| 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
$$
M_a = (14.631 + 4.779\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.631 |
| n |
4.779 |
| 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) |
| 2026-07-29 00:00 |
00:06:20.42 |
-11:14:05.1 |
HIP 608 |
19.52 |
| 2026-07-29 12:00 |
00:06:14.94 |
-11:15:54.5 |
HIP 608 |
21.71 |
| 2026-07-30 00:00 |
00:06:09.20 |
-11:17:45.2 |
HIP 608 |
23.98 |
| 2026-07-30 12:00 |
00:06:03.20 |
-11:19:37.1 |
HIP 609 |
26.05 |
| 2026-07-31 00:00 |
00:05:56.94 |
-11:21:30.3 |
HIP 609 |
26.08 |
| 2026-07-31 12:00 |
00:05:50.42 |
-11:23:24.7 |
HIP 609 |
26.37 |
| 2026-08-01 00:00 |
00:05:43.64 |
-11:25:20.3 |
HIP 609 |
26.95 |
| 2026-08-01 12:00 |
00:05:36.60 |
-11:27:17.2 |
HIP 609 |
27.79 |
| 2026-08-02 00:00 |
00:05:29.29 |
-11:29:15.1 |
HIP 609 |
28.90 |
| 2026-08-02 12:00 |
00:05:21.74 |
-11:31:14.3 |
HIP 609 |
30.27 |
| 2026-08-03 00:00 |
00:05:13.92 |
-11:33:14.6 |
HIP 609 |
31.87 |
| 2026-08-03 12:00 |
00:05:05.84 |
-11:35:16.0 |
HIP 524 |
31.50 |
| 2026-08-04 00:00 |
00:04:57.51 |
-11:37:18.5 |
HIP 266 |
30.66 |
| 2026-08-04 12:00 |
00:04:48.92 |
-11:39:22.1 |
HIP 266 |
27.73 |
| 2026-08-05 00:00 |
00:04:40.08 |
-11:41:26.8 |
HIP 266 |
24.75 |
| 2026-08-05 12:00 |
00:04:30.98 |
-11:43:32.5 |
HIP 266 |
21.70 |
| 2026-08-06 00:00 |
00:04:21.63 |
-11:45:39.3 |
HIP 266 |
18.60 |
| 2026-08-06 12:00 |
00:04:12.02 |
-11:47:47.0 |
HIP 266 |
15.45 |
| 2026-08-07 00:00 |
00:04:02.16 |
-11:49:55.8 |
HIP 266 |
12.25 |
| 2026-08-07 12:00 |
00:03:52.06 |
-11:52:05.5 |
HIP 266 |
9.00 |
| 2026-08-08 00:00 |
00:03:41.70 |
-11:54:16.2 |
HIP 266 |
5.74 |
| 2026-08-08 12:00 |
00:03:31.09 |
-11:56:27.8 |
HIP 266 |
2.61 |
| 2026-08-09 00:00 |
00:03:20.24 |
-11:58:40.3 |
HIP 266 |
1.96 |
| 2026-08-09 12:00 |
00:03:09.14 |
-12:00:53.7 |
HIP 266 |
5.02 |
| 2026-08-10 00:00 |
00:02:57.80 |
-12:03:07.9 |
HIP 266 |
8.48 |
| 2026-08-10 12:00 |
00:02:46.21 |
-12:05:23.0 |
HIP 177 |
10.81 |
| 2026-08-11 00:00 |
00:02:34.39 |
-12:07:38.8 |
HIP 177 |
10.93 |
| 2026-08-11 12:00 |
00:02:22.32 |
-12:09:55.4 |
HIP 177 |
12.22 |
| 2026-08-12 00:00 |
00:02:10.02 |
-12:12:12.8 |
HIP 177 |
14.39 |
| 2026-08-12 12:00 |
00:01:57.48 |
-12:14:30.9 |
HIP 177 |
17.16 |
| 2026-08-13 00:00 |
00:01:44.70 |
-12:16:49.7 |
HIP 177 |
20.31 |
| 2026-08-13 12:00 |
00:01:31.70 |
-12:19:09.2 |
HIP 95 |
21.82 |
| 2026-08-14 00:00 |
00:01:18.46 |
-12:21:29.3 |
HIP 95 |
23.69 |
| 2026-08-14 12:00 |
00:01:05.00 |
-12:23:50.0 |
HIP 95 |
26.06 |
| 2026-08-15 00:00 |
00:00:51.31 |
-12:26:11.3 |
HIP 72 |
23.53 |
| 2026-08-15 12:00 |
00:00:37.40 |
-12:28:33.1 |
HIP 72 |
21.49 |
| 2026-08-16 00:00 |
00:00:23.27 |
-12:30:55.5 |
HIP 72 |
20.12 |
| 2026-08-16 12:00 |
00:00:08.93 |
-12:33:18.3 |
HIP 72 |
19.58 |
| 2026-08-17 00:00 |
23:59:54.36 |
-12:35:41.6 |
HIP 72 |
19.97 |
| 2026-08-17 12:00 |
23:59:39.59 |
-12:38:05.3 |
HIP 118203 |
18.95 |
| 2026-08-18 00:00 |
23:59:24.60 |
-12:40:29.5 |
HIP 118203 |
17.58 |
| 2026-08-18 12:00 |
23:59:09.41 |
-12:42:54.0 |
HIP 118203 |
17.23 |
| 2026-08-19 00:00 |
23:58:54.01 |
-12:45:18.8 |
HIP 118203 |
17.98 |