MIPS Array Orientations

NOTE: The orientations shown below for all 3 arrays are flipped left-right relative to the display orientation for the data selected after IOC. This includes orientation relative to the boresight, which should be shown closest to the B-side of the 70um array.

This shows the orientation and relative placement of the arrays with respect to one another and the telescope boresight, as projected on the sky.

Also indicated are:
  • the numbering of the readouts
  • the locatation of pixel 1,1 for the 3 arrays
  • the direction of motion of sources vs. scan mirror postion
  • the location of the point sources on the arrays during LBTC testing at Ball
  • the location of the 70 µm readout that is shorted to chasis ground




70 µm Array Readouts and Modules

The 70 µm array orientation is changed from the natural order in which pixels are read out (upper panel, below) to one that is consistent with the orientation of the 24 and 160 µm arrays. This re-orientation is done by either SIRTFTLMPROC (JPL) or REPACK (Inst. Team) for flight data, but the re-orientation IS NOT done on data from the Lab system at the UofA (i.e. the lab/characterization array data are oriented as shown in the upper panel, below).

To convert from the intrinsic orientation (upper panel below) to the correct orientation (lower panel, below) perform a flip about the horizontal, and then rotate the result 90 degrees clockwise. In IDL this can be accomplished using the ROTATE funtion with the orientation flag = 6.




160 µm Array Readouts, Pixels, and Readout Order.

The 160 µm array has 8 readouts (labeled Outputs in the figure below), each of which handles the signals from 5 pixels plus 2 detector-free channels (Engineering Channels). The pixels are read out starting with RO 1, pixel 1, Readout 2, pixel 1,... Readout 8, pixel 1, (all engineering pixels). Then all pixel 2's are read out, then all pixels 3's, etc. with all pixel 7's (Eng. pixels) getting read out last. In the resulting images data from the real pixels is packed into a 2 x 20 array, and the engineering channel data are packed into a 2 x 8 array that is appended to the right of the data from the detectors.



70 µm Array, Pixel Readout Order

This illustration shows the readout order of the pixels of the 70 µm array relative to how the image appears when displayed on screen. In accordance with the MIPS tradition of being as confusing as reasonably possible when it comes to naming, numbering, and counting, the pixel numbers on Side B actually go in the same order as they do on Side A - only the readout order of those pixels is reversed on Side B (as shown here).

The order of pixel readout is RO 1, Module 1, pixel 1, then RO 2, Mod. 1, pix. 1, then RO 3, Mod. 1, pix 1, ... RO 3, Mod. 8, pix. 1, RO 4, Mod 8, pix. 1. These 32 pixels are readout at a sample rate of 4 µsec, so it takes 128 µsec to read them all out. After about 4 msec settling time for the MUX, all the pixel 2's in the array are read out, in the same sequence of Readouts and Modules as for pixel 1's. Then there is another 4 msec settle, and all the pixel 3's get read out, and the pattern continues till all the pixel 32's get read out. Note that there is a figure in the SDD which gives the pixel numbering for the array, but that that figure does not reflect the readout order of the pixels - this one does.