Size of OGLE-IV chips is 2048x4102 pix, vertical gaps are 100 pix wide, horizontal middle gap is 64 pix wide and two horizontal outer gaps are 374 pix wide. Widths (along RA) of the fields are 01:23:00 degrees (maximal width, rows 8-16 and 17-25) and 01:04:25 deg (minimal width, rows 1-7 and 26-32). Heights (along DEC) of the fields are 01:14:10 degrees (maximal, along inner columns) 00:35:35 deg (minimal, along two outermost columns). Pixel scale is ~ 0.2585 "/pix.
Orientation on the sky:
|↑ N||↑ DEC|
|← E||W →||← RA|
CCD type is deep depleted e2v CCD44-82-4D03, with "NIMO BT DD Astronomy process Broadband" coating. The full specification can be found here. Quantum efficiency curves can be found here: from manufacturer's specification and as minimal and maximal measured quantum efficiencies for real OGLE-IV chips. Different chips differ with overall normalization of QE curves, however the shape of the relation stays relatively similar. This can be seen on this plot, which shows the relative fluxes that should be observed in I and V by different CCD chips.
|Device Type (Details)||Pixel Size||Vert Px||Horiz Px||Image area||Pixel scale|
|e2v CCD44-82 (BI,NIMO)||15.0 μm||4096+6||2048||30.7 x 61.4 mm||0.2585 arcsec/px|
Filters are interference filters from Asahi Spectra Co., Ltd. (31cm x 31cm big).