Vixen SLV reassurance

[spike95609]

I bought a 6mm Vixen SLV recently for use in my 250px dob. The reasoning behind this was for a top quality be all and maybe end all planetary EP. I gave it a first light very late on yesterday, I'd been out all evening and missed what I believe were much better skies. A few clouds were starting to appear and within an hour or so it had blanketed over. So I had a look at Jupiter and I think what I saw was a lot of atmospheric turbulence as it kept on drifting in and out of focus, edges becoming blurred and then reasonably sharp for a fleeting moment, equatorial belts appearing and then vanishing. I switched to Mizar and could not get it in sharp focus at all. I don't think it's a collimation issue as it all looks good enough to my novice eyes, my 38x and 80x TV Plossls are fine, and on previous sessions the much derided 10mm Super MA that came with the scope was surprisingly sharp and clear at 120x. So I suspect this was a case of poor seeing rather than any problems with the EP. But I am wondering, have I gone for too much magnification here? It gives 200x in my scope, should I have gone for something around 130-150 for those nights where the sky is not brilliant - i.e. more often than not. I'm sure it will perform much better when the conditions allow, but I'm just looking for some reassurance that I've not gone and spent £109 on something that's not much use. It's a stunning looking EP though, solid and very well made.

Thanks,

Mark

[John]

I used a Vixen SLV 6mm with my 12" dob on Jupiter last night. Normally it's a superb combination but last night it was too much power (265x). I found 8mm / 9mm eyepieces did a more acceptable job on Jupiter last night, ie: sub-200x.

The Jetstream is causing some rather poor and unsteady seeing conditons at the moment which can humble the best equipment. My 6mm Ethos had just the same problems as the Vixen SLV did

On a decent night or better I reckon 200x would be quite within the capabilities of your scope. I'm assuming that the collimation is in reasonably good shape here.

It's amazing how we start doubting equipment which has otherwise proved fine, when the seeing conditions are the real culprit !

[Moonshane]

What you describe is spot on for medium-poor seeing in the uk. Try it on a different night or even a few minutes later sometimes and it is different again.

[spaceboy]

I actually found last nights observing to be above average for my location which allowed me to see features usually missed. That said I rarely go above x200 on anything other than the moon. I find observing Jupiter at x171 to give best results 75% of the time.

[jabeoo1]

Last nights Jupiter for me was very poor, difficult to focus, smudged limb (the worse I have ever seen) & to wrap it up very low surface detail.  Very difficult on such a bright object.  The orion nebula was superb however  

Try the E.P again another time Mark, it will deliver when its allowed to for sure.

[spike95609]

Thanks to all for the replies, they are reassuring! I suspected it was the atmosphere but it was somewhat disconcerting to see this mess when it's a new EP at a magnification that's way beyond what I've seen before. I'll keep trying it until everything settles down, and if necessary get something a little lower powered to help out when it's this bad.

[RikM]

I have the same telescope and use 7mm and 5mm eyepieces for high power. Your 6mm will be fine for the 250px when conditions allow. Sometimes I have to drop to 10mm, on (rare) very good nights I can use 3.5mm. It is nice to have a range of higher power EP's available.

I would probably try to add a 9 or 10mm in between your new 6mm and your 15mm.

[spike95609]

Thanks again. 9 or 10mm sounds good, I had anticipated having to plug that gap at some point. My plan with the current 32, 15 and 6mm EPs was that this establishes a start, middle and end to the range, with some room to maybe throw a 20mm in on the low power end and a couple of gaps around 8-9 and 10-12 at the higher end. I'll be good to my wallet though and persevere with what I've got for the moment until I've had enough experience with them to know what I need.

[Paul73]

Mark

I have the same scope / eyepiece combo.

As mentioned by previous posters. Amosphere is the killer here. The higher the magnification the more apparent the atmospheric become. In good seeing the glimpses become longer. Practice is the key. I was a bit disappointed when I first got it but my mind is now much better at mentally building a picture from the steady moments.

I have the 5mm version as well which is saved for the best seeing. Some nights 8mm seems like too much.

Also, it is a very very good Planetary Nebula eyepiece. This bright little beauties really start to show some detail in the 6mm.

Paul

[AndyWB]

I'm just looking for some reassurance that I've not gone and spent £109 on something that's not much use. It's a stunning looking EP though, solid and very well made.

Thanks,

Mark

You've not. I've the same scope; it's my primary planetary eyepiece. That said, sometimes x200 is too much; then I'll normally try x150 (and I've had a night or two when that was too much too). And rarely, x240 works too (Those are 8 and 5 mm respectively.)

[spike95609]

Thanks both. I'll be giving it another go as soon as the clouds go away, I might be able to sneak a look at Mercury and Venus this evening, but it's looking hopeless for the rest of the week. Oh and just in case my posts in this thread come across a bit disappointed, I should just say I'm not because the 250px is blumming fantastic! Even with the stock EPs, EVEN the 10mm, I've been very pleasantly surprised.

[John]

Don't be surprised if Venus and Mercury look a bit of a mess with the scope at high power. With their position (especially Mercury) being generally close to the horizon when we observe them, we are peering though lots of unsteady atmosphere which adds all sorts of unwanted "stuff" to the image including what looks like chromatic abberration.

[MattJenko]

I also have this combination, the 250px and the SLV 6mm. I also tried it out on Jupiter last night. It was one of the best views of it I have seen and that was with a frozen secondary and swimming seeing. The view was very intermittent though, and my claim of it being the best was those fleeting moments where everything settled for that split second or two. A 10mm (non SLV) provided more stable views.

[John]

I also have this combination, the 250px and the SLV 6mm. I also tried it out on Jupiter last night. It was one of the best views of it I have seen and that was with a frozen secondary and swimming seeing. The view was very intermittent though, and my claim of it being the best was those fleeting moments where everything settled for that split second or two. A 10mm (non SLV) provided more stable views.

Thats a good description of how it often is

Those little moments show what our equipment can really do. Occasionally a rare night comes along when the moments become long passeges of time but these are rather infrequent

Meanwhile we observe for the fleeting moments.

[spike95609]

Yes I would expect Venus and Mercury to be somewhat messy that low on the horizon, I saw them in binoculars last week and it gave the beginnings of that impression. But tonight I'm afraid dense cloud cover is doing more than the atmosphere ever could to prevent my seeing them! A slight possibility of a window late tonight though. For Jupiter that is. I'll need a very impressive eyepiece to see Mercury and Venus at midnight.

[russ.will]

Thats a good description of how it often is

Those little moments show what our equipment can really do. Occasionally a rare night comes along when the moments become long passeges of time but these are rather infrequent

Meanwhile we observe for the fleeting moments.

Quite. I can recall one night in my year with the 300p and a couple of nights with the ES305 when conditions and location conspired to give stable 300x views.

That's three nights in two years. It's the memory of those nights that keeps me out under the stars, ever hopeful....

Russell

[jkwhinfrey]

Unfortunately last night wasn't one of those nights... at least not for me. The cloud was bad enough, but the Seeing was pretty poor too. Oh well, as Russell pointed out, perhaps next time.

I've got a 9mm SLV and I like it in my 102mm F11 or in my 150PDS where I prefer it to my wide angle EPs. Last night was the first time I've pointed it in the direction of Jupiter, so not a fair test considering the conditions. Used to view the Moon it's excellent.

James

[spike95609]

Just wanted to post an update on the SLV, which has taken me such a long time to do because the weather in January has been dreadful. Even last night, which was supposed to be clear throughout, I was having to dodge clouds constantly. The seeing, however, was much better, and the SLV gave a very sharp view of Jupiter this time. No fading in or out, but the two main belts were there all the time and hints of quite a lot of others were coming and going. I can see what people mean about spending time at the eyepiece to get the most out of it - which wasn't an issue for me as I was enjoying the view so much there was nowhere else I was going to go. I declare myself satisfied! I still might get an EP somewhere in the 8-11mm range to fill the gap, but I'll get to know my current ones more before deciding on that.