{"id":8594,"date":"2018-08-06T15:17:33","date_gmt":"2018-08-07T01:17:33","guid":{"rendered":"http:\/\/www.eaobservatory.org\/jcmt\/?page_id=8594"},"modified":"2025-11-26T17:33:52","modified_gmt":"2025-11-27T03:33:52","slug":"namakanui","status":"publish","type":"page","link":"https:\/\/www.eaobservatory.org\/jcmt\/instrumentation\/heterodyne\/namakanui\/","title":{"rendered":"N\u0101makanui"},"content":{"rendered":"
\"GLT<\/a>

Receiver cartridges – 86, 230 and 345 GHz. N\u0101makanui (“Big-Eyes”) is a heterodyne receiver unit making use of the ALMA “insert” concept for a dewar that can hold three single-receiver inserts. These inserts are used singly when observing (i.e. only one at a time). This configuration mirrors that of the Greenland Telescope (GLT)\u00a0 instrumentation<\/a> (see here for link to the SPIE paper describing the GLT instrument<\/a>).<\/p><\/div>\n

N\u0101makanui<\/a> (an 86, 230 and 345 GHz instrument) was built by a team at ASIAA<\/a> (Taiwan) and is on loan the to the JCMT as a spare for the GLT<\/a>.\u00a0 N\u0101makanui was delivered to the facility in August 2019 with installation at the telescope in September 2019. First light was achieved early October.\u00a0
\n<\/strong><\/p>\n

Receivers<\/h2>\n

The three heterodyne receiver inserts work at 86<\/strong>, 230<\/strong> and 345 GHz.\u00a0<\/strong>The inserts are named \u02bb<\/a>Ala\u02bbihi<\/strong> (“Squirrelfish”) 86GHz<\/a>, \u02bb\u016a\u02bb\u016b<\/strong> (“Soldierfish”) 230GHz<\/a>, and \u02bb\u0100weoweo<\/strong> (“Big Eye”) 345GHz<\/a><\/span>. The 86 GHz insert is a dual polarization, 1-sideband mixer. The 230 and 345 GHz inserts have dual polarization 2-sideband mixers, producing four Intermediate Frequencies (IFs) with bandwidths of 4 \u2013 12 GHz each (although this may be restricted to 4 \u2013 8 GHz initially). Aweoweo (345 GHz) will be capable of supporting IFs in the 5 \u2013 9 GHz range. Please note that, at present, the ACSIS<\/a> IF system only supports IFs of 4 \u2013 7.3 GHz.<\/p>\n

The 230 and 345 GHz mixers are identical to those used by ALMA<\/a>. More technical details on the 230 GHz mixer are available here.<\/a>\u00a0The\u00a0230 GHz unit was produced by\u00a0NRAO<\/a>\u00a0for ALMA and the 345 GHz unit was produced by\u00a0<\/span>IRAM<\/a>\u00a0for ALMA.\u00a0<\/span>The most recent public user information on these receivers is given in Sections 4.2.4 and 4.2.5 of the ALMA Technical Handbook<\/a>. Due to each insert having a separate optical path (TMU position), only one receiver\/frequency range can be used at any one time.<\/span><\/p>\n

Kuntur<\/a>, a 690 GHz 2SB dual polarization single pixel receiver, can be installed in place of \u02bb\u0100weoweo<\/a>. See the current status<\/a> page for the currently installed configuration of receivers.<\/p>\n

Note that special considerations must be taken into account when observing targets with a strong continuum<\/a> such as the moon, the Sun, or planetary atmospheres.<\/p>\n

References for N\u0101makanui:<\/h2>\n