| Parameter |
Value |
| Designation |
C/1959 Q1 (Alcock) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1959-08-17T14:42:54.362880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:14Z |
| Obs used |
22 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1959-09-21.0000000 |
| e |
1.00130906 |
| q (au) |
1.150410 |
| a (au) |
-878.806801 |
| i (deg) |
48.258940 |
| Ω (om, deg) |
159.919935 |
| ω (w, deg) |
124.713032 |
| M (ma, deg) |
0.001301 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.983 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.983 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 1959-08-25 |
1959-11-05 |
+39.7685 |
-2.674 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
06:34:21.61 |
-20:25:16.3 |
HIP 31382 |
9.95 |
| 2026-07-29 12:00 |
06:34:22.81 |
-20:25:23.0 |
HIP 31382 |
9.70 |
| 2026-07-30 00:00 |
06:34:24.00 |
-20:25:29.9 |
HIP 31382 |
9.45 |
| 2026-07-30 12:00 |
06:34:25.18 |
-20:25:36.9 |
HIP 31382 |
9.20 |
| 2026-07-31 00:00 |
06:34:26.36 |
-20:25:43.9 |
HIP 31382 |
8.96 |
| 2026-07-31 12:00 |
06:34:27.54 |
-20:25:51.1 |
HIP 31382 |
8.72 |
| 2026-08-01 00:00 |
06:34:28.70 |
-20:25:58.3 |
HIP 31382 |
8.48 |
| 2026-08-01 12:00 |
06:34:29.87 |
-20:26:05.6 |
HIP 31382 |
8.25 |
| 2026-08-02 00:00 |
06:34:31.02 |
-20:26:13.0 |
HIP 31382 |
8.02 |
| 2026-08-02 12:00 |
06:34:32.18 |
-20:26:20.5 |
HIP 31382 |
7.79 |
| 2026-08-03 00:00 |
06:34:33.32 |
-20:26:28.1 |
HIP 31382 |
7.57 |
| 2026-08-03 12:00 |
06:34:34.46 |
-20:26:35.8 |
HIP 31382 |
7.35 |
| 2026-08-04 00:00 |
06:34:35.60 |
-20:26:43.6 |
HIP 31382 |
7.13 |
| 2026-08-04 12:00 |
06:34:36.72 |
-20:26:51.4 |
HIP 31382 |
6.93 |
| 2026-08-05 00:00 |
06:34:37.84 |
-20:26:59.4 |
HIP 31382 |
6.72 |
| 2026-08-05 12:00 |
06:34:38.96 |
-20:27:07.4 |
HIP 31382 |
6.52 |
| 2026-08-06 00:00 |
06:34:40.07 |
-20:27:15.5 |
HIP 31382 |
6.33 |
| 2026-08-06 12:00 |
06:34:41.17 |
-20:27:23.7 |
HIP 31382 |
6.15 |
| 2026-08-07 00:00 |
06:34:42.27 |
-20:27:32.0 |
HIP 31382 |
5.97 |
| 2026-08-07 12:00 |
06:34:43.36 |
-20:27:40.4 |
HIP 31382 |
5.80 |
| 2026-08-08 00:00 |
06:34:44.44 |
-20:27:48.9 |
HIP 31382 |
5.64 |
| 2026-08-08 12:00 |
06:34:45.52 |
-20:27:57.4 |
HIP 31382 |
5.49 |
| 2026-08-09 00:00 |
06:34:46.59 |
-20:28:06.1 |
HIP 31382 |
5.35 |
| 2026-08-09 12:00 |
06:34:47.65 |
-20:28:14.8 |
HIP 31382 |
5.22 |
| 2026-08-10 00:00 |
06:34:48.70 |
-20:28:23.6 |
HIP 31382 |
5.10 |
| 2026-08-10 12:00 |
06:34:49.75 |
-20:28:32.5 |
HIP 31382 |
4.99 |
| 2026-08-11 00:00 |
06:34:50.79 |
-20:28:41.4 |
HIP 31382 |
4.90 |
| 2026-08-11 12:00 |
06:34:51.83 |
-20:28:50.5 |
HIP 31382 |
4.82 |
| 2026-08-12 00:00 |
06:34:52.85 |
-20:28:59.6 |
HIP 31382 |
4.75 |
| 2026-08-12 12:00 |
06:34:53.87 |
-20:29:08.8 |
HIP 31382 |
4.70 |
| 2026-08-13 00:00 |
06:34:54.88 |
-20:29:18.1 |
HIP 31382 |
4.66 |
| 2026-08-13 12:00 |
06:34:55.89 |
-20:29:27.4 |
HIP 31382 |
4.63 |
| 2026-08-14 00:00 |
06:34:56.89 |
-20:29:36.9 |
HIP 31382 |
4.63 |
| 2026-08-14 12:00 |
06:34:57.87 |
-20:29:46.4 |
HIP 31382 |
4.63 |
| 2026-08-15 00:00 |
06:34:58.86 |
-20:29:56.0 |
HIP 31382 |
4.65 |
| 2026-08-15 12:00 |
06:34:59.83 |
-20:30:05.6 |
HIP 31382 |
4.69 |
| 2026-08-16 00:00 |
06:35:00.79 |
-20:30:15.4 |
HIP 31382 |
4.74 |
| 2026-08-16 12:00 |
06:35:01.75 |
-20:30:25.2 |
HIP 31382 |
4.80 |
| 2026-08-17 00:00 |
06:35:02.70 |
-20:30:35.1 |
HIP 31382 |
4.88 |
| 2026-08-17 12:00 |
06:35:03.64 |
-20:30:45.0 |
HIP 31382 |
4.97 |
| 2026-08-18 00:00 |
06:35:04.58 |
-20:30:55.1 |
HIP 31382 |
5.07 |
| 2026-08-18 12:00 |
06:35:05.50 |
-20:31:05.2 |
HIP 31382 |
5.18 |
| 2026-08-19 00:00 |
06:35:06.42 |
-20:31:15.4 |
HIP 31382 |
5.30 |