A Comparison Between NSFCam and SPEX
Prior to NSFCam's 2012-13 upgrade, we advised observers that Guidedog on SpeX was more sensitive for JHK imaging than NSFCam. This was on account of the higher read noise and greater number of bad pixels for NSFCam. NSFCam was more sensitive for L' and M' imaging since imaging at those wavelengths was sky noise limited despite the high read noise.
However, the situation is different now that NSFCam has been upgraded. Due to the lower read noise of the NSFCam electronics and higher throughput of the NSFCam optics, NSFCam is a more sensitive imager in the 1 to 2.5 micron range than Guidedog. At thermal wavelengths (L' and M' bands) NSFCam remains a more sensitive instrument. As such, we advise observers with purely imaging needs to use NSFCam instead of Guidedog/SpeX. Observers who want photometry to accompany their SpeX spectroscopy should continue to use Guidedog since Guidedog remains a capable near-IR imager.
Last updated: May 10, 2013