Review of the Svbony 15mm 70 degree 'Red' EP (SV154)

[Nik271]

Svbony recenty updated their 15mm EP. The old model (red line 68 degree Fov)  was definitely the weakest of their  'red' line up and in July I decided to try this new EP.

It's labelled SV154 and claims to be FMC and 70 degree FoV. It retails at about £45-50 pounds on ebay and amazon, so not so cheap, but still in the budget price band for eyepieces.

Mine arrived very quickly in a small box containg the EP, caps on both ends and a cleaning cloth. It is well made, all metal with rubberized twist-up eye cups. Here are some photos:

The front and back lens elements are certainly coated, and I haven't taken it apart to check the inner elements. (Svbony lists this EP has 5 lenses in 4 groups.)

The eye relief is a bit short at 13mm. I found that when I  use it with glasses I cannot see to edge of the field stop.

When I remove my glasses I get the full view to the field stop and with testing on the sun and terrestrial objects I can confirm that the field of view is indeed 70 degrees.

I have used this with my Maks, which at F/12 and F/15 are not really a challenge for most EPs. Views of the moon, planets and double stars are indeed very good, sharp across 85% of the field. This is notable improvement on the old red 15mm. The light scatter/ghosting seems well controlled, I had no issue even with a full moon. There is no kidney bean effect  at all (unlike the 9mm and 6mm models).

Overall I'm very happy with this new EP. My only criticism is the eye relief as I tend to observe with glasses and all my other EPs allow me to use them.

On the other hand the eye cup is an improvement on the flimsy rubber guards of the older model, and it does shield the external light quite well, even in sunshine when I look at the sun.

Would I buy this again? Yes. At this price I would not call it a great bargain but it's good value for money.

 

Nik

 

[McQ]

Thanks for the review, not many of this eyepiece. Any updated thoughts since September?

[Nik271]

I did a comparison of SV154 against the 12mm BST Starguider on Jupiter one night (in a F/12 Mak). They were very similar in the centre, very little light scatter from both.

At the edges the BST was sharper, considering its FOV is 60 degrees vs Svbony's 70 I think it's to be expected.  The eye relief of the BST was much more comforable with the larger and deeper eyecup which is a big plus for it.

I also note that in cold weather the front lens element mists up easily because of the proximity of my eye to the lens. 

I'm planning to test it on my F/5 Newtonian to see how it performs with a fast scope. I'm going to take it out the next clear night for some open clusters views and report.

[cajen2]

15 hours ago, Nik271 said:

 

I'm planning to test it on my F/5 Newtonian to see how it performs with a fast scope. I'm going to take it out the next clear night for some open clusters views and report.

I shall be VERY interested in your opinion of it in the newt. Mine is also an f/5 and I'm in the market for new EPs.

Edited November 8, 2021 by cajen2

[Nik271]

7 hours ago, cajen2 said:

I shall be VERY interested in your opinion of it in the newt. Mine is also an f/5 and I'm in the market for new EPs.

The weather is not very promising in the next few days unfortunately. The next clear sky is forecast for the weekend. It's a good season for the Cassiopeia open clusters and this is what I'm planning to test it on.

[Nik271]

There was a lucky break in the cloud cover last evening and I managed to test it with a 6 inch  F/5 Newtonian on many targets.

At F5 and 750mm focal length the EP is giving x50 magnification, 1.4 degree real field of view  and 3mm exit pupil, which is very suitable for DSOs.

The full report is linked below, here is my verdict.

I found the performance to be so-so. I estimate at F5 it is sharp only in the central 50% of the field, outside it the stars become increasingly comet like.

There is nothing surpising about coma, I was fully expecting it, but my BST starguiders did seem better at the edges and the views were somehow more satisfactory.

This is a personal thing I guess. Smaller star clusters which can fit in the sharp central part looked great. The large ones like the Double Cluster were disappointing to me since always one part of it was slightly out of focus. Having said that the views of some double stars like Almach and Achird were quite nice.

If you are thinking of widefield  views and have a fast scope my advice is: get a 32mm Plossl or save up for some quality glass from expensive brands.

Here is the full report:

 

 

Edited November 12, 2021 by Nik271

[cajen2]

Thanks for that, Nik. I've just bought the 6mm Svbony, as I wanted a relatively cheap way of assessing a short FL EP on my 6" dob. I'm not expecting miracles at that price. Of course, since it arrived, the clouds have been at 10/10ths.

[McQ]

Thanks for the update. These were 20% off a few days ago and I was kicking myself for not buying one but maybe it was a blessing in disguise. For now I'll stick with a 32mm plossl + 2x Barlow.