Askar FRA 400 mm - f/5.6 Quintuplet - Petzval APO Astrograph
- Quintuplet Petzval Lens Astrograph
- 400 mm Focal Length
- 72 mm Aperture; f/5.6
- Full-frame 44 mm Image Circle
- Generous 140 mm Back Focus
- With 2" and 1.25" diagonal/eyepiece for visual use
- 3" Big Focuser with microfine adjuster control
- 360° Rotator mechanism included
- M68x1 - M48 Adapter Included - Fits most cameras
- Multi-Function Tube Rings - Use with accessories
This newly designed Astrograph from Askar, the FRA400/5.6 is a refractive system designed for flat-field astro-imaging applications. The FRA designation stands for "Flatfield Refractive Astrograph". While this optical system can also be used for fine, highest quality APO visual observations with your own star diagonal and eyepieces, it really shines when used with your own camera for astrophotography purposes. It provides a super flat field image with versatile high-quality APO images of celestial objects.
This excellent and amazing design of Askar's first FRA series product is a quintuplet Petzval-like telescope with a 400 mm focal length, f/5.6 and 72 mm aperture, including two special ED glasses which have been used. A 44 mm full frame image circle is supported. The Askar FRA 400 mm - f/5.6 Quintuplet - Petzval APO Astrograph (telescope) tube, with its push-fit dew shield, and a 3" large rack-and-pinion focuser for microdriving adjustment in astrophotography and observation with a 360° rotator and 2" adapter ring and 1.25" eyepiece adapter with M68x1 thread provides features for a variety of applications.
It’s optical design is excellent in controlling and possibly avoiding chromatic aberrations, the image quality is also optimized to satisfy the a wide array of customers requirements for visual and photographic applications. Full APO image quality is assured for either visual observing or for astro-imaging use.
FRA 400/5.6 has a pair of patented multifunctional attachment tube rings. Besides being stylish and beautiful, the FRA shows well-conceived design and the rings provide a practical three-sided mounting platform, which is convenient for attaching various accessories for photography. Includes rotatable 3” rack-and-pinion focuser, M68-M48 adapter, 2” adapter ring, and 1.25”-2” adapter mounting rings, Vixen-style dovetail, and carrying handle.
A focal ratio of f/5.6 is relatively ‘fast’ for visual telescope or astrophotography purposes, however, in order to meet the needs of pro-level astronomers, Askar has specially designed an optional ultra-short f/3.9 focal reducer for the FRA400/5.6 which allows you to achieve an optically faster F3.9 focal ratio to reduce the exposure time. Full frame is also supported when the reducer is added, which is very rare for refractor telescopes.
This Askar FRA 400/5.6 APO Astrograph has a back focus of 140 mm, no need to calculate the distance, when attaching your photographic equipment, so you will conveniently see an in-focus image. Being stocky. robust, and portable in its mechanical design, this Askar FRA 400/5.6 Astrograph can combine with various accessories you have, to accommodate numerous tasks. It also is very simple to use, and you will discover that this is an effective and very versatile photo/visual companion for your astronomy needs.
|Mfr. SKU #:||FRA400-5.6|
|Function:||Astrograph; Petzval Quintuplet Lens|
|Prime Use For:||Astro-imaging, Astrophotography|
|Focal Length:||400 mm|
|Objective:||Quintuplet, Dual ED Air-spaced APO|
|Image Circle:||44 mm|
|Back Focus:||140 mm (from end of rotator thread)|
|Rotator Included:||Yes, Rotator Built-in|
|OAL Length:||317 mm (12.48 inches)|
|Weight:||2.56 kg (5.64 lb)|
|Options Weight:||2.88 kg|
|Back Adapter:||M68x1 Male thread, 2"/1.25" Adapter|
|Accessories:||Pair of Tube Rings w/Handle, a Dovetail Plate, an Inspection List from factory, User Manual|