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You are here: Home Telescopes Magellan Instruments IMACS Observing Cookbooks Observing Single Objects in Nod & Shuffle mode

Observing Single Objects in Nod & Shuffle mode


  • Follow instructions for Observing with Long Slit mask...



Note: Follow this sequence completely for every object that you wish to observe

  • For acquisition, please follow the same instructions as for Observing with Long Slit Mask.

Once your target is acquired in the slit...

  • You should now be ready to observe your object, but first you need to calculate the offset parameters for the nod. Do this by executing the IRAF imacs task "inodshuffle". Type "inod" at the IRAF CL prompt and you will be asked to enter the nod length (in arcsec). The task will then translate this to the appropriate offsets in RA and DEC.

Now, in the IMACS CamGUI, set Loops to "1" and ExpType to "N&Shuffle". The Nod&Shuffle definition dialog-box should appear. Edit Shuffle to be consistent with the length (in arcsec) of the slit you are using. Enter the R.A. and DEC offsets that you just calculated in the Telescope-Nod boxes. Finally, set the DwellTime and N-Cycles values as desired. A DwellTime of 30 or 60 sec is recommend to insure that the S-H measurements mesh well with the nodding and shuffling. Finally, hit the "Start" button to begin the exposure.

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