| Parameter |
Value |
| Designation |
C/1972 L1 (Sandage) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1972-11-14T18:55:18.753600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:21Z |
| Obs used |
146 |
| NEO |
- |
| M1 |
5.600 |
| K1 |
7.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1972-10-11.0000000 |
| e |
1.00634381 |
| q (au) |
4.275741 |
| a (au) |
-674.001905 |
| i (deg) |
79.368060 |
| Ω (om, deg) |
225.486355 |
| ω (w, deg) |
56.654504 |
| M (ma, deg) |
-0.001960 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.002 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.002 |
| n |
2.000 |
| gf |
0.998 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.998 |
| 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 |
03:47:00.13 |
-09:26:29.8 |
HIP 17650 |
3.96 |
| 2026-09-20 12:00 |
03:46:59.41 |
-09:26:42.7 |
HIP 17650 |
4.05 |
| 2026-09-21 00:00 |
03:46:58.68 |
-09:26:55.6 |
HIP 17650 |
4.14 |
| 2026-09-21 12:00 |
03:46:57.94 |
-09:27:08.5 |
HIP 17650 |
4.26 |
| 2026-09-22 00:00 |
03:46:57.19 |
-09:27:21.4 |
HIP 17650 |
4.38 |
| 2026-09-22 12:00 |
03:46:56.43 |
-09:27:34.2 |
HIP 17650 |
4.52 |
| 2026-09-23 00:00 |
03:46:55.66 |
-09:27:47.1 |
HIP 17650 |
4.68 |
| 2026-09-23 12:00 |
03:46:54.87 |
-09:27:59.9 |
HIP 17627 |
4.74 |
| 2026-09-24 00:00 |
03:46:54.08 |
-09:28:12.7 |
HIP 17627 |
4.63 |
| 2026-09-24 12:00 |
03:46:53.27 |
-09:28:25.4 |
HIP 17627 |
4.53 |
| 2026-09-25 00:00 |
03:46:52.45 |
-09:28:38.2 |
HIP 17627 |
4.44 |
| 2026-09-25 12:00 |
03:46:51.62 |
-09:28:51.0 |
HIP 17627 |
4.37 |
| 2026-09-26 00:00 |
03:46:50.78 |
-09:29:03.7 |
HIP 17627 |
4.32 |
| 2026-09-26 12:00 |
03:46:49.93 |
-09:29:16.4 |
HIP 17627 |
4.28 |
| 2026-09-27 00:00 |
03:46:49.07 |
-09:29:29.1 |
HIP 17627 |
4.26 |
| 2026-09-27 12:00 |
03:46:48.19 |
-09:29:41.7 |
HIP 17627 |
4.26 |
| 2026-09-28 00:00 |
03:46:47.31 |
-09:29:54.3 |
HIP 17627 |
4.28 |
| 2026-09-28 12:00 |
03:46:46.41 |
-09:30:06.9 |
HIP 17627 |
4.32 |
| 2026-09-29 00:00 |
03:46:45.51 |
-09:30:19.5 |
HIP 17627 |
4.38 |
| 2026-09-29 12:00 |
03:46:44.59 |
-09:30:32.1 |
HIP 17627 |
4.46 |
| 2026-09-30 00:00 |
03:46:43.66 |
-09:30:44.6 |
HIP 17627 |
4.55 |
| 2026-09-30 12:00 |
03:46:42.73 |
-09:30:57.1 |
HIP 17627 |
4.67 |
| 2026-10-01 00:00 |
03:46:41.78 |
-09:31:09.6 |
HIP 17627 |
4.80 |
| 2026-10-01 12:00 |
03:46:40.82 |
-09:31:22.0 |
HIP 17627 |
4.94 |
| 2026-10-02 00:00 |
03:46:39.85 |
-09:31:34.4 |
HIP 17627 |
5.10 |
| 2026-10-02 12:00 |
03:46:38.87 |
-09:31:46.8 |
HIP 17627 |
5.27 |
| 2026-10-03 00:00 |
03:46:37.88 |
-09:31:59.2 |
HIP 17627 |
5.46 |
| 2026-10-03 12:00 |
03:46:36.88 |
-09:32:11.5 |
HIP 17627 |
5.65 |
| 2026-10-04 00:00 |
03:46:35.87 |
-09:32:23.8 |
HIP 17627 |
5.86 |
| 2026-10-04 12:00 |
03:46:34.85 |
-09:32:36.0 |
HIP 17627 |
6.08 |
| 2026-10-05 00:00 |
03:46:33.82 |
-09:32:48.2 |
HIP 17627 |
6.30 |
| 2026-10-05 12:00 |
03:46:32.78 |
-09:33:00.4 |
HIP 17627 |
6.54 |
| 2026-10-06 00:00 |
03:46:31.73 |
-09:33:12.5 |
HIP 17627 |
6.78 |
| 2026-10-06 12:00 |
03:46:30.67 |
-09:33:24.6 |
HIP 17627 |
7.02 |
| 2026-10-07 00:00 |
03:46:29.60 |
-09:33:36.7 |
HIP 17627 |
7.28 |
| 2026-10-07 12:00 |
03:46:28.52 |
-09:33:48.7 |
HIP 17627 |
7.54 |
| 2026-10-08 00:00 |
03:46:27.43 |
-09:34:00.6 |
HIP 17627 |
7.81 |
| 2026-10-08 12:00 |
03:46:26.34 |
-09:34:12.6 |
HIP 17627 |
8.08 |
| 2026-10-09 00:00 |
03:46:25.23 |
-09:34:24.4 |
HIP 17627 |
8.35 |
| 2026-10-09 12:00 |
03:46:24.11 |
-09:34:36.3 |
HIP 17627 |
8.63 |
| 2026-10-10 00:00 |
03:46:22.99 |
-09:34:48.1 |
HIP 17627 |
8.92 |
| 2026-10-10 12:00 |
03:46:21.85 |
-09:34:59.8 |
HIP 17627 |
9.21 |
| 2026-10-11 00:00 |
03:46:20.71 |
-09:35:11.5 |
HIP 17627 |
9.50 |