Rare Opportunity: World’s Largest Solar Telescope Now On Sale at Optics Central (Only 10 ever made!)

Lunt LS230 HA Solar 
Telescope Bundle – Double Stack with
Pressure Tune Control (Pre-owned)

The Lunt LS230 HA Solar Telescope is
something special - it is one of the largest
consumer solar telescopes ever on the market…
and this telescope really is for sale at Optics Central.

Honestly folks, it’s enormous. This stock photo
(courtesy of Lunt) shows the scope alongside a human.

Oh my.

Lunt Staff member looking through an LS230


  • Objective: IR coated (Energy Rejection) 230mm doublet optimized at 656nm
  • f/ratio: 7
  • Etalon 1: Internal unobstructed 80mm pressure tuned.
  • Etalon 2: Internal unobstructed 80mm pressure tuned.
  • Blocking Filter: B3400 internal mount
  • Bandwidth: <0.5 Angstroms at 656.28nm
  • Pressure tune control: Computer control, dual support.
  • Focuser: Feather Touch
  • Mounting: Tube rings and mounting plate included

Lunt LS230 solar telescope on display with Celestron telescopes

The Lunt LS230 is a dedicated 230mm refractor telescope for viewing the Sun. The objective itself is coated for energy rejection and is a group of two lenses. The focal length of the lens is 1610mm, giving an f/ ratio of f/7. This is currently Lunt’s largest solar telescope produced, 52% larger than next best (Lunt LS152).

Because it’s a solar telescope, it filters out all light that isn’t within 0.5 Angstroms of 656.28nm in frequency. This is the Hydrogen Alpha signature wavelength. (For more information about solar filters read on)

The telescope filters all other wavelengths using two (a “doublestack”) so-called “etalons”. An etalon is a filter constructed from two partially reflective surfaces facing each other trapping light between them.

Through the magic of physics, the etalons can be tuned to very specific frequencies, using air pressure delivered by a separate unit which can be controlled by your computer. This means you don’t have to touch the telescope when adjusting the filters.

This telescope includes Lunt’s specialised B3400 Solar Blocking Filter (valued at $1798 USD) that maintains the integrity and performance of the Etalon System and must be used at all times. The telescope also features a two-speed FeatherTouch focuser, for maximum clarity and control.

Due to the enormous size and weight of the telescope, an equally impressive telescope mount is required (absolute minimum payload capacity of 32kg). This telescope may be purchased with a Celestron CGX-L Mount (Pre-owned) as a bundle or on a mount of your choice. The CGX-L is well suited for visual observation, but because of the Lunt’s weight, an EQ8 Mount or equivalent is required for photography

This telescope also includes a 7.3mm – 21.5mm zoom eyepiece (Valued at $349 brand new). At 21mm you can see the whole disk of the sun, and zoomed in, you will see a little less than one third of the sun’s diameter.

What comes in the bundle?

  • Lunt LS230 HA Solar Telescope (Pre-owned)
  • Lunt 7.3mm-21.5mm Zoom Eyepiece (Pre-owned)
  • Lunt B3400 Solar Blocking Filter (pre-fitted)
  • Pressure Tune Control
  • Double Stack Filter/Module

What is a solar telescope?

A solar telescope, as the name suggests, is one built exclusively for looking at the sun. There are two ways of watching the sun, white light, which is simply turning the brightness down, or frequency filtering, which picks what frequency you want to use and filtering everything above and below that. Of course, this telescope filters light above and below about 656 nanometers.

Looking at 656nm sounds odd, but there’s a reason for it. The Sun is made up mostly of hydrogen, with some helium. Hydrogen has one proton and one electron, which whizzes around the proton randomly. If that electron is hit by any type of photon (they come in different colours), it hops up to a higher energy level, before eventually falling back to its original state. When it does fall beck, it emits a photon of exactly 656.28nm. Because this happens all the time, there’s a lot of this precise frequency coming from the sun. Filtering out the rest gets rid of a lot of fuzz and leaves you with a clear, precisely focused image that shows the surface of the sun in incredible detail.

These images are both of the sun, photographed in white light (left) and using a Hydrogen alpha filter (right).

Images in white light and Ha. Credit: Russell Cockman

Both images courtesy of Dr Russell Cockman, Solar Section Director, Astronomical Society of Victoria.

Billo photographs the front of the Lunt LS230

Price is TBA. Please contact us at 1300 884 763, or email us at support@opticscentral.com.au.