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
1.25" 90° Amici prism
( 5 / 5 )
$ 24.90
ready for shipping in 24
h
Omegon
Carbonline 2", 90° mirror star diagonal, 99% dielectric
$ 189.00
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
Omegon
1,25'' Amici Prism 90°
( 5 / 5 )
$ 149.00
ready for shipping in 24
h
Omegon
45°, 1.25'' to 1.25'' Amici prism
$ 119.00
ready for shipping in 24
h
Omegon
1.25" 45° erecting prism
$ 39.90
ready for shipping in 24
h
Omegon
2'', 45° Amici prism
$ 189.00
ready for shipping in 24
h
Baader
Diagonal mirror ClickLock 2"
( 5 / 5 )
$ 344.00
ready for shipping in 1-2
weeks
/Omegon-Amici-prism-90d-2-.jpg)
Omegon
Amici prism 90° 2"
$ 369.00
ready for shipping in 24
h
Artesky
Diagonal mirror 90° 1.25"
( 5 / 5 )
$ 92.00
ready for shipping in 3-5
weeks
Baader
2" BBHS®-Click-Lock mirror star diagonal
$ 560.00
ready for shipping in 1-2
weeks
Baader
Diagonal prism 2" ClickLock BBHS®
$ 590.00
ready for shipping in 1-2
weeks
Bresser
Star diagonal 99 Percent Reflectivity 2"
$ 92.00
ready for shipping in 24
h
William Optics
Diagonal mirror Dura Bright 90° 2"
$ 289.00
ready for shipping in 24
h
Celestron
zenith prism 90°, 1.25"
( 5 / 5 )
$ 53.00
ready for shipping in 24
h
Omegon
Pro Penta Prisma 90° 1.25''
$ 219.00
ready for shipping in 24
h
Baader
Zenith prism T-2/90 degree, 32mm
$ 158.00
ready for shipping in 1-2
weeks
Celestron
Amici prism 45°, 1.25''
$ 53.00
ready for shipping in 24
h
TS Optics
Diagonal mirror 90° 1.25"
$ 134.00
ready for shipping in 3-7
days
Omegon
45°, 2'' to 1.25'' Amici prism
$ 199.00
ready for shipping in 24
h
Skywatcher
Diagonal Mirror Deluxe 90° 1,25"
$ 145.00
ready for shipping in 1-2
weeks
Omegon
Pro 1.25'', 45° penta-prism
$ 169.00
ready for shipping in 24
h
Skywatcher
Amici prism 90° 1,25"
$ 65.00
ready for shipping in 24
h
Baader
Diagonal mirror Maxbright Universal 90° T2
$ 258.00
ready for shipping in 1-2
weeks
TS Optics
Diagonal prism T2 90°
$ 104.00
ready for shipping in 3-7
days
Baader
BBHS® T2 mirror star diagonal
( 5 / 5 )
$ 319.00
ready for shipping in 1-2
weeks
Baader
90°, T2 star diagonal with 35mm of free aperture
$ 282.00
ready for shipping in 1-2
weeks
Bresser
Amici Prisma 45° 1.25''
$ 57.00
ready for shipping in 1-2
weeks
Baader
Amici prism ClickLock BBHS® 90° 2"
$ 780.00
ready for shipping in 1-2
weeks
William Optics
1,25'' 45° Amici prism on 1,25''
RRP:
$ 185.00
Our price:
$ 162.00
ready for shipping in 24
h
Celestron
Diagonal mirror Twist-Lock 2"
$ 394.00
Product can be shipped as of 12.11.2025
Baader
Amici prism 90° T2 BBHS®
$ 342.00
ready for shipping in 1-2
weeks
Baader
Amici prism 90° 2"
$ 339.00
ready for shipping in 1-2
weeks
TS Optics
Diagonal mirror 90°, dielectric full coating, 2'' Quartzprotection
$ 231.00
ready for shipping in 3-7
days
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.