Short Review of SvBONY 10-30mm zoom eyepiece

[Mark at Beaufort]

There has been a discussion elsewhere on the forum about SvBONY zoom eyepieces. I knew nothing about these zooms until a few days ago and was particularly interested in the 10-30mm zoom mainly to use on outreach work. I have had problems in the past when one of my the eyepieces has been covered in mascara eye make up and nearly ruined a Nagler EP.

So I ordered the 10-30mm zoom via Ebay and it arrived very quickly for the cost of £45.99 + free postage.

The eyepiece appears well made with its 1.25" design and has a thread for filters. Its appears well blacked and has a twist up eyecup with stated eye relief of 17mm-18.5mm. The FOV is 33 degree at the 30mm setting going to 51 degrees at 10mm. Total weight is 198g.

So how does it perform. I started using the zoom on the Heritage 130P (f/5) with the 2.25x baader barlow giving a zoom of 4.4 to 13.3. I looked at Jupiter (some bands visible), Saturn (no Cassini Division visible) but Titan was easily seen and Mars (South Polar Cap visible plus some surface markings). Without the Barlow the edges were going soft at the about 20% from the edge otherwise the views were okay.

Decided to take in some DSOs and had reasonable views of M13, M57, M27, The Veil (both these with TeleVue Nebustar filter), M2, M15, M31, NGC 7790, M33, Double Cluster and finally Almach (nicely split)

I did not cross check against other EPs because I wanted to use the PST Ha and test it against the TeleVue 8-24 zoom plus the Baader Classic 10mm Ortho.

This morning the Sun obliged for a while so I set both zooms at the 10mm setting + the Baader Ortho. Three nice Proms visible + a small filament + a bit of Plage. The result they all gave the same. The Proms were sharp so I cannot complain about the view of the SvBony.

Clearly the downside of the SvBony is the 33 degrees at the 30mm setting but overall its okay and will make a useful addition on the Heritage 130P which I use away from home - holidays etc. I know it will be said that you get what you pay for but at the moment it provides a reasonable observation view on a f/5 scope.