The Thirty Millimeter Telescope

TL;DR

This paper introduces the Thirty Millimeter Telescope, a near-infrared instrument designed for precise photometry of bright stars and monitoring variability along the northern Galactic plane, with demonstrated accuracy and operational performance.

Contribution

It details the design, calibration, and performance of a new small-aperture near-infrared telescope for bright star observation and variability monitoring.

Findings

Photometry uncertainty less than 5% for stars brighter than 7-6 mag

Repeatability of measurements better than 1% for bright stars

Capability to monitor bright variable stars in the northern Galactic plane

Abstract

A near-infrared telescope with an effective aperture diameter of thirty millimeters has been developed. The primary objective of the development is to observe northern bright stars in the $J$, $H$, and $K_{\rm s}$ bands and provide accurate photometric data on those stars. The second objective is to repeatedly observe a belt-like region along the northern Galactic plane ($|b| \le 5^\circ$ and $\delta \ge -30^\circ$) to monitor bright variable stars there. The telescope has been in use since December 2016. The purpose of this paper is to describe the design and operational performances of the telescope, photometric calibration methods, and our scientific goals. We show that the telescope has the ability to provide photometry with an uncertainty of less than 5\% for stars brighter than 7, 6.5, and 6~mag in the $J$, $H$, and $K_{\rm s}$ bands, respectively. The repeatability of the photometric measurements for the same star is better than 1\% for bright stars. Our observations will provide accurate photometry on bright stars that are lacking in the Two Micron Sky Survey and the Two Micron All-Sky Survey. Repeated observations at a good cadence will also reveal their nature of the variability in the near-infrared.