| 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) |
| 2026-07-29 00:00 |
03:32:38.25 |
-22:08:17.7 |
HIP 16608 |
20.08 |
| 2026-07-29 12:00 |
03:32:38.75 |
-22:08:30.4 |
HIP 16608 |
20.13 |
| 2026-07-30 00:00 |
03:32:39.25 |
-22:08:43.2 |
HIP 16608 |
20.18 |
| 2026-07-30 12:00 |
03:32:39.73 |
-22:08:56.0 |
HIP 16608 |
20.23 |
| 2026-07-31 00:00 |
03:32:40.20 |
-22:09:08.8 |
HIP 16608 |
20.29 |
| 2026-07-31 12:00 |
03:32:40.65 |
-22:09:21.8 |
HIP 16608 |
20.36 |
| 2026-08-01 00:00 |
03:32:41.10 |
-22:09:34.8 |
HIP 16608 |
20.43 |
| 2026-08-01 12:00 |
03:32:41.53 |
-22:09:47.9 |
HIP 16608 |
20.50 |
| 2026-08-02 00:00 |
03:32:41.95 |
-22:10:01.1 |
HIP 16608 |
20.59 |
| 2026-08-02 12:00 |
03:32:42.36 |
-22:10:14.3 |
HIP 16608 |
20.67 |
| 2026-08-03 00:00 |
03:32:42.75 |
-22:10:27.6 |
HIP 16608 |
20.77 |
| 2026-08-03 12:00 |
03:32:43.13 |
-22:10:41.0 |
HIP 16608 |
20.86 |
| 2026-08-04 00:00 |
03:32:43.51 |
-22:10:54.4 |
HIP 16608 |
20.97 |
| 2026-08-04 12:00 |
03:32:43.86 |
-22:11:07.9 |
HIP 16608 |
21.07 |
| 2026-08-05 00:00 |
03:32:44.21 |
-22:11:21.5 |
HIP 16608 |
21.19 |
| 2026-08-05 12:00 |
03:32:44.54 |
-22:11:35.1 |
HIP 16608 |
21.30 |
| 2026-08-06 00:00 |
03:32:44.86 |
-22:11:48.8 |
HIP 16608 |
21.43 |
| 2026-08-06 12:00 |
03:32:45.17 |
-22:12:02.5 |
HIP 16608 |
21.55 |
| 2026-08-07 00:00 |
03:32:45.46 |
-22:12:16.3 |
HIP 16608 |
21.68 |
| 2026-08-07 12:00 |
03:32:45.75 |
-22:12:30.2 |
HIP 16608 |
21.82 |
| 2026-08-08 00:00 |
03:32:46.02 |
-22:12:44.1 |
HIP 16608 |
21.96 |
| 2026-08-08 12:00 |
03:32:46.27 |
-22:12:58.1 |
HIP 16608 |
22.11 |
| 2026-08-09 00:00 |
03:32:46.52 |
-22:13:12.1 |
HIP 16608 |
22.25 |
| 2026-08-09 12:00 |
03:32:46.75 |
-22:13:26.2 |
HIP 16608 |
22.41 |
| 2026-08-10 00:00 |
03:32:46.97 |
-22:13:40.4 |
HIP 16608 |
22.56 |
| 2026-08-10 12:00 |
03:32:47.17 |
-22:13:54.6 |
HIP 16608 |
22.73 |
| 2026-08-11 00:00 |
03:32:47.36 |
-22:14:08.8 |
HIP 16608 |
22.89 |
| 2026-08-11 12:00 |
03:32:47.54 |
-22:14:23.1 |
HIP 16608 |
23.06 |
| 2026-08-12 00:00 |
03:32:47.71 |
-22:14:37.5 |
HIP 16608 |
23.23 |
| 2026-08-12 12:00 |
03:32:47.86 |
-22:14:51.9 |
HIP 16608 |
23.41 |
| 2026-08-13 00:00 |
03:32:48.00 |
-22:15:06.4 |
HIP 16608 |
23.59 |
| 2026-08-13 12:00 |
03:32:48.13 |
-22:15:20.9 |
HIP 16608 |
23.77 |
| 2026-08-14 00:00 |
03:32:48.24 |
-22:15:35.4 |
HIP 16608 |
23.96 |
| 2026-08-14 12:00 |
03:32:48.35 |
-22:15:50.0 |
HIP 16608 |
24.15 |
| 2026-08-15 00:00 |
03:32:48.43 |
-22:16:04.6 |
HIP 16608 |
24.34 |
| 2026-08-15 12:00 |
03:32:48.51 |
-22:16:19.3 |
HIP 16608 |
24.54 |
| 2026-08-16 00:00 |
03:32:48.57 |
-22:16:34.0 |
HIP 16608 |
24.74 |
| 2026-08-16 12:00 |
03:32:48.62 |
-22:16:48.8 |
HIP 16608 |
24.94 |
| 2026-08-17 00:00 |
03:32:48.65 |
-22:17:03.6 |
HIP 16608 |
25.14 |
| 2026-08-17 12:00 |
03:32:48.68 |
-22:17:18.5 |
HIP 16608 |
25.35 |
| 2026-08-18 00:00 |
03:32:48.69 |
-22:17:33.3 |
HIP 16608 |
25.56 |
| 2026-08-18 12:00 |
03:32:48.68 |
-22:17:48.3 |
HIP 16608 |
25.78 |
| 2026-08-19 00:00 |
03:32:48.67 |
-22:18:03.2 |
HIP 16608 |
25.99 |