ANGULAR RESOLUTION

Table 5, generated with the NRAO program SCHED (Walker 2006), gives the maximum lengths rounded to the nearest km ( $B^{\rm km}_{\rm max}$) for each of the VLBA's 45 internal baselines as well as the baselines to other HSA telescopes. Both the upper left and lower right portions of the table are filled to make it easier to use. A measure of the corresponding resolution ( $\theta_{\rm HPBW}$) in milliarcseconds (mas) is

$$\theta_{\rm HPBW} \sim 2063 \times {\lambda^{\rm cm} \over B^{\rm km}_{\rm max}}\ \ {\rm mas},$$ (1)

where $\lambda^{\rm cm}$ is the receiver wavelength in cm (Wrobel 1995). A uniformly weighted image made from a long $u$-$v$ plane track will have a synthesized beam with a slightly narrower minor axis FWHM. At the center frequencies appearing in Table 3 and for the longest VLBA baseline, $\theta_{\rm HPBW}$ is 22, 12, 5.0, 4.3, 3.2, 1.4, 0.85, 0.47, and 0.32 mas for receivers named 90, 50, 21, 18, 13, 6, 4, 2, and 1 cm, plus 0.17 mas at 7 mm. The longest VLBA-only baseline at 3 mm is currently the one between MK and NL, which is about 30% shorter than the longest baseline at other wavelengths.

0.25truein

Table 5: Maximum VLBI Baseline Lengths in km ( $B^{\rm km}_{\rm max}$)

	SC	HN	NL	FD	LA	PT	KP	OV	BR	MK	EB	AR	GB	Y27
SC	...	2853	3645	4143	4458	4579	4839	5460	5767	8611	6822	238	2708	4532
HN	2853	...	1611	3105	3006	3226	3623	3885	3657	7502	5602	2748	829	3198
NL	3645	1611	...	1654	1432	1663	2075	2328	2300	6156	6734	3461	1064	1640
FD	4143	3105	1654	...	608	564	744	1508	2345	5134	8084	3922	2354	515
LA	4458	3006	1432	608	...	236	652	1088	1757	4970	7831	4246	2344	226
PT	4579	3226	1663	564	236	...	417	973	1806	4795	8014	4365	2551	52
KP	4839	3623	2075	744	652	417	...	845	1913	4466	8321	4623	2939	441
OV	5460	3885	2328	1508	1088	973	845	...	1214	4015	8203	5255	3323	1025
BR	5767	3657	2300	2345	1757	1806	1913	1214	...	4398	7441	5585	3326	1849
MK	8611	7502	6156	5134	4970	4795	4466	4015	4398	...	10328	8434	7028	4835
EB	6822	5602	6734	8084	7831	8014	8321	8203	7441	10328	...	6911	6335	8008
AR	238	2748	3461	3922	4246	4365	4623	5255	5585	8434	6911	...	2545	4317
GB	2708	829	1064	2354	2344	2551	2939	3323	3326	7028	6335	2545	...	2516
Y27	4532	3198	1640	515	226	52	441	1025	1849	4835	8008	4317	2516	...

Note: See Tables 1 and 2 for exact coordinates.