| Parameter |
Value |
| Designation |
D/1977 C1 (Skiff-Kosai) |
| Type |
D |
| Perihelion (tp_cal, UTC) |
1976-08-03T23:51:26.127360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:24Z |
| Obs used |
8 |
| NEO |
- |
| M1 |
8.500 |
| K1 |
15.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1977-02-23.0000000 |
| e |
0.25917112 |
| q (au) |
2.849755 |
| a (au) |
3.846712 |
| i (deg) |
3.201388 |
| Ω (om, deg) |
80.768376 |
| ω (w, deg) |
26.550778 |
| M (ma, deg) |
26.520292 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.449 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.449 |
| n |
2.000 |
| 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 |
22:08:11.43 |
-15:21:25.1 |
HIP 109165 |
27.04 |
| 2026-07-29 12:00 |
22:07:56.12 |
-15:23:05.9 |
HIP 109165 |
23.15 |
| 2026-07-30 00:00 |
22:07:40.67 |
-15:24:47.2 |
HIP 109165 |
19.30 |
| 2026-07-30 12:00 |
22:07:25.09 |
-15:26:29.0 |
HIP 109165 |
15.55 |
| 2026-07-31 00:00 |
22:07:09.36 |
-15:28:11.2 |
HIP 109165 |
12.01 |
| 2026-07-31 12:00 |
22:06:53.49 |
-15:29:53.8 |
HIP 109165 |
9.01 |
| 2026-08-01 00:00 |
22:06:37.50 |
-15:31:36.8 |
HIP 109165 |
7.28 |
| 2026-08-01 12:00 |
22:06:21.37 |
-15:33:20.2 |
HIP 109165 |
7.79 |
| 2026-08-02 00:00 |
22:06:05.11 |
-15:35:03.9 |
HIP 109165 |
10.25 |
| 2026-08-02 12:00 |
22:05:48.72 |
-15:36:48.0 |
HIP 109165 |
13.67 |
| 2026-08-03 00:00 |
22:05:32.22 |
-15:38:32.5 |
HIP 109165 |
17.52 |
| 2026-08-03 12:00 |
22:05:15.59 |
-15:40:17.2 |
HIP 109165 |
21.58 |
| 2026-08-04 00:00 |
22:04:58.84 |
-15:42:02.2 |
HIP 108918 |
21.72 |
| 2026-08-04 12:00 |
22:04:41.97 |
-15:43:47.5 |
HIP 108918 |
17.43 |
| 2026-08-05 00:00 |
22:04:25.00 |
-15:45:33.1 |
HIP 108918 |
13.21 |
| 2026-08-05 12:00 |
22:04:07.91 |
-15:47:18.9 |
HIP 108918 |
9.19 |
| 2026-08-06 00:00 |
22:03:50.71 |
-15:49:04.9 |
HIP 108918 |
5.85 |
| 2026-08-06 12:00 |
22:03:33.41 |
-15:50:51.1 |
HIP 108918 |
4.96 |
| 2026-08-07 00:00 |
22:03:16.00 |
-15:52:37.5 |
HIP 108918 |
7.49 |
| 2026-08-07 12:00 |
22:02:58.50 |
-15:54:24.0 |
HIP 108918 |
11.38 |
| 2026-08-08 00:00 |
22:02:40.90 |
-15:56:10.7 |
HIP 108918 |
15.66 |
| 2026-08-08 12:00 |
22:02:23.21 |
-15:57:57.5 |
HIP 108918 |
20.10 |
| 2026-08-09 00:00 |
22:02:05.42 |
-15:59:44.3 |
HIP 108732 |
24.32 |
| 2026-08-09 12:00 |
22:01:47.55 |
-16:01:31.3 |
HIP 108732 |
25.05 |
| 2026-08-10 00:00 |
22:01:29.60 |
-16:03:18.3 |
HIP 108732 |
26.60 |
| 2026-08-10 12:00 |
22:01:11.56 |
-16:05:05.4 |
HIP 108732 |
28.83 |
| 2026-08-11 00:00 |
22:00:53.45 |
-16:06:52.4 |
HIP 108732 |
31.61 |
| 2026-08-11 12:00 |
22:00:35.27 |
-16:08:39.5 |
HIP 108732 |
34.81 |
| 2026-08-12 00:00 |
22:00:17.01 |
-16:10:26.5 |
HIP 108732 |
38.33 |
| 2026-08-12 12:00 |
21:59:58.69 |
-16:12:13.5 |
HIP 108732 |
42.11 |
| 2026-08-13 00:00 |
21:59:40.30 |
-16:14:00.3 |
HIP 108358 |
40.26 |
| 2026-08-13 12:00 |
21:59:21.86 |
-16:15:47.1 |
HIP 108358 |
37.08 |
| 2026-08-14 00:00 |
21:59:03.36 |
-16:17:33.8 |
HIP 108358 |
34.27 |
| 2026-08-14 12:00 |
21:58:44.80 |
-16:19:20.3 |
HIP 108358 |
31.93 |
| 2026-08-15 00:00 |
21:58:26.20 |
-16:21:06.7 |
HIP 108358 |
30.16 |
| 2026-08-15 12:00 |
21:58:07.55 |
-16:22:52.9 |
HIP 108358 |
29.08 |
| 2026-08-16 00:00 |
21:57:48.86 |
-16:24:38.8 |
HIP 108358 |
28.77 |
| 2026-08-16 12:00 |
21:57:30.14 |
-16:26:24.6 |
HIP 108358 |
29.26 |
| 2026-08-17 00:00 |
21:57:11.37 |
-16:28:10.1 |
HIP 108358 |
30.50 |
| 2026-08-17 12:00 |
21:56:52.58 |
-16:29:55.3 |
HIP 108358 |
32.43 |
| 2026-08-18 00:00 |
21:56:33.76 |
-16:31:40.3 |
HIP 108358 |
34.92 |
| 2026-08-18 12:00 |
21:56:14.92 |
-16:33:24.9 |
HIP 108358 |
37.87 |
| 2026-08-19 00:00 |
21:55:56.05 |
-16:35:09.3 |
HIP 108066 |
33.58 |