# US 4,400,065 A · Multi-purpose telescope

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- Number: US 4,400,065 A
- Document ID: US4400065A
- Status: Granted
- Kind: A
- Application number: 06/264,225
- Filed: 1981-05-18
- Granted: 1983-08-23
- Earliest claimed: 1981-05-18
- Inventors: Albert Nagler
- Web page: https://patentgrep.com/patent/US4400065A

## CPC

- G02B 27/0025: {for optical correction, e.g. distorsion, aberration}
- G02B 13/00: Optical objectives specially designed for the purposes specified below (with variable magnification {in general} G02B15/00)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

A multi-purpose telescope objective having a Petzval type lens configuration and including an iris diaphragm.

## Claims

### Claim 1

A multi-purpose telescope comprising a Petzval type objective having a front achromat and a rear achromat widely spaced from each other, and an iris disphragm located between said achromats and proximate to said rear achromat, and wherein said Petzval type objective includes lens elements LI and LIII made of BK-7 glass having a refractive index of 1.5168 and an Abbe number of 64.2 and lens elements LII and LIV made of SF-12 glass having a refractive index of 1.6477 and an Abbe number of 33.8 and said lens elements have the parameters specified in the following table wherein all dimensions are given in millimeters:
______________________________________ Lens Lens Lens Clear Ele- Thick- Separa- Aper- Outside ment Radii ness "d" tion "s" ture Diameter ______________________________________ r1=+411.43 LI d1=16.0 126 132 r2=-544.15 s1=6.0 r3=-501.7 LII d2=12.0 126 132 r4=-6890.0 s2=480.0 r5=+253.263 LIII d3=8.0 60 64 r6=-253.263 s3=0.0 r6=-253.263 LIV d4=8.0 60 64 r7=-1386.0 ______________________________________

### Claim 2

A Petzval type objective including lens elements LI, LII, LIII, and LIV wherein lens elements LI and LIII are made of BK-7 glass having a refractive index of 1.5168 and an Abbe number of 64.2 and lens elements LII and LIV are made of SF-12 glass having a refractive index of 1.6477 and an Abbe number of 33.8, and wherein said lens elements have the parameters specified in the following table where all dimensions are given in millimeters:
______________________________________ Lens Lens Lens Clear Ele- Thick- Separa- Aper- Outside ment Radii ness "d" tion "s" ture Diameter ______________________________________ r1=+411.43 LI d1=16.0 126 132 r2=-544.15 s1=6.0 r3=-501.7 LII d2=12.0 126 132 r4=-6890.0 s2=480.0 r5=+253.263 LIII d3=8.0 60 64 r6=-253.263 s3=0.0 r6=-253.263 LIV d4=8.0 60 64 r7=-1386.0 ______________________________________

### Claim 3 (depends on 2)

A telescope comprising a Petzval type objective according to claim 2 an iris diaphragm located between lens elements LII and LIII and proximate to lens element LIII, and an eyepiece.