| 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 |
-0.502 |
| 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 |
22:08:40.44 |
-14:15:57.8 |
HIP 109220 |
20.76 |
| 2026-05-12 12:00 |
22:08:54.83 |
-14:15:00.9 |
HIP 109392 |
22.03 |
| 2026-05-13 00:00 |
22:09:09.07 |
-14:14:05.0 |
HIP 109392 |
21.26 |
| 2026-05-13 12:00 |
22:09:23.15 |
-14:13:09.9 |
HIP 109395 |
20.37 |
| 2026-05-14 00:00 |
22:09:37.08 |
-14:12:15.7 |
HIP 109395 |
18.86 |
| 2026-05-14 12:00 |
22:09:50.84 |
-14:11:22.5 |
HIP 109395 |
17.94 |
| 2026-05-15 00:00 |
22:10:04.45 |
-14:10:30.1 |
HIP 109395 |
17.65 |
| 2026-05-15 12:00 |
22:10:17.90 |
-14:09:38.7 |
HIP 109395 |
18.02 |
| 2026-05-16 00:00 |
22:10:31.19 |
-14:08:48.1 |
HIP 109395 |
18.98 |
| 2026-05-16 12:00 |
22:10:44.32 |
-14:07:58.5 |
HIP 109395 |
20.42 |
| 2026-05-17 00:00 |
22:10:57.28 |
-14:07:09.9 |
HIP 109607 |
19.17 |
| 2026-05-17 12:00 |
22:11:10.09 |
-14:06:22.2 |
HIP 109607 |
16.60 |
| 2026-05-18 00:00 |
22:11:22.72 |
-14:05:35.4 |
HIP 109607 |
14.31 |
| 2026-05-18 12:00 |
22:11:35.20 |
-14:04:49.6 |
HIP 109607 |
12.43 |
| 2026-05-19 00:00 |
22:11:47.51 |
-14:04:04.8 |
HIP 109607 |
11.13 |
| 2026-05-19 12:00 |
22:11:59.65 |
-14:03:20.9 |
HIP 109624 |
10.42 |
| 2026-05-20 00:00 |
22:12:11.62 |
-14:02:38.0 |
HIP 109624 |
9.63 |
| 2026-05-20 12:00 |
22:12:23.43 |
-14:01:56.0 |
HIP 109624 |
9.71 |
| 2026-05-21 00:00 |
22:12:35.07 |
-14:01:15.1 |
HIP 109624 |
10.62 |
| 2026-05-21 12:00 |
22:12:46.53 |
-14:00:35.1 |
HIP 109683 |
9.60 |
| 2026-05-22 00:00 |
22:12:57.83 |
-13:59:56.1 |
HIP 109683 |
7.94 |
| 2026-05-22 12:00 |
22:13:08.96 |
-13:59:18.1 |
HIP 109683 |
7.07 |
| 2026-05-23 00:00 |
22:13:19.91 |
-13:58:41.2 |
HIP 109683 |
7.23 |
| 2026-05-23 12:00 |
22:13:30.70 |
-13:58:05.2 |
HIP 109683 |
8.32 |
| 2026-05-24 00:00 |
22:13:41.31 |
-13:57:30.2 |
HIP 109683 |
10.00 |
| 2026-05-24 12:00 |
22:13:51.74 |
-13:56:56.2 |
HIP 109683 |
11.99 |
| 2026-05-25 00:00 |
22:14:02.00 |
-13:56:23.3 |
HIP 109683 |
14.15 |
| 2026-05-25 12:00 |
22:14:12.09 |
-13:55:51.4 |
HIP 109683 |
16.38 |
| 2026-05-26 00:00 |
22:14:22.00 |
-13:55:20.5 |
HIP 109683 |
18.65 |
| 2026-05-26 12:00 |
22:14:31.73 |
-13:54:50.6 |
HIP 109683 |
20.91 |
| 2026-05-27 00:00 |
22:14:41.29 |
-13:54:21.8 |
HIP 109683 |
23.17 |
| 2026-05-27 12:00 |
22:14:50.67 |
-13:53:54.0 |
HIP 109941 |
24.12 |
| 2026-05-28 00:00 |
22:14:59.87 |
-13:53:27.3 |
HIP 109970 |
22.68 |
| 2026-05-28 12:00 |
22:15:08.89 |
-13:53:01.6 |
HIP 109970 |
20.89 |
| 2026-05-29 00:00 |
22:15:17.73 |
-13:52:37.0 |
HIP 109970 |
19.23 |
| 2026-05-29 12:00 |
22:15:26.38 |
-13:52:13.4 |
HIP 109970 |
17.71 |
| 2026-05-30 00:00 |
22:15:34.86 |
-13:51:50.9 |
HIP 109970 |
16.34 |
| 2026-05-30 12:00 |
22:15:43.15 |
-13:51:29.4 |
HIP 109970 |
15.16 |
| 2026-05-31 00:00 |
22:15:51.26 |
-13:51:09.1 |
HIP 109970 |
14.19 |
| 2026-05-31 12:00 |
22:15:59.18 |
-13:50:49.8 |
HIP 109970 |
13.45 |
| 2026-06-01 00:00 |
22:16:06.92 |
-13:50:31.6 |
HIP 109970 |
12.96 |
| 2026-06-01 12:00 |
22:16:14.47 |
-13:50:14.4 |
HIP 109970 |
12.73 |
| 2026-06-02 00:00 |
22:16:21.84 |
-13:49:58.4 |
HIP 109970 |
12.75 |