| Parameter |
Value |
| Designation |
C/1968 H1 (Tago-Honda-Yamamoto) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1968-05-16T06:29:47.762880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:17Z |
| Obs used |
35 |
| NEO |
- |
| M1 |
9.800 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1968-05-17.0000000 |
| e |
0.99621615 |
| q (au) |
0.680377 |
| a (au) |
179.810794 |
| i (deg) |
102.170261 |
| Ω (om, deg) |
233.108209 |
| ω (w, deg) |
50.446716 |
| M (ma, deg) |
0.000298 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.114 + 2.389\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.114 |
| n |
2.389 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.800 |
| δ90 |
1.000 |
| 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 |
03:29:32.83 |
-21:56:35.1 |
HIP 16324 |
13.83 |
| 2026-05-12 12:00 |
03:29:34.35 |
-21:56:30.3 |
HIP 16324 |
13.56 |
| 2026-05-13 00:00 |
03:29:35.87 |
-21:56:25.7 |
HIP 16324 |
13.29 |
| 2026-05-13 12:00 |
03:29:37.40 |
-21:56:21.2 |
HIP 16324 |
13.02 |
| 2026-05-14 00:00 |
03:29:38.92 |
-21:56:16.8 |
HIP 16324 |
12.75 |
| 2026-05-14 12:00 |
03:29:40.45 |
-21:56:12.6 |
HIP 16324 |
12.49 |
| 2026-05-15 00:00 |
03:29:41.97 |
-21:56:08.4 |
HIP 16324 |
12.23 |
| 2026-05-15 12:00 |
03:29:43.50 |
-21:56:04.4 |
HIP 16324 |
11.97 |
| 2026-05-16 00:00 |
03:29:45.02 |
-21:56:00.5 |
HIP 16324 |
11.72 |
| 2026-05-16 12:00 |
03:29:46.55 |
-21:55:56.7 |
HIP 16324 |
11.48 |
| 2026-05-17 00:00 |
03:29:48.08 |
-21:55:53.1 |
HIP 16324 |
11.24 |
| 2026-05-17 12:00 |
03:29:49.60 |
-21:55:49.5 |
HIP 16324 |
11.00 |
| 2026-05-18 00:00 |
03:29:51.13 |
-21:55:46.1 |
HIP 16324 |
10.77 |
| 2026-05-18 12:00 |
03:29:52.65 |
-21:55:42.8 |
HIP 16324 |
10.55 |
| 2026-05-19 00:00 |
03:29:54.18 |
-21:55:39.7 |
HIP 16324 |
10.33 |
| 2026-05-19 12:00 |
03:29:55.70 |
-21:55:36.6 |
HIP 16324 |
10.12 |
| 2026-05-20 00:00 |
03:29:57.22 |
-21:55:33.7 |
HIP 16324 |
9.91 |
| 2026-05-20 12:00 |
03:29:58.74 |
-21:55:30.9 |
HIP 16324 |
9.71 |
| 2026-05-21 00:00 |
03:30:00.27 |
-21:55:28.3 |
HIP 16324 |
9.52 |
| 2026-05-21 12:00 |
03:30:01.78 |
-21:55:25.7 |
HIP 16324 |
9.34 |
| 2026-05-22 00:00 |
03:30:03.30 |
-21:55:23.3 |
HIP 16324 |
9.17 |
| 2026-05-22 12:00 |
03:30:04.82 |
-21:55:21.0 |
HIP 16324 |
9.01 |
| 2026-05-23 00:00 |
03:30:06.34 |
-21:55:18.8 |
HIP 16324 |
8.85 |
| 2026-05-23 12:00 |
03:30:07.85 |
-21:55:16.8 |
HIP 16324 |
8.71 |
| 2026-05-24 00:00 |
03:30:09.36 |
-21:55:14.8 |
HIP 16324 |
8.57 |
| 2026-05-24 12:00 |
03:30:10.87 |
-21:55:13.0 |
HIP 16324 |
8.45 |
| 2026-05-25 00:00 |
03:30:12.38 |
-21:55:11.4 |
HIP 16324 |
8.34 |
| 2026-05-25 12:00 |
03:30:13.89 |
-21:55:09.8 |
HIP 16324 |
8.24 |
| 2026-05-26 00:00 |
03:30:15.39 |
-21:55:08.4 |
HIP 16324 |
8.15 |
| 2026-05-26 12:00 |
03:30:16.90 |
-21:55:07.1 |
HIP 16324 |
8.07 |
| 2026-05-27 00:00 |
03:30:18.40 |
-21:55:05.9 |
HIP 16324 |
8.01 |
| 2026-05-27 12:00 |
03:30:19.89 |
-21:55:04.8 |
HIP 16324 |
7.96 |
| 2026-05-28 00:00 |
03:30:21.39 |
-21:55:03.9 |
HIP 16324 |
7.92 |
| 2026-05-28 12:00 |
03:30:22.88 |
-21:55:03.1 |
HIP 16324 |
7.90 |
| 2026-05-29 00:00 |
03:30:24.37 |
-21:55:02.4 |
HIP 16324 |
7.88 |
| 2026-05-29 12:00 |
03:30:25.86 |
-21:55:01.8 |
HIP 16324 |
7.89 |
| 2026-05-30 00:00 |
03:30:27.35 |
-21:55:01.4 |
HIP 16324 |
7.90 |
| 2026-05-30 12:00 |
03:30:28.83 |
-21:55:01.1 |
HIP 16324 |
7.93 |
| 2026-05-31 00:00 |
03:30:30.31 |
-21:55:00.9 |
HIP 16324 |
7.97 |
| 2026-05-31 12:00 |
03:30:31.78 |
-21:55:00.8 |
HIP 16324 |
8.02 |
| 2026-06-01 00:00 |
03:30:33.25 |
-21:55:00.9 |
HIP 16324 |
8.08 |
| 2026-06-01 12:00 |
03:30:34.72 |
-21:55:01.0 |
HIP 16324 |
8.16 |
| 2026-06-02 00:00 |
03:30:36.19 |
-21:55:01.4 |
HIP 16324 |
8.25 |