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The referees have raise a number of important ambiguities which I will
now address.

Significance and Innovation

Referees A (DD40119) and C (DD53525) recognised the main thrust of
analysis will be on the relationship between the spin axes (as derived
from Chandra observations or orbit coupling in binaries) and the
proper motion. Referee B (DD52582) concentrates on the more
traditional SNR/PSR association methods, as he is unaware of the
number of clear cases of X-ray emission implying the spin axis
(currently fourteen Chandra pulsar wind nebulae can be found listed in
astro-ph, six of these are, or could be interpreted as, bow shock
nebulae). He makes no mention of the independent information derived
from binary systems, where one can assume that the spin axis was
aligned with the pre-SN orbit. This astronomical field is poised to
become a major research area. On the basis of this project I am a
collaborator on a NASA Long Term Space Astrophysics (LTSA) application
("In a spin; the origin and fate of neutron star rotation").

Approach and Methodology

Referee A and B complain that the source list was not included in the
application. None was given as it would have been out of date by the
time it reached the referees. The speed with which Chandra is
discovering new X-ray nebulae is daunting.

The number of Chandra sources with non-bow shock, axial symmetric
X-ray nebulae is ever increasing; currently I estimate eight. Six have
known radio pulsation, but two of those are extremely weak (<0.1
mJy). During this project I plan to make full observations of only
five new pulsars, as half the time will be spent on technical
development. More is not possible if one assumes a reasonable
multiplier for the observing time (of a total of six days a year) to
estimate time to publication (I have used twenty).

My current source list has seven pulsars in it, three where a
symmetrical X-ray PWN exists (B1509-69, B1706-44 and B1957+20), three
SNR associations (J0034-0721, B1757-24/J1801-2451 and B1643-43) which
include some archived observations, and the MS-NS system
B1259-63. B1706-44 is also associated with a SNR with an identifiable
centre, and B1957+20 is in a binary. This is not the final list, but
answers the concerns as to the number of sources. More targets will
come from the LTSA observing program. Referee A points out that as
B1259-63 is unique; it is indeed - otherwise we would not have been
granted time for such an intensive campaign. The conclusions drawn
from observations of the combination of all the objects will be
robust. Future observations, after this set, will require the next
generation of VLBI recorders and correlators. These will be GHz wide,
the current ones are already collecting 0.5 GHz.

I will use the VLBA for Northern sources, but the focus of the project
remains the development of ionospheric phase removal techniques. It is
possible to get the VLBA data transfered to S2 tapes (at Mitaka) and
correlated at Epping (as I previously did for correlator comparisons
using data from the VSOP experiment W032C). I am considering doing so
if it looks to be useful.

Referee C raised the problems getting time on Tidenbilla, for which
access has been difficult. The sentence that he refers to was
ambiguous and either Parkes or Tidenbilla would produce baselines with
sufficient sensitivity. Both (of course) would be best. Our (American)
collaborators on the LTSA project will apply for an extra allocation
of Deep Space Network time for this project (either as part of the LBA
or a separate University of Tasmania/DSN sub-array for the pulsars for
which this is feasible).
 
Referee B is correct that it can be hard to infer the true age of the
pulsar from the ill-defined centre of a SNR. However that is not
always the case; e.g. the SNR associated with B1643-43 (G341.2+0.9)
which has a clearly identifiable centre. Referee A quotes Gvaramadze
on SNR shape distortion. The example Gvaramadze uses (SNR G343.1-2.3)
is that same looked at by myself recently (Dodson & Golap, 2002 MNRAS,
334, L1) and I did not find evidence for molecular clouds distorting
the SNR. Gvaramadze also predicted water masers would be found if
there was a molecular cloud. I have searched for these and found
nothing (unpublished).

National Benefit

Referee B failed to appreciate the contribution this will make to the
LBA, the section of the project that brings this under the heading of
astronomical instrumentation (named in the photon science target
area). Both referee A and C appreciated this. This part of the project
is technically difficult, but not unduly so in the context of my track
record. The three possible independent approaches have met with
success in the US and I have had recent success in
finding a phase calibrator previously undetected for one archived
experiment. Other experiments, or even other runs should be more
successful as this one was effectively a two baseline observation.

Even if all approaches failed the project is feasible, but will depend
solely on the large dish collecting area to reduce the required
solution interval.