First Light for LINC-NIRVANA Pathfinder – with Adaptive Optics!

November 30, 2013

On November 17, the LINC-NIRVANA Pathfinder instrument was successfully tested at the Large Binocular Telescope in Arizona. The Pathfinder team succeeded not only in acquiring the instrument's first observation of a celestial object – its so-called "First Light" – but also in commissioning of the control loop for the adaptive optics.

Figure 1: The Pathfinder team celebrates first light for LINC-NIRVANA Pathfinder. — **Figure 1**: The Pathfinder team celebrates first light for LINC-NIRVANA Pathfinder.

**Figure 1**: The Pathfinder team celebrates first light for LINC-NIRVANA Pathfinder.

Figure 2: Image of the star Epsilon Aurigae before activation of the adaptive optics. The fuzzy blob arises due to turbulence in Earth's atmosphere. — **Figure 2:** Image of the star Epsilon Aurigae before activation of the adaptive optics. The fuzzy blob arises due to turbulence in Earth's atmosphere.

**Figure 2:** Image of the star Epsilon Aurigae before activation of the adaptive optics. The fuzzy blob arises due to turbulence in Earth's atmosphere.

Pathfinder is a precursor of the sophisticated near-infrared camera LINC-NIRVANA (LN), whose components are in final assembly, integration, and verification at the MPIA. LN will use so-called Multi – Conjugate Adaptive Optics and (eventually) an interferometric combination of the optical paths of the two 8.4m mirrors of the LBT. This will deliver high-resolution images that are effectively undisturbed by atmospheric turbulence. Implementing a large and complex instrument successfully at LBT requires carefully planning and on-site experimentation. Pathfinder is used as a test system on one of the LBT mirrors to demonstrate in advance the performance of LN systems in interaction with the telescope and its environment.

Figure 3: The same star, but now after activation of the adaptive optics. Although this picture was taken during 2.3 arcsecond seeing (which indicates very bad turbulence) and in visible light (where adaptive optics never works well – the LN camera will operate at infrared wavelengths), it shows a dramatic improvement in sharpness and intensity. — **Figure 3:** The same star, but now after activation of the adaptive optics. Although this picture was taken during 2.3 arcsecond seeing (which indicates very bad turbulence) and in visible light (where adaptive optics never works well – the LN camera will operate at infrared wavelengths), it shows a dramatic improvement in sharpness and intensity.

**Figure 3:** The same star, but now after activation of the adaptive optics. Although this picture was taken during 2.3 arcsecond seeing (which indicates very bad turbulence) and in visible light (where adaptive optics never works well – the LN camera will operate at infrared wavelengths), it shows a dramatic improvement in sharpness and intensity.

Only 35 minutes after Pathfinder saw starlight for the first time, the team (Figure 1) was able to activate the adaptive optics (Figures 2 and 3, and the video) – a particularly important milestone.

LN is designed and built by an international consortium led by MPIA. The partners include institutions in both Italy and Germany.

The LBT is a joint project of American, Italian and German institutions.