Lunt LS50THa B600PT H-alpha Solar Telescope
Lunt LS50THa B600PT H-alpha Solar TelescopeLunt LS50THa B600PT H-alpha Solar TelescopeLunt LS50THa B600PT H-alpha Solar Telescope

Lunt LS50THa B600PT H-alpha Solar Telescope

  (3 Reviews)
✓ 2 year warranty


Out of stock due 30-40 working days

About this product

Model:  lunt_LS50THa_B600PT
Part Number:  0551156

New 50mm f/7 refractor-based Hydrogen-alpha telescope from Lunt provides an excellent introduction to solar observing in Ha or solar photography using a suitable imaging camera.

Features an internally mounted etalon with Pressure Tuner adjustment and a B600 blocking filter. The larger B600 blocking filter is the better option for imaging. 

<0.75 Angstrom band pass!

Includes a clamshell with threaded holes for mounting.

Pressure Tuner

True Doppler Tuning (Pressure Tuning) allows for a shift into and away from the user, adding a 3D-like component to the viewing experience. While it has minimal effect on proms (due to them being at the edge of the disk) it does have an effect on filaments and active regions on the surface. While looking at a filament at the center of the Sun the user has the ability to Doppler shift from the base of the filament to the tip, following the filament through it’s structure toward you and away from you, allowing for enhanced visual and imaging capability for the observer as well as a research tool for the avid hobbyist. The pressure tuning system provides an order of magnitude more precision to the tuning of the desired features.

Double Stacking

An optional matching LS50C compact double stack filter is also available which allows you to lower the bandpass to <0.5 Angstrom which gives much greater surface detail. The double stack filter is easy to fit - it simply screws directly on to the LS50THa.

The image above shows the Lunt LS50THa H-alpha Solar Telescope fitted with the optional matching LS50C compact double stack filter as well as the TeleVue Sol Searcher finder and Lunt eyepiece.

Telescope Field of View Simulator


TypeSingle Interference Etalon
TuningInternal Pressure Tune (Doppler True Tuning)
Focal Length350mm
F RatioF7
Bandpass<0.75 Angstroms @ 656nm
FocuserHelical Focuser
MountingIntegrated clamshell style with 1/4-20 tapped base
ColorPearl White with Black and Red accents
DiagonalB400 or B600 Blocking Filter

Customer reviews

Average Rating (3 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
02 February 2022  | 

First class service again from FLO

Rating (max 5):  
Very nice performer
06 August 2021  | 

I purchased this instrument in the early summer 2020 after initially buying a Daystar Skyscout 60 which turned out not to work at all. So after returning the Daystar, to make up for the disappointment I spent a bit more money to get the Lunt50 with the 6mm blocking filter B600PT. The instrument arrived, and at first I thought again I could not see any structure. Until I read the manual ... and used the pressure tuner. Then - what a difference - I saw the chromosphere with the grainy structure across the sun, and prominences! What a relief! Since then I use the instrument regularely for visual observation and imaging, the latter with a Skyris 445 camera of Celestron. The only little things which could be better were a solar finder (I build one, then decided to piggyback it to a white light scope), and the camera attachment options. Due to the build of the instrument, DSLRs cannot be used and due to the manufacturer the emphasis of the Lunt50 is visual, with the larger Lunt60 being better for imaging as well (but beyond my funding opportunities ...). I found out that the 1.25" eyepiece holder screws off, revealing a T2 thread and I made an adapter to fit the monochrome Celestron Skyris 445 to it. Using 30s to 1min movies, Firecapture, Autostakkert and Registax, I can now get nice images of either the chromosphere or prominences. So if you like imaging, you have to consider to get a good monochrome imager with a C mount thread and a short adaptation to the diagonal with the blocking filters, using the T2 thread.

Another little niggle: After one year the rubber ring of the focuser dropped off. A typical problem that happened before on eyepieces and focusers, as the rubber is thin and does not live very long. I replaced it by some rubber O rings of an O ring assortment that can be purchased for a few quid in a hardware store, and I had no problem since.

So overall, apart from little issues a good performer which proves to be a nice way to get into the world of hydrogen alpha observation.

Rating (max 5):  
I sit in amazement !
07 January 2015  | 

I have done around 4-5 hours observation time so far with the following eyepieces:

Televue 25mm Plossl (x14)
Televue 15mm Plossl (x23.3)
Televue 11mm Plossl (31.8)
Takahashi LE 7.5mm (x46.6)

I noticed that to get sharp focus with the TV eyepieces, adding the supplied adapter between the focuser and B600 filter achieved it perfectly.

The helical focuser moves with a nice resistance as does the pressure tuner.
The point at which the focuser is moved from any current rested position I experience a very tiny free movement that does not influence the focal length of the scope. This tiny free movement is followed by a resistance which is the focuser engaged for very accurate & smooth course or fine focusing.
When the focuser is left there is no slop, its tight where its been left. Its possible to 'feel' the free movement on the focuser in clockwise and anti-clockwise direction without interfering with the focused image.

The scope is very intuitive to use with the information from the short instruction manual.

The sol finder was exactly aligned on first attempt and captured the sun in the 25mm EP, no tinkering needed. The helical focuser when turned produced a sharp limbed disc. The pressure tuner then bought out extensive detail of both disk and prominences, and a quick fine tune back on the helical focuser produced a sharp and pleasantly detailed image.

Seeing a hedgerow prominence for the first time was an outstanding start, and I was very satisfied with the ability to get a very sharp contrasted view. Different levels of density were really obvious, as was the changing state of the prominence. As the sun moved across the FOV I noticed that the prominence had the tendency to fade. With higher magnification this phenomenon is less obvious and is not present at all in the 7.5 mm @ x 46.6. Major features at lower power seem to benefit from placement within a 'sweet spot' in the field of view, especially if your aim is to tease out every last detail of that particular feature. This is in no way distracting and is no doubt part of the systems characteristics. Part of the charm is learning the knack of keeping the focus, the pressure tuner and FOV parameters in check to the feature/s you are trying to observe.

Scanning the solar limb once tuned to any prominence is great fun, especially as many more become apparent that may have been overseen completely. The pressure tuned etalon in use here is rewarding at bringing out the fullest potential of the morphology of the prominences.

With both the pressure tuner and focuser set, I found the 15mm did a lovely job of presenting a nice view of both limb and disc features at the same time. Only a little tweaking of the slow motion controls on the tripod to maintain the view or vary it slightly was needed. Quiet filament regions are presented well along with the sometimes subtle but lighter associated filament channels. Active regions also feature well. Sunspots appear very dark and sharp. With patience all features become more evident in complexity. The only thing I can compare the views to night viewing is a very dynamic Jupiter on steroids in excellent seeing. All this said with the Sun currently in winter placement I have not yet had the opportunity to release the instruments full potential.

Amazing views and for the money it packs a huge punch.


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Q1. What is the difference between the B400 blocking filter and the B600 blocking filter?

The B400 blocking filter is best for visual use. The B600 blocking filter has a larger field of view which is good for both visual and imaging.

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