150 ln/mm cross-disperser for the Echelle+CCD



To document the potential of the Echelle+CCD spectrograph equipped with the new 150 ln/mm cross-disperser a series of calibration and stellar spectra are presented, both with the original 2D frames and the extracted #26 order (covering the CaII near-IR triplet and the head of Paschen series).

The Thorium and FlatDome images serve as a guideline for pattern recorgnition and identification of Echelle orders and cross-disperser orders.

The HR 8079 (K5Ib), HR 7924 (A2Ia) and P Cyg spectra document the data one can expect to obtain when exploring the long-wavelength limit of the Echelle+CCD. Wavelength limits for each order are given. Bluer ranges are obtained changing the cross-disperser angle toward -11 degrees (orders get into touch at 4500 Ang with decker N.1). The reddest range is obtained changing the cross-disperser angle toward -10 degrees (orders get into touch at 5800 Ang with decker N.2). As a guideline consider the following two extrema configurations and annexed filters to suppress residual cross-disperser II order (filters to be installed in a removable configuration soon):

angle -11d 00'	decker 1	filter OG455	useful range 4500 - 8750 Ang
angle -10d 00'	decker 2	filter GG515	useful range 5300 - 10300 Ang

To illustrate the system capabilities (see thumbnails below) for the combination inclination -11:00 deg and NO filter (thus interfering II order from the cross-disperser is recorded for the hottest and/or emission line objects, but not for the cool K5Ib star HR 8079):

Thorium		5 sec expt
Flat Dome		200 sec expt
HR 7924 (A2Ia)	V= 1.3	30 sec expt	1998 Sept 9, UT 20:25
HR 8079 (K5Ib)	V= 3.7	600 sec expt	1998 Sept 9, UT 20:39
P Cyg	V= 4.8	120 sec expt	1998 Sept 9, UT 20:54

Click on the following thumbnails for the 2-D original CCD frames




To illustrate the system capabilities (see thumbnails below) for the combination inclination -10:45 deg and OG455 filter (thus interfering out cross-disperser wavelengths shortward of 4500 Ang in the I order, shortward of 9000 Ang in the II order):

Flat Dome		200 sec expt
P Cyg	V= 4.8	15 sec expt	1998 Oct 9, UT 18:52
HR 7924 (A2Ia)	V= 1.3	10 sec expt	1998 Oct 9, UT 19:35

Click on the following thumbnails for the 2-D original CCD frames



Click on the following thumbnails for 1-D extracted spectra