| 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) |
| 2026-07-29 00:00 |
03:47:05.08 |
-09:05:35.4 |
HIP 17582 |
17.42 |
| 2026-07-29 12:00 |
03:47:05.68 |
-09:05:44.7 |
HIP 17582 |
17.61 |
| 2026-07-30 00:00 |
03:47:06.28 |
-09:05:54.1 |
HIP 17650 |
17.78 |
| 2026-07-30 12:00 |
03:47:06.86 |
-09:06:03.6 |
HIP 17650 |
17.65 |
| 2026-07-31 00:00 |
03:47:07.43 |
-09:06:13.1 |
HIP 17650 |
17.53 |
| 2026-07-31 12:00 |
03:47:07.99 |
-09:06:22.7 |
HIP 17650 |
17.41 |
| 2026-08-01 00:00 |
03:47:08.54 |
-09:06:32.4 |
HIP 17650 |
17.29 |
| 2026-08-01 12:00 |
03:47:09.08 |
-09:06:42.1 |
HIP 17650 |
17.16 |
| 2026-08-02 00:00 |
03:47:09.60 |
-09:06:51.9 |
HIP 17650 |
17.04 |
| 2026-08-02 12:00 |
03:47:10.12 |
-09:07:01.8 |
HIP 17650 |
16.92 |
| 2026-08-03 00:00 |
03:47:10.62 |
-09:07:11.7 |
HIP 17650 |
16.79 |
| 2026-08-03 12:00 |
03:47:11.11 |
-09:07:21.7 |
HIP 17650 |
16.67 |
| 2026-08-04 00:00 |
03:47:11.58 |
-09:07:31.8 |
HIP 17650 |
16.55 |
| 2026-08-04 12:00 |
03:47:12.05 |
-09:07:41.9 |
HIP 17650 |
16.42 |
| 2026-08-05 00:00 |
03:47:12.50 |
-09:07:52.1 |
HIP 17650 |
16.30 |
| 2026-08-05 12:00 |
03:47:12.94 |
-09:08:02.4 |
HIP 17650 |
16.17 |
| 2026-08-06 00:00 |
03:47:13.37 |
-09:08:12.7 |
HIP 17650 |
16.05 |
| 2026-08-06 12:00 |
03:47:13.79 |
-09:08:23.1 |
HIP 17650 |
15.92 |
| 2026-08-07 00:00 |
03:47:14.19 |
-09:08:33.6 |
HIP 17650 |
15.79 |
| 2026-08-07 12:00 |
03:47:14.59 |
-09:08:44.1 |
HIP 17650 |
15.67 |
| 2026-08-08 00:00 |
03:47:14.97 |
-09:08:54.7 |
HIP 17650 |
15.54 |
| 2026-08-08 12:00 |
03:47:15.33 |
-09:09:05.3 |
HIP 17650 |
15.41 |
| 2026-08-09 00:00 |
03:47:15.69 |
-09:09:16.0 |
HIP 17650 |
15.28 |
| 2026-08-09 12:00 |
03:47:16.03 |
-09:09:26.8 |
HIP 17650 |
15.15 |
| 2026-08-10 00:00 |
03:47:16.36 |
-09:09:37.6 |
HIP 17650 |
15.02 |
| 2026-08-10 12:00 |
03:47:16.68 |
-09:09:48.5 |
HIP 17650 |
14.89 |
| 2026-08-11 00:00 |
03:47:16.99 |
-09:09:59.4 |
HIP 17650 |
14.76 |
| 2026-08-11 12:00 |
03:47:17.28 |
-09:10:10.4 |
HIP 17650 |
14.63 |
| 2026-08-12 00:00 |
03:47:17.56 |
-09:10:21.4 |
HIP 17650 |
14.49 |
| 2026-08-12 12:00 |
03:47:17.83 |
-09:10:32.5 |
HIP 17650 |
14.36 |
| 2026-08-13 00:00 |
03:47:18.08 |
-09:10:43.7 |
HIP 17650 |
14.22 |
| 2026-08-13 12:00 |
03:47:18.32 |
-09:10:54.9 |
HIP 17650 |
14.09 |
| 2026-08-14 00:00 |
03:47:18.55 |
-09:11:06.2 |
HIP 17650 |
13.95 |
| 2026-08-14 12:00 |
03:47:18.77 |
-09:11:17.5 |
HIP 17650 |
13.82 |
| 2026-08-15 00:00 |
03:47:18.97 |
-09:11:28.9 |
HIP 17650 |
13.68 |
| 2026-08-15 12:00 |
03:47:19.16 |
-09:11:40.3 |
HIP 17650 |
13.54 |
| 2026-08-16 00:00 |
03:47:19.34 |
-09:11:51.7 |
HIP 17650 |
13.40 |
| 2026-08-16 12:00 |
03:47:19.51 |
-09:12:03.3 |
HIP 17650 |
13.26 |
| 2026-08-17 00:00 |
03:47:19.66 |
-09:12:14.8 |
HIP 17650 |
13.11 |
| 2026-08-17 12:00 |
03:47:19.80 |
-09:12:26.4 |
HIP 17650 |
12.97 |
| 2026-08-18 00:00 |
03:47:19.93 |
-09:12:38.1 |
HIP 17650 |
12.83 |
| 2026-08-18 12:00 |
03:47:20.04 |
-09:12:49.8 |
HIP 17650 |
12.68 |
| 2026-08-19 00:00 |
03:47:20.14 |
-09:13:01.5 |
HIP 17650 |
12.54 |