A much more comfortable observing position can be achieved with a refractor or catadioptric telescope by using an erecting lens. The beam of light exiting the telescope is deflected by 90° before it enters the eyepiece. In this way, even objects close to the zenith can be observed comfortably.
Omegon
Carbonline 2'', 90° SC mirror star diagonal, 99% dielectric
$ 189.00
ready for shipping in 24
h
Omegon
Star diagonal with 99% reflection, 2"
( 5 / 5 )
$ 179.00
ready for shipping in 24
h
Omegon
Carbonline 1.25'', 90° mirror star diagonal, 99% dielectric
$ 129.00
ready for shipping in 24
h
Omegon
Mirror star diagonal, 90°, 1.25"
$ 17.90
ready for shipping in 24
h
William Optics
Diagonal mirror Dura Bright 90° 2"
$ 294.00
ready for shipping in 24
h
Baader
Diagonal mirror ClickLock 2"
( 5 / 5 )
$ 350.00
ready for shipping in 1-2
weeks
Artesky
Diagonal mirror 90° 1.25"
( 5 / 5 )
$ 94.00
ready for shipping in 24
h
Bresser
Star diagonal 99 Percent Reflectivity 2"
$ 94.00
ready for shipping in 1-2
weeks
Baader
2" BBHS®-Click-Lock mirror star diagonal
$ 570.00
ready for shipping in 24
h
TS Optics
Diagonal mirror 90° 1.25"
$ 136.00
ready for shipping in 3-7
days
Skywatcher
Diagonal Mirror Deluxe 90° 1,25"
$ 148.00
ready for shipping in 1-2
weeks
Celestron
Diagonal mirror Twist-Lock 2"
$ 401.00
ready for shipping in 1-2
weeks
Baader
BBHS® T2 mirror star diagonal
( 5 / 5 )
$ 325.00
ready for shipping in 1-2
weeks
Explore Scientific
3" 90° mirror star diagonal
$ 680.00
ready for shipping in 1-2
weeks
TS Optics
Diagonal mirror 90° SC/2"
$ 230.00
ready for shipping in 3-7
days
APM
Diagonal mirror 90° 99% 2"
$ 148.00
Product can be shipped as of 15.10.2025
APM
Star diagonal 99 Percent Reflectivity 2"
$ 212.00
ready for shipping in 1-2
weeks
Baader
Diagonal mirror Maxbright Universal 90° T2
$ 263.00
ready for shipping in 1-2
weeks
Skywatcher
Diagonal mirror 90° 2"
$ 117.00
ready for shipping in 1-2
weeks
TS Optics
Diagonal mirror 90°, dielectric full coating, 2'' Quartzprotection
$ 235.00
ready for shipping in 3-7
days
William Optics
Dura Bright 1.25" 90° mirror star diagonal
RRP:
$ 224.00
Our price:
$ 188.00
Product can be shipped as of 01.10.2025
Auriga
Diagonal mirror 90° 2"
$ 234.00
ready for shipping in 1-2
weeks
TS Optics
1.25", mirror star diagonal for Imaging Star apochromats
$ 165.00
ready for shipping in 3-7
days
Explore Scientific
Star diagonal 99 Percent Reflectivity 2"
$ 219.00
ready for shipping in 1-2
weeks
TeleVue
Everbrite 1.25" 60° star diagonal
RRP:
$ 495.00
Our price:
$ 417.00
ready for shipping in 6-10
weeks
TeleVue
Everbrite 2" 90° mirror star diagonal
RRP:
$ 590.00
Our price:
$ 496.00
ready for shipping in 6-10
weeks
Omegon
Carbonline 2", 90° mirror star diagonal, 99% dielectric
$ 189.00
Product can be shipped as of 01.12.2025
TS Optics
Diagonal mirror 90° SC/2"
$ 189.00
ready for shipping in 3-7
days
Skywatcher
Diagonal mirror 1,25" (90°)
$ 58.00
ready for shipping in 24
h
TeleVue
Everbrite 1.25" 90° star diagonal
RRP:
$ 436.00
Our price:
$ 367.00
ready for shipping in 6-10
weeks
TeleVue
Diagonal mirror Everbrite SC 90° 2"
RRP:
$ 630.00
Our price:
$ 527.00
ready for shipping in 6-10
weeks
Levenhuk
Diagonal mirror Ra 90° 2"
$ 224.00
ready for shipping in 1-2
weeks
Baader
2" M68 ClickLock star diagonal with M68 thread
$ 365.00
ready for shipping in 1-2
weeks
Artesky
Diagonal mirror 90° 2"
$ 165.00
ready for shipping in 3-5
weeks
TeleVue
Diagonal mirror 1,25" (90°)
RRP:
$ 283.00
Our price:
$ 238.00
ready for shipping in 6-10
weeks
Skywatcher
Diagonal Mirror Deluxe 90° 2"
$ 208.00
ready for shipping in 1-2
weeks
Erecting lenses are available as zenith mirrors, zenith prisms or Amici prisms. The latter are useful for terrestrial observation and are therefore also available with a flatter deflection angle of 45°.
- Without an erecting lens, the image in the telescope depicts north below and east to the right.
- With zenith mirrors and zenith prisms, the telescope depicts a laterally transposed image: north is at the top, east is at the right and, without tracking, stars wander to the left.
- Amici prisms show a correct image as it would be seen with the naked eye. Therefore, these prisms are essential for nature-watching. However, their more complicated construction makes them susceptible to image defects, which is why the laterally transposed image is preferred in astronomy.
Most erecting lenses have simple plug-in connectors, as is common seen with eyepieces. For SC telescopes, however, there are also models with screw threads.