C/1973 N1 (Sandage)
| Parameter |
Value |
| Designation |
C/1973 N1 (Sandage) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1973-11-08T03:45:29.695680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:22Z |
| Obs used |
27 |
| NEO |
- |
| M1 |
6.200 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1974-02-27.0000000 |
| e |
1.00022570 |
| q (au) |
4.812051 |
| a (au) |
-21320.457837 |
| i (deg) |
137.403627 |
| Ω (om, deg) |
279.241065 |
| ω (w, deg) |
72.546350 |
| M (ma, deg) |
0.000035 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.938 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.938 |
| n |
6.000 |
| gf |
0.996 |
| gb |
-1.000 |
| k |
0.800 |
| 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) |
| 2026-02-03 00:00 |
04:27:33.23 |
-06:20:59.8 |
HIP 20742 |
13.36 |
| 2026-02-03 12:00 |
04:27:32.50 |
-06:20:51.5 |
HIP 20742 |
13.22 |
| 2026-02-04 00:00 |
04:27:31.78 |
-06:20:43.1 |
HIP 20742 |
13.09 |
| 2026-02-04 12:00 |
04:27:31.07 |
-06:20:34.6 |
HIP 20742 |
12.96 |
| 2026-02-05 00:00 |
04:27:30.38 |
-06:20:26.1 |
HIP 20742 |
12.83 |
| 2026-02-05 12:00 |
04:27:29.70 |
-06:20:17.5 |
HIP 20742 |
12.72 |
| 2026-02-06 00:00 |
04:27:29.03 |
-06:20:08.9 |
HIP 20742 |
12.60 |
| 2026-02-06 12:00 |
04:27:28.38 |
-06:20:00.1 |
HIP 20742 |
12.50 |
| 2026-02-07 00:00 |
04:27:27.74 |
-06:19:51.4 |
HIP 20742 |
12.40 |
| 2026-02-07 12:00 |
04:27:27.11 |
-06:19:42.5 |
HIP 20742 |
12.31 |
| 2026-02-08 00:00 |
04:27:26.49 |
-06:19:33.6 |
HIP 20742 |
12.22 |
| 2026-02-08 12:00 |
04:27:25.89 |
-06:19:24.7 |
HIP 20742 |
12.14 |
| 2026-02-09 00:00 |
04:27:25.31 |
-06:19:15.7 |
HIP 20742 |
12.07 |
| 2026-02-09 12:00 |
04:27:24.73 |
-06:19:06.6 |
HIP 20742 |
12.01 |
| 2026-02-10 00:00 |
04:27:24.17 |
-06:18:57.4 |
HIP 20742 |
11.95 |
| 2026-02-10 12:00 |
04:27:23.63 |
-06:18:48.3 |
HIP 20742 |
11.90 |
| 2026-02-11 00:00 |
04:27:23.09 |
-06:18:39.0 |
HIP 20742 |
11.85 |
| 2026-02-11 12:00 |
04:27:22.57 |
-06:18:29.7 |
HIP 20742 |
11.81 |
| 2026-02-12 00:00 |
04:27:22.07 |
-06:18:20.4 |
HIP 20742 |
11.78 |
| 2026-02-12 12:00 |
04:27:21.57 |
-06:18:10.9 |
HIP 20742 |
11.75 |
| 2026-02-13 00:00 |
04:27:21.10 |
-06:18:01.5 |
HIP 20742 |
11.73 |
| 2026-02-13 12:00 |
04:27:20.63 |
-06:17:52.0 |
HIP 20742 |
11.72 |
| 2026-02-14 00:00 |
04:27:20.18 |
-06:17:42.4 |
HIP 20742 |
11.72 |
| 2026-02-14 12:00 |
04:27:19.74 |
-06:17:32.8 |
HIP 20742 |
11.72 |
| 2026-02-15 00:00 |
04:27:19.32 |
-06:17:23.1 |
HIP 20742 |
11.73 |
| 2026-02-15 12:00 |
04:27:18.91 |
-06:17:13.4 |
HIP 20742 |
11.74 |
| 2026-02-16 00:00 |
04:27:18.52 |
-06:17:03.6 |
HIP 20742 |
11.76 |
| 2026-02-16 12:00 |
04:27:18.14 |
-06:16:53.8 |
HIP 20742 |
11.79 |
| 2026-02-17 00:00 |
04:27:17.77 |
-06:16:44.0 |
HIP 20742 |
11.82 |
| 2026-02-17 12:00 |
04:27:17.41 |
-06:16:34.1 |
HIP 20742 |
11.86 |
| 2026-02-18 00:00 |
04:27:17.08 |
-06:16:24.1 |
HIP 20742 |
11.90 |
| 2026-02-18 12:00 |
04:27:16.75 |
-06:16:14.2 |
HIP 20742 |
11.95 |
| 2026-02-19 00:00 |
04:27:16.44 |
-06:16:04.1 |
HIP 20742 |
12.01 |
| 2026-02-19 12:00 |
04:27:16.14 |
-06:15:54.1 |
HIP 20742 |
12.07 |
| 2026-02-20 00:00 |
04:27:15.86 |
-06:15:43.9 |
HIP 20742 |
12.14 |
| 2026-02-20 12:00 |
04:27:15.59 |
-06:15:33.8 |
HIP 20742 |
12.21 |
| 2026-02-21 00:00 |
04:27:15.33 |
-06:15:23.6 |
HIP 20742 |
12.29 |
| 2026-02-21 12:00 |
04:27:15.09 |
-06:15:13.4 |
HIP 20742 |
12.37 |
| 2026-02-22 00:00 |
04:27:14.86 |
-06:15:03.1 |
HIP 20742 |
12.45 |
| 2026-02-22 12:00 |
04:27:14.65 |
-06:14:52.8 |
HIP 20742 |
12.55 |
| 2026-02-23 00:00 |
04:27:14.45 |
-06:14:42.5 |
HIP 20742 |
12.64 |
| 2026-02-23 12:00 |
04:27:14.27 |
-06:14:32.1 |
HIP 20742 |
12.74 |
| 2026-02-24 00:00 |
04:27:14.10 |
-06:14:21.7 |
HIP 20742 |
12.85 |