Eyepiece for a Lunt 35

[AndyWB]

I got talked into a Lunt 35 Delux a while back, and while I like the scope, I'm not convinced about the eyepiece it came with.

It's marked as a LS 70 degree SWA - 10mm. When it's in focus, well, it produces pleasing enough images - but it has damn all eye-relief, and it does feel to me like if it's in focus in the centre it's out at the edges, and vice versa (so I don't think it's this sweet spot thing).

To test this I took the eyepiece and used it in my 130p the other night - okay, so remembering that it's going from an f/11 scope to an f/5 one, but I could clearly see that as I adjusted focus I could make a ring of 'in focus image' expand from the centre of the moon out to the edges. It's like that plane the image is being projected onto isn't flat.

Anyway, all this leads me to the question, what would a good alternative? I did try my 5 & 8 mm BSTs, but I felt like I was having problems with things blacking out (this could have been user error), and I don't think the image was as sharp and detailed. However, they did seem to be in focus across the whole field of view.

So, what would people suggest? Give the BSTs more of a try? Or are there good alternatives out there? Eye-relief isn't such a big deal for me - I don't wear glasses - but a little more would be appreciated, especially as I'd like to be able to show the Sun to my friends. I do keep reading about people using zoom eyepieces, too, and that makes me wonder if that's a worthwhile idea? 

[Peter Drew]

I would definitely recommend a zoom eyepiece for solar viewing. I use a Seben 8 - 24 zoom exclusively for this purpose to great effect.     

[Spikey]

I also, almost exclusively use a Baader Hyperion zoom in my LS35 now.

I sometime use a 32mm EP if I've knocked the sol searcher out of line as it can be a pain to set up. 

[NGC 1502]

I've a Lunt 35, the basic version with the B400 blocking filter.  I think a wide angle EP is a bit of a waste, due to the restricted field of the B400,

but maybe more use with the DL version with the B600 blocking filter.

But I too find a zoom EP a great option.  One of the popular 8 - 24 zooms is so useful, at the 20 - 24mm end, nice low power views with excellent contrast with detail on the solar disc,

and up to 8mm for 50x in excellent conditions for prominences. I've tried higher power but think that 50x is the useful max, and most of the time much less, 25 - 35x.

Regards, Ed.

[Pig]

The attached are my findings.

It is based on a different size Lunt scope and Televue eyepieces. However, it may be of some help.

Lunt versus eyepieces.pdf

[michael.h.f.wilkinson]

My solar EPs are the 24 and 20mm MaxVisions (a bit of overkill, but for the price they are going for, who cares), and at the short end the Pentax XF 8.5mm In my case wide angles make a bit more sense because I picked up a B1200 blocking filter for the price of a B600 . I either put a 2x TeleXtender in the bag or the Nagler 12T4, and I find something around 12mm almost always gives the best views. I am considering a Meopta 7.3-14.6mm zoom which with the MaxVisions would be a nice lightweight travel EP set, both for the LS 35 and the 80mm APM.

[101nut]

I now use a Leica ASPH zoom in my Coronado Solarmax 40... that is overkill on the most stupidly impressive scale possible, but marvellous!  

The Baader Hyperion zoom is good as are BST eyepieces, both much more sensible and generally not too tight on eye relief for the average user ... 

I would agree with Michael that around 12mm is the sweet spot.

AndyG

[trazor]

Can't really go wrong with a good Zoom lens for Solar viewing.

[AndyWB]

Hmm. Okay, I'm a little confused - why are zooms so useful? Or rather, are they really useful in a Lunt 35? The 10mm seems a reasonable magnification at the 400mm focal length - x40. If we said 8 - 12 mm being good, wouldn't that leave a lot of lengths unused? Actually, scratch that - I'll try a lower power eyepiece or two as an experiment. I'm just not sure why I'd want to use lower than 15mm or so?

I can see with other, longer scopes it might be more useful, though maybe I'm missing something...

The Meopta looks lovely, and a nice range of powers for this scope - but probably out of my price bracket, for a fair while...

The Baader Hyperion Zoom - it that not a bit huge fitted in the diagonal? It looks a bit of a hand grenade.

And I'm even more confused about the Maxvisions - aren't they 2"? 

[Pig]

Andrew,

I have not had a solar scope for very long and the advice I have been given from the more experienced folk is that a 10mm eyepiece ends up being the preferred option. The 10mm Televue Radian seems a very popular choice. In my experiment the 8mm came out on top,

I am not sure if a low powered eyepiece would be the best choice for you as my 17,3mm was not as good as my 8mm, 10mm or even the 6mm, but ultimately this is your choice to make

Zooms have some very good attributes  IE

• Very useful for varying seeing conditions
• For setting up alignment with GoTo scopes as you can increase the magnification without changing eyepieces
• Great for field trips as you don't have to take all your eyepieces along
• Economics

However, they are not quite as sharp as a dedicated focal length eyepiece. I feel this sharpness difference is a must for viewing the intricate detail of the sun.

[NGC 1502]

 I'm just not sure why I'd want to use lower than 15mm or so?

I find that with my Lunt 35, I get better surface detail on the solar disc when using 20 - 25mm EPs.   In good conditions, the view is fabulous, filaments etc pop out all over the sun.

It takes a few moments of staring and careful focusing.

At higher powers, prominences are better seen, but contrast on the disc detail is less.

Could be my eyes, but it works like that for me.

Regards, Ed.

[Stu]

I almost exclusively use an 11mm TV Plossl in my PST. The eye relief may not be to your tastes but it is lovely and sharp and gives, to me, optimum magnification on most occasions. I sometimes try higher power but always come back to the 11mm pretty quickly.

Stu

[michael.h.f.wilkinson]

I tend to use the 20mm and 24mm for fainter prominences, and 8.5, 10, or 12mm for the surface detail, and detail within the stronger proms. I really just tried the 24mm in the LS35 for laughs, and for ease of finding the sun (although it is more necessary in that role in the APM 80mm for white light), but was impressed to see a faint detached prom that was invisible at higher magnification. Sine I got the 20mm, I tend to use that a bit more as initial EP. I still use the 24mm for very low surface brightness proms

[michael.h.f.wilkinson]

Hmm. Okay, I'm a little confused - why are zooms so useful? Or rather, are they really useful in a Lunt 35? The 10mm seems a reasonable magnification at the 400mm focal length - x40. If we said 8 - 12 mm being good, wouldn't that leave a lot of lengths unused? Actually, scratch that - I'll try a lower power eyepiece or two as an experiment. I'm just not sure why I'd want to use lower than 15mm or so?

I can see with other, longer scopes it might be more useful, though maybe I'm missing something...

The Meopta looks lovely, and a nice range of powers for this scope - but probably out of my price bracket, for a fair while...

The Baader Hyperion Zoom - it that not a bit huge fitted in the diagonal? It looks a bit of a hand grenade.

And I'm even more confused about the Maxvisions - aren't they 2"? 

In any H-alpha scope, chromatic aberration is not an issue, besides, the LS35 is very slow, so this is extremely forgiving on EPs. This might mean that the difference in quality between zoom EPs and regulars is nearly invisible in this scope. 

The MV20 and 24mm 68 deg EPs are 1.25"

[AndyWB]

Hmm. I suppose at the back of my head had just been the thought 'something around 10mm', but now I'm wondering if I've missed all sorts of low power, low brightness stuff away from the disc itself.

Right, that's the plan then - try some lower power viewing to see what that offers. If that's useful - maybe zoom. If not - well, maybe something good in 10mm-ish length. Naturally, Televue get the thumbs up - but I'm not sure I want to own Televue. They're pricey (well, actually, the Plossls aren't too bad second hand) I'd just worry about when I'll cover it in eyelash grease, dandruff, sneeze in it's general vicinity, etc..

I'll also try the BSTs a bit more, see if I can figure out why they felt like they were blacking out a lot more. Could be user error. Also, I've the 8 and 12mm, which is kind of towards the ends of the spectrum I expected to be looking at.

Actually, Michael makes a good point - given the LS35 being slow, does it really benefit from such high quality eyepieces? Or is it that solar astronomy tends to attract those who're already a bit connoisseur?

Oh, and thanks for all the help everyone, sorry about all the questions - I'm just a bit new to not using big mirrors, and unused to daylight...

[Spikey]

Hmm. I suppose at the back of my head had just been the thought 'something around 10mm', but now I'm wondering if I've missed all sorts of low power, low brightness stuff away from the disc itself.

Right, that's the plan then - try some lower power viewing to see what that offers. If that's useful - maybe zoom. If not - well, maybe something good in 10mm-ish length. Naturally, Televue get the thumbs up - but I'm not sure I want to own Televue. They're pricey (well, actually, the Plossls aren't too bad second hand) I'd just worry about when I'll cover it in eyelash grease, dandruff, sneeze in it's general vicinity, etc..

I'll also try the BSTs a bit more, see if I can figure out why they felt like they were blacking out a lot more. Could be user error. Also, I've the 8 and 12mm, which is kind of towards the ends of the spectrum I expected to be looking at.

Actually, Michael makes a good point - given the LS35 being slow, does it really benefit from such high quality eyepieces? Or is it that solar astronomy tends to attract those who're already a bit connoisseur?

Oh, and thanks for all the help everyone, sorry about all the questions - I'm just a bit new to not using big mirrors, and unused to daylight...

Andy, I see you're going to SGL9. If you come and find me in the day, you can borrow my Baader hyperion zoom to use in your scope. Or if my LS35 is already setup have a try out with it. Whichever is easier.

[sungazer]

Hi ,Without doubt a Zoom eyepiece is near ideal for most Ha solar scopes, as you view only one small part of the electromagnetic spectrum, hence an expensive eyepiece is very much overkill. I have used one for solar viewing for over 20 years. Try one ,well worth a go.

[AndyWB]

Andy, I see you're going to SGL9. If you come and find me in the day, you can borrow my Baader hyperion zoom to use in your scope. Or if my LS35 is already setup have a try out with it. Whichever is easier.

Yup, thanks, I'll probably take you up on that.

[Spikey]

Yup, thanks, I'll probably take you up on that.

I'm on pitch 107 and I'll be arriving on the Friday afternoon at some point. Just pop over and say hello; hopefully the sun will come out to greet us

[trazor]

I have a 60mm double stacked Lunt.

The eye piece which gives as good a view as any, in my opinion, is my Hyperflex-8E 7.5-22.5 Zoom lens.

Never really use any of my Televue 's, as I don't  see any visual benefit.

[Pepeporras69]

Hello/Hola, this is my first message at SGL... sorry but my english isn't enough good.

I've a Lunt 35, DLX version with the B600 blocking filter. The most versatile eyepiece that i use is Pentax XF Zoom 6.8-19.5

Even, TV smoothie Plossl 7.4mm (one eye watching), but very thight ER... , i have a couple with the binoviewer.... but i can't

Use witch the lunt because i need a 2x corrector (not baader 2x GPC... TV 2x amplifler),

Yes, i say BINOVIEWER with lunt35....

I thought search a twin for my Pentax zoom by i'm sure that is very heavy for the Lunt 35.

[AndyWB]

Hi Pepe, and welcome to SGL!

Interesting - that's not an eyepiece I'd heard of, but a bit of searching on Google seems to turn up lots of reports of it being very good for solar - but perhaps less so for night time observing. Interesting. A lot of comments about 'as good as Orthos'. I'll add that on the list for consideration.

PS - your English as as good as the natives, I wouldn't worry

[michael.h.f.wilkinson]

I heard the Pentax XF was fine for night-time observing as well. The short eye relief keeps me from getting one.

[Pepeporras69]

"..I heard the Pentax XF was fine for night-time observing as well...."

+1 yes, it is , but haven't lock position to binoviewing....