 Wed	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:40	9.01	73%	117.2°
2028-09-28 Thu	100	—	unknown	23:45–05:45 (good, 6.0 h)	72.5° 04:35	9.06	81%	105.1°
2028-09-29 Fri	100	—	unknown	23:50–05:45 (good, 5.92 h)	72.5° 04:30	9.11	88%	93.2°
2028-09-30 Sat	100	—	unknown	01:00–05:50 (good, 4.83 h)	72.5° 04:30	9.16	93%	81.3°
2028-10-01 Sun	74	—	unknown	02:30–05:50 (good, 3.33 h)	72.5° 04:25	9.2	97%	69.5°
2028-10-02 Mon	56	—	unknown	05:10–05:50 (good, 0.67 h)	72.5° 04:20	9.25	99%	57.7°
2028-10-03 Tue	37	—	unknown	23:35–05:50 (marginal, 6.25 h)	72.5° 04:15	9.3	100%	45.8°
2028-10-04 Wed	23	—	unknown	03:25–05:55 (marginal, 2.5 h)	72.5° 04:10	9.35	98%	33.8°
2028-10-05 Thu	19	—	unknown	04:35–05:55 (marginal, 1.33 h)	72.5° 04:10	9.39	95%	21.7°
2028-10-06 Fri	21	—	unknown	23:10–03:10 (marginal, 4.0 h)	72.5° 04:05	9.44	90%	9.5°
2028-10-07 Sat	29	—	unknown	22:50–05:55 (marginal, 7.08 h)	72.5° 04:00	9.49	84%	2.9°
2028-10-08 Sun	41	—	unknown	22:35–05:55 (marginal, 7.33 h)	72.5° 03:55	9.53	76%	15.4°
2028-10-09 Mon	57	—	unknown	22:20–06:00 (marginal, 7.67 h)	72.5° 03:55	9.58	66%	28.2°
2028-10-10 Tue	81	—	unknown	22:45–06:00 (good, 7.25 h)	72.5° 03:50	9.62	56%	41.4°
2028-10-11 Wed	90	—	unknown	22:40–06:00 (good, 7.33 h)	72.5° 03:45	9.67	45%	54.8°
2028-10-12 Thu	99	—	unknown	22:35–06:00 (good, 7.42 h)	72.5° 03:40	9.71	34%	68.7°
2028-10-13 Fri	100	—	unknown	22:30–06:05 (good, 7.58 h)	72.5° 03:35	9.76	24%	82.9°
2028-10-14 Sat	100	—	unknown	22:25–06:05 (good, 7.67 h)	72.5° 03:35	9.8	15%	97.5°
2028-10-15 Sun	100	—	unknown	22:25–06:05 (good, 7.67 h)	72.5° 03:30	9.84	7%	112.4°
2028-10-16 Mon	100	—	unknown	22:20–06:05 (good, 7.75 h)	72.5° 03:25	9.89	2%	127.5°
2028-10-17 Tue	100	—	unknown	22:15–06:05 (good, 7.83 h)	72.5° 03:20	9.93	0%	142.5°
2028-10-18 Wed	100	—	unknown	22:10–06:10 (good, 8.0 h)	72.5° 03:15	9.97	1%	157.5°
2028-10-19 Thu	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:15	10.01	5%	172.2°
2028-10-20 Fri	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.5° 03:10	10.06	11%	173.5°
2028-10-21 Sat	100	—	unknown	22:00–06:10 (good, 8.17 h)	72.5° 03:05	10.1	19%	159.6°
2028-10-22 Sun	100	—	unknown	21:55–06:10 (good, 8.25 h)	72.5° 03:00	10.14	28%	146.2°
2028-10-23 Mon	100	—	unknown	21:55–06:15 (good, 8.33 h)	72.5° 02:55	10.18	37%	133.3°
2028-10-24 Tue	100	—	unknown	21:50–06:15 (good, 8.42 h)	72.5° 02:55	10.22	47%	120.8°
2028-10-25 Wed	100	—	unknown	21:55–06:15 (good, 8.33 h)	72.5° 02:50	10.26	57%	108.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-09-26&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.