ASKAR REFRACTOR SQA106 PETZVAL

ASKAR REFRACTOR SQA106 PETZVAL

SQA serie - SQA106

AIR SPACED SD GLASS QUINTUPLET PETZVAL ASTROGRAPH

EXCELLENT STAR POINT QUALITY

Quintuplet air spaced optical design including two SD glass elements.
The SQA106 supports a 55 mm image circle.
The central star point has an RMS radius under 1.7 µm, and the star point at 55 mm is below 2.2 µm, demonstrating extremely fine stellar rendering.
It also provides excellent full field illumination and strong MTF performance.
Relative illumination can exceed 90 percent at a 44 mm image circle.

PETZVAL STRUCTURE

Integrated self flattened design requiring no extra field flattener and no additional back focus calculation.
With a connection distance between 48 mm and 78 mm, users can directly shoot once the OTA is focused.

RETRACTABLE DEW SHIELD

The dew shield uses a retractable structure that can be extended when needed.
It protects the lens from external and internal light impacts, as well as the optics themselves.

INTEGRATED TUBE RING

Large hand screws allow opening and closing of the ring without extra tools.

There are six M4 and M6 threaded holes on each side of the ring, convenient for installing a base, dovetail plate, or attaching various accessories.
A second OTA can even be mounted for imaging.

Integrated ring pair with a hollow center to reduce total weight.

The top mounted handle includes a slotted multifunction finder base, allowing installation of astronomical accessories.

FINDER BASES

On both sides of the focuser there are two finder bases.
They eliminate the need to remove equipment when repositioning the finder scope and provide additional mounting positions for other accessories.

DOVETAIL PLATE

The standard three hundred millimeter Losmandy format dovetail plate is easy to install and remove.

DIVERSIFIED PHOTOGRAPHIC APPLICATIONS

In addition to connection with an astronomical camera for astrophotography, the SQA106 can also be connected to mirrorless or DSLR cameras for general photography.

LARGE RIGID DUAL SPEED FOCUSER

Rigid dual speed rack and pinion focuser with a two point eight inch mechanism, compatible with most motorized focusers on the market.
Focusing travel is thirty millimeters, and the focuser tube features high precision engraved scales.
The entire focuser body is CNC machined with anti reflective internal structure and matte coating, providing extra suppression of stray light.

REAR ADAPTERS

The rear section of the SQA106 is equipped with multiple adapters, all toothed and ribbed for easy manual rotation without slipping.
Adapters are available in M sixty eight, M fifty four, and M forty eight formats and can be used to attach various accessories such as full frame cameras.

THREE HUNDRED SIXTY DEGREE ENLARGED ROTATOR

The rear of the focuser includes a high precision three hundred sixty degree rotator with an engraved scale for adjusting and saving rotation angles.
It is also equipped with a large locking screw ensuring easy locking even under high load.

OPTICAL PATH

The SQA106 uses a quintuplet air spaced lens design including two SD glass elements.

MTF CHART

The modulation transfer function is a quantitative measure of image sharpness, including resolution and contrast.
The vertical axis represents MTF value and the horizontal axis shows distance from image center to edge.

For both low and high frequency curves, even at the edge of the 55 mm image field, the spacing between sagittal and meridional plots remains very small.

At ten line pairs per millimeter, values stay above zero point nine, demonstrating excellent resolution and sharpness of the SQA106.

RELATIVE ILLUMINATION

Relative illumination represents the combined effect of light loss and corner attenuation.
The RI curve illustrates percentage illumination across the sensor.

Illumination variations can affect image performance.
The vertical axis shows illumination percentage, and the horizontal axis represents distance from image center to edge.

The SQA106 provides illumination above ninety percent at forty four millimeters, and above seventy five percent at fifty five millimeters, minimizing vignetting.

SPOT DIAGRAM

Image quality can be evaluated by analyzing the distribution of spots on the spot diagram.

The SQA106 provides a central star point RMS under one point sixty five microns and a corner spot below two point two microns, showing excellent star sharpness.

ZYGO OBJECTIVE CHART

The ZYGO interferometer is globally recognized as a reference instrument for testing optical quality.
Testing results for the SQA106 demonstrate excellent stellar performance.

ZYGO OBJECTIVE CHART

The ZYGO interferometer is internationally recognized as a reference instrument for testing optical quality.
The SQA106 test results demonstrate outstanding stellar performance.