| Parameter |
Value |
| Designation |
C/1959 Q2 (Alcock) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1959-09-15T21:07:08.423040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:14Z |
| Obs used |
14 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1959-09-04.0000000 |
| e |
1.00043121 |
| q (au) |
0.165808 |
| a (au) |
-384.520510 |
| i (deg) |
108.035726 |
| Ω (om, deg) |
225.841022 |
| ω (w, deg) |
300.535111 |
| M (ma, deg) |
-0.001553 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.563 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.563 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
1.000 |
| 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) |
| 2026-07-29 00:00 |
03:37:46.37 |
+80:58:53.3 |
HIP 17169 |
31.14 |
| 2026-07-29 12:00 |
03:37:49.03 |
+80:59:09.1 |
HIP 17169 |
31.38 |
| 2026-07-30 00:00 |
03:37:51.63 |
+80:59:24.9 |
HIP 17169 |
31.61 |
| 2026-07-30 12:00 |
03:37:54.18 |
+80:59:40.8 |
HIP 17169 |
31.85 |
| 2026-07-31 00:00 |
03:37:56.67 |
+80:59:56.7 |
HIP 17169 |
32.08 |
| 2026-07-31 12:00 |
03:37:59.09 |
+81:00:12.6 |
HIP 17169 |
32.32 |
| 2026-08-01 00:00 |
03:38:01.47 |
+81:00:28.5 |
HIP 17169 |
32.56 |
| 2026-08-01 12:00 |
03:38:03.78 |
+81:00:44.5 |
HIP 17169 |
32.81 |
| 2026-08-02 00:00 |
03:38:06.03 |
+81:01:00.4 |
HIP 17169 |
33.05 |
| 2026-08-02 12:00 |
03:38:08.22 |
+81:01:16.5 |
HIP 17169 |
33.30 |
| 2026-08-03 00:00 |
03:38:10.36 |
+81:01:32.5 |
HIP 17169 |
33.54 |
| 2026-08-03 12:00 |
03:38:12.43 |
+81:01:48.6 |
HIP 17169 |
33.79 |
| 2026-08-04 00:00 |
03:38:14.45 |
+81:02:04.6 |
HIP 17169 |
34.04 |
| 2026-08-04 12:00 |
03:38:16.40 |
+81:02:20.7 |
HIP 17169 |
34.29 |
| 2026-08-05 00:00 |
03:38:18.29 |
+81:02:36.9 |
HIP 17169 |
34.54 |
| 2026-08-05 12:00 |
03:38:20.13 |
+81:02:53.0 |
HIP 17169 |
34.80 |
| 2026-08-06 00:00 |
03:38:21.90 |
+81:03:09.2 |
HIP 17169 |
35.05 |
| 2026-08-06 12:00 |
03:38:23.61 |
+81:03:25.3 |
HIP 17169 |
35.31 |
| 2026-08-07 00:00 |
03:38:25.25 |
+81:03:41.5 |
HIP 17169 |
35.56 |
| 2026-08-07 12:00 |
03:38:26.84 |
+81:03:57.7 |
HIP 17169 |
35.82 |
| 2026-08-08 00:00 |
03:38:28.36 |
+81:04:14.0 |
HIP 17169 |
36.08 |
| 2026-08-08 12:00 |
03:38:29.82 |
+81:04:30.2 |
HIP 17169 |
36.34 |
| 2026-08-09 00:00 |
03:38:31.22 |
+81:04:46.4 |
HIP 17169 |
36.60 |
| 2026-08-09 12:00 |
03:38:32.55 |
+81:05:02.7 |
HIP 17169 |
36.86 |
| 2026-08-10 00:00 |
03:38:33.82 |
+81:05:19.0 |
HIP 17169 |
37.12 |
| 2026-08-10 12:00 |
03:38:35.03 |
+81:05:35.2 |
HIP 17169 |
37.38 |
| 2026-08-11 00:00 |
03:38:36.18 |
+81:05:51.5 |
HIP 17169 |
37.65 |
| 2026-08-11 12:00 |
03:38:37.25 |
+81:06:07.8 |
HIP 17169 |
37.91 |
| 2026-08-12 00:00 |
03:38:38.27 |
+81:06:24.1 |
HIP 17169 |
38.17 |
| 2026-08-12 12:00 |
03:38:39.22 |
+81:06:40.4 |
HIP 17169 |
38.44 |
| 2026-08-13 00:00 |
03:38:40.11 |
+81:06:56.7 |
HIP 17169 |
38.70 |
| 2026-08-13 12:00 |
03:38:40.93 |
+81:07:13.0 |
HIP 17169 |
38.97 |
| 2026-08-14 00:00 |
03:38:41.68 |
+81:07:29.3 |
HIP 17169 |
39.23 |
| 2026-08-14 12:00 |
03:38:42.37 |
+81:07:45.6 |
HIP 17169 |
39.50 |
| 2026-08-15 00:00 |
03:38:43.00 |
+81:08:01.8 |
HIP 17169 |
39.77 |
| 2026-08-15 12:00 |
03:38:43.56 |
+81:08:18.1 |
HIP 17169 |
40.03 |
| 2026-08-16 00:00 |
03:38:44.05 |
+81:08:34.4 |
HIP 17169 |
40.30 |
| 2026-08-16 12:00 |
03:38:44.48 |
+81:08:50.7 |
HIP 17169 |
40.57 |
| 2026-08-17 00:00 |
03:38:44.84 |
+81:09:06.9 |
HIP 17169 |
40.83 |
| 2026-08-17 12:00 |
03:38:45.13 |
+81:09:23.2 |
HIP 18209 |
40.97 |
| 2026-08-18 00:00 |
03:38:45.36 |
+81:09:39.4 |
HIP 18209 |
40.80 |
| 2026-08-18 12:00 |
03:38:45.53 |
+81:09:55.7 |
HIP 18209 |
40.64 |
| 2026-08-19 00:00 |
03:38:45.62 |
+81:10:11.9 |
HIP 18209 |
40.47 |