Nuller
Scientific Electronic Device
title: "Nuller" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["observational-astronomy", "optical-components"] description: "Scientific Electronic Device" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Nuller" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Scientific Electronic Device ::
A nuller is an optical tool used to block a strong source so that fainter signals near that source can be observed. An example of a nuller is being employed on the Keck Interferometer. This causes the light from a star to destructively interfere, effectively cancelling the star's image. As a result, the faint light from a ring of dust orbiting the star can then be detected. This project is part of a scientific effort to detect and observe nearby planets.
Interferometry
Nulling interferometry is a type of interferometry in which two or more signals are mixed to produce observational regions in which the incoming signals cancel themselves out. This creates a set of virtual "blind spots" which prevent unwanted signals from those areas from interfering with weaker nearby signals.
In 1978 Australian-American astronomer Ronald N. Bracewell suggested using nulling interferometry to search for planets around other stars. | last = Bracewell | first = Ronald N. | author-link = Ronald N. Bracewell | publication-date = 1978-08-24 | title = Detecting nonsolar planets by spinning infrared interferometer | volume = 274 | pages = 780–781 | issn = 0028-0836 | doi = 10.1038/274780a0 | year = 1978 | journal = Nature |bibcode = 1978Natur.274..780B | issue=5673| s2cid = 4210058 | last1 = Bracewell | first1 = Ronald N. | author1-link = Ronald N. Bracewell | last2 = MacPhie | first2 = Robert H. | publication-date = 1979-04-01 | title = Searching for nonsolar planets | volume = 38 | issue = 1 | pages = 136–147 | issn = 0019-1035 | doi = 10.1016/0019-1035(79)90093-9 | year = 1979 | journal = Icarus | bibcode=1979Icar...38..136B This technique was considered for use by both the Terrestrial Planet Finder (a canceled NASA mission) and Darwin (a canceled ESA mission). It is being used on the Keck Interferometer.
A different technique is called a coronagraph, using a physical obstacle to block the unwanted signals.
Experimental nullers
There has been a nuller built by the Jet Propulsion Laboratory that has flown on a NASA sounding rocket twice, once in 2011 and a second time in 2015. There is also a laboratory nuller at NASA Goddard Space Flight Center known as the Visible Nulling Coronagraph (VNC) that is actively conducting experiments. ::figure[src="https://upload.wikimedia.org/wikipedia/commons/7/73/VNC_at_NASA_GSFC.jpg" caption="The Visible Nulling Coronagraph (VNC) experimental breadboard at NASA Goddard Space Flight Center."] ::
References
::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::