Uncataloged objects

On this page, a list of previously likely uncataloged objects, which where mostly found in the results of the Northern Sky Narrowband Survey, is presented. Some of these objects may already be known or part of a largely unknown catalog. The data sources that where used for object identification are listed in section “Data sources”.

Tables

The object list is a merged, revised, and improved version of an earlier attempt to catalog unknown objects. Both versions are available in a GitHub repository, providing proper documentation of changes and updates.

The new list is divided into three categories, resulting in three tables (click the links):

Objects that are bright in Hα
This does not mean that other emission lines are faint. These objects where detected in Hα images and most of them are HII regions.
Objects that are bright in OIII
This does not mean that other emission lines are faint. These objects where detected in OIII (500.7 nm) and are candidates of Planetary nebulae.
Possible bubbles
These objects where detected in emission line images. Bubbles are usually formed by (ancient) supernovae.

Column description

Columns of all tables are the same:

ColumnDescription
1Link to a query for images on this site.
2An identifier consisting of a letter corresponding to the category (‘H’: HII; ‘O’: OIII; ‘B’: bubbles), the rounded galactic longitude in degrees, and optionally (if the longitude alone is ambiguous) the galactic latitude in degrees. Identifiers in brackets mark related objects, e.g., possible ionization sources or child-structures.
3, 4Equatorial J2000 coordinates. Column 3: Right ascension in hours, minutes and seconds. Column 4: declination in °, arcminutes and arcseconds.
5, 6Galactic coordinates in ° as decimal number. Column 3: longitude. Column 4: latitude.
7Major axis diameter in arcminutes.
8, 9Minor axis diameter in arcminutes (column 8) and orientation angle of the major axis in ° (column 9; 0 means north and 90 means east). These values are omitted if major and minor axis diameter are equal.
10Old name used in the first version
11Date when the entry was published in the GitHub repository. (Except of object A1 (formerly AA1) which was published in Cloudynights forum.)
12Comment

Data sources

These data sources were used for object identification, i.e., only nebulae that cannot be found there are listed in the tables above.

Rules

The tables above shall only contain objects that appear to be discrete and cannot be found in popular catalogs (namely those described in the previous section). Nebulae that seem to be part of larger structures or superstructures of known objects have therefore not been imported from the old lists. This also includes some remarkable ones, which are mentioned in then Appendix.

Furthermore, that does not mean that all objects in the tables above can be considered unknown. For example, H066.0 is clearly visible in Finkbeiner (2003), but cannot be found in the catalogs above or in Simbad.

Here is a summary of the rules for listing an object in the tables above:

Appendix: Objects not included in the revised list

Tables

The tables contain objects from the old lists that have not been imported into the revised list. The Column format of the tables is the same one as described above. Some of these objects may be imported later if new data becomes available.
HII regions
that could be identified in the meantime or that are too uncertain.
Reflection nebulae
in the old list seem to be bright parts of the galactic cirrus (like most LBN and LDN nebulae) and therefore have not been imported.
Arcs/rings/bubbles
that are too incomplete or too uncertain

Remarkable objects

Some remarkable objects from the old list were not imported into the new one because they do not satisfy the rules. Click on the link with the old name to find images of the object on this site.
E5
Large HII region that contains SH2-86 to SH2-88 and DU 26 to DU 30. Ionized by the VUL OB1 association.
F1
HII region that is ionized by the CMa OB1 association and which contains the Seagull Nebula (at least the body) along with various other emission nebulae, including SH2-295 to SH2-297. The Distance is about 1000 pc.
H1
Huge HII region that lies behind molecular clouds in Taurus and Perseus (because it is obscured by them), with the brightest part being the California Nebula.
FA1
Identified as the Gemini Hα ring.
B9, B10
Strange elliptical structures visible in continuum light. What 3-dimensional object is projected to an ellipse? Maybe just a random structure. (In order to improve the visibility In the JavaScript viewer, toggle the plots on and off by pressing the '2' key.)

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