DAO Telescope News

By / par David Bohlender (NRC Herzberg Astronomy & Astrophysics Research Centre)
(Cassiopeia – Winter / hivers 2020)

Unlike many telescopes around the world, the DAO 1.2-m and 1.8-m telescopes operated without interruption throughout the COVID-19 pandemic. Our ability to keep observing was thanks to the late-2019 implementation of robotic operation for the venerable 1.8-m Plaskett Telescope when configured for direct imaging. Robotic operation of the 1.2-m telescope and McKellar spectrograph has been available for more than 15 years. Since it has been a number of years since we have reminded Cassiopeia readers about the capabilities of the DAO Telescopes, it seems timely to do so now.

Both telescopes are scheduled on a relatively agile quarterly basis, with proposal deadlines on the first of December, March, June, and September or approximately one month before the start of each calendar quarter. They are well suited to monitoring programs and surveys requiring observations on various timescales including long individual observing runs, or programs scheduled monthly, quarterly or annually. Student projects are particularly encouraged.

The 1.8-m Plaskett Telescope offers imaging, spectroscopic, and spectropolarimetric capabilities. The imaging camera has a field of view of 24’ x 11’ with normal 2-pixel binning of the 2K x 4K E2V-1 CCD providing 0.62” pixel scale appropriate for the 2” seeing typical for the site. Robotic operation of the telescope (again, currently available only for imaging observations) is controlled by a text file containing the desired sequence of observations for a single night that the observer provides telescope staff.

The Cassegrain spectrograph has interchangeable gratings that provide spectral dispersions (resolutions) from 120Å/mm (R = 1,250) to 10Å/mm (R = 15,000). Wavelength coverage is currently limited by the 26mm length of the SITe-2 CCD. A polarimeter module, dimaPol, installed in place of the normal entrance slit to the spectrograph can provide Stokes I+V spectropolarimetry with a resolution of 15,000 for a spectral region centered on the H line. At the current time, spectroscopy and spectropolarimetry programs can only be carried out in person, although potential applicants should note that changes in the COVID-19 restrictions may restrict such operation for the next few quarters. A very modest amount of service observing support might be available based on other staff commitments.

The 1.2-m Telescope and two Coudé spectrographs permit spectroscopic observations with dispersions (resolutions) from 40.9Å/mm (R = 2,500) to 2.4Å/mm (R = 45,000). Again, the wavelength coverage is limited by the 61.4mm detector length, which in this case is the SITe-4 CCD. One of three sets of Coudé mirrors can be selected based on the spectral region of interest. For several years, approximately 70% of the scheduled observations on the 1.2-m telescope have been conducted in an unattended robotic mode. In good weather and seeing conditions, objects as faint as V = 10 can be observed. Data can be quickly processed for users if desired.

Data acquired on both of the DAO telescopes are available within minutes through the CADC’s Advanced Search interface. More than 700,000 digital datasets dating back to 2001 are currently available in the archive and older data are being added to the collection as time permits. If there are digital spectroscopic archival data of interest to users, we can readily process 1.2-m and 1.8-m spectra for them. The archive also includes a catalogue of photographic plates obtained with both telescopes, dating back to the first plate obtained with the Plaskett Telescope on 6 May 1918.

HAA staff are currently designing a new imaging camera for the Plaskett Telescope. This instrument will include a 6K x 6K drift-scan CCD as the detector and will increase the imaging field of view by a factor of approximately 4.5. The new camera will also benefit public outreach activities at the Observatory since visitors will be able view in real-time stars, nebulae, and galaxies passing through the telescope’s field of view instead of the usual static images.

Over the past year, the NRC has been conducting assessments of the current state of all of its laboratory facilities. As part of this process, an external panel carried out reviews of both DAO Telescope facilities in September. Our hope is that these reviews will make it possible for us to enhance the capabilities and operation of both DAO Telescopes by securing a modest amount of funding to upgrade spectrographs on both telescopes, enable robotic operation of the Plaskett Telescope for both imaging and spectroscopy, implement queued service observing, and perhaps even consider joining the Las Cumbres Observatory’s global network of telescopes if such access would be of interest to the Canadian community.

We would be delighted to hear your thoughts on possible future upgrades of the DAO Telescopes. In the meantime, anyone interested in applying for time on the DAO Telescopes can easily contact me at david.bohlender@nrc-cnrc.gc.ca to obtain additional information and a LaTeX template for their proposals.

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