Here is something I've put togther that may be of some help to observers. I will post this on our web site. - Karen G. Instrument Orientations and Offset Directions IRAF View This is the orientation of the image as viewed in an image display via IRAF (e.g. ximtool, saoimage). Note: This is different from the orentation of the image as viewed on a Macintosh, via Remark. Scroll down the page for the Macintosh orientation. A +X, +Y instrument offset will move a star in the direction indicated by the arrows. Directions of East and North are given for 0 degrees object rotation. Note: The offset direction depends upon which interface the offset command was issued in! INTERFACE: TCC MC REMARK GrIm2 ----------- ----------- ----------- f/5 | | | ^ | | ^ | | x | | y| | | |y | | *--> |E | *--> |E | <--* |E | y| | | x | | x | | V | | | | | ----------- ----------- ----------- N N N N N N GrIm2 ----------- ----------- ----------- f/10, | ^ | | | | | f/20 | y| | | x | | x | | *--> |E | *--> |E | <--* |E | x | | y| | | |y | | | | V | | V | ----------- ----------- ----------- N N N SPIcam ----------- ----------- ----------- | ^ | | | | | | y| | | x | | x | E| *--> | E| *--> | E| <--* | | x | | y| | | |y | | | | V | | V | ----------- ----------- ----------- DIS ----------- ----------- ----------- | | | ^ | | ^ | | x | | |y | | y| | E| <--* | E| <--* | E| *--> | | |y | | x | | x | | V | | | | | ----------- ----------- ----------- N N N DIS ----------- ----------- ----------- slit cam | | | ^ | | ^ | | x | | y| | | |y | | *--> |E | *--> |E | <--* |E | y| | | x | | x | | V | | | | | ----------- ----------- ----------- N N N Echelle ----------- ----------- ----------- slit cam | ^ | | | | | | y| | | x | | x | | *--> | | *--> | | <--* | | x | | y| | | |y | | | | V | | V | ----------- ----------- ----------- AOTF ----------- ----------- ----------- | | | ^ | | ^ | | x | | y| | | |y | | *--> | | *--> | | <--* | | y| | | x | | x | | V | | | | | ----------- ----------- ----------- MACINTOSH View This is the orientation of the image as viewed on a Macintosh (i.e. as displayed by Remark). Note: This is different from the orentation of the image as viewed by IRAF. Scroll up the page for the IRAF orientation. A +X, +Y instrument offset will move a star in the direction indicated by the arrows. Directions of East and North are given for 0 degrees object rotation. Note: The offset direction depends upon which interface the offset command was issued in! INTERFACE: TCC MC REMARK N N N GrIm2 ----------- ----------- ----------- f/5 | ^ | | | | | | y| | | x | | x | | *--> |E | *--> |E | <--* |E | x | | y| | | |y | | | | V | | V | ----------- ----------- ----------- GrIm2 ----------- ----------- ----------- f/10, | | | ^ | | ^ | f/20 | x | | y| | | |y | | *--> |E | *--> |E | <--* |E | y| | | x | | x | | V | | | | | ----------- ----------- ----------- N N N N N N DIS ----------- ----------- ----------- | ^ | | | | | | |y | | x | | x | E| <--* | E| <--* | E| *--> | | x | | |y | | y| | | | | V | | V | ----------- ----------- ----------- Echelle ----------- ----------- ----------- slit cam | | | ^ | | ^ | | x | | y| | | |y | | *--> | | *--> | | <--* | | y| | | x | | x | | V | | | | | ----------- ----------- ----------- APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 356 in the apo35-general archive. You can find APO the archive on http://www.astro.princeton.edu/APO/apo35-general/INDEX.html APO To join/leave the list, send mail to apo35-request@astro.princeton.edu APO To post a message, mail it to apo35-general@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO