Lunt 50 Ha - which eyepieces do you use?

[DRT]

I've just had a look through the Lunt 50 with my new TV 11mm, 15mm, 20mm and 25mm Plossls (courtesy of @jabeoo1 and @mert) and they are fantastic ?

Very sharp views of proms around the full disk and nice surface detail, particularly from the 11mm and 15mm. 

Best of all, they are all parafocal with my Ethos 8mm so I've now got all useable mags with this scope covered off ?

Thanks for the advice above. I'm delighted with the result. 

[Highburymark]

20 hours ago, DRT said:

I've just had a look through the Lunt 50 with my new TV 11mm, 15mm, 20mm and 25mm Plossls (courtesy of @jabeoo1 and @mert) and they are fantastic ?

Very sharp views of proms around the full disk and nice surface detail, particularly from the 11mm and 15mm. 

Best of all, they are all parafocal with my Ethos 8mm so I've now got all useable mags with this scope covered off ?

Thanks for the advice above. I'm delighted with the result. 

Excellent - glad they're delivering the goods Derek

[MattJenko]

I know you now have a working set, but for extra info, I found the ES 68 degree EPs work great, as do the Baader Morpheus EPs (well the 14mm one does). I have also successfully used Vixen SLVs and the BSTs work very well too.

[Highburymark]

On 15 April 2017 at 12:30, DRT said:

Sold it

I have tried various zooms in the Lunt 50 including the Baader Mk III and Mk IV, Pentax and Leica and none of them reached focus. I think the only zoom I found that worked with the scope was the Lunt 7-21mm. I might look for one of those and compare it to the TV Plossls.

I'm going to have to saw a cm off the barrel of my Pentax XF zoom to get it to focus in the LS50 after upgrading the focuser to a Moonlite. I suppose if we were starting out again it would make sense to get the Lunt zoom for this scope

[DRT]

24 minutes ago, Highburymark said:

I'm going to have to saw a cm off the barrel of my Pentax XF zoom to get it to focus in the LS50 after upgrading the focuser to a Moonlite. I suppose if we were starting out again it would make sense to get the Lunt zoom for this scope

Yikes! Not sure I'd be up for taking a saw to such a nice EP  

is the nose detachable? If so perhaps try to find a cheap EP with a nose that fits and keep the Pentax nose intact to retain its value?

[Pig]

I agree, it seems a drastic measure

[DRT]

Another thought: does the Pentax have a T-thread adapter? If so you might be able to remove the eyepiece holder from the blocking filter and screw the zoom onto the t-thread?

[Racey]

1 hour ago, Highburymark said:

I'm going to have to saw a cm off the barrel of my Pentax XF zoom to get it to focus in the LS50 after upgrading the focuser to a Moonlite. I suppose if we were starting out again it would make sense to get the Lunt zoom for this scope

May I ask if you've had any issues with other eyepieces since upgrading to the Moonlite please ? I've a LS50 that I'm thinking of putting the mini Moonlite on. At the moment I've been using a selection of Celestron X-Cel LX eyepieces with it... It hadn't crossed my mind that swapping from the Helical Focuser to a Moonlite might cause problems...

Simon

[Highburymark]

Sadly the nose is not detachable. The LS50 is the only scope I use the Pentax zoom with - it only really performs well as a solar EP and does so excellently. So otherwise would have to sell it.

[Highburymark]

15 minutes ago, Racey said:

May I ask if you've had any issues with other eyepieces since upgrading to the Moonlite please ? I've a LS50 that I'm thinking of putting the mini Moonlite on. At the moment I've been using a selection of Celestron X-Cel LX eyepieces with it... It hadn't crossed my mind that swapping from the Helical Focuser to a Moonlite might cause problems...

Simon

Hi Simon, my experience is that you lose a couple of mm of back focus with the Moonlite compared with the stock helical. I could just reach focus with the Pentax before the upgrade - now not possible. It's a lovely focuser, but the Feathertouch may be a better option if you're worried about some of your eps reaching focus - cannot confirm this, but just going by what I've read

[Racey]

3 minutes ago, Highburymark said:

Hi Simon, my experience is that you lose a couple of mm of back focus with the Moonlite compared with the stock helical. I could just reach focus with the Pentax before the upgrade - now not possible. It's a lovely focuser, but the Feathertouch may be a better option if you're worried about some of your eps reaching focus - cannot confirm this, but just going by what I've read

Thanks for the "Heads Up". I hadn't realised there was such a difference in drawtube travel... I had been drawn towards the Moonlite because of the 8:1 fine focus (and if I'm truly honest the colour too !!). Although I'm sure all the current eyepieces we use would be fine with that travel, the extra the Feathertouch offers might "future proof" us. Is it outward travel you lack with the Pentax Sir ?

[Highburymark]

42 minutes ago, DRT said:

Another thought: does the Pentax have a T-thread adapter? If so you might be able to remove the eyepiece holder from the blocking filter and screw the zoom onto the t-thread?

Have tried this too Derek. The only way to get the eyepiece into focus is to reduce the barrel length. 

[Highburymark]

5 minutes ago, Racey said:

Thanks for the "Heads Up". I hadn't realised there was such a difference in drawtube travel... I had been drawn towards the Moonlite because of the 8:1 fine focus (and if I'm truly honest the colour too !!). Although I'm sure all the current eyepieces we use would be fine with that travel, the extra the Feathertouch offers might "future proof" us. Is it outward travel you lack with the Pentax Sir ?

No - it's inward travel.

I don't have any problems with my fixed f/l EPs  - 11 and 15mm plossls, Nagler T6 11mm, Delite 7mm - it's just the Pentax zoom. 

[Racey]

4 minutes ago, Highburymark said:

No - it's inward travel.

I don't have any problems with my fixed f/l EPs  - 11 and 15mm plossls, Nagler T6 11mm, Delite 7mm - it's just the Pentax zoom. 

Got it... Should have put 2 & 2 together given the Hacksaw or Dremmel was being reached for... My bad !! 

The Feathertouch is a few mm shorter in "racked in" profile by the look of it than the Moonlite...  Would that be enough for you ? Could the Moonlite hit the classifieds to keep the Pentax intact Mark ??

[Highburymark]

11 minutes ago, Racey said:

Got it... Should have put 2 & 2 together given the Hacksaw or Dremmel was being reached for... My bad !! 

The Feathertouch is a few mm shorter in "racked in" profile by the look of it than the Moonlite...  Would that be enough for you ? Could the Moonlite hit the classifieds to keep the Pentax intact Mark ??

Yes - maybe that's a good idea Simon. Trouble is I've grown fond of two speed focusing......

[Racey]

Just now, Highburymark said:

Yes - maybe that's a good idea Simon. Trouble is I've grown fond of two speed focusing......

I can relate to that... We're used to that with our other refractors... That's what put the Moonlite on the radar over the Feathertouch. I'm sure you'll get your conundrum resolved. But I'm grateful for you bringing it to my attention...

[DRT]

3 hours ago, Racey said:

Got it... Should have put 2 & 2 together given the Hacksaw or Dremmel was being reached for... My bad !! 

The Feathertouch is a few mm shorter in "racked in" profile by the look of it than the Moonlite...  Would that be enough for you ? Could the Moonlite hit the classifieds to keep the Pentax intact Mark ??

From reading various specs I think the FT is the same as the Moonlight and stock focuser when racked in. It has a few mm more of outward focus. 

I have one on order from FLO so will measure and report back when it arrives. 

[Racey]

11 minutes ago, DRT said:

From reading various specs I think the FT is the same as the Moonlight and stock focuser when racked in. It has a few mm more of outward focus. 

I have one on order from FLO so will measure and report back when it arrives. 

The stats on Moonlite's site and Starizona's show differences to focuser length (2mm) when racked in and differences to drawtube lengths... 

I've double checked this with FLO too this afternoon...

[Highburymark]

5 minutes ago, DRT said:

From reading various specs I think the FT is the same as the Moonlight and stock focuser when racked in. It has a few mm more of outward focus. 

I have one on order from FLO so will measure and report back when it arrives. 

That would be interesting Derek - haven't seen any reports of the FT yet 

[Racey]

15 minutes ago, Highburymark said:

That would be interesting Derek - haven't seen any reports of the FT yet 

They're not the same. After your thought provocation I researched and there's 2mm difference 

[DRT]

1 hour ago, Racey said:

They're not the same. After your thought provocation I researched and there's 2mm difference 

Moonlite spec (from FLO)...

Quote

 

Minimum profile: 5.31cm / 2.09".

Maximum profile: 6.38cm / 2.51"

Drawtube Travel: 1.07cm / 0.42"

FeatherTouch spec (from Lunt)...

Quote

Focuser travel: 15mm

Minimum focus height: 48mm

That suggests that the Moonlite is 5mm longer than the FeatherTouch when racked in.

I think the standard focuser is 48mm, which means the Moonlite is adding 5mm to a situation where the inward focus is already too short

 

[DRT]

My FeatherTouch has arrived and is now installed on the Lunt 50.

I measure the minimum and maximum focal path as 48mm - 65mm compared with 48mm - 58mm of the stock helical focuser.

...and it is a thing of beauty...

[MattJenko]

Very tempted by this focuser for mine as well. Its been in the basket for a good few weeks now :). It does look like a proper upgrade...

[niallk]

Hi - I'm using the stock helical focuser with the Lunt 50mm.  I'm finding that my 15mm TV plossl barely reaches focus to my contact lens corrected eyes right at the racked out limit of the focuser...

Is this what others find??  Or perhaps it is peculiar to my eyes.  I'm pulling the ep barrel a little out of the holder to give me a +/- adjustment region, with the risk of introducing a little tilt.  Perhaps a par focalizing ring would be useful or something.

Right now I'm finding that a cheap TS/GSO 9mm plossl from an old set is giving great full disc views at nearly 40x. On a whim I tried unscrewing the lens from a cheap GSO barlow and attaching to the filter thread of the 9mm (giving approx. 6mm), and it is actually giving real nice views at nearly 60x for closer examination of proms/ARs. Both focus fine. I used to have a 6mm GSO plossl, but I took it apart to see the lens arrangement!  This GSO 6mm effective is nicer to view through than my cherished Nagler 7T6 in this scope, I'm finding.

Very interesting to read about additional outwards focus travel with the FT.

Cheers,

-Niall

[Moonshane]

An option Niall would be to take the glass out of any colour filter if you have one or can get a cheap one and then add this to the end of the eyepiece?