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Solar Observation > Solar telescopes > Coronado > SolarMax III > Coronado ST 90/800 SolarMax III BF15 <0.7Å OTA
Product no.: 59501

ST 90/800 SolarMax III BF15 <0.7Å OTA

$ 7,400.00 incl. VAT, plus shipping costs
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Product can be shipped as of 01.04.2025 + lead time

Product description

More about the series SolarMax III...

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!

It not only matters which telescope you buy but also where you buy it. Our additional services:

  • We are a leading telescope dealer and know the devices we sell. Our customer service team will gladly help you after your purchase if you have problems with assembly or operation.
  • We provide a copy of the 80-page "Telescope ABC" beginners handbook with every telescope.

Specifications

Optics


Type of build
Solar H-Alpha
Type
Refractor
Aperture (mm)
90
Focal length (mm)
800
Aperture ratio (f/)
8,9
Resolving capacity
1,53
Limit value (mag)
11,6
Light gathering capacity
170
Max. useful magnification
180
Tube weight (kg)
7,9
Bandwidth
< 0,7
etalon filters (mm)
90
Blocking Filter (mm)
15
Double Stack
no
Filter systems
H-alpha
Tube construction
Full tube

Focuser


Connection ( to eyepiece)
2
Type of build
Gear rack
Free aperture (mm)
51
Gear reduction
1:7 fine focusing
Connecting threaded socket (camera-side)
T2
Rotating
yes
Adjustment range (mm)
65

Mount


Type of build
OTA
Mounting type
no mount

Included accessories


Prism rail
Vixen-Style
Tube clamps
yes
Finder scope
Solar finder
1.25'' eyepieces
25mm, 18mm, 12mm
Transport cases
yes
Deviating optics
Blockfilter
Barlow Lens
2x

General


Series
SolarMax III

Area of application


Sun
yes (H-alpha)

Recommended for


Beginners
no
Advanced
yes
Observatories
yes

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*All prices include VAT plus shipping costs.

Coronado ST 90/800 SolarMax III BF15 <0.7Å OTA
Example image 1

Coronado ST 90/800 SolarMax III BF15 <0.7Å OTA

Example image 2

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