Short eyepiece for Lunt LS50?

[ThomasLondon]

Hi,

 

I love my Lunt 50mm scope, but it has a very short focal length - even with a 6mm eyepiece you see the whole disk. Any thoughts on a reasonable short eyepiece? The 52° ES 3mm looks reasonably priced. Will I get any benefit from a larger viewing angle given the 6mm blocking filter?

 

Best

Thomas

[Paz]

The shortest eyepiece I've got is a 2.5mm Vixen SLV but that would make for 140x magnification which is a lot for 50mm of aperture. At those short focal lengths a small change in focal length means a big change in magnification which will drop the brightness and contrast significantly. I don't know how far you can go with a Lunt 50 magnification wise but it's worth thinking about so that you don't end up with a great eyepiece but which asks too much of the scope.

[rwilkey]

Hi Thomas, the other one to consider might be the William Optics SPL 3mm though a little more expensive, the ones I have (6mm & 12.5mm) are superb quality and great to use.  I have a great respect for Explore Scientific as well, so either eyepiece will easily fit the bill.  Here is a link to the WO:

https://www.firstlightoptics.com/william-optics-eyepieces/william-optics-spl-eyepiece.html

Good luck in your choice!

[laudropb]

Hi Thomas. I have the same solar scope as you and have found that the shortest eps that give a sharp view are the ES 62 5.5 mm or a Celestron XL 5 mm. At higher magnifications the image becomes too soft and detail is lost. I have the WO SPL 3 mm but the mag of 117x is just too much for this scope. On a few occasions when the seeing and transparency are excellent I have used a 4 mm Vixen SLV 4 mm, but these conditions unfortunately seldom occur.                                                                 How long have you been using the Lunt scope ? With patience and experience you can still see some lovely detail at magnifications around 64 x It just takes a little time to get your eye in.

 

 

[Highburymark]

Wow - in my experience the shortest usable eyepieces for ha solar are around 6mm, though that's for UK skies - higher mags possible elsewhere. Even with the Lunt 60, my high power eyepiece is a Pentax XF zoom at 6.5mm giving 75x. On rare days of exceptional seeing I can go higher - particularly if the scope is tuned for proms. But never beyond 90-100x. 

[ThomasLondon]

1 hour ago, Highburymark said:

Wow - in my experience the shortest usable eyepieces for ha solar are around 6mm, though that's for UK skies - higher mags possible elsewhere. Even with the Lunt 60, my high power eyepiece is a Pentax XF zoom at 6.5mm giving 75x. On rare days of exceptional seeing I can go higher - particularly if the scope is tuned for proms. But never beyond 90-100x. 

Yes, but the focal length of the LS60 is 500mm, while the LS50 is only 350.... 

[ThomasLondon]

3 hours ago, laudropb said:

Hi Thomas. I have the same solar scope as you and have found that the shortest eps that give a sharp view are the ES 62 5.5 mm or a Celestron XL 5 mm. At higher magnifications the image becomes too soft and detail is lost. I have the WO SPL 3 mm but the mag of 117x is just too much for this scope. On a few occasions when the seeing and transparency are excellent I have used a 4 mm Vixen SLV 4 mm, but these conditions unfortunately seldom occur.                                                                 How long have you been using the Lunt scope ? With patience and experience you can still see some lovely detail at magnifications around 64 x It just takes a little time to get your eye in.

 

 

Thanks for this. I'll probably get a 4mm.

I have the scope for 2 years now. I agree - it is nice, once

- I manage to focus it - the helical focuser is just atrocious, I am getting the Moonlite now

- after getting clear view - the green glass of the blocking filter becomes cloudy when exposed to humid air, really annoying. Now storing the scope with Silicagel, but apparently the filter has to be replaced from time to time.

?

I am using the Lunt when the sun just lurks out - p and running in less than 5 min - and my Quark if I have the time.

Best

Thomas

 

[niallk]

I got a Moonlight for mine too - it is a wonderful upgrade!

I've used my Nagler 13T6 with a 2.5x Powermate for ~5.2mm sometimes, but generally just use a 15mm TV plossl, and screw in a 1.5x Barlow lens from a cheapo TS Barlow I have.

I have a double stack too - really, really worth it, imho.

[Highburymark]

On 09/03/2019 at 16:20, ThomasLondon said:

Yes, but the focal length of the LS60 is 500mm, while the LS50 is only 350.... 

I had an LS50 for a couple of years and I found 6.5mm was just about tops for an eyepiece also - but great if you can go further. The Moonlite is wonderful as Niall says. Also - am sure you know Thomas but Lunt will replace the blocking filter glass free of charge if it gets cloudy