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: 01-12 (23), 01-13 (20), 01-14 (18), 01-23 (18), 01-19 (17) — by astronomy; check the weather when the night is within four days.

2038-01-12astronomy score per night — click a bar for that night2038-02-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-01-12 Tue	23	—	unknown	18:55–19:50 (good, 0.92 h)	87.3° 13:55	11.28	44%	69.5°
2038-01-13 Wed	20	—	unknown	18:55–19:40 (good, 0.75 h)	87.3° 13:50	11.27	54%	74.0°
2038-01-14 Thu	18	—	unknown	18:55–19:20 (good, 0.42 h)	87.3° 13:45	11.24	63%	79.1°
2038-01-15 Fri	16	—	unknown	18:55–19:00 (good, 0.08 h)	87.3° 13:40	11.22	72%	84.8°
2038-01-16 Sat	15	—	unknown	18:55–19:00 (good, 0.08 h)	87.3° 13:35	11.2	81%	90.7°
2038-01-17 Sun	15	—	unknown	19:00–19:10 (good, 0.17 h)	87.3° 13:35	11.18	88%	96.8°
2038-01-18 Mon	16	—	unknown	19:00–19:20 (good, 0.33 h)	87.3° 13:30	11.15	94%	102.8°
2038-01-19 Tue	17	—	unknown	19:00–19:20 (good, 0.33 h)	87.3° 13:25	11.13	98%	108.3°
2038-01-20 Wed	17	—	unknown	19:00–19:25 (good, 0.42 h)	87.3° 13:20	11.11	100%	113.1°
2038-01-21 Thu	17	—	unknown	19:00–19:25 (good, 0.42 h)	87.2° 13:20	11.08	99%	116.6°
2038-01-22 Fri	17	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:15	11.05	96%	118.5°
2038-01-23 Sat	18	—	unknown	19:05–19:30 (good, 0.42 h)	87.3° 13:10	11.03	90%	118.5°
2038-01-24 Sun	16	—	unknown	19:05–19:25 (good, 0.33 h)	87.3° 13:05	11.0	82%	116.4°
2038-01-25 Mon	15	—	unknown	19:05–19:20 (good, 0.25 h)	87.3° 13:00	10.97	72%	112.7°
2038-01-26 Tue	13	—	unknown	19:10–19:20 (good, 0.17 h)	87.3° 13:00	10.94	61%	107.7°
2038-01-27 Wed	12	—	unknown	19:10–19:15 (good, 0.08 h)	87.3° 12:55	10.91	50%	101.7°
2038-01-28 Thu	12	—	unknown	18:35–19:45 (marginal, 1.17 h)	87.3° 12:50	10.88	39%	95.3°
2038-01-29 Fri	11	—	unknown	19:10–19:40 (marginal, 0.5 h)	87.3° 12:45	10.85	28%	88.7°
2038-01-30 Sat	10	—	unknown	19:10–19:35 (marginal, 0.42 h)	87.3° 12:40	10.82	19%	82.3°
2038-01-31 Sun	9	—	unknown	19:15–19:35 (marginal, 0.33 h)	87.3° 12:40	10.79	11%	76.3°
2038-02-01 Mon	9	—	unknown	05:40–06:00 (marginal, 0.33 h)	87.3° 12:35	10.75	6%	71.0°
2038-02-02 Tue	9	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.3° 12:30	10.72	2%	66.6°
2038-02-03 Wed	9	—	unknown	05:35–06:00 (marginal, 0.42 h)	87.3° 12:25	10.69	0%	63.4°
2038-02-04 Thu	8	—	unknown	05:30–05:55 (marginal, 0.42 h)	87.2° 12:25	10.65	0%	61.6°
2038-02-05 Fri	9	—	unknown	05:25–05:55 (marginal, 0.5 h)	87.3° 12:20	10.62	3%	61.3°
2038-02-06 Sat	10	—	unknown	05:20–06:25 (marginal, 1.08 h)	87.3° 12:15	10.58	7%	62.4°
2038-02-07 Sun	10	—	unknown	05:50–05:55 (good, 0.08 h)	87.3° 12:10	10.55	13%	64.7°
2038-02-08 Mon	11	—	unknown	05:50–05:55 (good, 0.08 h)	87.3° 12:05	10.51	20%	68.1°
2038-02-09 Tue	11	—	unknown	05:45–05:50 (good, 0.08 h)	87.3° 12:00	10.47	28%	72.4°
2038-02-10 Wed	12	—	unknown	05:40–05:50 (good, 0.17 h)	87.3° 11:55	10.44	36%	77.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-01-12&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.