SV245 Eyepiece Prototype Testing: Insights from a German Customer Review

SVBONY has been providing high-quality astronomical equipment, and the SV245 zoom eyepiece is no exception. After thorough testing, a German customer Bogdan shared their detailed review, offering valuable insights into the product's design, optics and overall usability. Here's a breakdown of the key takeaways from their evaluation.

Hardware Evaluation: Design & Features

Are the product appearance dimensions satisfactory, especially the outer diameter of the eyepiece

• It looks and feels very well made
  Size makes it look premium
  It's on the bigger side as eyepiece sizes go, but this isn't a problem at all
  Two of the SV245 can be used in a binoviewing configuration without a problem

Is the 1.25-inch & 2-inch dual interface design necessary?

• The only benefit of the 2'' interface is the reduced backfocus requirement when using the SV245 in combination with a Newtonian Reflector. This is because the 1.25'' focuser adapter isn't necessary and a precious few millimeters can be saved.
  Also maybe think of a 2'' to T2 etc. adapter for attaching the SV245 eyepiece directly to the telescope or diagonal. This will save up a few more Millimeters of focus.
  

Filter Mounting Thread

Keeping the filter mounting thread for both 1.25-inch and 2-inch interfaces is justified, particularly for the added convenience it offers when using filters.

Is there still market demand for the M43 camera photography interface?

Yes, as there are still astronomers out there who are pairing their eyepiece directly with the DSLR.

Is it necessary to keep the support for diopter installation?

Yes, definitely. Since the target demographic is older, a lot of the hobby astronomers are fighting with astigmatism and since you can't always wear your glasses, a lot of them use a diopter.

How is the feel of the positioning bead design? 

The design feels good and works well
If you can apply more lubrication to the mechanism, then do it. It could be smoother.
Having a step for each focal length is such a great and helpful feature. This is important as you operate the eyepiece in the dark where it is very hard to read the labeling. Habing haptic and acoustic feedback you can simply count the steps without having to look at the eyepiece.

Optical Performance

63-Degree Constant Field of View

Optical tests showed that the AFOV is constant from 8 to 16mm of focal length

Parfocal Performance

Optical tests showed that the SV245 parfocal eyepiece  is to 90%-95% parfocal

Field of View Flattening

It's not perfectly flat, but close enough to call it a flat field eyepiece

Recommended Equipment

Works well with Refractors and Newtonian Reflectors
Should work well with binoviewing

Comparisons to Other Eyepieces

SV230 Eyepiece

Comparable image quality
Slightly better viewing comfort - less kidney beaning
The thicker rubber ring around the waist of the eyepiece feels better than on the SV230
The parfocal aspect of the SV245 is slightly better than on the SV230
Size and weight similar

Combination and application scenarios

What combination is recommended

MK105/MK127 OTA + SV245 zoom eyepiece for visual planetary observations
SV245 zoom eyepiece  + SV216 Barlow Lens for wide range focal length options covering medium and high power observation scenarios

Recommended Usage Scenarios

Planets and the Moon
Longest focal length setting is too long for DSO observations

Conclusion

The SV245 parfocal eyepiece has proven to be a highly capable and well-rounded option for astronomers, offering excellent optical performance, a comfortable user experience, and versatile compatibility with various telescopes. Whether you're observing planets, the Moon, this clickstop eyepiece shows promise in both design and function. 

Stay tuned for this exciting new product from SVBONY!