LUNT LS50THa Alpha Telescope with Pressure Tuner User Manual
- June 6, 2024
- LUNT
Table of Contents
LUNT LS50THa Alpha Telescope with Pressure Tuner User Manual
Complete Solar Telescope with 50mm aperture. An internal Etalon with advanced air-pressure tuning adjustment allows for a <0.75 Angstrom bandwidth. The “Pressure Tuner” system adapted the Etalon to varying altitudes and atmospheric pressures for always optimal performance. Blocking filter is the B400 or the B600. The star diagonal in which the blocking filter is installed, is equipped as standard for 1.25″ eyepieces. Fine adjustment is achieved with a non-rotating Helical focuser.
What is delivered with the system?
- H-alpha telescope with 50mm aperture
- Internal Etalon with Pressure Tuner
- Blocking filter B400 or B600
- non-rotating Helical focuser
- Tube ring with 1/4”-20 connection for photo tripods
- Instruction manual
Please note: Please keep the foam insert from the delivery box. The optionally available transport-case for the LS50THa (item number 0554010) is not supplied without such a foam insert, the original foam insert from the delivery box fits exactly into this transport-case.
Congratulations and thank you on your purchase of a Lunt Solar Systems solar telescope! The Lunt Solar Systems are a new generation of solar viewing instruments utilizing the most current technologies to provide the highest quality contrast and resolution in their class.
Safety Information:
There are inherent dangers when looking at the Sun thru any instrument. Lunt Solar Systems has taken your safety very seriously in the design of our systems. With safety being the highest priority we ask that you read and understand the operation of your telescope or filter system prior to use. Never attempt to disassemble the system. Do not use your system if it is in someway compromised due to mishandling or damage. Please contact our customer service with any questions or concerns regarding the safe use of your instrument.
Never look at the Sun with your naked eye or with a telescope that is not specifically designed to do so. Permanent and irreversible eye damage may result!
Never leave the solar telescope unsupervised while pointed at the Sun. People who are not familiar with the correct operating procedures of the system may inadvertently replace the blocking-filter diagonal not being aware of the integrated safety features of it.
The Lunt Solar filter/telescopes are not interchangeable with competitor products.
A Lunt Solar Systems solar telescope houses many optical elements that are all pre-aligned and fixed at the factory. There are no user serviceable parts inside the scope. The telescope should never be taken apart. This will not only void your warranty leading to costly repairs, it can only serve to further damage the instrument and compromise its safety!
Most Lunt Solar Systems filters and telescopes house a delicate optical element referred to as an Etalon. These Etalons are suspended in the system housing in an effort to both protect it and isolate it from outside influences, which could de-tune the Etalon filter. Extensive research has been done to assure the best performance of what is essentially the “heart” of the system while protecting it from the day-to-day bumps, jarring, and vibrations of normal use. However, the instrument should never be subjected to shock due to being dropped. Mishandling of the filters system will cause the Etalon to de-contact (not covered under warranty!) and will render the instrument useless until repaired.
The instrument should be stored in its original box. As with any precision
optical instrument it should be kept in as low a humidity area as possible.
With proper handling and care the filter should last a lifetime.
Using the telescope:
Note:
- Please check before the telescope is removed from the transport box that the locking of the blocking filter is applied. Maybe it can happen elsewhere, that when removing the telescope the block filter slip out of the focuser and fall off.
Safety First!
- Always check any telescope before use. Do not use any telescope or filter that appears to be damaged.
- The Blocking Filter diagonal must always be used with the Lunt telescope.
Attach the telescope and clamshell to your mount of choice. There is a ¼-20 threaded hole on the underside of the clamshell. Attach the scope directly to a photographic tripod, or attach a Vixen-style dovetail plate to the clamshell for installing at a astronomical mount.
Slide the Blocking Filter into the focuser and lock it down with the thumb screw. Insert a low power eyepiece into the blocking filter. A 25 mm eyepiece is a good choice for a large field of view.
Tuning: Here is where the magic begins. On the side of the scope is a
large black cylinder on a brass barrel. This cylinder is the Pressure Tuning
system for the LS50THaPT. The black handle of the cylinder has a short start-
thread attaching it to the brass cylinder. Unscrew the black handle
completely. There may be some resistance and a faint “popping” sound. That’s
normal when adjusting pressure for your altitude. Carefully install the handle
onto the cylinder, engaging the threads about one turn. While looking through
the eyepiece, gently turn the black handle clockwise onto the cylinder. There
will be little resistance at first, but as the pressure in the
cylinder builds, the resistance increases slightly. As you turn the cylinder,
centering the 656.28 nm wavelength on- band, you should see features come into
view. Continued tuning will result in the wavelength shifting past 656.28 nm,
and details will begin to disappear. Fine-tune for the best images.
A few details regarding the pressure tune system. The amount of pressure being supplied to the etalon cavity is minimal. It is the equivalent of going from -150m below sea level to about 3,000m. Or around 0.1 Bar, there is no risk of explosion. We are dealing with only a fraction of 1 atmosphere. When not in use we recommend that you release the pressure by simply backing off the black handle from the cylinder body. If the system unthreads completely, simply thread it back on 1 turn. It is not necessary to re-set the system every time it is used. Resetting may only be required if the system has been sitting for a long period of time.
Re-Focus: When you feel you have tuned effectively, re-focus the telescope. The finer details should come into view. Try to relax the eye while observing and let the details come to you.
Change the eyepiece: When you have a good feel for observing at lower magnifications try to increase the magnifications in small steps. Place an interesting artifact in the center of the field. Replace the 25mm with a 8 – 12mm eyepiece. Look thru the eyepiece and re-focus carefully. The image has dimmed slightly due to higher magnification but the details should be easier to see. You can push the magnification as seeing conditions allow.
Seeing conditions: Please note that seeing conditions can affect the performance of your telescope in H-alpha wavelength. Cloud cover, wind, humidity, and air turbulence caused by heat play a major role and can complicate the observation of details.
Double-Stacking:
Double stacking is also possible with the LS50THa telescope. The additionally available double-stack filters LS50C (item number 0550210) can be simply screwed onto the front of the LS50THa, no additional adapters are required. This will reduce the bandwidth to <0.55 Angstroms. This significantly increases the contrast on the surface of the sun, which makes much more details visible on the solar surface.
Recommended accessories:
- LUNT dovetail bar LS100PS for installing the telescope at astronomical mounts (item number 0554401)
- LUNT Sol-Searcher (item number 0554301)
- LUNT LS7-21ZE zoom-eyepiece 7.2mm to 21.5mm (item number 0554501)
- LUNT transport-case for LS50THa (item number 0554010)
Please note: Please keep the foam insert from the delivery box. The optionally available transport-case for the LS50THa (item number 0554010) is not supplied without such a foam insert, the original foam insert from the delivery box fits exactly into this transport-case.
Cleaning
As with most telescopes and equipment there will be a build up of dust and debris on the lens and mechanical components after sitting out all day. For those who are familiar with cleaning telescopes we recommend you use the same techniques. For those who are new to the care of these instruments we can offer the following guidelines:
Blow off loose dust and dirt using a clean dry air source at low volume. Do
not use shop compressed air, which contains oil and will further contaminate
the instrument. Stubborn particulates can be brushed from the surface with a
static free lens brush. Use gentle sweeping motions. Fingerprints and smudges
can be removed using lens tissue or a Kleenex type tissue product. Fold the
tissue or cloth to make a “pad”, apply a cleaning product to the end of the
pad dampening it evenly (do not apply solution to the lens), wipe in circular
motion starting at the
center and working around the edge and off in one complete motion. Be firm,
but do not rub. Blow lightly to help remove residual solution before it
“spots” the surface. Residual dust from the cloth can be blown off. Consult
your local dealer or call Lunt Solar Systems with any questions or concerns.
Do not use Acetone or strong degreaser type products, household cleaning
agents, paper towels, tissues with added scent or color (plain tissues only),
or bleach or acidic products which will damage the anodized surfaces.
A few more definitions
Hydrogen-alpha: The wavelength of light in the spectrum that these scopes allow you to look at. Centered at 656.28nm.
Bandwidth: The width of light at a given wavelength that is allowed to pass. The LS50THa with Pressure Tuner is <0.75 Angstrom. As bandwidth is reduced more surface detail of the Sun can be resolved. This can be accomplished thru double-stacking with an LS50C Filter (<0.55 Angstrom).
Angstrom: The unit of measurement for light. 1 Angstrom = 0.1nm.
Etalon: A resonating cavity produced thru the fabrication of highly precise optical surfaces.
Lunt-Solar-Systems – Exclusive European Distributor
Bresser GmbH
Gutenbergstrasse 2, D-46414 Rhede, Germany
Phone: +49 (0) 2872 – 80 740
E-Mail: info@bresser.de
www.bresser.de
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