All Figures

$\begin{figure} \par\includegraphics[angle=-90,width=8.1cm,clip]{1088fig1.ps}\end{figure}$ Figure 1: A Carlina version using six computer-controlled winches to define the position and attitude of the focal beam combiner. These can be combined as three differential winches.
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In the text

$\begin{figure} \par\includegraphics[width=7.4cm,clip]{1088fig2.ps} \end{figure}$ Figure 2: The optics in the gondola will consist of a clam-shell corrector of spherical aberration, a pupil densifier and an EM-CCD camera. Adaptive optics will also be needed to correct the positioning errors of the fixed primary mirrors, in tip-tilt and piston, as well as the atmospheric seeing.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{1088fig3.ps}\end{figure}$ Figure 3: Equatorial mode of star tracking with a Carlina. A single computer-controlled winch suffices to track the star.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.1cm,clip]{1088fig4.ps} \end{figure}$ Figure 4: Clam-shell corrector of spherical aberration and coma calculated with the Lasso code for F/2 acceptance. The paraxial and marginal foci of the primary mirror M1 ( located far at right and not shown) are indicated. The corrected focus is at left, near the central hole of M2.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=7.5cm,clip]{1088fig5.ps} \end{figure}$ Figure 5: Spot in the image plane of the clam-shell Mertz corrector for stars located up to 16.7'' (top-right) from the optical axis, as calculated with the Lasso code. The smaller scale units on the X and Y axes correspond to 5 microns.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.2cm,clip]{1088fig6.ps} \end{figure}$ Figure 6: Coudé feed in the gondola's focal optics. After the focal corrector of spherical aberration and the pupil densifier, using a pair of lens arrays, a flat mirror directs a coudé beam towards the focal station at ground level. The mirror must be rotated to accomodate different stellar declinations
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.1cm,clip]{1088fig7.ps} \end{figure}$ Figure 7: Alternate scheme to Fig. 6 for coudé optics, using a small tiltable flat mirror and a paraboloidal mirror. The pupil densifier and the CCD are in the coudé station at ground level.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{1088fig8.ps} \end{figure}$ Figure 8: The top-left of the figure shows a preliminary measurement of the residual oscillations at OHP. A gondola without optics is placed under a balloon at 35.6 m above ground. It oscillates by a few millimeters (rms) in the wind ( $\Delta$ is the translation amplitude measured with a small telescope at ground level pointed at a sheet of millimetric paper glued on the gondola). The graph drawing at top-right and bottom-left shows a simple coudé train design, obtained with Zemax software. The corresponding spot diagram is at bottom right. At the top-right the gondola carries a small flat and a paraboloidal mirror (such as in Fig. 7 but without spherical aberration corrector). It is moved by 5 mm from the perfect position. At the bottom-left the light arrives on a focal station telescope focalized from the gondola. The light is translated by about one meter from the center of the mirror. The bottom-right picture shows the image on the CCD (scale: 100 $\mu$ m). The CCD is placed behind a lens that is in a pupil plane.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=7.9cm,clip]{1088fig9.ps} \end{figure}$ Figure 9: Test optics arranged in the optical tunnel to develop phasing techniques. Two Carlina mirror segments spaced 35 cm apart produce fringes in the image of a point source located at their common center of curvature, 71.2 m away. A camera records the fringes, found by using a laser with adjustable coherence length. With a white source, the piston balance can be adjusted within one micron.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{1088fig10.ps} \end{figure}$ Figure 10: Scale drawing of the Carlina prototype at the observatory. Pending crater sites, the flat ground is usable with a limited sky coverage in declination. The 4 mm Kevlar cables are thickened to make them visible. The 20-m dome of the 193 cm telescope appears on top to indicate the scale. The 1.5 m boule telescope at bottom-left, initially built as a prototype for the Optical Very Large Array (Arnold et al. 1999), is here potentially usable as a coudé collector receiving light from the focal gondola (described in Sect. 2.3).
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=7.8cm,clip]{1088fig11.ps} \end{figure}$ Figure 11: Star acquisition system for Carlina. A small telescope is placed at the edge of the primary mirror segment and tracks the star. The light of a LED near the CCD in the gondola is reflected from the primary mirror segment towards a corner-cube reflector attached on top of the small telescope. The LED and the star are seen in the telescope eye-piece and must be superposed by moving the gondola.
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In the text

$\begin{figure} \par\includegraphics[height=10.2cm,width=7.5cm,clip]{1088fig12.ps} \end{figure}$ Figure 12: top: tethered balloon, 140 m above ground. The black disc seen near the tail of the balloon is at the curvature center of the primary mirror, 71.2 m above it, and also at the top of the fixed cable tripod (see Fig. 3). The black triangle frame is the gondola, about 3 m in size and made of 16 mm diameter carbon fiber tubes, which carries the CCD, 35.6 m below this point. Bottom: first light for the Carlina prototype with a single primary mirror segment on star "Psi Ursae Majoris'' obtained on 02/03/2004. The lateral field of the CCD image shown is about one arc minute and the size of the star image is close to 7 arcsec due to astigmatism, focus error and seeing.
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In the text

$\begin{figure} \par\includegraphics[height=5.5cm,width=7.5cm,clip]{1088fig13.ps} \end{figure}$ Figure 13: Fringes obtained on Vega with the pair of adjacent mirrors stopped down to about 5 cm and providing a 40 cm baseline.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.1cm,clip]{1088fig1.ps}\end{figure}$	Figure 1: A Carlina version using six computer-controlled winches to define the position and attitude of the focal beam combiner. These can be combined as three differential winches.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=7.4cm,clip]{1088fig2.ps} \end{figure}$	Figure 2: The optics in the gondola will consist of a clam-shell corrector of spherical aberration, a pupil densifier and an EM-CCD camera. Adaptive optics will also be needed to correct the positioning errors of the fixed primary mirrors, in tip-tilt and piston, as well as the atmospheric seeing.
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$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{1088fig3.ps}\end{figure}$	Figure 3: Equatorial mode of star tracking with a Carlina. A single computer-controlled winch suffices to track the star.
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$\begin{figure} \par\includegraphics[angle=-90,width=8.1cm,clip]{1088fig4.ps} \end{figure}$	Figure 4: Clam-shell corrector of spherical aberration and coma calculated with the Lasso code for F/2 acceptance. The paraxial and marginal foci of the primary mirror M1 ( located far at right and not shown) are indicated. The corrected focus is at left, near the central hole of M2.
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$\begin{figure} \par\includegraphics[angle=-90,width=7.5cm,clip]{1088fig5.ps} \end{figure}$	Figure 5: Spot in the image plane of the clam-shell Mertz corrector for stars located up to 16.7'' (top-right) from the optical axis, as calculated with the Lasso code. The smaller scale units on the X and Y axes correspond to 5 microns.
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$\begin{figure} \par\includegraphics[angle=-90,width=8.2cm,clip]{1088fig6.ps} \end{figure}$	Figure 6: Coudé feed in the gondola's focal optics. After the focal corrector of spherical aberration and the pupil densifier, using a pair of lens arrays, a flat mirror directs a coudé beam towards the focal station at ground level. The mirror must be rotated to accomodate different stellar declinations
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$\begin{figure} \par\includegraphics[angle=-90,width=8.1cm,clip]{1088fig7.ps} \end{figure}$	Figure 7: Alternate scheme to Fig. 6 for coudé optics, using a small tiltable flat mirror and a paraboloidal mirror. The pupil densifier and the CCD are in the coudé station at ground level.
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$\begin{figure} \par\includegraphics[height=5.5cm,width=7.5cm,clip]{1088fig13.ps} \end{figure}$	Figure 13: Fringes obtained on Vega with the pair of adjacent mirrors stopped down to about 5 cm and providing a 40 cm baseline.
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