Observing with AzTEC on the LMT

AzTEC has four observing modes on the 32m LMT:

1) Large Map Mode – this is a raster-scanned map and is the ONLY way of making maps larger than the observing modes given below. Since it is a raster-scan, achieving good sky rotation is critical for minimizing the scanning artifacts in the map. The sensitivity/integration time calculator gives our estimate of the integration time required to image the sky to a given sensitivity and over a given area. We have not included overheads in the calculation as these are yet to be determined (but will be less than a factor of 2).

Large Map mode calculator

2) Photometry mode – in photometry mode the telescope follows a pre-determined Lissajous pattern to map a 30″ diameter region of sky. Since many detectors are not imaging that region to make the map, a better atmosphere subtraction is possible. All overheads are included in this mapping calculation.

Photometry mode calculator

3) Small Map Mode – this is a specialized multi-Lissajous map designed to image a 1.5 arcminute diameter region with uniform sensitivity. All overheads are included in this mapping calculation.

Small Map mode calculator

4) Rastajous Map Mode – this observing mode combines the raster-scan mode and a Lissajous pattern to produce a 5′ diameter map, to a constant depth, with almost negligible turnaround overheads. Integration times for this mode can be estimated using the Large Map mode calculator assuming a fixed 20 sq. arcmin map area.