Imaging: Optical Parameters

The 1024x1024 Raytheon (previously SBRC) InSb array has 27 micron pixels and the plate scales for the three camera modules are shown in the above table. The UIST display shows (approximately) East up and North to the left; the array columns are slightly offset from true East-West as shown in the above table (to get columns exactly E-W one would have to rotate an image counterclockwise by the angle given above).

You can rotate your reduced image in the Gaia display by clicking the button; this will show current and future images with North up and East to the left.

The position of a target on the array is set by the "instrument aperture", a number set by JAC staff that does not change from run to run (it only changes when the instrument or telescope tertiary mirror is taken off/put back on the telescope). A given telescope base position (e.g. target coordinates) should coincide with pixel [480,480] on the full-array, or [224,224] on the 512x512 sub-array. Inprecise telescope pointing or inaccurate guide star or target coordinates can move a target by a few arcseconds, and so your source may not coincide exactly with this pixel-coordinate on the array. When using a subarray with the smaller pixels it is advisable to use movie mode to check your positioning. When peaking up in imaging mode (as opposed to spectroscopic imaging acquisition) the command "left" moves the target up and "up" moves it to the right.