Metadata

Parameter	Value
Designation	C/1942 X1 (Whipple-Fedtke-Tevzadze)
Type	C
Perihelion (tp_cal, UTC)	1943-02-06T17:18:23.040000Z
Orbit solution date (soln_date, UTC)	-
Obs used	166
NEO	-
M1	-
K1	-
PC	-

Osculating Elements

Parameter	Value
Epoch (epoch_cal, TDB)	1943-02-05.0000000
e	0.99219600
q (au)	1.353647
a (au)	173.455536
i (deg)	19.712700
Ω (om, deg)	100.799000
ω (w, deg)	39.843200
M (ma, deg)	-0.000743

Magnitude

Scatter + Global Linear

$$ M_a = (3.857 + 3.863\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

Model Parameters

Parameter	Value
H0	3.857
n	3.863
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
1942-12-15	1943-02-06	+38.1961	-4.915
1943-02-06	1943-04-13	+2.8278	-0.764
1943-04-13	1943-06-05	-2.7997	+0.823

log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)

Ephemeris

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-05-12 00:00	20:54:51.09	-27:04:41.1	HIP 103182	28.08
2026-05-12 12:00	20:54:50.91	-27:04:44.9	HIP 103182	28.13
2026-05-13 00:00	20:54:50.71	-27:04:48.7	HIP 103182	28.18
2026-05-13 12:00	20:54:50.51	-27:04:52.5	HIP 103182	28.23
2026-05-14 00:00	20:54:50.29	-27:04:56.3	HIP 103182	28.28
2026-05-14 12:00	20:54:50.06	-27:05:00.2	HIP 103182	28.33
2026-05-15 00:00	20:54:49.83	-27:05:04.2	HIP 103182	28.38
2026-05-15 12:00	20:54:49.58	-27:05:08.1	HIP 103182	28.43
2026-05-16 00:00	20:54:49.32	-27:05:12.1	HIP 103182	28.48
2026-05-16 12:00	20:54:49.05	-27:05:16.2	HIP 103182	28.53
2026-05-17 00:00	20:54:48.77	-27:05:20.2	HIP 103182	28.58
2026-05-17 12:00	20:54:48.47	-27:05:24.3	HIP 103182	28.64
2026-05-18 00:00	20:54:48.17	-27:05:28.5	HIP 103182	28.69
2026-05-18 12:00	20:54:47.86	-27:05:32.6	HIP 103182	28.74
2026-05-19 00:00	20:54:47.54	-27:05:36.8	HIP 103182	28.79
2026-05-19 12:00	20:54:47.20	-27:05:41.1	HIP 103182	28.84
2026-05-20 00:00	20:54:46.86	-27:05:45.3	HIP 103182	28.90
2026-05-20 12:00	20:54:46.50	-27:05:49.6	HIP 103182	28.95
2026-05-21 00:00	20:54:46.14	-27:05:54.0	HIP 103182	29.00
2026-05-21 12:00	20:54:45.76	-27:05:58.3	HIP 103182	29.05
2026-05-22 00:00	20:54:45.38	-27:06:02.7	HIP 103182	29.11
2026-05-22 12:00	20:54:44.98	-27:06:07.1	HIP 103182	29.16
2026-05-23 00:00	20:54:44.57	-27:06:11.6	HIP 103182	29.22
2026-05-23 12:00	20:54:44.15	-27:06:16.1	HIP 103182	29.27
2026-05-24 00:00	20:54:43.73	-27:06:20.6	HIP 103182	29.33
2026-05-24 12:00	20:54:43.29	-27:06:25.1	HIP 103182	29.38
2026-05-25 00:00	20:54:42.84	-27:06:29.7	HIP 103182	29.44
2026-05-25 12:00	20:54:42.38	-27:06:34.3	HIP 103182	29.50
2026-05-26 00:00	20:54:41.91	-27:06:38.9	HIP 103182	29.55
2026-05-26 12:00	20:54:41.44	-27:06:43.6	HIP 103182	29.61
2026-05-27 00:00	20:54:40.95	-27:06:48.3	HIP 103182	29.67
2026-05-27 12:00	20:54:40.45	-27:06:53.0	HIP 103182	29.73
2026-05-28 00:00	20:54:39.94	-27:06:57.7	HIP 103182	29.79
2026-05-28 12:00	20:54:39.42	-27:07:02.5	HIP 103182	29.85
2026-05-29 00:00	20:54:38.90	-27:07:07.3	HIP 103182	29.91
2026-05-29 12:00	20:54:38.36	-27:07:12.1	HIP 103182	29.97
2026-05-30 00:00	20:54:37.81	-27:07:17.0	HIP 103182	30.03
2026-05-30 12:00	20:54:37.25	-27:07:21.8	HIP 103182	30.10
2026-05-31 00:00	20:54:36.69	-27:07:26.7	HIP 103182	30.16
2026-05-31 12:00	20:54:36.11	-27:07:31.6	HIP 103182	30.22
2026-06-01 00:00	20:54:35.52	-27:07:36.6	HIP 103182	30.29
2026-06-01 12:00	20:54:34.93	-27:07:41.5	HIP 103182	30.35
2026-06-02 00:00	20:54:34.32	-27:07:46.5	HIP 103182	30.42