{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":5.33,"best_label":"good","best_window":"22:00\u201303:20","dark_hours":6.62,"date":"2028-04-26","moon_free_dark_hours":6.32,"moon_illumination":5,"moon_separation":123.1,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"23:30","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":5.25,"best_label":"good","best_window":"22:05\u201303:20","dark_hours":6.57,"date":"2028-04-27","moon_free_dark_hours":5.23,"moon_illumination":10,"moon_separation":110.1,"score":null,"score_astronomy":93,"score_weather":null,"transit_alt":50.2,"transit_local":"23:25","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":5.17,"best_label":"good","best_window":"22:05\u201303:15","dark_hours":6.51,"date":"2028-04-28","moon_free_dark_hours":4.23,"moon_illumination":18,"moon_separation":97.0,"score":null,"score_astronomy":92,"score_weather":null,"transit_alt":50.2,"transit_local":"23:20","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":5.08,"best_label":"good","best_window":"22:05\u201303:10","dark_hours":6.45,"date":"2028-04-29","moon_free_dark_hours":3.38,"moon_illumination":27,"moon_separation":83.6,"score":null,"score_astronomy":89,"score_weather":null,"transit_alt":50.2,"transit_local":"23:20","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":4.92,"best_label":"good","best_window":"22:10\u201303:05","dark_hours":6.39,"date":"2028-04-30","moon_free_dark_hours":2.65,"moon_illumination":37,"moon_separation":70.0,"score":null,"score_astronomy":84,"score_weather":null,"transit_alt":50.2,"transit_local":"23:15","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":4.92,"best_label":"good","best_window":"22:10\u201303:05","dark_hours":6.33,"date":"2028-05-01","moon_free_dark_hours":2.03,"moon_illumination":48,"moon_separation":56.3,"score":null,"score_astronomy":81,"score_weather":null,"transit_alt":50.2,"transit_local":"23:10","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":3.75,"best_label":"good","best_window":"22:50\u201302:35","dark_hours":6.28,"date":"2028-05-02","moon_free_dark_hours":1.5,"moon_illumination":59,"moon_separation":42.6,"score":null,"score_astronomy":54,"score_weather":null,"transit_alt":50.2,"transit_local":"23:05","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":5.08,"best_label":"marginal","best_window":"22:15\u201303:20","dark_hours":6.22,"date":"2028-05-03","moon_free_dark_hours":1.03,"moon_illumination":70,"moon_separation":28.9,"score":null,"score_astronomy":36,"score_weather":null,"transit_alt":50.2,"transit_local":"23:05","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":4.92,"best_label":"marginal","best_window":"22:15\u201303:10","dark_hours":6.16,"date":"2028-05-04","moon_free_dark_hours":0.57,"moon_illumination":80,"moon_separation":16.0,"score":null,"score_astronomy":28,"score_weather":null,"transit_alt":50.2,"transit_local":"23:00","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":4.67,"best_label":"marginal","best_window":"22:15\u201302:55","dark_hours":6.1,"date":"2028-05-05","moon_free_dark_hours":0.1,"moon_illumination":89,"moon_separation":9.6,"score":null,"score_astronomy":22,"score_weather":null,"transit_alt":50.2,"transit_local":"22:55","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":4.33,"best_label":"marginal","best_window":"22:20\u201302:40","dark_hours":6.05,"date":"2028-05-06","moon_free_dark_hours":0.0,"moon_illumination":95,"moon_separation":18.5,"score":null,"score_astronomy":18,"score_weather":null,"transit_alt":50.2,"transit_local":"22:50","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":4.17,"best_label":"marginal","best_window":"22:20\u201302:30","dark_hours":5.99,"date":"2028-05-07","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":31.6,"score":null,"score_astronomy":20,"score_weather":null,"transit_alt":50.2,"transit_local":"22:45","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":4.33,"best_label":"marginal","best_window":"22:20\u201302:40","dark_hours":5.93,"date":"2028-05-08","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":45.2,"score":null,"score_astronomy":31,"score_weather":null,"transit_alt":50.2,"transit_local":"22:45","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":0.92,"best_label":"good","best_window":"22:25\u201323:20","dark_hours":5.88,"date":"2028-05-09","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":58.8,"score":null,"score_astronomy":43,"score_weather":null,"transit_alt":50.2,"transit_local":"22:40","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":2.67,"best_label":"good","best_window":"22:25\u201301:05","dark_hours":5.82,"date":"2028-05-10","moon_free_dark_hours":0.48,"moon_illumination":95,"moon_separation":72.0,"score":null,"score_astronomy":75,"score_weather":null,"transit_alt":50.2,"transit_local":"22:35","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":3.5,"best_label":"good","best_window":"22:25\u201301:55","dark_hours":5.77,"date":"2028-05-11","moon_free_dark_hours":1.38,"moon_illumination":89,"moon_separation":85.0,"score":null,"score_astronomy":83,"score_weather":null,"transit_alt":50.2,"transit_local":"22:30","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":3.58,"best_label":"good","best_window":"22:30\u201302:05","dark_hours":5.71,"date":"2028-05-12","moon_free_dark_hours":2.12,"moon_illumination":82,"moon_separation":97.6,"score":null,"score_astronomy":87,"score_weather":null,"transit_alt":50.2,"transit_local":"22:25","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":3.58,"best_label":"good","best_window":"22:30\u201302:05","dark_hours":5.66,"date":"2028-05-13","moon_free_dark_hours":2.68,"moon_illumination":73,"moon_separation":109.9,"score":null,"score_astronomy":89,"score_weather":null,"transit_alt":50.2,"transit_local":"22:25","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":3.58,"best_label":"good","best_window":"22:30\u201302:05","dark_hours":5.6,"date":"2028-05-14","moon_free_dark_hours":3.15,"moon_illumination":64,"moon_separation":121.9,"score":null,"score_astronomy":89,"score_weather":null,"transit_alt":50.2,"transit_local":"22:20","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":3.5,"best_label":"good","best_window":"22:35\u201302:05","dark_hours":5.55,"date":"2028-05-15","moon_free_dark_hours":3.55,"moon_illumination":55,"moon_separation":133.6,"score":null,"score_astronomy":86,"score_weather":null,"transit_alt":50.2,"transit_local":"22:15","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":3.5,"best_label":"good","best_window":"22:35\u201302:05","dark_hours":5.5,"date":"2028-05-16","moon_free_dark_hours":3.88,"moon_illumination":46,"moon_separation":145.1,"score":null,"score_astronomy":85,"score_weather":null,"transit_alt":50.2,"transit_local":"22:10","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":3.42,"best_label":"good","best_window":"22:35\u201302:00","dark_hours":5.45,"date":"2028-05-17","moon_free_dark_hours":4.22,"moon_illumination":36,"moon_separation":156.2,"score":null,"score_astronomy":84,"score_weather":null,"transit_alt":50.2,"transit_local":"22:10","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":3.25,"best_label":"good","best_window":"22:40\u201301:55","dark_hours":5.39,"date":"2028-05-18","moon_free_dark_hours":4.53,"moon_illumination":27,"moon_separation":166.2,"score":null,"score_astronomy":81,"score_weather":null,"transit_alt":50.2,"transit_local":"22:05","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":3.17,"best_label":"good","best_window":"22:40\u201301:50","dark_hours":5.34,"date":"2028-05-19","moon_free_dark_hours":4.85,"moon_illumination":19,"moon_separation":170.2,"score":null,"score_astronomy":79,"score_weather":null,"transit_alt":50.2,"transit_local":"22:00","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":3.17,"best_label":"good","best_window":"22:40\u201301:50","dark_hours":5.29,"date":"2028-05-20","moon_free_dark_hours":5.23,"moon_illumination":12,"moon_separation":162.9,"score":null,"score_astronomy":77,"score_weather":null,"transit_alt":50.2,"transit_local":"21:55","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":3.0,"best_label":"good","best_window":"22:45\u201301:45","dark_hours":5.24,"date":"2028-05-21","moon_free_dark_hours":5.22,"moon_illumination":6,"moon_separation":151.8,"score":null,"score_astronomy":74,"score_weather":null,"transit_alt":50.2,"transit_local":"21:50","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":2.92,"best_label":"good","best_window":"22:45\u201301:40","dark_hours":5.2,"date":"2028-05-22","moon_free_dark_hours":5.18,"moon_illumination":2,"moon_separation":139.7,"score":null,"score_astronomy":73,"score_weather":null,"transit_alt":50.2,"transit_local":"21:50","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":2.83,"best_label":"good","best_window":"22:45\u201301:35","dark_hours":5.15,"date":"2028-05-23","moon_free_dark_hours":5.13,"moon_illumination":0,"moon_separation":127.0,"score":null,"score_astronomy":71,"score_weather":null,"transit_alt":50.2,"transit_local":"21:45","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":2.75,"best_label":"good","best_window":"22:45\u201301:30","dark_hours":5.1,"date":"2028-05-24","moon_free_dark_hours":5.08,"moon_illumination":0,"moon_separation":113.9,"score":null,"score_astronomy":69,"score_weather":null,"transit_alt":50.2,"transit_local":"21:40","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":2.67,"best_label":"good","best_window":"22:50\u201301:30","dark_hours":5.06,"date":"2028-05-25","moon_free_dark_hours":5.03,"moon_illumination":3,"moon_separation":100.6,"score":null,"score_astronomy":66,"score_weather":null,"transit_alt":50.2,"transit_local":"21:35","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":"2028-04-26","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}}