| 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) |
| 2026-06-01 00:00 |
06:31:50.35 |
-20:23:53.6 |
HIP 31094 |
20.70 |
| 2026-06-01 12:00 |
06:31:51.56 |
-20:23:48.2 |
HIP 31094 |
20.86 |
| 2026-06-02 00:00 |
06:31:52.78 |
-20:23:42.9 |
HIP 31094 |
21.01 |
| 2026-06-02 12:00 |
06:31:54.00 |
-20:23:37.7 |
HIP 31094 |
21.17 |
| 2026-06-03 00:00 |
06:31:55.23 |
-20:23:32.7 |
HIP 31094 |
21.33 |
| 2026-06-03 12:00 |
06:31:56.46 |
-20:23:27.7 |
HIP 31166 |
21.38 |
| 2026-06-04 00:00 |
06:31:57.69 |
-20:23:22.8 |
HIP 31166 |
21.22 |
| 2026-06-04 12:00 |
06:31:58.93 |
-20:23:18.0 |
HIP 31166 |
21.06 |
| 2026-06-05 00:00 |
06:32:00.18 |
-20:23:13.3 |
HIP 31166 |
20.91 |
| 2026-06-05 12:00 |
06:32:01.42 |
-20:23:08.7 |
HIP 31166 |
20.77 |
| 2026-06-06 00:00 |
06:32:02.68 |
-20:23:04.2 |
HIP 31166 |
20.62 |
| 2026-06-06 12:00 |
06:32:03.93 |
-20:22:59.9 |
HIP 31166 |
20.49 |
| 2026-06-07 00:00 |
06:32:05.20 |
-20:22:55.6 |
HIP 31166 |
20.35 |
| 2026-06-07 12:00 |
06:32:06.46 |
-20:22:51.4 |
HIP 31166 |
20.23 |
| 2026-06-08 00:00 |
06:32:07.73 |
-20:22:47.4 |
HIP 31166 |
20.11 |
| 2026-06-08 12:00 |
06:32:09.00 |
-20:22:43.4 |
HIP 31166 |
19.99 |
| 2026-06-09 00:00 |
06:32:10.28 |
-20:22:39.5 |
HIP 31166 |
19.88 |
| 2026-06-09 12:00 |
06:32:11.56 |
-20:22:35.8 |
HIP 31166 |
19.77 |
| 2026-06-10 00:00 |
06:32:12.84 |
-20:22:32.2 |
HIP 31166 |
19.68 |
| 2026-06-10 12:00 |
06:32:14.13 |
-20:22:28.6 |
HIP 31166 |
19.58 |
| 2026-06-11 00:00 |
06:32:15.42 |
-20:22:25.2 |
HIP 31166 |
19.50 |
| 2026-06-11 12:00 |
06:32:16.72 |
-20:22:21.9 |
HIP 31166 |
19.42 |
| 2026-06-12 00:00 |
06:32:18.02 |
-20:22:18.6 |
HIP 31166 |
19.34 |
| 2026-06-12 12:00 |
06:32:19.32 |
-20:22:15.5 |
HIP 31166 |
19.27 |
| 2026-06-13 00:00 |
06:32:20.62 |
-20:22:12.5 |
HIP 31166 |
19.21 |
| 2026-06-13 12:00 |
06:32:21.93 |
-20:22:09.6 |
HIP 31166 |
19.16 |
| 2026-06-14 00:00 |
06:32:23.24 |
-20:22:06.9 |
HIP 31166 |
19.11 |
| 2026-06-14 12:00 |
06:32:24.55 |
-20:22:04.2 |
HIP 31166 |
19.07 |
| 2026-06-15 00:00 |
06:32:25.87 |
-20:22:01.6 |
HIP 31166 |
19.04 |
| 2026-06-15 12:00 |
06:32:27.19 |
-20:21:59.2 |
HIP 31166 |
19.01 |
| 2026-06-16 00:00 |
06:32:28.51 |
-20:21:56.8 |
HIP 31166 |
18.99 |
| 2026-06-16 12:00 |
06:32:29.83 |
-20:21:54.6 |
HIP 31166 |
18.97 |
| 2026-06-17 00:00 |
06:32:31.16 |
-20:21:52.4 |
HIP 31166 |
18.97 |
| 2026-06-17 12:00 |
06:32:32.49 |
-20:21:50.4 |
HIP 31166 |
18.97 |
| 2026-06-18 00:00 |
06:32:33.82 |
-20:21:48.5 |
HIP 31166 |
18.98 |
| 2026-06-18 12:00 |
06:32:35.15 |
-20:21:46.7 |
HIP 31166 |
18.99 |
| 2026-06-19 00:00 |
06:32:36.48 |
-20:21:45.0 |
HIP 31275 |
18.97 |
| 2026-06-19 12:00 |
06:32:37.82 |
-20:21:43.4 |
HIP 31275 |
18.73 |
| 2026-06-20 00:00 |
06:32:39.16 |
-20:21:41.9 |
HIP 31275 |
18.50 |
| 2026-06-20 12:00 |
06:32:40.50 |
-20:21:40.5 |
HIP 31275 |
18.26 |
| 2026-06-21 00:00 |
06:32:41.84 |
-20:21:39.3 |
HIP 31275 |
18.03 |
| 2026-06-21 12:00 |
06:32:43.18 |
-20:21:38.1 |
HIP 31275 |
17.81 |
| 2026-06-22 00:00 |
06:32:44.52 |
-20:21:37.1 |
HIP 31275 |
17.59 |