next up previous
Next: The Offset Guider Up: User Manual for COSMIC Previous: Flat-field and Arc Lamps

Orientation of COSMIC


Direct Imaging Mode

The rotation of COSMIC is controlled in the instrument window by the Base Position Angle. The nominal angle is 180o, which produces the following orientation for the IRAF command ``display ccd001 1'':

N
W E
S


Reimaged Mode

The rotation of COSMIC is controlled in the instrument window by the Base Position Angle. The nominal angle is 180o, which produces the following orientation for the IRAF command ``display ccd001 1'':

S
E W
N

For this display mode, spectra will have blue at the bottom of the image.

For the IRAF command ``display ccd001[*,-*] 1'', the orientation is:

N
E W
S

which is the usual sky parity. For this display mode, spectra will have blue at the top of the image.

If the Base PA is set to 270o, then for the IRAF command ``display ccd001[*,-*] 1'', the orientation is:

W
N S
E

If the Base PA is set to 90o, then for the IRAF command ``display ccd001[*,-*] 1'', the orientation is:

E
S N
W

In the default Base PA of 180o, the longslits will run E-W (i.e. slit PA is +90o). If you wish for the slit PA to be +45o, for example, then you will set the Base PA to be 225o.

The Base PA has an allowed range of between 70o to 300o .


next up previous
Next: The Offset Guider Up: User Manual for COSMIC Previous: Flat-field and Arc Lamps
Roy Gal
2/11/1999