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Milkyway Panorama by Digital Sky LLC

Ursa Naked Eye Catalogue of Deep Sky Objects

UNE is the catalogue of deep sky objects visible with unaided eye. It includes ordinary deep sky object with catalogue designations, star clusters, nebulae and even some galaxies. There are also some very large stellar associations, e.g. Ursa Major and Antares moving clusters and several Milky Way features.

The catalogue includes the main catalogue and the appendix of suspected naked eye objects. The confirmed observation of the suspected object raises it to the main catalogue and gives it the UNE designation.

Short history

The first versions of the catalogue, with name Veikko's Naked Eye Catalogue of Deep Sky Objects (VNE), were compiled by Veikko Mäkelä already in early 1990s. It had 51 objects and 40 suspected objects.

Later in the beginning of the new millennium, Jarmo Moilanen joined to compile the catalogue and it got the name UNE catalogue, Ursa Naked Eye catalogue of Deep Sky Objects. Ursa stands on Ursa Astronomical Association, the compilers' astronomical association.

Like many other projects, it has lasted for a long time. The version 1.1 of VNE was available as packed text files in ftp.funet.fi since 1995. In 2008, The UNE Catalogue got its first modern network version. It was moved to the Ursa wiki system thereafter. Due to the scheduled discontinuation of Ursa wikis in early 2024, the catalogue is now accessible at the website of the Finnish Deep Sky Observing Group.

Numbering scheme

An example of a UNE designation: 0123.

Numbers 01 tell the right ascension (R.A.) zone the object is located. Eg. 01 is in zone 1-2 h. Zone 24 is reserved for large multiple zone Milky Way features.

Numbers 23 is the running number of the objects in the zone. Because UNE has been supplemented several times, the numbers are not necessarily fully in the right ascension order.

Object types

codeobject type
BN
Bright nebula
DN
Dark nebula
GbGlobular cluster
OCOpen cluster
OCnOpen cluster with nebulosity
S0Lenticular galaxy
SabSpiral galaxy, type a-b
SbSpiral galaxy, type b
ScSpiral galaxy, type c
SBBarred spiral galaxy
SBcBarred spiral galaxy, type c
SBpBarred spiral galaxy, peculiar
mwMilky Way area or star cloud

Visibility index

Visibility Index is a short coded description of the appearance of the object. It describes how easy it is too see, and whether there are any details visible with unaided eye.

There are three groups on codes:

The index consists of three parts including following digits and letters: 1234 npsm fc

  • visibility class:
    • 1 easy
    • 2 moderate
    • 3 difficult, possible with average eyesight in good conditions
    • 4 very difficult, possible with good eyesight in good conditions, or suspect visibility
  • appearance:
    • n nebulous or glow
    • p starlike (with nebulae)
    • s one star
    • m multiple stars
  • details, shape, color:
    • f recognizable shape or details, "features"
    • c color visible
    • none no shape or details

Examples

  • 1 m f = easy, multiple stars, details or shape
  • 2 nm f = moderately easy, nebulous with multiple stars, details or shape

Thanks

Several Finnish Deep Sky observers have helped in gathering data of unaided observations on deep sky objects. Special thanks go to Jaakko Saloranta, Risto Heikkilä, and Riku Henriksson. The contribution of Timo Karhula from Sweden is also worth mentioning.

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