Observing Applications

Instrument Notes
The upgraded Cassegrain Spectrograph (SpUpNIC) is available. Information on calculating exposure times can be found here.
GIRAFFE is currently unavailable for applications.
STE3 and STE4 are no longer available on the 1.9-metre telescope.

Telescope Time Applications & Review Process
In keeping with its role as the National Facility for optical/infrared astronomy, SAAO makes telescope time available to qualified astronomers and post-graduate students in South Africa and SALT partners. A certain percentage of time is also granted to astronomers from around the world, to promote scientific and technological collaboration and to promote the exchange of ideas and information. Availability of observing time is advertised under Rota. Time allocations will be made on the basis of scientific merit and technical feasibility. Proposals are reviewed by the Sutherland Telescopes TAC (Time Assessment Committee) which conducts the business of providing a recommended list of observing programmes electronically. This occurs in the month following each deadline. The TAC consists of astronomers from the local and international community of users of the Sutherland telescopes. Prospective applicants for observing time should consult the pages for the telescope(s) and instrument(s) they may need to use.

Note that only researchers based at South African or Japanese institutions are eligible to apply for observing time on the IRSF. Those who are interested in applying for observing time on IRSF, and are not based at South African or Japanese institutions, should consider collaborating with researchers from South Africa and/or Japan. After the deadline, the IRSF proposals from South African applicants are sent to the IRSF ‘TAC’ in Japan for review and time allocation. The IRSF TAC is also responsible for the IRSF Rota as well as informing the applicants about the results of their applications.

Application Process
Please note that the application form has been updated again and can now be submitted electronically. You will have to register on the SAAO observer portal by signing up for a user account. You can then apply as usual by clicking on ‘Applications’ followed by ‘Apply Now’.
Note the following deadlines for submission of applications.

For Service Observing, detailed information and application forms can be found here. Applications for Service Observing can be submitted at any time.

Deadlines
Deadlines for applications are as follows:
15 September for Jan/Apr observing, and
15 January for May/Aug observing.
15 May for Sep/Dec observing;

Notes for Applicants
Night assistants are no longer available. Please state in your application form if you will require a support astronomer to start you off on the first night of your run.
There is significant strain on accommodation and transport to and from Sutherland. Visitors are therefore requested to plan for no more than two observers for each run. It is accepted that there are instances in which more than two observers are desirable (e.g. training of graduate students). If you feel you have such a case, please discuss this with Ramotholo Sefako well before your run, who will present this request to the Director.

Reports on Research done at SAAO
Authors using observations made from SAAO should include a note in the acknowledgements section of each paper with the words ‘This paper uses observations made at the South African Astronomical Observatory (SAAO)‘. This information should be passed on to anyone to whom observations made at SAAO may be supplied.
Authors are requested to notify the librarian at SAAO Cape Town of any paper they publish using data obtained at SAAO.

Observing
For astronomers visiting the SAAO to observe on our telescopes, you will require a visitor visa. Application for this should be directed to the South African embassy in the country from which you originate. Visit.

Important Note for Prospective Observers
Due to an increased demand in accommodation in Sutherland as a result of more activities at SALT due to ongoing recommissioning, accommodation has once again become a big challenge. And this is going to be even more serious in the coming weeks due to a large number of people that are anticipated to be involved in the recommissioning teams. As a result, we will need to limit the number of observers at each of our telescopes that we can accommodate on site at the hostel to 2 (two). Therefore, if you are planning to send more than two observers at any of our telescopes, please be aware that you may be sent to accommodation in town for the extra observer(s), or be prepared to share a room between yourselves. Otherwise you will need to give a strong motivation to and require approval from the SAAO director detailing why you need more than two observers.

Although we encourage student involvement in your observational visits to Sutherland given the importance of training future astronomers, in some instances, we will need to put more than one student in a room, and therefore students should ALWAYS be prepared to share a room on site. Irrespective of whether they are observing on their own or not; if necessary, students may be asked to share a room.
Please note that we have already increased the number of hostel rooms available by two (as a result of the recent refurbishment of the south wing). And we continue to push for the necessary funding to construct a dedicated student block as part of the hostel.

Notes for Observers

Calendar/Booking System/Rota

The below links will take you to the master copy of the observing rotas for Sutherland:

January, February, March, April, May, June, July, August, September, October, November, December, IRSF Rota

The instrument shown in the rota will be the standard configuration. If something other than the normal instrumental configuration is required, then send a text file which describes your requirements to observer@saao.ac.za. This could include the filter set to be used, CCD type, or anything else which differs from the standard configuration. The information you send will be linked to the record of your observing run on the rota.

The observing rota for Sutherland is compiled every quarter. Remember to check this schedule for possible changes which may affect your observing run. If you want to make changes to your observing request, contact observer@saao.ac.za.

Cape Town info for Visiting Observers

Location

SAAO is situated in the suburb of Observatory, about 5 km SE of central Cape Town, 13 km from Cape Town’s international airport, and about 1 km from Observatory station. Shops and guest houses are nearby, and hotels and larger shopping districts are readily accessible by train and bus. The University of Cape Town (UCT) is about 3 km away. The precise location of the Observatory (Gill transit circle) is 18°28´35.7″, 33°56´02.5″ S. The mean time in South Africa is South African Standard Time (SAST). SAST is ahead of UT by 2 hr.

Communicating with SAAO

The postal address of the Observatory is:

South African Astronomical Observatory
P.O. Box 9
Observatory, Cape Town, 7935
South Africa

The street address is:

South African Astronomical Observatory
Observatory Road
Observatory, Cape Town, 7925
South Africa

Telephone No: 447-0025 (office hours–0800 to 1630)
Fax No.: 447-3639
Dialling codes: National: 021; International: +27 21
E-mail address: enquiries@saao.ac.za

Administration

The Business Manager is in charge of administration and is responsible to the Director. Any administrative questions should be directed to the Business Manager in the first instance. Visitors are requested to assist as follows:

Travel Arrangements

In order to avoid difficulties at the start of an observing run, visiting observers should allow adequate time for discussions and preparation in Cape Town, and should arrange to visit SAAO on the Monday preceding their trip to Sutherland or earlier. In any event, visitors are advised to arrange to arrive in Cape Town at the latest on the Sunday before a run, to allow time for acclimatisation and recovery from their trip, and to safeguard against late arrival of a flight. Visitors should arrange to spend sufficient time (usually two working days) in Cape Town after their run if reductions or data copying are to be undertaken by SAAO staff. Normally, visitors arriving at Cape Town airport should take a taxi to their hotel or guest house, and the same procedure should be followed on departure.

Accommodation

The Koornhoop Manor House is located within walking distance of the Observatory. Other guest houses can also be found nearby, and some may be cheaper. Numerous hotels and guest houses are available elsewhere in Cape Town at a wide range of prices, but travel to the Observatory by public transport can be difficult from some areas.

Alternatively there is self-catering accommodation available within the tranquil grounds of the Observatory in Cape Town. Rates are displayed below. Reduced rates are available for long term stays. Payments can be made by credit card.

Please confirm accommodation rates at the time of your booking as they are subject to change.

Please contact Valencia Cloete regarding your accommodation arrangements. Visitors who arrange their own accommodation should supply the Observatory with an address and telephone number for emergency purposes.

Transport

A transport officer is in charge of all official vehicles and none of them may be driven without a driving licence that is valid in South Africa (e.g. an international licence or one bearing the driver’s photograph). Visitors may not drive official vehicles before providing a copy of their licences to Valencia Cloete. Unscheduled trips require pre-approval and the visitor will be responsible for the invoice.

Catering

There is no cafeteria or canteen, but a microwave in the kitchen can be used to heat lunches or parts thereof. Morning tea (10:30) is provided in the library, afternoon tea (15:00) in the kitchen. A number of restaurants and a miniature “supermarket” are located a short distance away in the village business centre of Observatory.

Library

Visiting observers are welcome to use the library facilities during their stay. Desks can be found in the Atlas Room. Any queries can be directed to the librarian.

Sutherland Observers Info

Location

The village of Sutherland is located North-East of Cape Town, about 370 km by road. The observatory is about 18 km to the East of the village, at an elevation of 1798 m. The precise geographical position of the 1.0-m telescope is 20° 48´ 38.5” E; 32° 22´ 46” S.

From Cape Town, the N1 National Road is followed for about 250 km to Matjiesfontein where one turns left on to the Sutherland road. The speed limit on the N1 is 120 km/h. From Sutherland, vehicles should follow the road to Fraserburg for the remaining 14 km to the observatory gate, which – with its somewhat incongruous avenue of pine trees in the desert – is difficult to miss. The route is depicted on the map below.

If petrol is required en-route, it can be obtained at Komkyk Motors (green sign) or the Petroport (red sign) where the N1 passes Touws River, at about the halfway point. Drivers refueling observatory vehicles must do so at the Petroport. Snacks are available at either establishment at any time, though most observers stop for fast food lunches at the Petroport. An alternative is to stop for lunch at the turn-of-the-century resort of Matjiesfontein (The Laird’s Arms serves pub lunches and snacks all day from 10:00; a coffee shop is open from 09:00 to 17:00).

Route to SAAO, Sutherland

Communications

The main telephone number for the Observatory is 023 571 1205. During office hours calling this number will ring through to the switchboard; if no answer, or after hours, calls will be directed to an Interactive Voice Recording and the caller will be able to enter an extension number to reach their destination.

Calls to the outside world can be made from any of the domes; visitors should request a telephone PIN number from the IT Department (helpdesk@saao.ac.za). Call duration is monitored and calls will be charged to the visitor’s account. Some of the domes have an outside line and can receive calls from outside the observatory without going via the switchboard:

1.9-m: 023 100 0221
1.0-m: 023 100 0222
IRSF: 023 100 0223

Other domes amy also have direct numbers. If so, this number will be displayed on the telephone.

There is a fax machine in the reception at SAAO Hostel. Faxes are not printed by default, rather they are delivered via email to the receptionist. The fax number is 023 571 1413.

Data links to the Internet are available from a PC in each dome and from one in the hostel library. Visitors are encouraged to connect to their home institutes via the Internet, but for an extended stay, a private account on the SAAO system can be arranged. If you need such an account, please contact the SAAO IT Department (helpdesk@saao.ac.za) in good time to request an account. Connectivity is provided in the form of a 1Gbps link directly to Cape Town and then out to the internet over our fibre link to our ISP, TENET. Current international bandwidth is 17Mbps so please use with consideration and throttle the speeds of any large data transfers.

Transport

Transport of observers and their equipment to Sutherland normally leaves Cape Town on Tuesdays at about 10:00 (arriving at the site at about 16:00). The returning transport officially leaves Sutherland at 14H00 on Wednesdays but this time various at the discretion of departing astronomers. Transport of visiting observers on these scheduled runs is free of charge. Should visitors request a special journey, the Observatory reserves the right to ask for reimbursement from the visitor or his parent establishment.

Accommodation & Catering

Accommodation is available for observers on-site, about 1 km by road from the telescopes. Rooms with private bathrooms are provided in two chalets and a hostel with 17 single rooms (which are now all en-suite), a communal sitting room, reading room and dining room. Smokers will need to step outside into the brisk (especially in July) Karoo air.

Three Meals per Day are Provided:

Breakfast: 07H30 – 09H30
Lunch: 13H00 – 14H00
Supper: 17H00 – 18H00 depending on time of year

Observers requiring lunch at 13H00 should write their request on the blackboard in the hostel dining room by breakfast time. “Night lunches” will be prepared for each observer to collect from the kitchen and take to the telescope each night. The contents of the night lunch should be arranged with the kitchen staff on arrival at the hostel. Observers with special dietary requirements (vegetarian, allergies, etc.) should notify the observatory in advance.

Accommodation rates

Credit card payments can be made in Sutherland or in Cape Town. Please contact Valencia Cloete with any queries.

Dome keys, car keys and torches should be collected from Reception in the hostel foyer on the first day of the observing run, and should be returned before departure to Cape Town.

There are no general laundry facilities, but the hostel staff are prepared to do laundry on a private basis at rates similar to those charged by laundries in Cape Town. To arrange this, observers should speak to the hostel manager, Magdalena van Wyk.

Office Accommodation

There are now internet connections in most bedrooms. There is a computer connected to the internet in the small hostel library, and at least one in each telescope dome. There are printers in each SAAO dome and a printer/copier in the Hostel Office.

Technical Assistance

Visiting observers who are unfamiliar with the telescope/instrument they are scheduled to use, and who have requested assistance on their telescope time application form, will be allocated a support astronomer. This will be either an SAAO staff astronomer, or an observer who is familiar with the instrumentation to be used, and whose name will appear below the observer’s on the rota. Typically, the support astronomer will be present at the telescope for as long as necessary on the first night of the run, in order to assist visitors in making an efficient start. Occasionally it is not possible to allocate a support astronomer, in which case the observer may be asked to arrive at Sutherland in sufficient time to spend e.g. 1-2 days overlapping with the previous week’s observer.

Resident technical staff will give assistance and tend to problems and faults where necessary. Electronic, mechanical and IT technicians are on call in case of breakdown of telescopes or equipment during the night. Their contact numbers are displayed in each dome.

Instrument Changes and Response to Reported Faults

Instrument Changes

Necessary instrument changes are generally carried out at Sutherland on Wednesday mornings. Normally, the largest telescope requiring a change is done first followed by the next largest and so on. Depending on availability of personnel, work may proceed on two telescopes at once. Usually, all changes are completed by lunch time. Occasionally a fault is discovered in the course of the change which is judged to require a lengthy effort to repair. The technicians may at that stage proceed to the next telescope, with a view to completing as many changes as possible before returning to repair the fault. As part of the instrument change procedure, technicians will carry out necessary tests to ensure things are working, all cables are correctly connected and that computers are working, etc.

It is up to the observer to make sure in good time that the equipment is working satisfactorily after the instrument change. This means that tests should be carried out on Wednesday afternoon. There should be no surprises (like an unexpected instrument, etc) when work starts on Wednesday night. At instrument change time, responsibilities are shared between observers and technical staff as follows:

Observer:

Electronics:

Mechanical:

SAAO has agreements with some organisations that have installations at Sutherland to provide technical support. Occasionally there will be representatives of these organisations at Sutherland for a short period to carry out some specific installation, upgrade, etc. SAAO technical staff will usually be required to provide assistance to the visitors during this period. At such times there may be delays in obtaining technical assistance for the telescopes, though every effort will be made to ensure a telescope is fully operational at the beginning of the night. Observers will be kept informed of these activities, and are requested to curb their natural impatience in the face of such delays.

Fault Response

For all faults they encounter, observers are requested to write a factual, unemotional account of the problem in the online fault forum page dedicated to each telescope. Symptoms should be described fully – it is not sufficient merely to cite the reference number of a previous similar fault – and observers should refrain from diagnosing the fault or describing at some length the technical work that was done to correct it. All major faults should be reported promptly to the relevant duty technician (phone numbers are prominently displayed in the dome). At night, every effort will be made to rectify the fault immediately, but if after several hours of work without solution or if the problem is judged to be too severe for there to be any useful progress made, the technician may suspend work until the next morning. Minor problems encountered at night that have little impact on observing should be reported in the fault forum and will be worked on the next day.

Once the fault is rectified the technician will add a note to the fault forum, indicating the action taken. Observers are encouraged to report back under the corresponding fault, on whether the repairs had been satisfactory.

On rare occasions a major fault may occur in one of the international partner installations that would jeopardise the entire operation if not attended to immediately (eg, threatened loss of coolant from the SAGOS superconducting gravity meter). Under these circumstances, the SAAO technician responsible, in most instances the electronics technician, may give first priority to rectifying the fault, in which case it is conceivable that astronomical observing time may be lost if a fault is encountered at the same time with a telescope or instrument, but every effort will be made to avoid this. Otherwise, SAAO telescope faults have priority over minor faults in the international installations.

Observing Records & Feedback Forms

Completed Observing Records (together with the bottom copy of each triplicate logbook page, in the case of SpCCD, GIRAFFE and SAAO CCD data) should be placed in the “End of Run” tray in the dome on the last night of the observing run. Please also fill in the online Observers’ Feedback Form at the end of your run. If you have any difficulties, please contact Hannah Worters.

Observing Conditions

The weather patterns at Sutherland are not highly seasonal, and the clear weather appears to be fairly uniformly distributed throughout the year. Approximately 50% of the available hours are photometric, and about 75% are suitable for spectroscopy. Temperatures (especially at night) tend to be unpredictable. Snow has been known to fall at Christmas in the heart of summer, and cold weather may occur at any time of year! Observers are strongly advised to bring cold weather gear (a winter jacket, hat, gloves, etc.).

Facilities in the Domes

In every dome there is a kitchen equipped with a sink, kettle, coffee maker, microwave, toaster, snackwich maker, crockery and cutlery. Teas, coffees and sugar are provided.
Each dome now houses an iPod/iPhone-compatible music system with a radio and CD player, and which plays mp3s from a CD or USB stick. (Music not provided.)
There are wireless access points in the 1.9-m and 1.0-m domes.

Electrical Matters

Most outlets normally supply 230V 50 Hz current. Uninterruptible power supplies (UPSs) are provided in the domes for sensitive instrumentation and computers. Almost all of the plugs are of the 3-pin 15A type (round pins, not the rectangular type used in the UK). Observers bringing their own equipment (e.g. laptops) should also bring their own adaptors. In the event of a power failure, the observatory has a 650 kVA generator.

Time Service

The central time service at Sutherland (installed October 1993) is a PC-based system with a mean time oscillator (ageing rate 1 X 10-9 per day) locked to signals from a GPS receiver once each minute. The resulting drift is no more than 1-2 microseconds per minute under normal conditions. Sidereal time is calculated from the mean time. Multiplexed time information is distributed to each dome via a fibre optic cable. In each dome the signal is demodulated and demultiplexed into separate RS422 signals (mean time, sidereal time, 1kHz pulse and 1 minute pulse). The RS422 signals are used by the instrument computer, telescope control system and time display. If you believe the time displayed is not correct, please notify the electronics technician.

Library

The library at Sutherland is housed in the reading room of the hostel, with some publications shelved in the Visitor Centre. The library contains a small collection of charts, atlases (including the ESO B survey) and runs of journals. Observers using the SAAO network can access our e-journals. A suitably undistinguished collection of light reading for cloudy nights resides in the hostel lounge.

Visitor Centre & Shop

There are some interesting exhibits in the visitors centre and a shop selling souvenirs on-site.

Lesedi

SAAO is currently commissioning a new 1-metre alt-az telescope for use by the local and international astronomical community.  The telescope has been named Lesedi – meaning light or enlightenment in Sesotho – a name selected from competition entries submitted by South Africa’s Grade 6-12 learners. The telescope will be offered for traditional observing proposals in week-long blocks, as well as service applications, in due course.

The telescope has two identical Nasmyth foci, with high throughput down to UV wavelengths.  A custom-made wide-field camera – designed and built at SAAO – is currently being developed to exploit the widest field-of-view of any of our telescopes.  In the interim period, a SHOC instrument with UBVRI and clear filters will be offered.  SHOC has a field-of-view of 5.7×5.7 arcmin2 on Lesedi. The telescope’s basic parameters are given in the Table below.

Calls for proposals will be announced on the web page and by email to our usual mailing list once commissioning is complete.

Southern African Large Telescope

The Southern African Large Telescope (SALT) is the largest single optical telescope in the southern hemisphere and among the largest in the world. It has a hexagonal primary mirror array 11 metres across, comprising 91 individual 1m hexagonal mirrors. Although very similar to the Hobby-Eberly Telescope (HET) in Texas, SALT has a redesigned optical system resulting in a larger field of view and effective collecting area.

SALT can detect the light from faint or distant objects in the Universe, a billion times too faint to be seen with the unaided eye – as faint as a candle flame would appear at the distance of the moon. The telescope and instruments are designed to operate from the near ultraviolet to the near infrared (320 to 1700 nm), and offer some unique or rare capabilities on a telescope of this size.

SALT is situated at the South African Astronomical Observatory (SAAO) field station near the small town of Sutherland, in the Northern Cape province, and is ~380 km from Cape Town. SALT is funded by a consortium of international partners from South Africa, the United States, Germany, Poland, India, the United Kingdom and New Zealand. The construction phase was completed at the end of 2005 and from 2006 to 2009 it entered a period of commissioning and performance verification. Since September 2011, observing is now in full swing and the telescope is finally realising its huge potential as Africa’s Giant Eye on the Universe.

Telescope Instruments

Instruments List by telescope

1.9-m Telescope

SpUpNIC (formerly the Cassegrain Spectrograph, upgraded and recommissioned Oct 2015)
SHOC
HIPPO
GIRAFFE: Fibre-fed Echelle (not available for applications at present, pending upgrades)
Grating Spectrograph

1.0-m Telescope

SAAO CCD Camera (STE3/STE4)
SHOC

Lesedi

SHOC
WinCam

SAAO Instruments

SHOC: Sutherland High Speed Optical Cameras

SHOC: Sutherland High Speed Optical Cameras

SHOC mounted with the focal reducer on the 1.9m telescope. The large bluish rectangle near the center of the image is the box containing the SHOC computer and electronics; the camera is the small gray object at the end of the long, black focal reducer tube.

Two nearly identical instruments named SHOC are available for use on the SAAO 1.9-m and 1.0-m telescopes, and on the new 1.0-m telescope, Lesedi. SHOC 1 and 2 are high-speed, visible-wavelength systems, mounted at Cassegrain focus and using the existing filter wheels employed by the SAAO CCDs. The SHOC cameras allowed the UCT CCD camera to be decommissioned  in 2012.

The SHOC design is based on POETS (Portable Occultation, Eclipse, and Transit Systems; developed by a collaboration between groups at the Massachusetts Institute of Technology (MIT) and Williams College) and MORIS (MIT Optical Rapid Imaging System) at NASA’s 3-m IRTF on Mauna Kea, Hawaii.

Technical Specifications

The SHOC instruments employ Andor iXon 888 EM CCD cameras, which have an electron-multiplying (EM) capability. They are 2048×1024 13-μm pixel detectors, operated in frame-transfer mode (imaging area 1024×1024 pixels). The following characteristics apply:

The cameras have selection of amplifiers (four different speeds; two conventional and four EM), each having multiple electron to ADU gain settings.  Binning and subframing are also user selectable. Operating at the lowest readout speed (lowest read noise) with appropriate binning for Sutherland’s median seeing, a minimum cycle time of ~0.5 seconds is typical. With further binning, windowing and higher readout speed, the cycle time can be decreased to 0.01 seconds. The SHOC 1 and 2 systems contain identical components, except that the cameras have slightly different technical properties (read noise, well depth, etc.). See the SHOC 1 camera specification sheet and the SHOC 2 camera specification sheet.

There is an online calculator to help with estimating observing times, signal-to-noise ratios, and limiting magnitudes.

Current Status & Availability

The instruments are open for general use.  The software has been overhauled and integrated during the two years following commissioning, and is now running on a web-based platform with js9 display. Please note the following:

Observers are invited to apply for time using SHOC on the 1.9-m and 1.0-m telescopes. SHOC 2 is currently mounted on the new 1.0-m telescope at all times.  Those new to SHOC must request assistance for the first night of their run; students must be accompanied by their supervisor.  Please reference the SHOC instrument paper in your publications (see below).

Filters

Lesedi has its own filter wheel containing Bessell U B V R I and clear filters.  Only these filters are available on this telescope at the present time.

For the 1.9-m and original 1.0-m telescopes, the available filter sets are listed below (click on filter name to view transmission curve); there is also an empty slot in each filter wheel for white light observations:

• Bessell U B V R I
• SDSS u’ g’ r’ i’ z’
• Hα wide (20 nm)
• Hα narrow (3 nm)
• Redshifted Hα at 667, 681 & 686 nm
• [O III] 501 nm
• BG38
• Z

Please be sure to list every filter you require for your program in the GRATINGS AND FILTERS field of the SAAO Telescope Time Application form.  This will ensure that your desired filters are scheduled for your run.

Visitor filters up to 51 mm square and 10 mm thick can also be accommodated.  Visitors wishing to use their own filters should contact the Head of Telescope Operations (rrs at saao.ac.za) to discuss this when applying for telescope time.

Further Information

Further information can be found on the SHOC commissioning website. Available here are links to the online user manual and the SHOC data reduction pipeline (start with the README!).

Selected publications from commissioning:

HIPPO: High speed Photo-Polarimeter

HIPPO is SAAO’s newest (2008) high-speed photo-polarimeter. It is capable of high-speed, multi-filtered, simultaneous all-Stokes observations of point sources. Its high-speed capabilities make it especially ideal for investigating rapidly varying astronomical sources such as magnetic cataclysmic variables. HIPPO was designed and built in order to replace its highly successful but ageing single channel equivalent, namely the University of Cape Town (UCT) photo-polarimeter (Cropper 1985).

The instrument makes use of rapidly counter-rotating (10Hz), super-achromatic half- and quarter-waveplates, a fixed Glan-Thompson beamsplitter and two photo-multiplier tubes that record the modulated O and E beams. Each modulated beam permits an independent measurement of the polarisation and therefore simultaneous 2 filter observations. All Stokes parameters are recorded every 0.1sec and photometry every 1 millisecond. Post-binning of data is possible in order to improve the signal. First light was obtained in February 2008.

Current Status & Availability

HIPPO is open for general use on the 1.9m telescope only. Potential applicants should contact the PI (Stephen Potter: sbp at saao dot ac dot za) if first time users or would like to collaborate.

The HIPPO control software runs on a Linux operating system with a real-time linux kernel patch in order to guarantee absolute and relative timing accuracies. On-the-fly preliminary data reduction produces live photometry and polarimetry light curves.

A user manual is available here and a reference manual is available here.

Offline Data Reduction

A set of data reduction algorithms are available. The routines are written for unix based operating systems (Linux and MacOS) and are compiled (e.g. using a gcc compiler) and executed from the command line. The data reduction process in split into three sets of reduction routines written in C. The first set deal with splitting the raw data file(s) into more manageable files sorted by target name, filter and channel. The second set extracts the photometry and handles binning, sky-subtraction and co-adding. The third set extracts the polarisation and handles binning, sky-subtraction, co-adding and polarisation calculation.

Software and sample reduction instructions are currently available upon request (Stephen Potter: sbp at saao dot ac dot za).

Publications

Please email the PI (Stephen Potter: sbp at saao dot ac dot za) if you are aware of any publications that have made use of HIPPO observations that are not listed below.

Yudin, R. V.; Potter, S. B.; Townsend, L. J.   2017MNRAS.464.4325, First multicolour polarimetry of TeV γ-ray binary HESS J0632+057 close to periastron passage

Buckley, D. A. H.; Meintjes, P. J.; Potter, S. B.; Marsh, T. R.; Gänsicke, B. T.  2017NatAs…1E..2, Polarimetric evidence of a white dwarf pulsar in the binary system AR Scorpii

Pekeur, N. W.; Taylor, A. R.; Potter, S. B.; Kraan-Korteweg, R. C., 2016MNRAS.462L..80 Evidence for quasi-periodic oscillations in the optical polarization of the blazar PKS 2155-304

Potter, Stephen B.,  2016ASSL..439..179 Stokes Imaging: Mapping the Accretion Region(s) in Magnetic Cataclysmic Variables

Potter, S.B.  2015AcPPP…2..139 High-Speed Photo-Polarimetry of Magnetic Cataclysmic Variables

Buckley, D. A. H.; Potter, S. B.; Kotze, E.; Kotze, M.; Breytenbach, H.  2014EPJWC..6407005 New Observations of Accretion Phenomena in Magnetic Cataclysmic Variables

Kniazev A. Y. et al. ApJ, 2013, 770, 124: Characterization of the nearby L/T Binary Brown Dwarf WISE J104915.57-531906.1 at 2 Pc from the Sun

Potter S. The fourth Gaia Science Alerts workshop, 2013: South African Astronomy and Observatories

Potter S. IAUS, 2012, 285, 117: Polarimetric Variability

Potter et al, MNRAS, 2012, 420, 2596: On the spin modulated circular polarization from the intermediate polars NY Lup and IGR J15094-6649

Potter S., LSST all hands meeting, 2012: Time Domain Science and LSST Follow-up in South Africa

Andersson B.-G.; Potter S. B. ASPC, 2011, 449, 134: Observational Evidence for Radiative Interstellar Grain Alignment

Potter S. et al, ASPC, 2011, 449, 27: First Science Results from the High Speed SAAO Photo-polarimeter

Potter S. et al, MNRAS, 2011, 416, 2202: Possible detection of two giant extrasolar planets orbiting the eclipsing polar UZ Fornacis

Revnivtsev M. et al. MNRAS, 2011, 411, 1317: Observational evidence for matter propagation in accretion flows

Russell D. et al. 2011,ArXiv1104, 837: Rapid variations of polarization in low-mass X-ray binaries

Russell D. et al. PoS, htra-IV, 2010: Rapid variations of polarization in low-mass X-ray binaries

Andersson B.-G.; Potter S. B. ApJ, 2010, 720, 1054: Observations of Enhanced Radiative Grain Alignment Near HD 97300

Andersson B.-G.; Potter S. B. AAS, 2010, 42, 320: Observations of Enhanced Radiative Grain Alignment Near HD 97300

Potter S. et al. MNRAS, 2010, 402, 1161: Polarized QPOs from the INTEGRAL polar IGRJ14536-5522 (=Swift J1453.4-5524) also describes HIPPO commissioning

Potter S. et al. SPIE, 2008, 7014, 179: A new two channel high-speed photo-polarimeter (HIPPO) for the SAAO

SAAO CCD Camera (STE3/STE4)

Two SAAO CCD cameras are available for direct imaging on the 1.0-m telescope, but currently unavailable on the 1.9-m telescope due to failure of the DOS control system. The two cameras are distinguished by their detectors: STE4, a 1024×1024 pixel back-illuminated CCD, and STE3, a 512×512 pixel version of the same chip, with one quarter of the field of view of STE4.  The control software is Linux-based (manual available here).  Software is available at the telescope for determining guide star positions, as described in the TCS manual for each telescope.

Filters

Bessell U B V R I filters are available for use with the SAAO CCDs and are mounted at all times (click on filter name to view transmission curve); there is also an empty slot in the filter wheel for white light observations.  We have one of each of the following filters, available on request:

Please be sure to list every filter you require for your program in Section 4 of the SAAO Telescope Time Application form.  This will ensure that your desired filters are scheduled for your run.

Visitor filters up to 51 mm square and 10 mm thick can also be accommodated.  Visitors wishing to use their own filters should contact the Head of Telescope Operations (rrs at saao.ac.za) to discuss this when applying for telescope time.

Detector Properties

The table below gives the properties of STE4.  Where the attributes of STE3 differ, they are given in square brackets.

Data Reduction

There are Linux PCs located in the domes for image processing using IRAF and a pipeline based on DoPHOT.  The latter can be used for real-time reductions, to obtain reduced CCD photometry of stellar fields while observing. As each image is written to disc, the program picks out the correct flatfield, cleans and flatfields the frame and writes it out as a FITS file. It then runs DoPHOT on the image to produce aperture and profile-fitted magnitudes. If you are observing the same field repeatedly, DoPHOT will display differential profile-fitted magnitudes as a function of time. The results from DoPHOT can be further processed using routines in the local STAR package to produce the final results.

Data Backup & Archiving

Observers can backup their data to their laptop, or transfer it to their home institute via ftp.  Alternatively, observers may arrange with IT staff to write their data to DVD for them.  The computers in the domes do not have DVD-writing facilities, nor functioning USB ports.

SpUpNIC: Spectrograph Upgrade – Newly Improved Cassegrain 

The Cassegrain Spectrograph Upgrade project was completed in October 2015 and the instrument (SpUpNIC) has been in routine operation and well subscribed ever since.  A SpUpNIC paper was presented at the SPIE Astronomical Telescopes and Instrumentation conference in Edinburgh in June 2016.

SpUpNIC still uses the same set of surface-relief diffraction gratings, arc lamps (CuAr and CuNe – now available simultaneously) and order blocking filters (BG38, BG39 and GG495) as before, but the instrument has new camera and collimator optics, as well as a new detector system.  The new optics and CCD slightly reduce the dispersion, but significantly increase the wavelength ranges delivered by the various gratings – see the table below for details. The original slit mechanism is still in use and offers slit widths ranging from 0.15″ to 4.2″ (in 0.15″ increments).

The spectrograph camera’s new Folded-Schmidt optical design is much more efficient than the old Maksutov-Cassegrain system, and the new CCD provides an additional sensitivity boost.  The introduction of a rear-of-slit viewing camera allows far more accurate positioning of the target on the slit, and being able to view the star going down the slit makes it easier to focus the telescope reliably.  These critical aspects have substantially increased the spectrograph throughput and overall observing efficiency, particularly for faint targets.  The new instrument control software, as well as the quick-look data reduction tool, further streamline the process and provide access to the data which can be extracted and approximately wavelength calibrated as soon as an image is read out.

Sample spectra are shown in the figure below, with the SDSS g magnitudes of the stars listed to the right.  Most were obtained with the low resolution G7, but the shorter spectrum (second from the bottom) was a 900s exposure with a 1.5″ slit using G6.  The G7 spectra employed slit widths between 1.5″ and 2.7″ (depending on the seeing) and the exposure times ranged between 1800 sec for 16-18 mag, 1200 sec for 15-16 mag, 600-900 sec for 13-15 mag and 200 sec for 11th/12th mag standard stars.  The faintest target observed for this campaign was 18th mag and that required a 2400 sec exposure.  The most extreme use of the high resolution blue G4 has been to observe a V~17.5 mag star for 1200 sec and be able to classify the object as a white dwarf.

Spectro-photometric Standards with Grating 4

Spectro-photometric Standards with Grating 5

Spectro-photometric Standards with Grating 6

Spectro-photometric Standards with Grating 7

The instrument team is completing remaining commissioning tasks and tests, and making refinements to the system – specifically the software, as well as the grating mechanism which proved to be mechanically unstable.  The latter has been significantly improved and ought to be resolved with the modifications currently in progress.  As a result, we do not yet have a good feel for the instrument’s performance in terms of measuring radial velocities.  This information will be added once the grating stability issues have been addressed and the RV capabilities of the instrument can be established.

The SpUpNIC Wiki page provides detailed information for observers at the telescope, start-offs are provided for new users and telephonic support is available throughout the night should problems arise at the telescope.

SpUpNIC Exposure Time Information

For users wishing to estimate exposure times from real SpUpNIC data, the following files give extracted 1D spectra from a representative subset of a suite of spectrophotometric standards observed with SpUpNIC during 2015 Nov-Dec.  The most reliable way to estimate exposure times is probably to measure S/N directly in the wavelength range of interest, with the setup which most closely matches yours, and then to scale accordingly.

Measurements are given for the two most commonly used gratings, G4 and G7, and at typical grating angles.  These conversion factors should be approximately unchanged for small changes in grating angle.  Other gratings will be added as the information becomes available.

Each _1D.txt file contains wavelength (A) and [sky subtracted] counts summed over the extraction window in the spatial direction.  This is the raw counts observed in the total exposure time.  Exposure times and other useful info are given in the NOTES file.  These files are the output from V2 (May 2016) of the quick look GUI and include automatic wavelength calibration.  These are not yet finely tuned, but should be accurate to better than ~2A, and thus fine for comparing with flux standards.

Also included are files containing the conversion factors to convert from **counts/second/pixel** into flux units in 10^-16 erg/s/cm^2/A.  So, in order to go from the observed counts in the _1D.txt files, it is necessary to divide by the exposure time and then multiply by the appropriate conversion factor.

All of these observations were made in “Faint & Slow” mode, which has a gain of 1.145e-/ADU.  No aperture correction has been made.

A more detailed version of this table: NOTES

The observed S/N may be simply estimated in the wavelength range of interest by, for example in python:

x,y = np.loadtxt(‘a0071110_1D.txt’,unpack=True, usecols=(0,1)) # read in data

ok = np.where( (x>5100.) & (x<5200.) )[0] # choose wavelength range relatively free of absorption lines

print median(y[ok])/std(y[ok])

76.043849269

Therefore, for LTT 377 at ~5150A (flux ~1.2e-13 erg/s/cm^2/A) SpUpNIC reaches a S/N ~76 PER CCD PIXEL in 600s.

Flux calibration curves

gr7_calfac_grang17.0
gr7_calfac_grang15.3
gr4_calfac_grang4.1

The Hamuy standards used in the calibration can be found here:

ftp://ftp.eso.org/pub/stecf/standards/ctiostan/  NOTE: LTT377 is cd_34d241

Approximate polynomial fits to a series of standard stars, giving the factor by which to multiply the raw counts (per second), to get to flux, as described above.  The plots below show the stars used (and the variation from object-to-object) for G4 and G7 respectively.  Note: LTT1020 seems to be an outlier and has been rejected from the fits.  It may be necessary to interpolate the wavelengths onto a common grid before multiplying.

Quick Python Example:

x,y = np.loadtxt(‘a0071110_1D.txt’,unpack=True, usecols=(0,1)) # read in data

y = y / 600. # convert to counts/s

a,b = np.loadtxt(‘gr7_calfac_grang15.3.txt’,unpack=True, usecols=(0,1)) # read in appropriate flux conversion factor

# interpolate to same wavelength bins:

ib = np.interpol(x,a,b)

plot(x, y*ib*1e-16 ) # flux calibrated in erg/s/cm^2/A

Comparison with Pre-Upgrade Spectrograph

For users preferring to scale their exposure times from previous experience, the following may be more useful.

G4

Comparison of pre-upgrade (blue) vs SpUpNIC (green) in e-s per second **per A**.  Note: the dispersion has changed from 0.495 A/pix to 0.622 A/pix and this conversion factor has been included.  The old gain was 1e-/ADU.  To compare values per CCD pixel, SpUpNIC will be 0.622/0.495 times higher than plotted. To compare old and new counts, SpUpNIC will be 1.145 times lower (the new gain).

SpUpNIC Instrument Team

SpUpNIC was an effort undertaken by a large team of people, over a very long period of time. The PI on the project was Lisa Crause (aka the fearless leader).

We encourage proper credit be given to the instrument teams, which means that co-authorship for the following groups would be appreciated for publications stemming from data taken during commissioning time.  This follows the standard instrument commissioning agreement for SpUpNIC.

Full Instrument Team

L.A. Crause, D.B. Carter, A. Daniels, G.P. Evans, P. Fourie, D. G. Gilbank, M. Hendricks, W. Koorts, D. Lategan, E. Loubser, S. Mouries, J. O’Connor, D. O’Donoghue, S.B. Potter, C. Sass, A.A. Sickafoose, J. Stoffels, P. Swanevelder, C. van Gend, M. Visser, H.L. Worters

The full team includes all staff who have made a significant contribution to the project. Notably, this includes workshop staff and technicians (non-scientists).

Typically, the instrument PI is the lead author on the papers and publications in which the instrument is described. Regardless of the first author, the full instrumentation team should be provided the opportunity to be coauthors on the first instrument presentation (e.g. at an SPIE meeting) and on the instrument publication. The decision to be a co-author rests with each individual, such that they can opt out if desired.

Instrument Science Team

L.A. Crause,  D. G. Gilbank, D. O’Donoghue, S.B. Potter, A.A. Sickafoose, C. van Gend, H.L. Worters

The science team consists of PhD-level staff who have contributed significant time and/or effort to the construction of the instrument. This is a subset of the full instrument team.

Users of an instrument while it is undergoing commissioning are strongly encouraged to credit the instrument science team in all publications stemming from data taken during that time.  Without these people, the instrument would not be available!

Hosted Instruments

TRIPOL

TRIPOL is a three-colour imaging camera operating simultaneously in Sloan g’, r’ and i’ bands.  It is a visiting instrument from Nagoya University that we are pleased to offer on the SAAO 0.75-m telescope from Quarter 4 of 2012.

The beam is split by two dichroics, then directed to three SBIG cameras via the fixed Sloan filters, resulting in three FITS images for each exposure (g’, r’ and i’).  The instrument is operated from the command line, and interfaces with the TCS such that telescope positional information is written to the FITS headers.  The telescope can be slewed automatically to objects in a catalogue file stored on the instrument PC, and pointing offsets can be applied from the command line (e.g. for dithering).

Technical Specification

Further information

Further information on the operation of TRIPOL can be found in the preliminary Users’ Guide.  Please direct queries to nagayama(at)z.phys.nagoya-u.ac.jp

Instrumentation Electronics

The Electronics department of the Instrumentation Division is responsible for developing, maintaining and supporting the electronic components of the telescopes and instruments.

Team members include Hitesh Gajjar (head of department), Piet Fourie, Willie Koorts, Pieter Swanevelder, Michael Rust, Reggie Klein and Keegan Titus.

Software Framework

We have developed a new software framework which we intend using for all new and upgraded instruments on the SAAO small and medium telescopes. The framework is distributed, in that it allows components to exist independently yet communicate through a network, and language-agnostic, in that it allows components to be written in whichever language is most suitable to the task at hand.

At its core is the Apache Thrift package. This allows interfaces to be defined in a straightforward way, and then generates boiler-plate code to implement the interface. Thrift provides both a means of interprocess communication and remote procedure calls.

The framework allows the user interface to be separate and remote from the back-end code. We are using this framework to develop web-based interfaces, so that in future users will not neccessarily need to be at the telescope to operate the instruments.

The framework has been applied to the Sutherland High-speed Optical Camera (SHOC) systems, where the user is now able to interact with the filter wheel, global positioning system (GPS) and camera through a single (web-based) interface. We installed the revamped SHOC systems in early 2015. We also used the framework to develop software for the upgraded Cassegrain spectrograph on the 74-inch telescope, which went live in October 2015.

Our current projects include developing a web-interface to RTS2, the telescope control system for the new 1-metre telescope, and a full software control suite (also with a web-interface) for the Wide-field Nasmyth Camera (WiNCam) which is being built to take advantage of the new telescope’s wide field of view. Both of these projects make use of the new software framework.

A schematic diagram of the new software framework, applied to a simple two-component system.

Instruments We’re Building

We are continuously upgrading and improving our instruments, and we’ve always got several things on the go. Our highest priority project at the moment is WiNCam, a wide-field camera to be mounted on one of the Nasmyth ports of Lesedi (the SAAO’s new 1-metre telescope). This will incorporate the largest detector ever handled by our instrumentation team (6k x 6k pixels!) and we are using the IDSAC controller developed by the Indian Inter-University Centre for Astronomy and Astrophysics (IUCAA). The cryostat, instrument housing, filter and shutter mechanisms have all been designed and are being built-in-house, in out mechanical and electronics workshops. The software is being developed using the software framework previously developed and used for the SHOC and SpUpNIC instruments.

The SAAO recently acquired a new 1-metre telescope, named Lesedi. This was installed in August 2016, and is currently being commissioned. Until the WiNCam instrument is ready, we are using one of the SHOC instruments for this. We are also developing a web-based interface to the telescope control system supplied with which the telescope.

We have developed a new software framework which we are now using for all new and upgraded instrumentation projects. The framework supports a distributed set of instrument components, and allows a web-based user interface to be implemented. This is in line with our long-term goal of having the instruments be remotely (and eventually robotically) operable.

We recently comprehensively overhauled the Cassegrain Spectrograph on the 74″ telescope and it was installed in the October 2015. The upgrade includes a much improved optical design, re-coated optics and a significantly better light throughput. There is also a new user interface, and the software was developed using our new software framework (see below). A webcam followed the progress of the instrument as it was built, and there’s a blog describing the building and commissioning of the instrument.

The software for the SHOC instruments has been re-written using the new framework, and went live in the second quarter of 2015. As part of the rewrite, a web interface to the instrument is provided, and all the hardware components (camera, GPS and filterwheel) are controlled from a single interface. This also allows the generated FITS data files to be populated with information from all components.

Other planned projects include upgrading GIRAFFE and HIPPO.

In addition to the instruments,  we are also developing new control systems for the telescopes. The Telescope Control System integrates all the different functions of the telescope such as telescope movement, dome and shutter control and any other parts of the telescope that requires control. We are working towards full remote control of the telescope and telescope environment.  Safety features are incorporated in the designs to ensure that the telescope or users are protected in the events such as power failures, bad weather conditions and moving of the telescope or dome where things can be damaged. Some of these features that we have developed for telescopes and environment are incorporated by some of the other facilities we host at SAAO.

We proudly utilize the following software in the design and development of our instruments:

Sutherland Telescope Users Committee (STUC)

The Sutherland Telescopes Users’ Committee (STUC) has been formed to advise the director on scientific, technical and operational issues relating to the running of the SAAO telescopes in Sutherland.