| 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) |
| 2026-09-20 00:00 |
21:37:43.76 |
-18:02:36.8 |
HIP 106741 |
24.44 |
| 2026-09-20 12:00 |
21:37:30.79 |
-18:03:27.1 |
HIP 106741 |
23.12 |
| 2026-09-21 00:00 |
21:37:18.01 |
-18:04:16.2 |
HIP 106741 |
22.20 |
| 2026-09-21 12:00 |
21:37:05.41 |
-18:05:04.1 |
HIP 106673 |
21.11 |
| 2026-09-22 00:00 |
21:36:53.01 |
-18:05:50.8 |
HIP 106673 |
19.13 |
| 2026-09-22 12:00 |
21:36:40.80 |
-18:06:36.4 |
HIP 106673 |
17.48 |
| 2026-09-23 00:00 |
21:36:28.78 |
-18:07:20.7 |
HIP 106673 |
16.26 |
| 2026-09-23 12:00 |
21:36:16.96 |
-18:08:03.9 |
HIP 106673 |
15.51 |
| 2026-09-24 00:00 |
21:36:05.33 |
-18:08:45.9 |
HIP 106673 |
15.30 |
| 2026-09-24 12:00 |
21:35:53.91 |
-18:09:26.6 |
HIP 106673 |
15.61 |
| 2026-09-25 00:00 |
21:35:42.68 |
-18:10:06.2 |
HIP 106673 |
16.38 |
| 2026-09-25 12:00 |
21:35:31.66 |
-18:10:44.6 |
HIP 106673 |
17.54 |
| 2026-09-26 00:00 |
21:35:20.84 |
-18:11:21.7 |
HIP 106673 |
18.98 |
| 2026-09-26 12:00 |
21:35:10.23 |
-18:11:57.7 |
HIP 106673 |
20.64 |
| 2026-09-27 00:00 |
21:34:59.83 |
-18:12:32.5 |
HIP 106673 |
22.44 |
| 2026-09-27 12:00 |
21:34:49.63 |
-18:13:06.0 |
HIP 106673 |
24.33 |
| 2026-09-28 00:00 |
21:34:39.64 |
-18:13:38.4 |
HIP 106470 |
24.26 |
| 2026-09-28 12:00 |
21:34:29.87 |
-18:14:09.5 |
HIP 106470 |
23.76 |
| 2026-09-29 00:00 |
21:34:20.30 |
-18:14:39.4 |
HIP 106470 |
23.49 |
| 2026-09-29 12:00 |
21:34:10.95 |
-18:15:08.2 |
HIP 106415 |
23.41 |
| 2026-09-30 00:00 |
21:34:01.82 |
-18:15:35.7 |
HIP 106415 |
21.82 |
| 2026-09-30 12:00 |
21:33:52.90 |
-18:16:02.0 |
HIP 106415 |
20.38 |
| 2026-10-01 00:00 |
21:33:44.20 |
-18:16:27.0 |
HIP 106415 |
19.12 |
| 2026-10-01 12:00 |
21:33:35.72 |
-18:16:50.9 |
HIP 106415 |
18.05 |
| 2026-10-02 00:00 |
21:33:27.45 |
-18:17:13.6 |
HIP 106415 |
17.19 |
| 2026-10-02 12:00 |
21:33:19.41 |
-18:17:35.0 |
HIP 106415 |
16.56 |
| 2026-10-03 00:00 |
21:33:11.60 |
-18:17:55.2 |
HIP 106415 |
16.15 |
| 2026-10-03 12:00 |
21:33:04.00 |
-18:18:14.2 |
HIP 106415 |
15.97 |
| 2026-10-04 00:00 |
21:32:56.63 |
-18:18:32.0 |
HIP 106415 |
16.00 |
| 2026-10-04 12:00 |
21:32:49.49 |
-18:18:48.5 |
HIP 106382 |
15.92 |
| 2026-10-05 00:00 |
21:32:42.57 |
-18:19:03.8 |
HIP 106382 |
15.73 |
| 2026-10-05 12:00 |
21:32:35.88 |
-18:19:17.9 |
HIP 106382 |
15.73 |
| 2026-10-06 00:00 |
21:32:29.42 |
-18:19:30.8 |
HIP 106382 |
15.90 |
| 2026-10-06 12:00 |
21:32:23.19 |
-18:19:42.5 |
HIP 106382 |
16.21 |
| 2026-10-07 00:00 |
21:32:17.19 |
-18:19:52.9 |
HIP 106382 |
16.64 |
| 2026-10-07 12:00 |
21:32:11.42 |
-18:20:02.1 |
HIP 106382 |
17.17 |
| 2026-10-08 00:00 |
21:32:05.89 |
-18:20:10.1 |
HIP 106382 |
17.78 |
| 2026-10-08 12:00 |
21:32:00.58 |
-18:20:16.9 |
HIP 106382 |
18.44 |
| 2026-10-09 00:00 |
21:31:55.52 |
-18:20:22.4 |
HIP 106382 |
19.14 |
| 2026-10-09 12:00 |
21:31:50.68 |
-18:20:26.7 |
HIP 106382 |
19.86 |
| 2026-10-10 00:00 |
21:31:46.09 |
-18:20:29.8 |
HIP 106382 |
20.60 |
| 2026-10-10 12:00 |
21:31:41.72 |
-18:20:31.7 |
HIP 106382 |
21.34 |
| 2026-10-11 00:00 |
21:31:37.60 |
-18:20:32.4 |
HIP 106382 |
22.07 |