Appendix D, ACF and SC Optical Systems

APPENDIX D:

ACF AND SC OPTICAL SYSTEMS

	(2)	(1)
(1)		(2)
		Ray (2)
Ray (1)
(2)
(1)		Secondary
		Secondary
Focal		Mirror
Focal
Plane		Secondary
Primary Baffle Tube		Baffle
		Baffle
Field Stops		Correcting
		Correcting
Primary Mirror		Plate
Primary Mirror

The Meade Advanced Coma-Free Optical System

OPTICAL SYSTEMS

Unlike Schmidt-Cassegrain systems, Meade’s Advanced Coma-Free (ACF) optical system provides razor-sharp pin-point star images all the way to the very edge of the ﬁeld of view. This aplanatic (coma-free) optical system brings the highest level of performance to the amateur astronomer.

In the ACF design of the Meade LT Series, light enters from the right, passes through a thin lens with 2-sided aspheric correction (“correcting plate”), proceeds to a spherical primary mirror, and then to a hyperbolic secondary mirror. The hyperbolic secondary mirror multiplies the effective focal length of the primary mirror and results in a focus at the focal plane, with light passing through a central perforation in the primary

mirror.

All models of the Meade LT includes oversize primary mirrors, yielding a fully illuminated ﬁeld-of-view signiﬁcantly wider than is possible with a standard-size primary mirror. Note that light ray (2) in the ﬁgure would be lost entirely, except for the oversize primary. It is this phenomenon which results in Meade ACF having off-axis ﬁeld illuminations about 10% greater, aperture- for-aperture, than other systems utilizing standard-size primary mirrors. Field stops machined into the inside- diameter surface of the primary mirror bafﬂe tube signiﬁcantly increase lunar, planetary, and deep-space image contrast. These ﬁeld stops effectively block off- axis stray light rays.

	(2)	(1)
		(1)
(1)		(2)
		Ray (2)
Ray (1)
(2)
(1)		Secondary
		Secondary
Focal		Mirror
Focal
Plane		Secondary
Primary Baffle Tube		Baffle
		Baffle
Field Stops		Correcting
		Correcting
Primary Mirror		Plate
Primary Mirror

The Meade Schmidt-Cassegrain Optical System

In the Schmidt-Cassegrain design of the Meade LT, light enters from the right, passes through a thin lens with 2-sided aspheric correction (“correcting plate”), proceeds to a spherical primary mirror, and then to a convex secondary mirror. The convex secondary mirror multiplies the effective focal length of the primary mirror and results in a focus at the focal plane, with light passing through a central perforation in the primary mirror.

All models of the Meade LT Schmidt-Cassegrain includes oversize primary mirrors, yielding a fully

illuminated ﬁeld-of-view signiﬁcantly wider than is possible with a standard-size primary mirror. Note that light ray (2) in the ﬁgure would be lost entirely, except for the oversize primary. It is this phenomenon which results in Meade Schmidt-Cassegrains having off-axis ﬁeld illuminations about 10% greater, aperture-for- aperture, than other Schmidt-Cassegrains utilizing standard-size primary mirrors. Field stops machined into the inside-diameter surface of the primary mirror bafﬂe tube signiﬁcantly increase lunar, planetary, and deep-space image contrast. These ﬁeld stops effectively block off-axis stray light rays.

INDEX

LT Series, LT ACF Series, LT SC Series specifications

The Meade LT SC Series, LT ACF Series, and LT Series telescopes are designed to meet the diverse needs of amateur astronomers and astrophotographers alike. Each of these series caters to various levels of experience while incorporating advanced features and technologies that enhance observational stability and image quality.

The Meade LT SC Series, featuring the advanced Schmidt-Cassegrain design, excels in versatility. This series includes different aperture sizes, allowing users to view celestial objects ranging from the moon to distant galaxies. The telescopes come equipped with an AudioStar hand controller that provides a database of over 30,000 celestial objects, enabling users to easily locate and track their subjects. The built-in GPS feature facilitates effortless alignment by automatically determining the user’s location and time.

In contrast, the LT ACF Series showcases Meade's innovative Advanced Coma-Free (ACF) optics. This design minimizes coma and field curvature, providing sharp, crisp images across a wider field of view. Ideal for astrophotography, this series is enhanced by features like a fast focal ratio for better imaging of dim objects and a robust construction that ensures stability during use. The LT ACF telescopes also support advanced imaging techniques, allowing users to capture stunning images of deep-sky objects while minimizing aberrations.

The classic LT Series remains a favorite among beginners. Known for its straightforward setup and usability, this series is designed with a lightweight and portable frame. The LT Series telescope is equipped with an altazimuth mount, making it user-friendly for quick observations. The simplicity allows new astronomers to start observing with minimal technical knowledge. Additionally, these telescopes support a variety of accessories such as smartphone adapters, making it easy for users to capture their observations.

All three series incorporate Meade's proprietary StarLock technology in certain models, which facilitates automated tracking. This feature frees astronomers from the complexities of manual tracking, allowing them to focus more on the experience of observing celestial wonders.

In summary, the Meade LT SC Series, LT ACF Series, and LT Series deliver exceptional optical performance and user-friendly features, making them suitable for a wide range of astronomy enthusiasts. Whether you are a seasoned astrophotographer or a novice sky-watcher, Meade's telescopes provide the technology and capabilities needed to explore the universe.

Meade LT Series, LT SC Series, LT ACF Series Appendix D, ACF and SC Optical Systems

Models: LT Series LT ACF Series LT SC Series