{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":2.75,"best_label":"good","best_window":"02:15\u201305:00","dark_hours":8.04,"date":"2031-04-02","moon_free_dark_hours":1.07,"moon_illumination":76,"moon_separation":51.6,"score":null,"score_astronomy":80,"score_weather":null,"transit_alt":50.2,"transit_local":"01:10","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":7.92,"best_label":"marginal","best_window":"21:30\u201305:25","dark_hours":7.98,"date":"2031-04-03","moon_free_dark_hours":0.55,"moon_illumination":84,"moon_separation":39.5,"score":null,"score_astronomy":54,"score_weather":null,"transit_alt":50.2,"transit_local":"01:05","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":6.83,"best_label":"marginal","best_window":"22:20\u201305:10","dark_hours":7.93,"date":"2031-04-04","moon_free_dark_hours":0.03,"moon_illumination":91,"moon_separation":27.3,"score":null,"score_astronomy":33,"score_weather":null,"transit_alt":50.2,"transit_local":"01:00","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":7.33,"best_label":"marginal","best_window":"21:35\u201304:55","dark_hours":7.87,"date":"2031-04-05","moon_free_dark_hours":0.0,"moon_illumination":96,"moon_separation":15.6,"score":null,"score_astronomy":27,"score_weather":null,"transit_alt":50.2,"transit_local":"00:55","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":7.17,"best_label":"marginal","best_window":"21:30\u201304:40","dark_hours":7.82,"date":"2031-04-06","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":8.9,"score":null,"score_astronomy":24,"score_weather":null,"transit_alt":50.2,"transit_local":"00:50","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":6.92,"best_label":"marginal","best_window":"21:35\u201304:30","dark_hours":7.76,"date":"2031-04-07","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":16.7,"score":null,"score_astronomy":27,"score_weather":null,"transit_alt":50.2,"transit_local":"00:50","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":6.83,"best_label":"marginal","best_window":"21:35\u201304:25","dark_hours":7.7,"date":"2031-04-08","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":29.5,"score":null,"score_astronomy":36,"score_weather":null,"transit_alt":50.2,"transit_local":"00:45","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":0.75,"best_label":"good","best_window":"21:35\u201322:20","dark_hours":7.65,"date":"2031-04-09","moon_free_dark_hours":0.77,"moon_illumination":94,"moon_separation":43.2,"score":null,"score_astronomy":86,"score_weather":null,"transit_alt":50.2,"transit_local":"00:40","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":4.17,"best_label":"good","best_window":"21:35\u201301:45","dark_hours":7.59,"date":"2031-04-10","moon_free_dark_hours":1.87,"moon_illumination":87,"moon_separation":57.2,"score":null,"score_astronomy":91,"score_weather":null,"transit_alt":50.2,"transit_local":"00:35","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":5.83,"best_label":"good","best_window":"21:40\u201303:30","dark_hours":7.53,"date":"2031-04-11","moon_free_dark_hours":2.92,"moon_illumination":78,"moon_separation":71.3,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:30","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":6.33,"best_label":"good","best_window":"21:40\u201304:00","dark_hours":7.48,"date":"2031-04-12","moon_free_dark_hours":3.83,"moon_illumination":68,"moon_separation":85.4,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:30","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":6.42,"best_label":"good","best_window":"21:40\u201304:05","dark_hours":7.42,"date":"2031-04-13","moon_free_dark_hours":4.65,"moon_illumination":57,"moon_separation":99.5,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:25","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":6.33,"best_label":"good","best_window":"21:45\u201304:05","dark_hours":7.36,"date":"2031-04-14","moon_free_dark_hours":5.32,"moon_illumination":46,"moon_separation":113.4,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:20","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":6.33,"best_label":"good","best_window":"21:45\u201304:05","dark_hours":7.31,"date":"2031-04-15","moon_free_dark_hours":5.92,"moon_illumination":34,"moon_separation":127.2,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:15","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":6.33,"best_label":"good","best_window":"21:45\u201304:05","dark_hours":7.25,"date":"2031-04-16","moon_free_dark_hours":6.43,"moon_illumination":24,"moon_separation":140.7,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:10","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":6.25,"best_label":"good","best_window":"21:45\u201304:00","dark_hours":7.19,"date":"2031-04-17","moon_free_dark_hours":6.92,"moon_illumination":16,"moon_separation":153.7,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:10","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":6.08,"best_label":"good","best_window":"21:50\u201303:55","dark_hours":7.13,"date":"2031-04-18","moon_free_dark_hours":7.12,"moon_illumination":8,"moon_separation":165.6,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:05","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":6.08,"best_label":"good","best_window":"21:50\u201303:55","dark_hours":7.07,"date":"2031-04-19","moon_free_dark_hours":7.07,"moon_illumination":4,"moon_separation":170.9,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"00:00","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":6.0,"best_label":"good","best_window":"21:50\u201303:50","dark_hours":7.02,"date":"2031-04-20","moon_free_dark_hours":7.0,"moon_illumination":1,"moon_separation":162.6,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"23:55","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":5.83,"best_label":"good","best_window":"21:55\u201303:45","dark_hours":6.96,"date":"2031-04-21","moon_free_dark_hours":6.95,"moon_illumination":0,"moon_separation":150.8,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"23:55","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":5.75,"best_label":"good","best_window":"21:55\u201303:40","dark_hours":6.9,"date":"2031-04-22","moon_free_dark_hours":6.88,"moon_illumination":2,"moon_separation":138.7,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"23:50","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":5.67,"best_label":"good","best_window":"21:55\u201303:35","dark_hours":6.84,"date":"2031-04-23","moon_free_dark_hours":6.68,"moon_illumination":5,"moon_separation":126.6,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"23:45","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":5.58,"best_label":"good","best_window":"22:00\u201303:35","dark_hours":6.78,"date":"2031-04-24","moon_free_dark_hours":5.73,"moon_illumination":10,"moon_separation":114.6,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"23:40","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":5.5,"best_label":"good","best_window":"22:00\u201303:30","dark_hours":6.72,"date":"2031-04-25","moon_free_dark_hours":4.87,"moon_illumination":16,"moon_separation":102.8,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"23:35","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":5.42,"best_label":"good","best_window":"22:00\u201303:25","dark_hours":6.67,"date":"2031-04-26","moon_free_dark_hours":4.08,"moon_illumination":24,"moon_separation":91.0,"score":null,"score_astronomy":92,"score_weather":null,"transit_alt":50.2,"transit_local":"23:35","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":5.25,"best_label":"good","best_window":"22:05\u201303:20","dark_hours":6.61,"date":"2031-04-27","moon_free_dark_hours":3.38,"moon_illumination":32,"moon_separation":79.3,"score":null,"score_astronomy":89,"score_weather":null,"transit_alt":50.2,"transit_local":"23:30","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":5.17,"best_label":"good","best_window":"22:05\u201303:15","dark_hours":6.55,"date":"2031-04-28","moon_free_dark_hours":2.77,"moon_illumination":42,"moon_separation":67.6,"score":null,"score_astronomy":86,"score_weather":null,"transit_alt":50.2,"transit_local":"23:25","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":5.17,"best_label":"good","best_window":"22:05\u201303:15","dark_hours":6.49,"date":"2031-04-29","moon_free_dark_hours":2.2,"moon_illumination":51,"moon_separation":55.9,"score":null,"score_astronomy":82,"score_weather":null,"transit_alt":50.2,"transit_local":"23:20","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":3.83,"best_label":"good","best_window":"22:55\u201302:45","dark_hours":6.43,"date":"2031-04-30","moon_free_dark_hours":1.7,"moon_illumination":61,"moon_separation":44.0,"score":null,"score_astronomy":65,"score_weather":null,"transit_alt":50.2,"transit_local":"23:15","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":5.42,"best_label":"marginal","best_window":"22:10\u201303:35","dark_hours":6.38,"date":"2031-05-01","moon_free_dark_hours":1.2,"moon_illumination":70,"moon_separation":32.0,"score":null,"score_astronomy":41,"score_weather":null,"transit_alt":50.2,"transit_local":"23:15","verdict":"unknown","weather_source":"none","weekday":"Thu"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2031-04-02","target":{"dec":2.05238823,"morphology":"E3","name":"3C 273","ra":187.27791594,"simbad_url":"https://simbad.cds.unistra.fr/simbad/sim-id?Ident=3C%20273","source":"sesame","type":"BLL","type_text":"BL Lac object \u2014 a blazar","vmag":14.83}}