Remote Observing at ESO’s La Silla : The Legacy 20 Years After

Recalled by former students at one of ESO’s most exciting science-operations schools ever, conducted by dozens of Visiting Astronomers and uncounted La Silla staff

Dietrich Baade (ESO-Garching) Albert Zijlstra (University of Manchester, formerly ESO-Garching) Anders Wallander (ITER, formerly ESO-Garching) Andrea Balestra (Osservatorio Astronomico di Padova, formerly ESO-Garching) Elisabeth Hoppe (ESO-Garching) Francisco Labraña (ESO-La Silla) Geert Dobbels (I.H.T.S. S.L., Vitoria, formerly ESO-Garching) Gianni Raffi (München, formerly ESO-Garching) Jesús Rodríguez Ulloa (ESO-Garching)

Credit for all illustrations: ESO A Generation Ago, Remote Observing Hit the Headlines

• ADS lists 20 papers on observing with La Silla telescopes under remote control (RC) between 1984 and 1997. • Few other topics at ESO received so intensive joint attention by engineers & astronomers. • All major ground-based talked about RC. Most implemented it in some form.

• ESO offered full RC with 3 telescopes and 5 instruments.

m MPG/ESO Telescope MPG/ESO m

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2.2

m CAT m

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m NTT m

- 1.4 Direct camera 3.5 EMMI B&C spectropgraph CES SUSI Tempora Mutantur

Routine remote observing at ESO began.

(Following first thoughts in 1982 and a first test run from La Serena in 1984.)

The Messenger, 57, 38 (1989) Airport München-Riem (closed in 1992)

ESO Movie 01: Remote Observing

Charlie Ounnas (1945-2008) RC system manager Past Predictions of the (Now Past) Future (mostly by engineers; astronomers were more conservative/cautious) Remote Observing will: • Save travel time • Permit students to be trained ➢ Achieved. Carbon footprint reduced. (Today, astronomers are still traveling less often to . But not because of RC.)

• Save operations cost ➢ Has not come true.

• Enable flexible scheduling ➢ Did happen in a completely different way.

• Shorten feedback loop between developers and users (same building) ➢ Achieved.

• The unpredicted ➢ Identified in this talk. Top-level Requirements for ESO’s Remote Control Programme

• Give users full control over the equipment. • Offer identical control environment. Just 12,000 km away.

Garching

• As much as possible, enable same observing efficiency and quality. • Permit seamless changes between local and remote mode. • Develop portable user end. • Provide simulation mode for testing and training. • …

All achieved. Implementation

• Guest Observers o traveled to Garching instead of La Silla (successful full-RC test run took place from Trieste/Italy in 1992). o often came with a student for training purposes. o used instruments in exactly the same way as conventionally done. • Telescope operated by La Silla Telescope Operator (as in local mode). • Additional RC Operator in Garching vital for recovery from failures.

• La Silla extremely supportive. • La Silla and Garching formed joint multidisciplinary operations team of equals distributed over two continents and two working cultures. Those Allegedly Good Old Days Could Be Quite Tough

• Communication bandwidth reduced by 99% w.r.t. local mode: ➢ Had to simultaneously transmit digital (science images, control signals) and analog data (auxiliary video cameras, voice) via one 64 Kbit/s line. ➢ File transfer would take 1/2 hour per Mpixel with non-lossy compression. ➢ Donald-Duck-style voices. • Idiosyncracies of national (still state-owned) telecom companies. • 30-fold increased bandwidth with roof-to-roof system cost less. o But 600-ms handshakes initially drastically reduced actual benefit. • Garching time zone is 4-6 hours ahead of La Silla: ➢ Observations only started around midnight in Garching. ➢ Observers needed place to sleep at daytime. ➢ Observers had no time to buy food. • … Good Performance Was Achieved Anyway – Even Royally Recognized

RC Facility was the technical show piece in Garching (here: visit by Crown Prince [now: x: local King] Philippe of Belgium in 1990/91) •: remote

Wallander & Zijlstra 1996 Observing efficiency with EMMI and SUSI @ NTT (%) @ NTT SUSI and EMMI with efficiency Observing Night number (between 25/10/94 and 20/06/95) How far Did Remote Observing Enter into ESO’s Operations Paradigm?

• 2.2-m MPG/ESO Telescope: RC ended in 1992 following installation of EFOSC2 whose control software was not compatible with RC system.

• NTT: For Big Bang of Upgrade Project, NTT was taken out of service in 1997/98. RC not resumed thereafter because deemed unnecessary for VLT.

• 1.4-m Coudé Auxiliary Telescope (CAT): Once ~70% of all observing proposals requested RC mode, ESO prescribed RC as default. Nevertheless, following NTT/VLT policy, RC observations with CAT discontinued in 1998. Was Remote Observing a Failure?

• This is not the question: o Technically, RC was as perfect as such things get. • Decisive point was that RC did not surmount threshold from “nice to do” to “must do”. • Some issues addressed by RC proved less pressing than expected. Ultimate Lesson Learned: “The Answer is 2.5”

• One second (every second!) of VLT UT time costs 2.5€: ➢ Weather, time-domain astrophysics, uneven distribution of objects in sky, etc. require flexible scheduling. • The RC lessons: o RC cannot by itself achieve efficient flexibility. o Another large factor affecting operating efficiency concerns experience and preparedness of observers (as La Silla had learned long before).

• 1s of head scratching costs 2.5€ - regardless of whether the head is local or remote. ➢ RC cannot make a difference. The Impact of Remote Observing

1. Ultimately, RC experience contributed to ESO’s concept of Observation Blocks (OBs) and Observing Templates which • enabled service-mode (SM) observing with flexible scheduling and predictable performance. • much reduced the head-scratching problem in visitor mode.

2. Response by community to both RC and SM followed same pattern, from “It just can’t work” in the beginning to “Please, can you do it!” in the end. • Successful step of RC towards absentee observing accelerated acceptance of SM. (“Yes, ESO can.”)

3. Techniques for sharing by distributed CPUs of real-time databases (at a time when the WWW was being invented). 4. First distributed operations team at ESO; enabled NTT Team. The True Future of Remote Observing at ESO (through Nowcasting)

Paranal has relaxed former fortress mode and opened up itself to: 1. Eavesdropping Mode (POEM). • Offers remote observing without remote control but by editing OBs through web interface. • Brings service-mode users in contact with observing process and operations staff. 2. remote engineering from both Vitacura and Garching†. • Drastically reduces response time to technical issues.

† With instruments being built by community consortia, ESO-Garching is mainly a center of expertise in common control features. The Upshot

• In the end, remote observing has helped ESO to advance on much more important matters than originally considered: o development by ESO and acceptance by the community of service mode o techniques for database sharing by multiple CPUs o distributed operations teams, welding Garching and La Silla together

• POEM and remote engineering combine the best of the world and ESO for the future. Georg Kraus Acknowledgements Peter Biereichel Manfred Ziebell (extracted from technical RC@ESO publications) Charlie Ounnas Walter Nees Vicente Reyes Night Assistants: TRS Department ESO Postdoctoral Fellows • Alberto Alvarez Hans-Martin Adorf ESO Students • Manuel Bahamodes Pascal Angebault Night Assistants • Victor Meriño John Danziger TRS Department • Jorge Miranda Preben Grosbøl Daniel Hofstadt • Hernan Nuñez Bruno Gilli Steven Jörsäter Operations Group • Manuel Pizarro Joar Brynnel Massimo Tarenghi Paul Le Saux • Luis Ramirez Mauro Pucillo Marie-Hélène Ulrich Guest Observers • Gorki Roman Claudio Vuerli Stefano Cristiani • Hector Vega Paolo Marcucci Riccardo Smareglia Georg Kraus Claudio Corte Manfred Ziebell John M. Kerr Electronics Group Garching Gaetano Andreoni TRS Department La Silla Operations Group Night Assistants Manuel Pizarro Robin Arsenault Mauro Comin Enzo Brocato Bruno Gilli Patrick François Joar Brynnel Edmond Giraud Peter Biereichel Paolo Santin Walter Nees Observatory of Trieste Manfred Ziebell Paul Felenbok John M. Kerr Peter Biereichel Manfred Ziebell Thierry Fauconnier CFHT Daniel Hofstadt Joar Brynnel Observatoire de Meudon Gaetano Andreoni TRS staff Miguel Albrecht La Silla Observatory