... Near Infrared Camera and Multi-Object Spectrometer Instrument Handbook for Cycle 17 > Appendix D: Techniques for Dithering, Background Measurement andMapping > D.1 Introduction . ... Multiple exposures with small offsets in the pointing of the telescope between exposures are recommended for NICMOS observations. ... It is strongly advised that provision for direct measurement of the background be included in proposals whenever observations at wavelengths greater than 1.7?m are performed. ...