MEGARA is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the 10.4m GTC. MEGARA operates in two observing modes that cover different sky areas:
The next table provides a summary of the characteristics of the two MEGARA modes and the corresponding spectral resolutions set as a requirement for each VPH.
|Spaxel size||0.62 arcsec||0.62 arcsec|
|Field of View||12.5 x 11.3 arcsec2||3.5 x 3.5 arcmin2|
|R = λ/Δλ||LR||R ∼ 6,000
||R ∼ 6,000
|MR||R ∼ 12,000
||R ∼ 12,000
|HR||R ∼ 18,700
||R ∼ 18,700
Out of the total 18 VPHs to be built, a total of 11 of them can be simultaneously mounted on the MEGARA spectrograph VPH wheel. We anticipate the use of the instrument two different spectral configurations: (i) LR+HR, when the entire optical spectrum is simultaneously available at low resolution (all 6 LR VPHs), a significant fraction is covered at mid-spectral resolution (3 out of the 10 MR VPHs) plus two spectral windows at high resolution (all 2 HR VPHs) and (ii) MR+HR, when the entire optical window is available at either mid- or high-spectral resolution (9 MR VPHs and 2 HR VPHs).