Cosmic Dawn Intensity Mapper

The Cosmic Dawn Intensity Mapper (CDIM) is a concept for an NASA 83-cm space near infrared telescope for intensity mapping Lyman alpha and H-alpha out to z = 10. It would also map other spectral lines (H-beta, [N II], [O III]) to help distinguish them from the two lines of interest, as well as for their own benefit. The concept is similar to SPHEREx, with a similar wavelength-range and similar use of linearly variable filters (as opposed to a typical spectroscope), but CDIM has better spectral resolution and angular resolution, and rather than all-sky, it would use smaller survey fields, a deep survey of 15 square degrees, a medium survey of 30 square degrees and a wide survey of 300 square degrees.