Applying for Time
Danny Lennon (Head of Astronomy, ING)
*
Over the years the instrument suite at the WHT has changed many times. One
constant in all these changes is that our intermediate dispersion spectrograph
ISIS continues to win the largest share of the observing time across all
our three TACs. It’s therefore good to see some improvements coming to this
venerable instrument. The past 6 months have seen the commissioning of a
new dichroic beam splitter, and initial tests indicate that the infamous
ripples which plagued the old dichroic set are substantially reduced. Throughput
in both blue and red arms is improved, while the response of the new blue
fold mirror is also substantially better than before (details may be found
on the
ISIS web pages).
This is the only dichroic which will be offered in service mode, and will
be the default dichroic offered to visiting observers unless an alternative
is specified. It is expected that the older dichroics will be phased out
of use pending feedback from users.
We have also commissioned the new ISIS TV slit viewing camera, discussed
in the article by Simon Tulloch in
ING Newsletter,
8, 20. This camera is based on a Peltier cooled frame transfer
CCD, and can be controlled in much the same way as any other CCD at the ING.
Besides offering better image quality and improved ease of acquisition for
ISIS it offers the additional advantage that one can now take an acquisition
image of the slit during a science exposure. Finally during the coming year
we expect to see the image slicer commissioned on ISIS, this will have a
2 arcsec entrance aperture and a 0.5 arcsec sliced output image, nicely matched
to the optimum resolution of the ISIS CCDs.
The digital media storage landscape continues to change very rapidly, which
is just as well given the increasing rate of data acquisition in astronomy.
A number of survey programmes using the
WFC on the INT have highlighted
this issue recently due to their extremely high data rates (and short exposure
times), and the ING now has a provision to allow users to copy their data
to external firewire discs. If users can demonstrate a clear need for this
facility on the INT and wish to avail themselves of the service they should
contact Robert Greimel (
greimel@ing.iac.es).
Despite some minor teething problems during 2004B,
LIRIS continues to perform
very well at Cassegrain. We will therefore continue with our policy of only
offering LIRIS for use at this focal station for IR imaging (and spectroscopy),
INGRID will continue
to be used with
NAOMI, our natural
guide star AO system.
OASIS is performing
as expected, however it should be noted that with OASIS there is the choice
of using the instrument with or without AO correction. Furthermore, during
2005A, we expect to finish commissioning a mode of operation in which only
tip-tilt correction is applied, somewhat relaxing the constraint on the magnitude
of the guide star while still providing attractive performance in the
I-band.
The
Director’s Message has already referred to
the
questionnaire
which has been released by ING in order to gauge the views of the astronomical
community on the future of the observatory. While individual responses are
confidential, the overall results will be fed into the ING review process
later this year and will have an influence on the future development of ING
and its instrumentation suite. For example, the default situation on the
future for the WHT is essentially the continuation of the existing suite
of instruments, which now comprises optical and IR imaging and spectroscopic
capability, multi-object spectroscopy, and adaptive optics (AO) at optical
and IR wavelengths. Our ongoing development currently focuses on extending
the use of the AO suite through the use of a Rayleigh laser beacon which
will dramatically increase the sky coverage and hence the scientific potential
of the existing AO system. The INT is currently a single instrument telescope,
utilising the Wide Field Camera, and no change in this status is as yet decided
upon. It is very important therefore that our users complete and submit the
questionnaire if they wish to have their say on the future of ING. ¤
*: Email contact: Danny Lennon (
djl@ing.iac.es)
