What Is the HIP Catalog?
HIP is short for Hipparcos, the name of the European Space Agency mission that measured the positions and movements of stars from space.
Each entry in the main catalog has a HIP number. This number acts as a stable catalog identifier.
A familiar star may have several different names or designations. Vega, for example, is also identified as HIP 91262 in the Hipparcos catalog. The common name may be easier to remember, but the catalog number provides an unambiguous way to identify the astronomical object.
Depending on the available catalog fields, an entry can include information such as:
- HIP identifier
- Right ascension
- Declination
- Apparent magnitude
- Parallax
- Proper motion
- Color information
- Notes about variability or multiple-star systems
Not every field needs to be shown to the customer. The purpose of the catalog is to provide a reliable astronomical foundation for selecting and identifying the star.
The personal name chosen by the customer does not replace the HIP identifier or the scientific designation. It becomes part of the personal registry entry and gift experience connected to that star.
How a Star Is Selected Step by Step
The exact selection depends on the package and any additional choices made during personalization.
1. The Package Defines the Required Star Type
The selected package establishes the first set of criteria.
A single-star package requires one eligible individual star. A constellation package requires an eligible star within the selected constellation. A binary-star package requires a suitable paired system. A brightness selection restricts the candidate pool to a particular magnitude cluster.
This means the same selection rule is not applied to every order.
2. The Candidate Pool Is Filtered
The system then narrows the catalog data to stars that meet the package requirements.
Depending on the order, the relevant filters can include:
- Individual star or paired star system
- Selected constellation
- Magnitude-based brightness category
- Availability within the private registry
- Suitability for the chosen product
A constellation choice does not mean that a new star is placed inside that constellation. It means that the eligible catalog entries are limited to stars already located within that part of the sky.
For help choosing a meaningful constellation, read our guide to choosing a constellation for a named star.
3. An Eligible Star Is Assigned
A qualifying star is selected from the filtered candidate pool.
The assigned catalog entry already has its own HIP identifier and astronomical position. The personal name, date and dedication supplied by the customer are then connected with that specific star in the private registry experience.
4. The Coordinates Are Connected to the Order
The selected catalog position provides the coordinates used to identify the star.
The first portion of the coordinate line represents right ascension, or RA. The second portion represents declination, or DEC. Together, they describe the star’s position on the celestial sphere.
If you want to understand the coordinate notation in detail, see Star Coordinates Explained: What RA, DEC and Magnitude Mean.
5. The Registry Entry and Certificate Are Created
After the star has been assigned, the selected name, meaningful date and dedication are connected with the star’s details.
The order receives a registration number that links the personalized certificate, private registry entry and Universe Star Finder App experience.
How Magnitude Determines the Brightness Category
Magnitude is the astronomical scale used to describe how bright an object appears.
The scale may initially seem counterintuitive because lower numbers indicate brighter objects:
- A star with magnitude 2 appears brighter than a star with magnitude 4.
- Very bright objects can have a magnitude close to zero or even a negative value.
- A star with a larger positive magnitude is fainter.
The scale is logarithmic. A difference of five magnitude values represents a brightness ratio of 100. A difference of one magnitude corresponds to a brightness factor of approximately 2.512.
For star selection, the important point is simple:
The lower the apparent magnitude, the brighter the star appears under comparable viewing conditions.
Star-Naming.com uses magnitude to group eligible catalog stars into brightness clusters. If a customer selects a bright or very bright star option, the candidate pool is restricted to the corresponding magnitude category.
These product categories are practical selection groups. They should not be confused with universal scientific classes officially called “standard,” “bright” or “very bright.” Astronomers use the numerical magnitude value; commercial product labels make that scale easier for customers to understand.
Magnitude is used during the selection process even though it is not printed as a separate value on the Star-Naming.com certificate.
Reading time: 9 min.
