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Astronomical Data Analysis Software and Systems VI ASP Conference Series, Vol. 125, 1997 Gareth Hunt and H. E. Payne, eds.

Remote Eavesdropping at the JCMT via the World Wide Web
Tim Jenness, Frossie Economou, R. P. J. Tilanus
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Joint Astronomy Centre, 660 N. A'ohoku Place, University Park, Hilo, HI 96720 Abstract. The James Clerk Maxwell telescop e (JCMT), a submillimetre facility on Mauna Kea, has recently adopted flexible scheduling. This is exp ected to result in fewer astronomers travelling out to Hawaii, and more data b eing taken by local observatory staff. In order to allow astronomers to monitor their data from their home institutions, JCMT has adopted the WWW Observing Remotely Facility (WORF) already offered by the United Kingdom Infrared Telescop e (UKIRT). WORF allows astronomers to eavesdrop on their data using the Netscap eTM browser with minimal impact on observatory staff and computer systems. The UKIRT implementation has b een extended to meet the differing exp ectations of the JCMT community, and has many additions including a telescop e status screen, the ability to access the observation log and the use of a conferencing tool b etween the observer and the eavesdropp er(s).

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Introduction

The James Clerk Maxwell Telescop e (JCMT) is a UK-Canada-Netherlands 15m submillimetre telescop e situated on the summit of Mauna Kea, Hawaii. In order to use good observing conditions more efficiently, the JCMT is moving to full flexible-scheduling. This will result in fewer astronomers travelling out to Hawaii, and more observations taken by observatory staff. It also implies that astronomers may only b e given a few hours notice b efore observations in their program are taken. Although JCMT users understand the advantages of flexible scheduling, they are reluctant to relinquish the ability to modify observing strategy on-the-fly as new data come in. We are anticipating the community's requirement for a way to monitor remotely their observations by developing the World Wide Web Observing Remotely Facility (WORF). WORF had b een develop ed previously for the United Kingdom Infra-Red Telescop e (UKIRT), where the HTTP based implementation was shown to have clear advantages (Economou et al. 1995); the JCMT sp ecific development has b ecome known as WORF2.

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Netherlands Foundation for Research in Astronomy (NFRA)

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© Copyright 1997 Astronomical Society of the Pacific. All rights reserved.


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Jenness, Economou, and Tilanus
EAVESDROPPER

Authentication

Select data directory

View telescope Status screen

Data preview

View observing log

EWGIE WWW Telescope

Run Tel. Status server

Create observing log

OBSERVER

Figure 1. 2. User Interface

The structure of the WORF2 system.

Each at th have They Web

successful prop osal for JCMT time is assigned a user name and password e b eginning of the semester. The first thing the p otential eavesdropp ers to do is authenticate themselves, as access to data directories is restricted. can then enter the WORF2 system, whose user interface consists of four pages (the locations of which are shown in Figure 1):

· Data Preview. This is the main display window of the WORF2 system. Here the eavesdropp er is presented with a list of completed observations from which to choose a particular one and display sp ectral line data, adjusting the plotting scale as desired. · Telescop e status. This is a continuously up dating (every 60 s) display of basic telescop e parameters. The most imp ortant of those are the Right Ascension and Declination, which reassures the eavesdropp er that the telescop e is indeed p ointing at her source. It is also imp ortant that the observer can check the current instrumentation configuration. · Observation log. The p erson actually observing at the telescop e can use in-house software to generate a log consisting of basic information ab out the observations and additional comments on the quality of the data. This window enables the eavesdropp er to p eek at this log file.


Remote Eavesdropping at the JCMT via the World-Wide-Web

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· Conferencing tool. A WWW based conferencing tool2 is also used so that the observer and astronomer(s) can discuss details of the run using b oth text and diagrams.

3. 3.1.

Implementation Data Preview

The data previewing CGI backend is written entirely in Perl5 (Wall, Christiansen, & Schwartz 1996). JCMT observations are stored in a telescop e sp ecific GSD format originally develop ed for single-dish radio telescop es. Using the flexible Perl extension mechanism, we first had to develop a module allowing access to the C GSD library. Data from the JCMT digital autocorrelation sp ectrometer (DAS) needs to b e processed b efore b eing displayed in a manner meaningful to an astronomer. The processed data is plotted into a GIF image via pgp erl, the Perl PGPLOT module,3 and is then served via HTTP. File naming conventions do not provide sufficient information for the eavesdropp er to determine the typ e of observation contained in a file. Rather than reading in every file in the data directory to extract this information, an observing log generated by the scientist at the telescop e is used instead. In the absence of such an observing log, only observation numb ers are displayed. 3.2. Security

Data privacy is a sub ject dear to the heart of many an astronomer. The eavesdropp er is authenticated by the HTTP server and the login name thus provided is compared against the ownership of each individual file requested thereafter (data ownership is determined by an entry in the file header). This takes advantage of the way observations from different pro jects are taken and stored at the JCMT. 3.3. EWGIE

We use the public domain Easy Web Group Interaction Enabler (EWGIE) conferencing tool. This Java based tool provides a "chat area" as well as a "whiteb oard" allowing diagrams to b e exchanged b etween multiple participants over HTTP. 3.4. Browsers

The data preview comp onent of WORF2 will run on most graphical WWW browsers. EWGIE requires Java supp ort. The observation log and telescop e status screens make use of client pull in order to automatically up date, a feature which is not currently supp orted by many browsers other than Netscap eTM . These pages can, of course, b e up dated manually by reloading the page.

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EWGIE, developed by Kevin Hughes at kevinh@commerce.net. (http://www.eit.com/ewgie/) http://www.ast.cam.ac.uk/AAO/lo cal/www/kgb/pgperl/


404 4. Future

Jenness, Economou, and Tilanus

JCMT has recently taken delivery of SCUBA, a much anticipated submillimetre b olometer array, which will provide our users with imaging data for the first time. Data from SCUBA is stored in the Starlink N-dimensional Data Format (NDF), which is widely used in the UK community. We have already develop ed a Perl module allowing access to the fortran Starlink libraries, and intend to take full advantage of the on-line data reduction pip eline written for SCUBA. WORF2 is already in use, mainly by Dutch astronomers who were the first JCMT partner to move to flexible scheduling. We exp ect it will b e used more widely as the British and Canadian allocated telescop e time switches to flexible scheduling later this year. We are in the process of adding more features to WORF2 but, as with WORF, other asp ects of the software group's work are of higher op erational priority. A demo of the data preview comp onent of WORF24 is also available. References Economou, F., Bridger, A., Daly, P. N., & Wright, G. S. 1996, in ASP Conf. Ser., Vol. 101, Astronomical Data Analysis Software and Systems V, ed. G. H. Jacoby & J. Barnes (San Francisco: ASP), 384 Wall, L., Christiansen, T., & Schwartz, R. L. 1996, Programming Perl, 2nd edn. (Sebastop ol, CA: O'Reilly)

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http://jach.hawaii.edu/worf2/worf2.csh