Cassini meridian line
E522102
The Cassini meridian line is a monumental 17th-century astronomical sundial and meridian marker in Bologna used to measure the Sun’s position and refine the length of the year.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Cassini meridian line canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T5483432 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Cassini meridian line Context triple: [Basilica of San Petronio, containsWork, Cassini meridian line]
-
A.
Humboldt meridian
The Humboldt meridian is a principal survey meridian used as a reference line for land surveying and mapping in parts of northern California.
-
B.
Great Arc of the Meridian
The Great Arc of the Meridian was a monumental 19th-century geodetic survey line across the Indian subcontinent that played a key role in measuring the Earth’s shape and refining global maps.
-
C.
San Bernardino meridian
The San Bernardino meridian is a principal survey meridian used as a reference line for land surveying and mapping in Southern California and parts of Nevada.
-
D.
Vera Rubin Ridge
Vera Rubin Ridge is a geologic feature on Mars explored by NASA's Curiosity rover, named in honor of pioneering astronomer Vera Rubin.
-
E.
Kniphausen
Kniphausen is a historical territory in present-day Germany that once functioned as a small semi-independent lordship under various regional powers.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Cassini meridian line Target entity description: The Cassini meridian line is a monumental 17th-century astronomical sundial and meridian marker in Bologna used to measure the Sun’s position and refine the length of the year.
-
A.
Humboldt meridian
The Humboldt meridian is a principal survey meridian used as a reference line for land surveying and mapping in parts of northern California.
-
B.
Great Arc of the Meridian
The Great Arc of the Meridian was a monumental 19th-century geodetic survey line across the Indian subcontinent that played a key role in measuring the Earth’s shape and refining global maps.
-
C.
San Bernardino meridian
The San Bernardino meridian is a principal survey meridian used as a reference line for land surveying and mapping in Southern California and parts of Nevada.
-
D.
Vera Rubin Ridge
Vera Rubin Ridge is a geologic feature on Mars explored by NASA's Curiosity rover, named in honor of pioneering astronomer Vera Rubin.
-
E.
Kniphausen
Kniphausen is a historical territory in present-day Germany that once functioned as a small semi-independent lordship under various regional powers.
- F. None of above. chosen
Statements (44)
| Predicate | Object |
|---|---|
| instanceOf |
astronomical instrument
ⓘ
meridian line ⓘ scientific monument ⓘ sundial ⓘ |
| astronomerInCharge | Giovanni Domenico Cassini ⓘ |
| constructionEnd | 1657 ⓘ |
| constructionStart | 1655 ⓘ |
| coordinateReference | local meridian of Bologna ⓘ |
| coordinateSystem | meridian ⓘ |
| country | Italy ⓘ |
| designer | Giovanni Domenico Cassini ⓘ |
| epochOfUse |
17th century
ⓘ
18th century ⓘ |
| feature |
pinhole gnomon
ⓘ
small aperture in the church wall ⓘ |
| heritageStatus |
cultural heritage of Italy
ⓘ
tourist attraction in Bologna ⓘ |
| historicalPeriod |
Baroque period
ⓘ
linked to:
Baroque
|
| inception | 1650s ⓘ |
| length | approximately 66.8 meters ⓘ |
| locatedIn | Bologna ⓘ |
| locatedInBuilding | Basilica of San Petronio ⓘ |
| material |
brass inlay
ⓘ
marble pavement ⓘ |
| methodOfOperation |
Sun’s image crosses the line at local solar noon
ⓘ
projects an image of the Sun onto the floor ⓘ |
| namedAfter | Giovanni Domenico Cassini ⓘ |
| observationType |
measurement of equinoxes
ⓘ
measurement of solstices ⓘ solar transit observations ⓘ |
| partOf | historical scientific instruments of Bologna ⓘ |
| purpose |
astronomical observation
ⓘ
determine solar noon ⓘ measure the Sun’s position ⓘ refine the length of the tropical year ⓘ |
| relatedTo |
Gregorian calendar reform
ⓘ
linked to:
Gregorian reform of 1582
history of astronomy in Italy ⓘ |
| significance |
contributed to precision measurement of the solar year
ⓘ
important example of church-based observatory ⓘ one of the largest meridian lines in the world ⓘ used to verify and improve astronomical tables ⓘ |
| usedFor |
calendar refinement
ⓘ
measurement of solar declination ⓘ measurement of the ecliptic longitude of the Sun ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Cassini meridian line Description of subject: The Cassini meridian line is a monumental 17th-century astronomical sundial and meridian marker in Bologna used to measure the Sun’s position and refine the length of the year.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.