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 V1057 Cyg: 01-17 (27), 01-18 (26), 01-19 (25), 01-20 (24), 01-21 (23) — by astronomy; check the weather when the night is within four days.

2028-01-17astronomy score per night — click a bar for that night2028-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-01-17 Mon	27	—	unknown	19:00–19:55 (good, 0.92 h)	87.3° 13:35	11.19	60%	120.3°
2028-01-18 Tue	26	—	unknown	19:00–19:50 (good, 0.83 h)	87.3° 13:30	11.17	49%	114.7°
2028-01-19 Wed	25	—	unknown	19:00–19:45 (good, 0.75 h)	87.3° 13:25	11.14	38%	108.2°
2028-01-20 Thu	24	—	unknown	19:00–19:45 (good, 0.75 h)	87.3° 13:25	11.12	28%	101.1°
2028-01-21 Fri	23	—	unknown	19:00–19:40 (good, 0.67 h)	87.3° 13:20	11.09	20%	93.8°
2028-01-22 Sat	21	—	unknown	19:05–19:35 (good, 0.5 h)	87.3° 13:15	11.07	12%	86.5°
2028-01-23 Sun	19	—	unknown	19:05–19:30 (good, 0.42 h)	87.3° 13:10	11.04	7%	79.4°
2028-01-24 Mon	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:10	11.01	3%	72.7°
2028-01-25 Tue	16	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	10.99	0%	66.6°
2028-01-26 Wed	15	—	unknown	19:05–19:20 (good, 0.25 h)	87.3° 13:00	10.96	0%	61.4°
2028-01-27 Thu	13	—	unknown	19:10–19:15 (good, 0.08 h)	87.3° 12:55	10.93	2%	57.4°
2028-01-28 Fri	12	—	unknown	18:35–19:45 (marginal, 1.17 h)	87.3° 12:50	10.9	5%	54.9°
2028-01-29 Sat	10	—	unknown	19:10–19:45 (marginal, 0.58 h)	87.3° 12:50	10.87	10%	54.0°
2028-01-30 Sun	9	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.3° 12:45	10.84	16%	54.9°
2028-01-31 Mon	8	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.3° 12:40	10.81	23%	57.5°
2028-02-01 Tue	8	—	unknown	05:45–06:00 (marginal, 0.25 h)	87.3° 12:35	10.77	32%	61.6°
2028-02-02 Wed	8	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:30	10.74	41%	67.0°
2028-02-03 Thu	8	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.3° 12:30	10.71	51%	73.4°
2028-02-04 Fri	8	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.3° 12:25	10.67	62%	80.6°
2028-02-05 Sat	8	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.3° 12:20	10.64	72%	88.4°
2028-02-06 Sun	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.3° 12:15	10.6	81%	96.6°
2028-02-07 Mon	9	—	unknown	05:20–06:25 (marginal, 1.08 h)	87.3° 12:15	10.57	90%	104.8°
2028-02-08 Tue	8	—	unknown	05:15–05:55 (marginal, 0.67 h)	87.3° 12:10	10.53	96%	112.5°
2028-02-09 Wed	9	—	unknown	05:10–05:50 (marginal, 0.67 h)	87.3° 12:05	10.49	99%	119.0°
2028-02-10 Thu	9	—	unknown	05:05–05:50 (marginal, 0.75 h)	87.3° 12:00	10.46	100%	123.7°
2028-02-11 Fri	9	—	unknown	05:05–06:20 (marginal, 1.25 h)	87.3° 11:55	10.42	97%	125.9°
2028-02-12 Sat	10	—	unknown	05:45–05:50 (good, 0.08 h)	87.3° 11:50	10.38	92%	125.2°
2028-02-13 Sun	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.3° 11:45	10.34	84%	121.9°
2028-02-14 Mon	11	—	unknown	05:40–05:45 (good, 0.08 h)	87.3° 11:40	10.3	75%	116.6°
2028-02-15 Tue	12	—	unknown	05:35–05:45 (good, 0.17 h)	87.3° 11:35	10.27	65%	110.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-01-17&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.