Q: When is the next AO due to be released?
A:
The sixth Announcement of Opportunity (AO) was released on 7 May 2001
with a proposal deadline of Friday 1 June 2001 -- see the
AO page for details.
It is not anticiapted that another AO will be released: with the withdrawal
of NASA-funded mission elements, the mission has changed focus and has
placed the emphasis on completing the VSOP Survey Program
of 289 active galactic nuclei at 5 GHz.
Q:
Where can I find up-to-date HALCA orbital elements?
A:
The
Simulation Software
page was updated in August 2000.
Q:
When will my observation be scheduled?
A: Look at the
Observing page
for details of upcoming observations.
The Principal Investigator
(or nominated contact person) on each proposal will be contacted
2--4 weeks before each observation and given a chance to comment on
the ground radio telescope schedule files.
Q: How can I find the status of my observation?
A: An
Observation Status page has been added to the WWW site.
Work is continuing on bringing this page up to date.
Q: I see an observation code
v330 -- were there that many proposals for the first AO period??
A: No -- see the
Observation Code explanation page for details.
Q: Where is my data?
A: Once correlation is completed and the
correlated data checked it will be sent to the address given on the
proposal sheets and included in the ground radio telescope schedule
files. When checking these files make sure this address is correct!
Q: Why is there no data from the
satellite for three minutes mid-way through a Ku band tracking pass?
A: Occasionally during a tracking pass
HALCA's K-u band antenna reaches its azimuth limit, and it takes
three minutes to `unwrap' the antenna.
Q: Where is the calibration data?
A: Calibration data for the ground radio
telescopes is available from the usual regional FTP sites.
HALCA calibration data is now described on
the HALCA calibration page.
Files are (or will be!) available for each observation, and nominal system temperature
values, which have found to work well in practice, are also given.
HALCA gain information is also provided.
Q: What's the story with 22 GHz?
A:
The detection of
22GHz fringes to HALCA
is good news, however few sources are are strong as Orion-KL during outburst!
It is likely that only the very strongest sources in the sky can be detected
at 22 GHz, and that any successful 22 GHz observations will require
considerable effort on the part of mission personnel.
Any 22 GHz observations carried out in the foreseeable future will
be made as In-Orbit Checkout observations.
Q: What happens if my observation fails?
A: It depends on what fails. If one
ground radio telescope or tracking station fails but the data is
still sufficient to meet the scientific goals of the proposal, the
observation will not be rescheduled. If HALCA does not observe or
the majority of ground telescopes or tracking stations fail, the
observation will be re-scheduled.
Q: How do I analyze my data?
A:
Fringe-fitting should be carried out in
AIPS.
The recently revised Chapter 9 of the
AIPS CookBook
`Reducing VLBI Data in AIPS' has the relevant details.
The AIPS FAQ
also contains useful information for those not familiar with this
software package.
You will need the most recent version of AIPS (00DEC31 version) in order
to successfully reduce your VSOP data. The use of the regularly
updated development version of AIPS, which is available at the
regional user-support facilities and data-reduction centers, is
recommended where possible.
Imaging can be carried out with either
AIPS or
Difmap
both of which have been upgraded to handle space VLBI data.
There is now an updated DIFMAP cookbook, with a new section (section 11) on using DIFMAP to process space VLBI data. Note that the 2.3c release of DIFMAP is required for space VLBI data.
Q:
How can I find when HALCA was at apogee or perigee?
A:
Fringe finding may be easier closer to perigee (but not too close, as
HALCA is moving fastest, and orbital uncertainty is largest, at perigee).
Check the
List of HALCA's apogee and perigee times. Apogee and perigee times given in this file
are expected to be accurate to within a minute or so. This information
is also available on an observation by observation basis for most
observations from the files linked to the
Observation Status page.
Q: Are all of these really
Frequently Asked Questions?
A: No, we made some up.