Mr Spock

OK, CO is saying 100% cloud. I'm looking out of the window and seeing 0% cloud... If it holds I'll get some doubles in. Sat shows a band of cloud coming across but nothing the other side of it.

This eyepiece is popular. It's the best thing since sliced bread But let's be honest, you can't see much with sliced bread...

I want to know who the 1% is so I can eliminate them

Eat my shorts losers 🤣

nerd /nəːd/ INFORMAL noun 1. a person who is extremely enthusiastic and knowledgeable about a particular subject, especially one of specialist or niche interest. 2. someone who is more intelligent and knowledgeable than you... verb engage in or discuss a technical field obsessively or with great attention to detail.

Yes. It will be nice to do a comparison on Jupiter especially. Some of the fine detail in the belts is a good test for any eyepiece.

Fluorescent orange. You can see it in the dark and it won't spoil your night vision

We've been to the moon, why can't we go to the sun? We can go at night when its dark.

My review of this eyepiece was conducted over several nights using a StellaLyra 12” Dobsonian, and a Takahashi FC-100. Each focal length was compared to a number of eyepieces of similar focal length on both double stars and the moon. Seeing on each night was very good to excellent. As usual for my location transparency was poor due to light pollution. This eyepiece rates very highly with a lot of observers. At the current price (I paid £81 for mine) it is extremely good value for money. It is interesting to compare this zoom with fixed focal length eyepieces costing many times more each. The eyepiece itself appears well built with an excellent build quality for the price. It has an undercut on the barrel which isn’t too severe and shouldn’t cause problems with twist grips. In action the zoom movement is quite stiff. The top part of the eyepiece remains in the same position but moves outwards when zooming in. The zoom twist grip itself has a knurled appearance and is quite easy to grip. Due to the stiff action I tend to hold the top part of the eyepiece while twisting the zoom grip. Although nominally a zoom which goes from 8mm to 3mm in 1mm click stops, it does measure quite differently. The stops are actually at 8.1mm, 7mm, 6mm, 5.2mm, 4.4mm, 3.5mm. The field of view is close to 58° throughout the range. Eye relief can get quite tight towards 3mm, and I had to observe with the eyecup folded down. Not an eyepiece I’d recommend for those who need to wear glasses. Double Stars This was mainly conducted with the FC-100 as despite the decent seeing the 12” wasn’t really showing clean airy disks in any eyepiece. At all settings the eyepiece presented clean looking airy disks in the FC-100. There wasn’t really any noticeable difference between this eyepiece and any of my others. The eyepiece was close to par focal at all focal length with just minor tweaks needed towards the short end. Highly recommended for double stars. For the FC-100 that would mean for me just three eyepieces: the 42mm LVW for a finder, the 17mm LVW for a wide view, then the 8-3 for splitting. Perfect! The Moon I’ll concentrate on the 12” first as this is where a few problems started to appear. 8mm: the centre of the image was sharp but not quite up to the 8mm LVW but very similar to the 7mm (which measures 8mm) Nirvana. Unlike the Svbony, however, the 7mm Nirvana was sharp to the edge; the Svbony showing very marked field curvature. You could re-focus the edge, so that confirms it is field curvature. Very poor. 7mm: Compared to the 7mm Circle-T Orthoscopic the view was very similar. The 43° view of the ortho matched the in-focus area of the Svbony. The ortho lost out due to light scatter from its non-existent coatings. The Svbony seemed quite well controlled in this respect throughout its range. Again, very poor field curvature. 6mm: Compared to the 6mm SLV it was again close with the SLV just a touch sharper. It’s not something you would notice unless viewing side by side. Compared to the 6mm Circle-T orthoscopic it was very similar in most ways. 5mm: Compared to the 5mm LVW the LVW had a more relaxed view though I’ve found with the 12” this eyepiece needs accurate eye positioning. The Svbony felt quite comfortable as far as eye relief was concerned and overall, the performance was quite similar. 4mm: Compared to the 4mm Nirvana, 4mm Circle-T Orthoscopic and 4mm TOE. This was no contest with the TOE showing much finer detail than the others. At over £300 each I’d have been a bit disappointed if the TOE had failed here! The Svbony’s field curvature wasn’t so pronounced at this focal length and just about acceptable. The 4mm Nirvana, as with the 7mm, was sharp to the edge. For eye relief the 4mm Ortho was actually easier to look through than the Svbony, though this ortho has more ‘haze’ from scatter than the other eyepieces used. 3mm: or more correctly, 3.5mm. Compared here to the 3.5mm LVW and 3.3mm TOE. Eye relief in the Svbony was so tight I rolled the eyecup down. As before central definition of the Svbony was excellent and just a touch behind the TOE and LVW. As with the 5mm, the 3.5mm LVW suffers critical eye positioning and blackouts are frequent and annoying. Using the same set of eyepieces, the FC-100 is up next. 8mm: The field curvature seen in the 12” was not evident here. There was just a bit of falling away on the outer edge. Definition was quite pleasing with good contrast and detail. The 8mm LVW was just a touch crisper and the 7mm Nirvana similar. 7mm: The Svbony was preferred to the ortho due to the lack of scatter. The orthos are much better on planets like Jupiter where there isn’t that extreme brightness. 6mm. Very little field curvature and a very similar performance to the 6mm SLV. 5mm. No blackouts from the LVW at this focal length so it won this contest. The margin was very small though with the Svbony exhibiting excellent sharpness. 4mm: No surprise the TOE was ahead here. In particular the way it showed Gassendi N and the rille next to it. It was just so much cleaner and crisper than the Svbony or the Nirvana. 3mm: Same result as above v the TOE. However, without the blackout issues of the 12”, the 3.5mm LVW moved ahead here. The view was just so much more relaxed than either of the other two. Especially compared to the tight eye relief of the Svbony. I spent the rest of the night (several hours) enjoying the moon though the 3.5mm LVW. Going back to Gassendi N, it was very sharp with a finely etched rille close by, in both the TOE and LVW; the Svbony was just a little less distinct, but certainly not a lot in it. Verdict. What’s not to like about an eyepiece with this level of almost high-end performance across a decent range of 8.1mm to 3.5mm and at just £81. My recommendation? At this price v performance everyone (except glasses wearers) should have one. Just be wary of potential field curvature in some scopes. Overall, though, it really is the bargain of the century!

Absolutely. There's no logic in allowing the scope to cool then heating it up again! If you use a dew heater, turn it on to get rid of dew then turn it off again. Or use a hair dryer.

Sharp edge to edge.

That isn't the finding of people who are using it. I find it just a little behind the 3.3mm TOE at the 3mm (3.5mm) setting.

Yes, that's the effect. Try focusing the edge and see what happens.

I always wanted a Chromacor for it. It's a fine, well corrected, scope. Pretty good on doubles with minimal CA. Very noticeable on planets though. The continuum is such a narrow band it removes all of that and just leaves a clean, sharp image. It's one of the original Helios scopes - can't remember how long I've had it.

I would add to that - my 120mm achro with continuum filter is incredibly sharp on the sun. Knocks the spots (groan) off the 4" by a considerable margin. I don't really fancy a reflector with solar film, I don't believe its going to be sharp enough.

Hmm, my 30mm UFF is flat in both the refractor and reflector. The Svbony is flat (almost) in the refractor but curved in the reflector. Same goes for my LVWs, Nirvanas (except 16mm) and TOEs - they are flat in both. Perhaps a topic for another thread as this one is just about the Svbony.

The 125 SL is fast gaining a reputation as a good scope. Plus it's no where near the size and bulk of a 130 despite only being 5mm different. I wouldn't mind one myself (inner me say no - you have too many already lol).

Seeing the pup is all about seeing conditions. If you can get Sirius as an airy disk without fuzziness or twinkling then your chances of seeing the pup increase. I find smaller scopes better as Sirius is too bright in larger ones and more prone to fuzziness. My best views have been with the 100mm.

Terrific lunar session last night. I was at it for hours. Stopped half way to take in a few doubles. Views through the 3.5mm LVW were magical - x211.

Don't forget your mirror is probably 203mm

About that. What you would do is measure from the edge of the secondary to the edge of the mirror. Or just subtract half the secondary size from half the mirror size. It works much better if next to the mirror due to diffraction.

Here's how it works: With a 300mm scope you should be able to get around 125mm without obstruction. So around f12 and completely CA free.

We'll let you be the guinea pig Let us know what you find.

Yes - the one on the left has 'retired'.

The variable polariser I use is the Astro Essentials from FLO. Not that expensive. I have a 2" and 1.25" OIII - I sold my UHC. None work that well in my light pollution.