New Eyepiece - A little bit of fun

[Naemeth]

It was honestly difficult not to at the bargain price of £50. A controllable exit pupil of 6.66mm in my ED80 (no problems dilating to that size because I'm shielded from all other light sources) and 3.75 degrees (12x), but it's not really an eyepiece for the big dob at an exit pupil of 10.64mm :shocked: . In a C14 (considering for a few years' time) it gives around 80x, so quite a nice low magnification really, especially if the seeing isn't up to much .

Fun picture for you all:

From left to right: 8mm TV Plossl, 32mm TV Plossl, 50mm LV

(Sorry about the pink/red tinge, you know how it is with astro-modified cameras )

[michael.h.f.wilkinson]

That looks like a very nice deal. The two LVs (7 and 9 mm) I have had were very nice indeed, I am curious to hear how you 50 mm performs.

[Naemeth]

That looks like a very nice deal. The two LVs (7 and 9 mm) I have had were very nice indeed, I am curious to hear how you 50 mm performs.

Indeed, if it's like the other 3 I've got it should be a treat .

One thing, it's not supplied with an eyecup, but finding the right eye position in the daytime is rather easy. The eye relief is very long, 30mm eye relief is printed on the eyepiece, shouldn't be a problem though .

[Stargazer_00]

I assume the 50mm is the eyepiece on discussion here?   £1 for 1mm has to be a record bargain for an eyepiece of this quality!

I've often wondered what a giant exit pupil looks like, I've never bought anything that goes over 6mm I think.

[Naemeth]

I assume the 50mm is the eyepiece on discussion here?   £1 for 1mm has to be a record bargain for an eyepiece of this quality!

I've often wondered what a giant exit pupil looks like, I've never bought anything that goes over 6mm I think.

Yes, it is the 50mm on discussion. I've used a 6.4mm exit pupil before with no problems (32mm in F/5), all that is different is you notice a grey background if your pupil isn't dilated enough. If it is, you get the usual black background .

[michael.h.f.wilkinson]

These large exit pupils can work (slightly depending on age). I used my former 40mm Paragon with my F/6 scope, yielding 6.67mm exit pupil, and massive 5.67 deg FOV. This does work under very dark skies, but with the slightest LP the background becomes a bit grey. I now use the 31T5 as my widest EP (5.17mm exit pupil, and (still massive) 5.3 deg FOV).

[John]

The LV's had a good reputation but I do feel an eye cup is needed with eyepieces having long eye relief, ie: where it's going to require your eye to be away from the top of the eyepiece some distance. This was the flaw I found with the Hutech 25mm ortho recently - hovering the eye above the eyepiece is not relaxing and stray light does get onto the eye lens reducing contrast. Perhaps these things don't bother everybody though ?.

[Naemeth]

I suppose so John. If I find it irritating I will get an eye cup, but until then I can always use a finger as a sort of eye cup (curled around the top) .

Might get a first light tonight, depends on how tired I am after work and whether or not it's clear.

[John]

See how you get on Jonathan. Another member here found a smooth side Meade 56mm plossl (no eye cup) almost unusable recently because of stray light and not being able to find the eye placement. Fortunately it had only cost him a few quid !

You can get 2" eye cups from SCS Astro I seem to recall, if you find you need one. 

[Pig]

Looks a complete bargain to me

[Stu]

Certainly sounds like a bargain price, the LV's are very nice eps.

I used to have a 40mm in 1.25", similar 45 degree fov. It could be a little like looking down a drinking straw, though the quality was excellent. I would think the 2" will be different though, but could have a tendency to be washed out.

Will be interesting how you get on with the eye relief etc

Hope it works out.

Cheers,

Stu

[Naemeth]

Thanks for the comments everyone . Things are looking good for tonight, although that Moon really is rather bright! A good job really, not really up to dragging out the 10" dob, tonight is about some general stargazing sweeping around the sky, for which the LV 50mm will be perfect . I may do some lunar observation with it too, but 12x isn't going to show much...

[John]

The 10" dob with the 50mm eyepiece will deliver a 10.6mm exit pupil  

[Naemeth]

The 10" dob with the 50mm eyepiece will deliver a 10.6mm exit pupil  

Yeah, I thought about that... too much light loss really... Wasn't really thinking of ever even trying the 50mm on the dob or anything faster than about F/7.

[russ.will]

Hang on! I though your astro spend had ended, again!

Told ya.

Russell

[Naemeth]

Hang on! I though your astro spend had ended, again!

Told ya.

Russell

I've since changed my mind

Just back from a lovely short dew-rich session with the new eyepiece. Boy it's a large eyepiece, but the AZ-4 handles it just as smoothly, and I don't need to worry about any counterbalancing either .

With the Moon so full I decided to give it a go, and the view was pleasant at 12x, but bear in mind this will never be an eyepiece I normally use for the Moon. It was nice and sharp almost to the edge, but I did detect some pincushion at the edges of the field of view, and noticeable CA (blue), but this really doesn't bother me as I'm hardly going to use 12x on the Moon much! Much better view than my current binoculars at a similar magnification (and similar aperture as I tested with part of the lens cap on). I was having fun until I decided, for some unknown reason, to try my Astronomik 2" OIII Filter on the Moon. I really wished I hadn't... after a second or so of looking at the Moon in that bright green I realised it had slightly imprinted the light on my eye (as looking at the Sun often does), and I was seeing pink in the centre of my eye for a bit.. I won't be doing that again.

Just swinging the scope around I decided to look at M45, and it sure is weird seeing it with a TFOV of 3.75 degrees, it makes it look small! Lovely white stars though, excellent viewing .

The eye relief is long, really long. It's so long that I put the end of my nose on the eyepiece and that gives roughly the right distance. So large infact that you can catch a good glimpse with your head a long way away from the eyepiece. But personally I quite like that, it sometimes actually makes the viewing position more comfortable in a refractor (pushing it higher off the ground). 

Satisfied overall, I might get an eye cup, but I'm happy for now .

Who's up for me trying it with the big dob?

[John]

Who's up for me trying it with the big dob? 

Go for it Jonathan - it's good to experiment 

[Pig]

Why not it will be interesting to know the outcome esp with your young eyes  that you keep reminding us about