Our Quest for the H0ligrail


In the recently founded HOLIGRAIL (HOher LIst GRAvItational Lensing) project we use the 1m Telescope operated by the Argelander-Institut für Astronomie at Hoher List Observatory to monitor multiply-lensed quasars aiming at the determination of time-delays between the different light paths. These can be used to study the individual radial mass profile of the lensing galaxies, or -from a larger ensemble- to constrain the Hubble Constant H0. This programme has been inspired by the COSMOGRAIL project.

Apart from our scientific goals, the H0LIGRAIL project comprises a technical upgrade of the 1m Telescope and the introduction of a new lab course experiment, performing and analyzing H0LIGRAIL data, which is now part of the advanced lab course in Physics at Bonn University.


People involved

Your name on this list? We are looking for people to develop code, documentation, or go observing. Interested? Talk to Benjamin!




If you are going there by public transport take a RB train from Bonn Hbf or Bonn Duisdorf to Euskirchen, then change to a RE or RB train to Gerolstein. For connections see bahn.de. From there you can take the bus 500 (direction Cochem) to Schalkenmehren-Kirche, which is the village below Hoher List.

If you have a student ID or job ticket you can travel for free until Gerolstein.

Before going to Hoher List you should in any case call the observatory (06592/98258-0) and let them know you are comming.

If you arrive during office hours the kind people of the workshop might be able to pick you up either in Gerolstein or at Schalkenmehren-Kirche if you ask.
If you want to travel by car see instructions at the this webpage.

Project timeline

22/02/2010 New Hoher List Control System (HOLICS) Version 1.0.0 released. (Link)
01/12/2009 Preliminary analysis of 1 year of Holigrail data: The data is of sufficient quality to be used by Cosmograil.
01/11/2009 Successful first tests of new automatic liquid nitrogen refilling station at the 1m telescope.
01/09/2009 New emergency telescope shutdown via SMS.
27/06/2009 Hoher List hit by lightning: Considerable damage to several electronics components including CCD. Repair takes several weeks.
01/11/2008 Regular remote observations from Bonn start.
20/10/2008 HOLIGRAIL receives the Alumni award for the best student initiative by the Universitaetsgesellschaft Bonn.
01/10/2008 Wide-angle sky camera at Hoher List is online.
15/09/2008 First remote test observations from Bonn are performed.
08/09/2008 First observations after the re-aluminization and the mirror alignment in very good conditions. Sub-arcsecond seeing is achieved.
01/09/2008 H0LIGRAIL workshop at AIfA.
01/08/2008 The mirrors are back. Several studies to improve the quality of the mirror alignment follow.
23/05/2008 Re-aluminization of the telescope mirrors starts.
26/04/2008 H0LIGRAIL will become part of COSMOGRAIL. During Frederic Courbin's visit targets to be monitored are selected.
05/03/2008 H0LIGRAIL lab course starts as regular constituent of the advanced lab course in physics at Bonn University.
14/01/2008 Software meeting in Bonn. A schedule for steps towards remote/ automated observation is set up.
01/01/2008 New cloud sensor delivers weather information.
11/12/2007 A preliminary data analysis shows that H0LIGRAIL is in principle capable of performing lens monitoring.
16/10/2007 Project Status meeting. The holigrail project is producing data and technical advances are achieved.
05/10/2007 First test run of the H0LIGRAIL lab course starts.
03/09/2007 The H0LIGRAIL Project starts regular observations.
10/05/2007 Technical discussion meeting at Hoher List Observatory.
08/05/2007 Kick-off Meeting in Bonn. Sub-teams are defined.
06/05/2007 First version of the homepage online.
03/05/2007 Tim gives a lens-seminar talk to promote the project at AIfA. The number of people who want to contribute is impressive.
17/04/2007 Benjamin suggests the project name "H0LIGRAIL".
08/04/2007- 17/04/2007 Pilot study carried out by Tim, Benjamin, and the students of the astronomy lab course: Richard Hanson, Omar Rahman, Fabian Schneider, Philipp Simon, Philip Thielen, Marcel Usner. We observed a large bunch of lens systems. The system performance was better than expected: Seeing: best: 0.9'', worst: 1.8'', median: 1.4''. Limiting magnitude: R ~ 22.7 mag in 1 hour (5 sigma point source in 1.5'' aperture for seeing 1.0''). The prospects for lens monitoring appear good.
08/2006- 04/2007 Frederic Courbin (EPFL, Lausanne) and Tim exchange a couple of emails after the Oort Workshop in Leiden to discuss if lens monitoring at Hoher List Observatory makes sense. Some test data shall be taken.