| 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 |
1.000 |
| 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) |
| 2026-09-20 00:00 |
04:32:53.65 |
-06:12:02.0 |
HIP 21278 |
35.69 |
| 2026-09-20 12:00 |
04:32:53.11 |
-06:12:14.4 |
HIP 21278 |
35.56 |
| 2026-09-21 00:00 |
04:32:52.55 |
-06:12:26.7 |
HIP 21278 |
35.43 |
| 2026-09-21 12:00 |
04:32:51.99 |
-06:12:39.1 |
HIP 21278 |
35.31 |
| 2026-09-22 00:00 |
04:32:51.41 |
-06:12:51.4 |
HIP 21278 |
35.19 |
| 2026-09-22 12:00 |
04:32:50.82 |
-06:13:03.7 |
HIP 21278 |
35.07 |
| 2026-09-23 00:00 |
04:32:50.21 |
-06:13:16.1 |
HIP 21278 |
34.96 |
| 2026-09-23 12:00 |
04:32:49.60 |
-06:13:28.4 |
HIP 21278 |
34.84 |
| 2026-09-24 00:00 |
04:32:48.97 |
-06:13:40.7 |
HIP 21278 |
34.74 |
| 2026-09-24 12:00 |
04:32:48.32 |
-06:13:53.0 |
HIP 21278 |
34.63 |
| 2026-09-25 00:00 |
04:32:47.67 |
-06:14:05.3 |
HIP 21278 |
34.53 |
| 2026-09-25 12:00 |
04:32:47.00 |
-06:14:17.6 |
HIP 21278 |
34.43 |
| 2026-09-26 00:00 |
04:32:46.32 |
-06:14:29.9 |
HIP 21278 |
34.34 |
| 2026-09-26 12:00 |
04:32:45.62 |
-06:14:42.1 |
HIP 21278 |
34.24 |
| 2026-09-27 00:00 |
04:32:44.92 |
-06:14:54.4 |
HIP 21278 |
34.16 |
| 2026-09-27 12:00 |
04:32:44.20 |
-06:15:06.6 |
HIP 21278 |
34.07 |
| 2026-09-28 00:00 |
04:32:43.47 |
-06:15:18.8 |
HIP 21278 |
33.99 |
| 2026-09-28 12:00 |
04:32:42.72 |
-06:15:31.1 |
HIP 21278 |
33.92 |
| 2026-09-29 00:00 |
04:32:41.97 |
-06:15:43.3 |
HIP 21278 |
33.84 |
| 2026-09-29 12:00 |
04:32:41.20 |
-06:15:55.4 |
HIP 21278 |
33.77 |
| 2026-09-30 00:00 |
04:32:40.42 |
-06:16:07.6 |
HIP 21278 |
33.71 |
| 2026-09-30 12:00 |
04:32:39.63 |
-06:16:19.8 |
HIP 21278 |
33.65 |
| 2026-10-01 00:00 |
04:32:38.82 |
-06:16:31.9 |
HIP 21278 |
33.59 |
| 2026-10-01 12:00 |
04:32:38.00 |
-06:16:44.0 |
HIP 21278 |
33.54 |
| 2026-10-02 00:00 |
04:32:37.17 |
-06:16:56.1 |
HIP 21278 |
33.49 |
| 2026-10-02 12:00 |
04:32:36.33 |
-06:17:08.2 |
HIP 21278 |
33.45 |
| 2026-10-03 00:00 |
04:32:35.48 |
-06:17:20.2 |
HIP 21278 |
33.41 |
| 2026-10-03 12:00 |
04:32:34.61 |
-06:17:32.2 |
HIP 21278 |
33.38 |
| 2026-10-04 00:00 |
04:32:33.73 |
-06:17:44.2 |
HIP 21278 |
33.35 |
| 2026-10-04 12:00 |
04:32:32.84 |
-06:17:56.2 |
HIP 21278 |
33.32 |
| 2026-10-05 00:00 |
04:32:31.94 |
-06:18:08.2 |
HIP 21278 |
33.30 |
| 2026-10-05 12:00 |
04:32:31.03 |
-06:18:20.1 |
HIP 21278 |
33.29 |
| 2026-10-06 00:00 |
04:32:30.10 |
-06:18:32.0 |
HIP 21278 |
33.28 |
| 2026-10-06 12:00 |
04:32:29.17 |
-06:18:43.9 |
HIP 21278 |
33.27 |
| 2026-10-07 00:00 |
04:32:28.22 |
-06:18:55.7 |
HIP 21278 |
33.27 |
| 2026-10-07 12:00 |
04:32:27.26 |
-06:19:07.5 |
HIP 21278 |
33.28 |
| 2026-10-08 00:00 |
04:32:26.29 |
-06:19:19.3 |
HIP 21278 |
33.29 |
| 2026-10-08 12:00 |
04:32:25.30 |
-06:19:31.1 |
HIP 21278 |
33.30 |
| 2026-10-09 00:00 |
04:32:24.31 |
-06:19:42.8 |
HIP 21278 |
33.33 |
| 2026-10-09 12:00 |
04:32:23.30 |
-06:19:54.5 |
HIP 21278 |
33.35 |
| 2026-10-10 00:00 |
04:32:22.28 |
-06:20:06.1 |
HIP 21278 |
33.38 |
| 2026-10-10 12:00 |
04:32:21.26 |
-06:20:17.7 |
HIP 21278 |
33.42 |
| 2026-10-11 00:00 |
04:32:20.22 |
-06:20:29.3 |
HIP 21278 |
33.46 |