ST 90/800 SolarMax III BF15 <0.5Å Double Stack OTA

ST 90/800 SolarMax III BF15 <0.5Å Double Stack OTA

Solar telescope for the observation and photography of our sun in H-Alpha light with extensive equipment.

  • Fully equipped H-Alpha telescope - 90 mm aperture - 800 mm focal length - f/8.9
  • Coronado RichView Tuning System
  • BF15 block filter
  • True Etalon filter with 90 mm diameter
  • Sol-Ranger sun finder included
  • Includes tube rings, dovetail bar and 3x Eyepieces & 2x Barlow
  • In high-quality carrying case
  • Bandwidth: < 0.5 Ångström
Manufacturer : CORONADO
SKU : Ni-59502
Price: 10399.00 € incl tax 19% (Germany)
Delivery date : 3-4 days
Product description

Observing the sun in H-Alpha is a lot of fun using these compact SolarMax III telescopes! The integrated ‘True’ Etalon filter provides higher contrast and a sharper image than other solar telescopes with smaller filters.

SolarMax III telescopes have an improved focuser with sensitive focusing and other high-quality features. The filters can be removed from the Solarmax III, allowing the solar telescope to also be used as an achromat for observing the night sky.

The sun is observed at a wavelength of 656 nanometers - known as H-alpha - showing an ever active solar surface and prominences at the sun's edge. There is always something to see on the sun in the H-alpha!!

RichView™ tuning: The Doppler effect causes the wavelengths of interesting structures to vary around the H-alpha line of 656.3 nanometers. This effect is particularly noticeable in the change between the central solar disk and the edge (prominences). The RichView™ tuning system allows you to adjust the filter, to find the best possible contrast.

Double stack: Every SolarMax telescope also comes with double stack. This means that two etalon filters are fitted one behind the other. This reduces the half width of the light which passes through the H-alpha line to less than 0.5 Angstroms. Without double stack, the half width is less than 0.7 Angstroms. The half width is provided in the product name and in the telescope's technical information.

The smaller half width results in higher contrast. The Sun’s structures appear three-dimensional. The image is also darker and needs to be finely readjusted using the tuning system due to the filter’s smaller half width.

BF blocking filter: The deflection optics with the eyepiece receiver also accommodate the blocking filter. This filter reduces the brightness of the solar image and is therefore a very important part of the solar telescope, and which must under no circumstances be removed! For purely visual observing, a small blocking filter is sufficient, but for photography a larger one should be selected.

Sol Ranger: Pointing a telescope at the sun is more difficult than you may think and can often involve involuntary glimpses of the sun with unprotected eyes! The Sol Ranger finder scope is a special solar finder that uses a ground glass screen. This allows you to point your telescope at the sun easily, safely and quickly.

Delivery includes Cemax eyepieces and the Cemax-Barlow. The coatings used for these eyepieces and Barlow lens has been optimized for use with the H-alpha telescope - giving maximum light transmission and contrast!

Scope of Delivery:
  • Optical Tube
  • Double Stack Filter
  • Mounting Plate
  • Tuberings
  • 12mm, 18,, and 25mm Eyepiecees and 2x Barlow
  • Case
  • Finderscope
  • Blocking Filter

Products specifications
ViewfinderSolar Finder
Blocking Filterd=15mm (Diagonal)
Connection to eyepiece2"/1.25"
Focal length800mm
Band Pass<0.5Ä
Type of telescopeSolarscope H-Alpha
Focal ratiof8.9
FocuserR&P 1:7 Step Down