Lunt Solar Systems are proud to begin the introduction of a new addition to our lineup.
We estimate that this product will be available for demo and pre-order at NEAF.
(We are currently not accepting pre-orders).
The LS40mm - Hybrid
The LS40mm is a 40mm aperture f10, Hydrogen-alpha dedicated solar telescope with a bandpass of 0.6 Angstroms in it's base configuration.
The LS40mm - Hybrid will be available in 3 etalon variations.
The base model includes an internally mounted pressure tuned etalon system.
The Pro version will internally house a newly designed etalon system that will achieve 0.45A.
The Pro+ version will be a DS version of either the base or Pro version with the addition of a front mounted 40mm filter bringing the bandpass down to est. 0.35A.
A Note about Specifications:
The Lunt pressure tuned system is by far the most advanced way to tune an air spaced etalon.
By simply changing the refractive index of the air in the etalon cavity you can make uniform and repeatable non-contact modifications to the central wavelength of the etalon.
Anyone that has handled an etalon directly with their fingers knows that it only takes incredibly small amounts of differential pressure and/or changes in heat from the fingers to grossly change the transmitted wavefront across the etalon aperture, resulting in huge increases in bandpass.
While an etalon can be specified at any one point in the aperture, it is the addition of all points across the entire etalon that should dictate the true bandpass specification.
Lunt etalons have historically been specified at <0.65A.
The theoretical specification of a Lunt Etalon, as calculated, is 0.55A with a +/-0.1A tolerance.
Over the years we have improved that tolerance to better than +/-0.05A.
Generally speaking, etalons that are physically compressed have a bigger bandpass tolerance due to the inconsistencies inherent to mechanical manufacturing.
Lunt do not physically compress our etalons. By doing so we remove any errors induced to this precision optical component as a result of mechanical error and thermal transfer as a result of physical contact.
Center foot: The center foot was used to take commercially available plates, polished to 1/20th wave or better, and "bend" them parallel. Typically, we would make all plates slightly convex. The residual shape of the TWF across the aperture was a slight bird shape. With the lower points of the tuning at the edge and center.
Physical compression is done at the center and the edge. This pressure increases the bird shape with a result of a larger range of CWL across the aperture, leading to a reduced performance.
If the plates were polished to 1/50th wave, there would be no need for a center foot.
Back to regular programming.
The base price is currently estimated at US$899. This is subject to change a little as we nail down some of the 3rd party component costs and ride the wave of supplier price increases that are typical at the beginning of each year.
We will continue to post updates as we get closer to the official launch.
Image attached shows the optional FT.
We thank you all for your continued interest in Lunt products. And I look forward to your feedback and questions.
-Andy and the Lunt Team
