| Parameter |
Value |
| Designation |
366P/Spacewatch |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-01-05T10:45:06.180480Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:37Z |
| Obs used |
74 |
| NEO |
- |
| M1 |
13.100 |
| K1 |
17.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-03-17T04:21:57.024000Z |
| Discovery magnitude (MPC) |
20.20 N |
| Discovery observatory (MPC) |
J04 · ESA Optical Ground Station, Tenerife |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-05-04.0000000 |
| e |
0.34736448 |
| q (au) |
2.284924 |
| a (au) |
3.501073 |
| i (deg) |
8.853746 |
| Ω (om, deg) |
70.797085 |
| ω (w, deg) |
153.581562 |
| M (ma, deg) |
268.005489 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.629 + 4.782\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.629 |
| n |
4.782 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
22:40:16.84 |
-15:50:54.2 |
HIP 111911 |
6.94 |
| 2026-03-26 12:00 |
22:40:55.01 |
-15:47:43.7 |
HIP 111911 |
14.93 |
| 2026-03-27 00:00 |
22:41:33.09 |
-15:44:33.7 |
HIP 111911 |
24.20 |
| 2026-03-27 12:00 |
22:42:11.08 |
-15:41:24.1 |
HIP 112192 |
21.16 |
| 2026-03-28 00:00 |
22:42:48.97 |
-15:38:14.9 |
HIP 112192 |
17.51 |
| 2026-03-28 12:00 |
22:43:26.78 |
-15:35:06.2 |
HIP 112192 |
18.74 |
| 2026-03-29 00:00 |
22:44:04.49 |
-15:31:57.9 |
HIP 112356 |
20.34 |
| 2026-03-29 12:00 |
22:44:42.11 |
-15:28:50.1 |
HIP 112356 |
12.65 |
| 2026-03-30 00:00 |
22:45:19.63 |
-15:25:42.8 |
HIP 112356 |
9.50 |
| 2026-03-30 12:00 |
22:45:57.06 |
-15:22:36.0 |
HIP 112356 |
14.24 |
| 2026-03-31 00:00 |
22:46:34.40 |
-15:19:29.7 |
HIP 112526 |
18.14 |
| 2026-03-31 12:00 |
22:47:11.64 |
-15:16:23.8 |
HIP 112526 |
9.81 |
| 2026-04-01 00:00 |
22:47:48.79 |
-15:13:18.5 |
HIP 112526 |
6.65 |
| 2026-04-01 12:00 |
22:48:25.85 |
-15:10:13.7 |
HIP 112526 |
13.09 |
| 2026-04-02 00:00 |
22:49:02.81 |
-15:07:09.3 |
HIP 112526 |
21.83 |
| 2026-04-02 12:00 |
22:49:39.68 |
-15:04:05.5 |
HIP 112797 |
24.02 |
| 2026-04-03 00:00 |
22:50:16.45 |
-15:01:02.2 |
HIP 112797 |
17.63 |
| 2026-04-03 12:00 |
22:50:53.12 |
-14:57:59.5 |
HIP 112797 |
14.87 |
| 2026-04-04 00:00 |
22:51:29.70 |
-14:54:57.3 |
HIP 112797 |
17.52 |
| 2026-04-04 12:00 |
22:52:06.18 |
-14:51:55.6 |
HIP 112797 |
23.80 |
| 2026-04-05 00:00 |
22:52:42.57 |
-14:48:54.5 |
HIP 112920 |
24.65 |
| 2026-04-05 12:00 |
22:53:18.85 |
-14:45:53.9 |
HIP 113117 |
21.72 |
| 2026-04-06 00:00 |
22:53:55.05 |
-14:42:53.9 |
HIP 113117 |
19.13 |
| 2026-04-06 12:00 |
22:54:31.14 |
-14:39:54.5 |
HIP 113117 |
20.74 |
| 2026-04-07 00:00 |
22:55:07.13 |
-14:36:55.7 |
HIP 113117 |
25.76 |
| 2026-04-07 12:00 |
22:55:43.03 |
-14:33:57.4 |
HIP 113292 |
27.85 |
| 2026-04-08 00:00 |
22:56:18.83 |
-14:30:59.8 |
HIP 113378 |
20.86 |
| 2026-04-08 12:00 |
22:56:54.53 |
-14:28:02.7 |
HIP 113378 |
11.87 |
| 2026-04-09 00:00 |
22:57:30.13 |
-14:25:06.3 |
HIP 113378 |
3.67 |
| 2026-04-09 12:00 |
22:58:05.62 |
-14:22:10.4 |
HIP 113395 |
5.39 |
| 2026-04-10 00:00 |
22:58:41.02 |
-14:19:15.2 |
HIP 113395 |
11.38 |
| 2026-04-10 12:00 |
22:59:16.32 |
-14:16:20.7 |
HIP 113395 |
19.83 |
| 2026-04-11 00:00 |
22:59:51.51 |
-14:13:26.7 |
HIP 113631 |
13.81 |
| 2026-04-11 12:00 |
23:00:26.60 |
-14:10:33.4 |
HIP 113631 |
7.14 |
| 2026-04-12 00:00 |
23:01:01.59 |
-14:07:40.8 |
HIP 113631 |
8.50 |
| 2026-04-12 12:00 |
23:01:36.47 |
-14:04:48.8 |
HIP 113675 |
11.83 |
| 2026-04-13 00:00 |
23:02:11.25 |
-14:01:57.6 |
HIP 113798 |
15.45 |
| 2026-04-13 12:00 |
23:02:45.93 |
-13:59:06.9 |
HIP 113798 |
16.10 |
| 2026-04-14 00:00 |
23:03:20.50 |
-13:56:17.0 |
HIP 113798 |
20.89 |
| 2026-04-14 12:00 |
23:03:54.97 |
-13:53:27.8 |
HIP 113798 |
27.73 |
| 2026-04-15 00:00 |
23:04:29.33 |
-13:50:39.3 |
HIP 114094 |
29.88 |
| 2026-04-15 12:00 |
23:05:03.58 |
-13:47:51.5 |
HIP 114094 |
21.23 |
| 2026-04-16 00:00 |
23:05:37.72 |
-13:45:04.4 |
HIP 114094 |
12.77 |