ϑ҈ꗗ (List of Observers) - 2012-13 Apparition
| Observer | Location | Telescope | Days | | Disks | Maps | Animations | Others | Measurements |
| Akutsu, Tomio | Philippines | 35cm SC | 58 | | 531 | | | 1 | 1 | 1564 |
| Asada, Hideto | Kyoto, Japan | 31cm Refl. | 6 | | 73 | 1 | | | | | | |
| Adachi, Makoto | Shiga, Japan | 31cm Refl. | 10 | * | 20 | | | | | | | | |
| Ikemura, Toshihiko | Aichi, Japan | 38cm Refl. | 18 | | 51 | | | | | | | 163 |
| Ishibashi, Tsutomu | Kanagawa, Japan | 31cm Refl. | 56 | | 135 | | | | | | | 199 |
| Iwamasa, Ryuichi | Kanagawa, Japan | 35cm SC | 31 | | 62 | | | | | | | 414 |
| Einaga, Hideo | Hyogo, Japan | 30cm Refl. | 111 | | 620 | 87 | | | | | 2740 |
| Ota, Satoshi | Okinawa, Japan | 30cm Refl. | 48 | | 64 | | | | | | | 628 |
| Oyamada, Hiroyuki | Gumma, Japan | 20cm Refl. | 10 | | 19 | | | | | | | | |
| Kazemoto, Akira | Kyoto/Okinawa, Japan | 31cm/50cm Refl. | 6 | | 8 | | | | | | | 51 |
| Karasawa, Hideyuki | Tokyo, Japan | 30cm Refl. | 9 | | 9 | | | | | | | | |
| Kanno, Seiichi | Yamagata, Japan | 30cm Refl. | 10 | | 38 | | | | | | | | |
| Kumamori, Teruaki | Osaka, Japan | 28cm SC | 60 | | 60 | | | 1 | | | 650 |
| Kozawa, Tokujiro | Tokyo, Japan | 33cm Refl. | 99 | | 220 | | | | | | | 887 |
| Suzuki, Takashi | Tokyo, Japan | 18cm MC | 15 | | 18 | | | | | | | | |
| Takimoto, Ikuo | Kagawa, Japan | 31cm Refl. | 2 | | 6 | | | | | | | | |
| Nakai, Kenji | Hiroshima, Japan | 25cm SC | 3 | | 3 | | | | | | | | |
| Hasebe, Takao | Aichi, Japan | 28cm SC | 9 | | 10 | | | | | | | 79 |
| Hatanaka, Akitoshi | Mie, Japan | 40cm Refl. | 10 | | 19 | | | | | | | | |
| Hayashi, Toshio | Kyoto, Japan | 35cm SC | 3 | | 9 | | | | | | | | |
| Horikawa, Kuniaki | Kanagawa, Japan | 30cm Refl. | 81 | * | 136 | | | | | | | 411 |
| Mishina, Toshiro | Kanagawa, Japan | 20cm Refl. | 22 | | 57 | | | | | | | | |
| Miyazaki, Isao | Okinawa, Japan | 40cm Refl. | 65 | | 92 | | | | | | | 1413 |
| Yamazaki, Akihiro | Tokyo, Japan | 31cm Refl. | 39 | | 110 | 7 | | | | | 304 |
| Yunoki, Kenkichi | Osaka, Japan | 26cm Refl. | 24 | | 56 | | | | | | | 245 |
| Yoshida, Tomoyuki | Tochigi, Japan | 30cm Refl. | 58 | | 107 | | | | | | | 910 |
| Yoneyama, Seiichi | Kanagawa, Japan | 25cm Refl. | 80 | | 265 | 2 | | | | | 63 |
| Abel, Paul | UK | 20cm/50cm Refl. | 19 | * | 23 | 5 | | | | | | |
| Delcroix, Marc | France | 32cm/100cm Refl./25cm SC | 19 | | 111 | | | | | | | 272 |
| Go, Christopher | Philippines | 35cm/28cm SC | 92 | | 387 | | | | | | | 1486 |
| Kowollik, Silvia | Germany | 20cm Refl. | 2 | | 1 | 1 | | | | | | |
| Pellier, Christophe | France | 25cm Refl. | 14 | | 86 | 1 | | | | | 243 |
| Phillips, Jim | USA | 20cm Refr./25cm Refl. | 16 | | 21 | | | | | | | 89 |
| Wesley, Anthony | Australia | 33cm Refl. | 9 | | 15 | | | | | | | | |
| Total | | | | | 3442 | 104 | 2 | 1 | 12811 |
|
| * | visual observation |