Progress of the Project, Summer 2012
- Jean-Paul Rochaix installed the focal gondola’s supporting cable. The original manual wire was replaced by an 800m-long cable equipped with an anchored electrical winch, which makes the operations of raising and lowering the gondola easier.
- Two spherical mirrors of 150mm diameter and 200m radius of curvature, polished by David Vernet, were installed in their support tripods and placed on a north-south axis, at a distance of 16m from each other.
- Two prototype optical gondolas were updated and tested on site; mirror alignment tests were performed on site using a range finding laser.
- An optical device for receiving and recording the stellar image sent by the gondola was installed in the south point.
- The cables for monitoring the diurnal movement of the gondola were installed and motorized (using a step-by-step motor). A counterweight system anchored in the trees guaranties the possibility of monitoring this movement for about 1 hour.
- Denis Mourard and Rémi Prud’homme updated the cable-control software (synchronization at east and west points).
- Rémi Prud’homme installed a WI-FI system for data transferring between different points of the installation.
- Jean-Paul Rochaix set up a tipi tent that works with solar power. Equipped with a Satcom/Internet antenna, heatable, this tent serves as a field laboratory and allows working in sheltered conditions.
- A signal cable for civil aviation and bird protection devices were installed.
- Dashboards and detailed laboratory notebooks were maintained.
See the images:
Current work, 2012-2013
- In collaboration with Martine Roussel and Jérôme Maillot, a detailed mapping of the terrain was undertaken by the “Institut national de l’information géographique et forestière (IGN)” using a differential GPS.
- An application for European funding has been made, which aims to increase the number of permanent team members.
Preparation for Spring-Summer 2013 fieldwork
- Initial tests for star tracking
- Optical tests on the sky
- Fine tuning of the two mirrors
- Increasing the number of mirrors
The team coordinated by Antoine Labeyrire and Denis Mourard wishes to:
- validate the diurnal tracking system,
- develop a reliable and fast method to adjust and stabilize the position of the mirrors on the theoretical sphere of the diluted mirror,
- obtain the “first fringes” with two small mirrors (without adaptive optics at first),
- gradually increase the amount of mirrors.
The first objects observed with the ground telescope in Haute Ubaye won’t be exo-planets but bright stars, in particular Vega, which is easy to observe during the summer. Once the technical steps have been accomplished, the first scientific studies will concern “resolved” stars. The observations made on these stars will evolve according to the technical evolution of the installation.
As with radio interferometers, the hypertelescope in Ubaye lends itself to a modular-evolving installation. It presents, therefore, the same advantage, making it possible to produce scientific results before the completion of the installation. It is difficult to predict in advance the rhythm and timing of the evolution of the installation as it depends on the results of preliminary tests.
The schedule for co-phasing the mirrors by adaptive optics, and then by laser-guide star, as well as the extension of the meta-aperture to 200m, will be a function of:
- the experience acquired during initial tests,
- the scientific prospects,
- the funding and human resources available.
The duration of the scientific use of the hypertelescope installed in Ubaye will depend both on the initial results obtained on site and on the interest that European or international astronomical institutions could show for an envisaged project in collaboration with Indian astronomers: the construction in the Himalayas or the Andes of a larger version of the hypertelescope. However, if this Extremely Large Hypertelescope (ELHyT) were to take place, the scientific exploitation of the hypertelescope in Ubaye should continue during the years necessary for the study and construction of the new instrument.