Vixen SLV 4mm (v) SW Planetary 4mm.

[Geoff Barnes]

This was a subject that has been bugging me for quite a while, are top class eyepieces better on axis than decent cheaper alternatives?

Well the proof of the pudding is in the eating so they say, so armed with my new Vixen SLV 4mm which arrived courtesy of FLO on Thursday and  a wonderfully clear sky with which to do some side by side comparisons, out with the 12 inch SW Dob in tracking mode and let battle commence!

I only had two targets in mind to do the comparisons, Jupiter and Saturn, both very high in the sky and at or near opposition, so about as good as it gets for viewing.

First in with the SW Planetary as I have used this a lot recently and been so impressed with its performance, especially on Saturn which takes higher magnification than Jupiter - 4mm in the 4.9mm FL Dob giving 375x.

Jupiter at 74 degrees altitude was large and bright and the GRS was in the centre of the planet. I find 375x just a bit too much on Jupiter with surface features becoming slightly less sharp and contrasty than at say 300x. There was however great detail visible in the better more stable periods of seeing, all the main bands and belts both tropical and temperate, two big festoons digging deep into the equatorial zone, both with a distinct purplish brown hue. A couple of very dark barges embedded in the north tropical belt and one very bright oval. The GRS a vibrant orange and the faintest hint of the darker spot in its centre.

Okay, that was quite impressive with the Skywatcher Planetary, now the moment of truth, in with the shiny new SLV. First surprise, almost parfocal just a tiny tweek needed and concentrate.....hmmm, looks exactly the same. Study all those main features again, could I see any difference? No I couldn't, not at all. Okay, back in with the SW, study hard on all the features, let the seeing settle to its best, give it a good 15 minutes or so to soak it all in and then quick swap back to the SLV, and concentrate...… nope, just the same. Swap back and forth several more times, still no difference.

A bit puzzling, time to try both EP's on Saturn at 65 degrees altitude.

Start with the SW Planetary which I knew gave me incredible sharp views of Saturn a week or two back. First impression at 375x is how much sharper Saturn is at this magnification than Jupiter, really tack sharp and clear. Cassini sharp and jet black, the C Ring as good as I've seen it, easily visible against the black gap between it and the disc. The Encke Division clearly there as a darker band. The B Ring showing subtle variations in brightness. Northern Equatorial and Tropical Belt a faint purple/grey tone against the white Equatorial Zone. A pale bluish tint to the North Polar Region, all in all a sublime view!

Okay in with the SLV, this is where I expected to see it show its class, and...… again it all looked exactly the same, all the amazing sharpness and clarity was there, but not any more detail at all than the SW. Again swap back and forth time and time again, waiting for stablest seeing and finally had to accept there was absolutely no difference in the views between the two. 

Now I was only seeing both planets perfectly on axis with the tracking Dob, I had no interest in what was going on around the edges ( though the occasional glances here showed a little astigmatism with both), but I have to say I was really wanting the SLV to show an obvious improvement over the cheap SW Planetary and it really didn't in any way at all. The seeing was very good, the Dob was collimated very well (star tests were spot on), and I gave equal time to both EP's over the course of 3 hours.

Conclusion: both EP's give superb sharp contrasty views in great seeing conditions and given the limitations of my 63 year old eyes I could not separate them at all in performance no matter how I tried.

I had a wonderful 3 hours with two of the best sights in all the night sky, who could ask for more?  

Edited July 7, 2019 by Geoff Barnes

[Pig]

Nice report Geoff,

300 X mag for observing Jupiter is very impressive, I find anything above 200 and the view starts to get very soft indeed  😀

[NGC 1502]

 

Hi Geoff, enjoyed your careful comparison of the two eyepieces, and envious of the high elevation of Jupiter and Saturn compared to what we have in the UK right now.

What I’ve found, especially with planetary viewing, is that the state of the atmosphere is the main restriction with seeing a crisp view.  Poor seeing ( turbulence ) makes it a rubbish view even with top EPs,  a steady atmosphere brings out the detail and cheaper EPs can perform surprisingly well especially in the centre of field of view.  Off axis of course can be a lot worse.

Best regards from the northern hemisphere, Ed.

[laudropb]

Very nice report Geoff. I have recently compared the performance of both these eps in my SW 72 Ed scope for observing doubles. I found that the Vixen gave slightly sharper views, but there was not much in it. Where the Vixen performed better was in colour rendition. Colour differences  were just more noticeable. Having said that, the SW 4 mm is still a very nice ep for the price and for anyone on a tight budget can be recommended. It also has the advantage of wider FOV.

[Geoff Barnes]

1 hour ago, Pig said:

Nice report Geoff,

300 X mag for observing Jupiter is very impressive, I find anything above 200 and the view starts to get very soft indeed  😀

Thanks Pig, I certainly wouldn't have wanted to go any higher with the magnification, it was bordering on being too soft but the conditions were so good that it enabled me to see fantastic details. I did try my Morpheus 6.5mm at the end and it was much sharper than either of the 4mm EP's on Jupiter, but gave a much smaller image of course at 230x.

10 minutes ago, NGC 1502 said:

What I’ve found, especially with planetary viewing, is that the state of the atmosphere is the main restriction with seeing a crisp view.  Poor seeing ( turbulence ) makes it a rubbish view even with top EPs,  a steady atmosphere brings out the detail and cheaper EPs can perform surprisingly well especially in the centre of field of view.  Off axis of course can be a lot worse.

Thanks Ed, you're right, the conditions and also the very high elevations were certainly conducive to the best possible seeing.

[chiltonstar]

Very interesting Geoff! It is said that there is a lot of eyepiece snobbery about, and maybe it is true.

I don't have a 4mm SLV, but I do have theVixen 15mm SLV which is now my main EP for Jupiter (x190). What I can say (cpd with an SW EP of similar fl and a BST one) is that the contrast is better in the central region of the field of view, the colours more natural and unlike the BST, it doesn't have an annoying reflection which skips around as the eye moves. It does have an area of CA though around the outer field of view.

I wonder though how much of the benefit with an EP like the Vixen SLV is scope-dependant? Clearly fast scopes need better EPs than very slow ones.

Chris

[Geoff Barnes]

3 minutes ago, laudropb said:

Very nice report Geoff. I have recently compared the performance of both these eps in my SW 72 Ed scope for observing doubles. I found that the Vixen gave slightly sharper views, but there was not much in it. Where the Vixen performed better was in colour rendition. Colour differences  were just more noticeable. Having said that, the SW 4 mm is still a very nice ep for the price and for anyone on a tight budget can be recommended. It also has the advantage of wider FOV.

Thanks laudropb, I can imaging your SW 72 ED would give better views of doubles than my Dob, sharper and cleaner I would imagine. Bright stars through my Dob tend to have a fair bit of fuzziness about them, but colour wise it gives great views.

[Geoff Barnes]

6 minutes ago, chiltonstar said:

Very interesting Geoff! It is said that there is a lot of eyepiece snobbery about, and maybe it is true.

Thanks Chris, not for me to say really, we all see things differently I suppose. 

Based on my findings with these two EP's I've decided to order the SW 5mm Planetary, which should give a sharper view of Jupiter than the 4mm which was on the borderline of being too soft.

Got to make the most of these planets while they're up above my head! 😉

[John]

Very interesting comparison Geoff. I've not used either of the eyepieces concerned so it is useful to have your feedback on them.

When I tested the Vixen SLV's the focal lenghts that I had were 6mm, 12mm and 20mm. I recall comparing the 6mm Vixen to the excellent Baader Genuine Ortho 6mm over several nights on Saturn and being really impressed that the more complex and comfortable Vixen equalled the Baader GO in all respects performance-wise.

I think the SW Planetary eyepieces may well be related to the TMB planetaries. Here is a report from a while back which includes the 4mm that you have tried:

 

[Timebandit]

 

 

I have a 4mm vixen NLV , the forerunner to the SLV. Your findings do not really come as to much of a surprise to me. I tried my 4mm NLV in my dob reflector and I was not that impressed with the results, a bit disappointing really(as this eyepiece was purchased second hand I thought I may of purchased a bit of a dud). But when the 4mm was placed into the SW ED frac I have, it was a completely different story. On planetary and lunar(when the UK seeing conditions allow) then this eyepiece really did perform. Not only was it very comfortable to use. But it had very sharp and detailed views when it came to planetary. I did compare the vixen 4mm to Ortho in the same scope, and it was right up there. So good in fact that it was nearly in the Pentax XW league. I think sometimes the eyepiece result can be a bit scope dependent, what may not be such a good eyepiece in one scope, can come into its own in a different scope.

 

 

[John]

43 minutes ago, Timebandit said:

 

 

..... I think sometimes the eyepiece result can be a bit scope dependent, what may not be such a good eyepiece in one scope, can come into its own in a different scope.

 

 

I agree. Also sometimes target dependant. When I've been comparing eyepieces I've sometimes found that one is better on, say, the moon than another but when I observed Jupiter, the results were the other way around. Not big differences but noticable.

It's a bit extravagant to have a number of eyepieces of one focal length though, eg: this is my lunar 4mm eyepiece and this is my Saturn 4mm, and this my binary star 4mm .... etc, etc

(any old excuse to have a bigger eyepiece collection though !)

[Geoff Barnes]

1 hour ago, Timebandit said:

I think sometimes the eyepiece result can be a bit scope dependent, what may not be such a good eyepiece in one scope, can come into its own in a different scope.

I also agree, I think there is definitely some truth I this. I seem to recall reading a thread on CN about this very subject. There was unanimous agreement it seemed that Televue EP's worked well with any scope, but other makes and types were more inconsistent shall we say.

For me with my 12 inch SW Dob I find my Baader Morpheus and Zoom both work wonderfully well, and yet my ES 4.7mm 82 degree EP I just cannot warm to even though it is a very fine piece, I can't put my finger on exactly why but the views through it just don't feel as nice  as they do with the Baaders.

Again, the views through the SW Planetary and now the new Vixen SLV feel really nice, maybe it is to do with eye relief and large eye lenses as much as anything?

[John]

One further thing I'd say is to give it some time before reaching a decision between eyepieces of similiar spec / performance.

For me, I needed to use them quite extensively over a number of sessions, with different scopes and a range of targets before reaching conclusions. As I'm in the UK this is why it often took me a couple of months to produce comparison reports for the forum - UK weather !

[Geoff Barnes]

7 hours ago, John said:

One further thing I'd say is to give it some time before reaching a decision between eyepieces of similiar spec / performance.

I had actually intended to have several sessions before posting but alas we are in winter here and the weather has turned ugly for the foreseeable future. Rest assured I shall definitely make further reports as and when I am able.

[Paul73]

Thanks for the considered review. A pleasure to read.

How did they compare for comfort of viewing? I have found some pin sharp eyepieces quite tiring over relatively short viewing session. Although, the fact that you managed 2 hours would suggest that both are very comfy to use.

Paul

[Geoff Barnes]

21 minutes ago, Paul73 said:

How did they compare for comfort of viewing? I have found some pin sharp eyepieces quite tiring over relatively short viewing session. Although, the fact that you managed 2 hours would suggest that both are very comfy to use.

Very comfortable Paul, both of them have long eye relief and large eye lenses which enabled me to study without any fatigue at all (apart from cold feet!). And it was a good 3 hour session not 2, to boot!  

Edited July 8, 2019 by Geoff Barnes

[Mark at Beaufort]

Geoff what an excellent report and the review of these two EPs.

I don't currently have a high powered EP so for the cost I might just get one of these SW Planetary EPs. The 4mm in my 12" Dob (FL1520) will be too much for the UK but a 6mm will give a 253x mag.

So thanks for your 'heads up' on the SW Planetary it is certainly worth experimenting before committing to a much more expensive EP.

[Geoff Barnes]

Thanks Mark. I think because of the very high positions of the planets down here they would probably look good through the bottom of a glass milk bottle!  

Without a doubt though the SW Planetary EP's do punch well above their weight for such a low price.