Barlow lenses
E95782
Barlow lenses are optical accessories used in telescopes to effectively increase focal length and magnification by diverging the light path before it reaches the eyepiece.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Barlow lens | 1 |
| Barlow lenses canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T806554 — 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: Barlow lenses Context triple: [Cassegrain focus, usedWith, Barlow lenses]
-
A.
Cassegrain focus
Cassegrain focus is a telescope optical configuration in which light is reflected by a secondary mirror back through a hole in the primary mirror to form a compact, accessible focal point behind the primary.
-
B.
Optica
Optica is a leading scientific society dedicated to advancing the study and application of optics and photonics worldwide.
-
C.
Ritchey–Chrétien reflector
A Ritchey–Chrétien reflector is a specialized type of reflecting telescope that uses hyperbolic primary and secondary mirrors to produce a wide, coma-free field of view ideal for professional astronomical imaging.
-
D.
Cooke
Cooke is a surname of English origin, often considered a variant spelling of "Cook."
-
E.
Schwarzschild telescope
The Schwarzschild telescope is a specialized two-mirror optical design that eliminates spherical aberration and coma, enabling wide-field, high-resolution astronomical imaging.
- 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: Barlow lenses Target entity description: Barlow lenses are optical accessories used in telescopes to effectively increase focal length and magnification by diverging the light path before it reaches the eyepiece.
-
A.
Cassegrain focus
Cassegrain focus is a telescope optical configuration in which light is reflected by a secondary mirror back through a hole in the primary mirror to form a compact, accessible focal point behind the primary.
-
B.
Optica
Optica is a leading scientific society dedicated to advancing the study and application of optics and photonics worldwide.
-
C.
Ritchey–Chrétien reflector
A Ritchey–Chrétien reflector is a specialized type of reflecting telescope that uses hyperbolic primary and secondary mirrors to produce a wide, coma-free field of view ideal for professional astronomical imaging.
-
D.
Cooke
Cooke is a surname of English origin, often considered a variant spelling of "Cook."
-
E.
Schwarzschild telescope
The Schwarzschild telescope is a specialized two-mirror optical design that eliminates spherical aberration and coma, enabling wide-field, high-resolution astronomical imaging.
- F. None of above. chosen
Statements (51)
| Predicate | Object |
|---|---|
| instanceOf |
diverging lens
ⓘ
optical accessory ⓘ person ⓘ telescope accessory ⓘ |
| alters | light path before it reaches the eyepiece ⓘ |
| canBePlaced | in front of a camera adapter for astrophotography ⓘ |
| canBeUsedWith |
double star observing
ⓘ
lunar imaging ⓘ planetary imaging ⓘ solar observing with proper solar filters ⓘ visual observing ⓘ |
| compatibleWith |
catadioptric telescopes
ⓘ
reflecting telescopes ⓘ refracting telescopes ⓘ |
| differsFrom | telecompressor (focal reducer) ⓘ |
| hasAdvantage |
can improve edge performance of some eyepieces
ⓘ
reduces need to buy many short focal length eyepieces ⓘ |
| hasComponent |
eyepiece holder
ⓘ
lens barrel ⓘ negative lens group at the front ⓘ telescope-side barrel ⓘ |
| hasDisadvantage |
adds more glass elements in the optical path
ⓘ
can introduce vignetting with some eyepieces ⓘ can magnify optical aberrations of the telescope or eyepiece ⓘ can reduce image brightness at high magnifications ⓘ |
| hasEffect |
allows use of longer focal length eyepieces to achieve high magnification
ⓘ
increases effective focal ratio (f-number) of the telescope ⓘ increases eye relief for many eyepieces ⓘ reduces field of view for a given eyepiece ⓘ spreads light over a larger image scale ⓘ |
| hasOpticalDesign | negative (diverging) lens group ⓘ |
| historicalPeriod | 19th century origin ⓘ |
| mayInclude |
compression ring eyepiece clamp
ⓘ
filter threads ⓘ removable lens cell ⓘ |
| mountStandard |
1.25-inch barrel
ⓘ
2-inch barrel ⓘ |
| namedAfter | Peter Barlow ⓘ |
| occupation |
mathematician
ⓘ
physicist ⓘ |
| placed | between telescope focuser and eyepiece ⓘ |
| relatedTo | telecentric amplifier ⓘ |
| typicalMagnificationFactor |
1.5x
ⓘ
2x ⓘ 3x ⓘ 5x ⓘ |
| usedBy |
amateur astronomers
ⓘ
professional astronomers ⓘ |
| usedFor |
increasing effective focal length of a telescope
ⓘ
increasing magnification of a telescope-eyepiece combination ⓘ |
| usedIn | telescope ⓘ |
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: Barlow lenses Description of subject: Barlow lenses are optical accessories used in telescopes to effectively increase focal length and magnification by diverging the light path before it reaches the eyepiece.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Barlow lenses