Eucalyptus
With the aim of testing the use of 50mm core fibers for the SOAR IFU spectrograph, and the training of the team in some techniques necessary to the construction of the SOAR instrument, we planned and built a prototype spectrograph that is currently operating on the 1.6m Observatório do Pico dos Dias telescope.
This prototype was built by a team of the LNA and IAG-USP, based on the projects of the SPIRAL spectrograph, from the Anglo-Australian Observatory. The name Eucalyptus was chosen because it is a native Australian tree that adapted very well in Brazil.
The first scientific data obtained in february / 2001, confirm the possibility of using 50mm fibers, both from the point of view of efficiency as of stability to torsions and tensions caused by the telescope movement.
Eucalyptus Main Characteristics
I F U |
|
| Fibers | Polymicro blue fibers - 50 mm core |
| Number of fibers | 512 |
| Microlenses | Limo cylindrical array 16 x 32 (1 mm pitch) |
| IFU Focal ratio input - output | f /10 - f / 5.5 |
| Spatial coverage | 0.9" per microlens ( 15"x 30" ) |
Spectrograph |
|
| Bench mounted, quasi Littrow | |
| Spectral Resolution | 4 000 ( 600 grooves / mm grating) |
| 12 000 (1800 grooves / mm grating) | |
| Wavelength coverage | 400 - 900 nm |
| 40 nm in one shot ( CCD 106, 600 grooves/mm gr.) | |
| Calibration Unit | He - Ne - Ar lamps |
Efficiency |
|
| Sky | ~ 80 % |
| Telescope | 78 % |
| Foreoptics | 90 % |
| IFU | 53 % |
| Spectrograph | 56 % (without coating) |
| CCD | 60 % (# 106 - at 650nm) |
| Grating | ~ 60 % (at 650nm) |
| Total | 6 % (expected 11 % with coating + new CCD) |