Intro

Usually kit accessories are cheap and have relatively low quality. Sometimes they are totally useless as Barlow Lens x2 that were in my telescope kit.

I suppose, that is pretty common for the most of entry level telescopes.

The explanation of it from manufacturer point of view is obvious: this makes telescope more affordable. Good quality eyepiece price easily reach $50 and more while telescope costs $250 including everything you need to start.

After I spent some time observing stars and planets, I mentioned that field of view of kit eyepieces is small (~1deg for 26mm eyepiece).

Unboxing

Comparison Method

In order to compare eyepieces I choose a region near Andromeda Galaxy and couple of stars there.

I compared following parameters:

True Field of View (bigger is better)

Magnitude limit (bigger is better)

9mm Kit vs 9mm Goldline

Choose the winner between these two eyepieces is was really easy.

FOV Comparison

Goldline eyepiece has (as expected) much wider field of view. Image below is built in assumption that 9mm Kit eyepiece has 52deg aFOV (calculator).

Magnitude Limit

The star TYC 2801-272-1 with magnitude 9.63 was clearly seen with a Goldline eyepiece and not seen with kit eyepiece.

20mm Goldline vs 26mm Kit

The first of all, this comparison is not 100% correct due to different size of exit pupil: 2.6mm for 26mm eyepiece vs 2 for 20mm eyepiece. That means that 26mm eyepiece is brighter.

But since 20mm is the longest focal length for Goldline and 26mm is the closest to it, I compared them.

FOV Comparison

Both eyepieces has approximately the same FOV, that makes me think that 26mm Kit eyepiece has ~52deg aFOV.

Magnitude Limit

Well I spent about one hour switching between two eyepieces trying to find a star that will not be seen, but no success.

Kit eyepiece seems to give a slightly brighter image but it doesn’t add new details.

Other Parameters

Due to the fact that kit eyepiece gives smaller magnification, it seems to be little bit more suitable for observation of objects like galaxies and nebulae, because it concentrates the light on smaller surface.

On the other side because of bigger magnification 20mm eyepiece allows to identify stars easier in accordance to their neighbors.

Also 20mm eyepiece feels more comfortable.

26mm Kit vs 20mm Goldline Summary

Both eyepieces have their pros.

Keeping in mind the fact that 20mm eyepiece has smaller exit pupil, but has no difference in stars that may be seen, I can definitely say that it has better optic quality

So since then usually 20mm is my first choice.