| 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) |
| 2026-05-12 00:00 |
23:32:30.91 |
-11:39:45.3 |
HIP 116163 |
8.37 |
| 2026-05-12 12:00 |
23:32:58.54 |
-11:37:46.4 |
HIP 116163 |
12.34 |
| 2026-05-13 00:00 |
23:33:26.03 |
-11:35:48.7 |
HIP 116163 |
18.24 |
| 2026-05-13 12:00 |
23:33:53.38 |
-11:33:52.1 |
HIP 116398 |
19.28 |
| 2026-05-14 00:00 |
23:34:20.59 |
-11:31:56.6 |
HIP 116398 |
12.89 |
| 2026-05-14 12:00 |
23:34:47.65 |
-11:30:02.3 |
HIP 116398 |
7.55 |
| 2026-05-15 00:00 |
23:35:14.56 |
-11:28:09.1 |
HIP 116398 |
6.54 |
| 2026-05-15 12:00 |
23:35:41.33 |
-11:26:17.0 |
HIP 116398 |
11.03 |
| 2026-05-16 00:00 |
23:36:07.96 |
-11:24:26.1 |
HIP 116398 |
17.09 |
| 2026-05-16 12:00 |
23:36:34.44 |
-11:22:36.4 |
HIP 116398 |
23.51 |
| 2026-05-17 00:00 |
23:37:00.76 |
-11:20:47.9 |
HIP 116398 |
30.03 |
| 2026-05-17 12:00 |
23:37:26.94 |
-11:19:00.5 |
HIP 116398 |
36.57 |
| 2026-05-18 00:00 |
23:37:52.97 |
-11:17:14.3 |
HIP 116398 |
43.11 |
| 2026-05-18 12:00 |
23:38:18.85 |
-11:15:29.4 |
HIP 116841 |
41.39 |
| 2026-05-19 00:00 |
23:38:44.58 |
-11:13:45.6 |
HIP 116841 |
36.11 |
| 2026-05-19 12:00 |
23:39:10.15 |
-11:12:03.0 |
HIP 116841 |
31.32 |
| 2026-05-20 00:00 |
23:39:35.57 |
-11:10:21.7 |
HIP 116841 |
27.26 |
| 2026-05-20 12:00 |
23:40:00.83 |
-11:08:41.6 |
HIP 116841 |
24.27 |
| 2026-05-21 00:00 |
23:40:25.94 |
-11:07:02.7 |
HIP 116841 |
22.73 |
| 2026-05-21 12:00 |
23:40:50.90 |
-11:05:25.0 |
HIP 116841 |
22.91 |
| 2026-05-22 00:00 |
23:41:15.70 |
-11:03:48.6 |
HIP 116841 |
24.74 |
| 2026-05-22 12:00 |
23:41:40.34 |
-11:02:13.4 |
HIP 116975 |
24.08 |
| 2026-05-23 00:00 |
23:42:04.82 |
-11:00:39.5 |
HIP 116975 |
21.78 |
| 2026-05-23 12:00 |
23:42:29.14 |
-10:59:06.9 |
HIP 116975 |
21.10 |
| 2026-05-24 00:00 |
23:42:53.30 |
-10:57:35.5 |
HIP 117093 |
20.27 |
| 2026-05-24 12:00 |
23:43:17.30 |
-10:56:05.3 |
HIP 117093 |
14.63 |
| 2026-05-25 00:00 |
23:43:41.15 |
-10:54:36.5 |
HIP 117093 |
9.59 |
| 2026-05-25 12:00 |
23:44:04.82 |
-10:53:08.9 |
HIP 117093 |
6.52 |
| 2026-05-26 00:00 |
23:44:28.34 |
-10:51:42.6 |
HIP 117093 |
8.02 |
| 2026-05-26 12:00 |
23:44:51.69 |
-10:50:17.6 |
HIP 117093 |
12.48 |
| 2026-05-27 00:00 |
23:45:14.88 |
-10:48:53.9 |
HIP 117093 |
17.76 |
| 2026-05-27 12:00 |
23:45:37.91 |
-10:47:31.5 |
HIP 117212 |
16.89 |
| 2026-05-28 00:00 |
23:46:00.76 |
-10:46:10.4 |
HIP 117212 |
14.69 |
| 2026-05-28 12:00 |
23:46:23.45 |
-10:44:50.7 |
HIP 117212 |
14.59 |
| 2026-05-29 00:00 |
23:46:45.98 |
-10:43:32.2 |
HIP 117212 |
16.60 |
| 2026-05-29 12:00 |
23:47:08.33 |
-10:42:15.1 |
HIP 117212 |
20.04 |
| 2026-05-30 00:00 |
23:47:30.52 |
-10:40:59.3 |
HIP 117212 |
24.30 |
| 2026-05-30 12:00 |
23:47:52.53 |
-10:39:44.9 |
HIP 117212 |
28.98 |
| 2026-05-31 00:00 |
23:48:14.38 |
-10:38:31.8 |
HIP 117212 |
33.88 |
| 2026-05-31 12:00 |
23:48:36.05 |
-10:37:20.0 |
HIP 117528 |
36.34 |
| 2026-06-01 00:00 |
23:48:57.55 |
-10:36:09.7 |
HIP 117528 |
34.42 |
| 2026-06-01 12:00 |
23:49:18.87 |
-10:35:00.7 |
HIP 117528 |
33.26 |
| 2026-06-02 00:00 |
23:49:40.02 |
-10:33:53.0 |
HIP 117528 |
32.93 |