The INT Photometric H-Alpha Survey

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The INT Photometric H-Alpha Survey
Alternative namesIPHAS

The INT Photometric H-Alpha Survey (IPHAS) is an astronomical survey of the northern plane of our Galaxy, the Milky Way, as visible from the Isaac Newton Telescope (INT) in the Canary Islands, Spain. [1] The survey uses two broad-band filters and a narrow H-alpha filter to obtain deep images of nebulae in our Galaxy and for identifying rare types of stars. Observations for the survey began in 2003 and are almost complete. The survey is being complemented by a sister survey of the southern Galactic Plane, VPHAS+. [2] Once these two surveys are completed the data are expected to provide a significant leap in our knowledge of the extreme phases of stellar evolution.


The goals of the survey include:

Because of the selection for young stars and nebulae, the survey will also increase the number of known OB associations, and other clusters.


Newly discovered planetary nebula IP6.jpg
Newly discovered planetary nebula

The survey has already discovered a large number of previously unknown planetary nebulae, such as the Necklace Nebula in this image.

Related Research Articles

<span class="mw-page-title-main">Galaxy</span> Large gravitationally bound system of stars and interstellar matter

A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek galaxias (γαλαξίας), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies.

<span class="mw-page-title-main">Planetary nebula</span> Type of emission nebula

A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.

<span class="mw-page-title-main">Seyfert galaxy</span> Class of active galaxies with very bright nuclei

Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.

<span class="mw-page-title-main">Photometry (astronomy)</span> Determination of light intensities of astronomical bodies

Photometry, from Greek photo- ("light") and -metry ("measure"), is a technique used in astronomy that is concerned with measuring the flux or intensity of light radiated by astronomical objects. This light is measured through a telescope using a photometer, often made using electronic devices such as a CCD photometer or a photoelectric photometer that converts light into an electric current by the photoelectric effect. When calibrated against standard stars of known intensity and colour, photometers can measure the brightness or apparent magnitude of celestial objects.

<span class="mw-page-title-main">Spiral galaxy</span> Class of galaxy that has spiral structures extending from their cores.

Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, form part of the Hubble sequence. Most spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. These are often surrounded by a much fainter halo of stars, many of which reside in globular clusters.

<span class="mw-page-title-main">Zone of Avoidance</span> Area of sky obscured by the Milky Way

The Zone of Avoidance, or Zone of Galactic Obscuration (ZGO), is the area of the sky that is obscured by the Milky Way.

<span class="mw-page-title-main">Messier 58</span> Intermediate barred spiral galaxy in the constellation Virgo

Messier 58 is an intermediate barred spiral galaxy with a weak inner ring structure located within the constellation Virgo, approximately 68 million light-years away from Earth. It was discovered by Charles Messier on April 15, 1779 and is one of four barred spiral galaxies that appear in Messier's catalogue. M58 is one of the brightest galaxies in the Virgo Cluster. From 1779 it was arguably the farthest known astronomical object until the release of the New General Catalogue in the 1880s and even more so the publishing of redshift values in the 1920s.

<span class="mw-page-title-main">Messier 90</span> Intermediate spiral galaxy in the constellation Virgo

Messier 90 is an intermediate spiral galaxy exhibiting a weak inner ring structure about 60 million light-years away in the constellation Virgo. It was discovered by Charles Messier in 1781.

<span class="mw-page-title-main">Astronomical survey</span> General map or image of a region of the sky with no specific observational target.

An astronomical survey is a general map or image of a region of the sky that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of objects that share a common type or feature. Surveys are often restricted to one band of the electromagnetic spectrum due to instrumental limitations, although multiwavelength surveys can be made by using multiple detectors, each sensitive to a different bandwidth.

<span class="mw-page-title-main">NGC 2022</span> Planetary nebula in the constellation Orion

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<span class="mw-page-title-main">Sextans B</span> Dwarf irregular galaxy in the constellation Sextans

Sextans B is an irregular galaxy that may be part of the Local Group, or lie just beyond it. Sextans B is 4.44 million light-years away from Earth and thus is one of the most distant members of the Local Group, if it is indeed a member. It forms a pair with its neighbouring galaxy Sextans A. It is a type Ir IV–V galaxy according to the galaxy morphological classification scheme. Sextans B may also be gravitationally associated with the galaxies NGC 3109 and the Antlia Dwarf.

<span class="mw-page-title-main">9 Sagittarii</span> Star in the constellation Sagittarius

9 Sagittarii is a massive binary star in the constellation Sagittarius. It has an apparent magnitude of 5.97. Both components are highly luminous O-type main-sequence stars.

<span class="mw-page-title-main">Necklace Nebula</span> Planetary nebula in the constellation Sagitta

The Necklace Nebula is a 19-trillion-kilometre-wide planetary nebula located about 15,000 light-years away in the northern constellation Sagitta. It was discovered in 2005 from the Isaac Newton Telescope Photometric H-alpha Survey (IPHAS), a ground-based H-alpha planetary nebula study of the North Galactic Plane.

<span class="mw-page-title-main">WR 31a</span> Wolf Rayet star in the constellation Carina

WR 31a, commonly referred to as Hen 3-519, is a Wolf–Rayet (WR) star in the southern constellation of Carina that is surrounded by an expanding Wolf–Rayet nebula. It is not a classical old stripped-envelope WR star, but a young massive star which still has some hydrogen left in its atmosphere.

<span class="mw-page-title-main">WR 93b</span> Wolf-Rayet star in the constellation of Cygnus

WR 93b is a Wolf-Rayet star in the constellation Scorpius, an extremely rare star on the WO oxygen sequence. It appears near NGC 6357 in the tail of the scorpion.

<span class="mw-page-title-main">NGC 5643</span> Intermediate spiral galaxy in the constellation Lupus

NGC 5643 is an intermediate spiral galaxy in the constellation Lupus. Based on the tip of the red-giant branch distance indicator, it is located at a distance of about 40 million light-years. NGC 5643 has an active galactic nucleus and is a type II Seyfert galaxy.

<span class="mw-page-title-main">NGC 2527</span> Open cluster in the constellation Puppis

NGC 2527 is an open cluster in the constellation Puppis. It was discovered by William Herschel on December 9, 1784. The cluster was also observed by John Herschel on January 7, 1831. He also observed it on February 5, 1837, identifying it as a different object, which was catalogued as NGC 2520. It is a poor cluster and with no central concentration, with Trumpler class III1p.

<span class="mw-page-title-main">Antlia-Sextans Group</span> Small galaxy group in the constellations of Hydra, Sextans, Antlia and Leo

The Antlia-Sextans Group is a small grouping of galaxies in the constellations Hydra, Sextans, Antlia and Leo. It is generally considered to be at the very edge of the Local Group and thus part of it. However, other researchers indicate it is an independent group, and thus the nearest group to the Local Group. It is, on average, approximately 4.3 million light-years away from the Milky Way.

<span class="mw-page-title-main">Ou 5</span> Planetary nebula in the constellation Cygnus

Ou 5, also known as IPHASXJ211420.0+434136, is a planetary nebula in the constellation of Cygnus. It was discovered by the IPHAS project in data taken on August 1, 2010, and independently by the French amateur astronomer Nicolas Outters in September 2012. Located two degrees east of the North American Nebula, it is an unusual planetary nebula because its central star is a short period eclipsing binary.


  1. Drew, Janet E.; Greimel, R.; Irwin, M. J.; Aungwerojwit, A.; Barlow, M. J.; Corradi, R. L. M.; Drake, J. J.; Gānsicke, B. T.; Groot, P.; Hales, A.; Hopewell, E. C.; Irwin, J.; Knigge, C.; Leisy, P.; Lennon, D. J.; Mampaso, A.; Masheder, M.R. W.; Matsuura, M.; Morales-Rueda, L.; Morris, R. A. H.; Parker, Q. A.; Phillipps, S.; Rodriguez-Gil, P.; Roelofs, G.; Skillen, I.; Sokoloski, J. L.; Steeghs, D.; Unruh, Y. C.; Viironen, K.; Vink, J. S.; Walton, N. A.; Witham, A.; Wright, N.; Zijlstra, A. A.; Zurita, A. (September 2005). "The INT Photometric Hα Survey of the Northern Galactic Plane (IPHAS)". Monthly Notices of the Royal Astronomical Society. 362 (3): 753–776. doi:10.1111/j.1365-2966.2005.09330.x. S2CID   17913846 . Retrieved 5 June 2022.
  2. Drew, J. E.; Gonzalez-Solares, E.; Greimel, R.; Irwin, M. J.; Kŭpcŭ Yoldas, A.; Lewis, J.; Barentsen, G.; Eislöffel, J.; Farnhill, H. J.; Martin, W. E.; Walsh, J. R.; Walton, N. A.; Mohr-Smith, M.; Raddi, R.; Sale, S. E.; Wright, N. J.; Groot, P.; Barlow, M. J.; Corradi, R. L. M.; Drake, J. J.; Fabregat, J.; Frew, D. J.; Gãnsicke, B. T.; Knigge, C.; Mampaso, A.; Morris, R. A. H.; Naylor, T.; Parker, Q. A.; Phillipps, S.; Ruhland, C.; Steeghs, D.; Unruh, Y. C.; Vink, J. S.; Wesson, R.; Zijlstra, A. A. (May 2014). "The VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+)". Monthly Notices of the Royal Astronomical Society. 440 (3): 2036–2058. Bibcode:2014MNRAS.440.2036D. doi:10.1093/mnras/stu394. hdl: 10722/209029 . Retrieved 5 June 2022.