First light with Lunt LS50

[JeremyS]

Hello Highburymark,

good to hear you are now getting focus with your eyepieces.

I normally use an Opticstar 7.2 to 21.5 mm zoom (which is a great performer). When I read of your problems I thought to try my Takahashi LE eyepieces in my LS50 and found that they all reach focus (well, I only actually tested the 5, 7.5., 10, 12.5 and 18 mm) 

I am using a B600 filter - what model do you have, B400 or B600?

[Highburymark]

Jeremy,

Sounds like you've got an excellent set up there - and great you can reach focus with all those superb EPs.

Baader Hyperion zoom, by comparison, is difficult to focus in the LS50, according to the reports of others.

I bought the B400 filter version, as I'm not into imaging. But I wonder whether the size of blocking filter affects focusing with the Lunt in any way?

[Pete Presland]

Jeremy,

Sounds like you've got an excellent set up there - and great you can reach focus with all those superb EPs.

Baader Hyperion zoom, by comparison, is difficult to focus in the LS50, according to the reports of others.

I bought the B400 filter version, as I'm not into imaging. But I wonder whether the size of blocking filter affects focusing with the Lunt in any way?

I have the b600 and I will try my range of eye pieces when I get back.

Sent from my GT-N7100 using Tapatalk

[JeremyS]

Jeremy,

Sounds like you've got an excellent set up there - and great you can reach focus with all those superb EPs.

Baader Hyperion zoom, by comparison, is difficult to focus in the LS50, according to the reports of others.

I bought the B400 filter version, as I'm not into imaging. But I wonder whether the size of blocking filter affects focusing with the Lunt in any way?

I don't really understand how the blocking filter could effect focus either. However, when I tried a B400 on my LS50 (out of curiosity) it didn't reach focus, so I swapped it back straightaway. I didn't experiment to try to get it to focus, only trying one eyepiece, and I don't have the B400 filter anymore to test, but thought I'd mention it.

[Highburymark]

I don't really understand how the blocking filter could effect focus either. However, when I tried a B400 on my LS50 (out of curiosity) it didn't reach focus, so I swapped it back straightaway. I didn't experiment to try to get it to focus, only trying one eyepiece, and I don't have the B400 filter anymore to test, but thought I'd mention it.

Very interesting. Could a different blocking filter slightly alter the focal length or the back focus?

[Highburymark]

The other thing I noticed today which I haven't before is that surface detail - which is obviously less of a feature with single stack set ups - is suddenly more apparent when light cloud starts to roll in. It's only transitory - but it seemed to me that the dimming of the surface helped improve contrast and depth.

[Hyperion76]

With all the eyepieces listed I achieve focus on a b400 version(25mm 20mm 9mm vixen lv 12mmbst 7mm tmbII down to 4 mm tmbII) ,as stated before it is the early version focuser with no marks on it.Light cloud improves contrast this has been noted on the forum before.

[jabeoo1]

I did a little test today which may not tell us much but anyhow.  I took my 25mm, 20mm, 15mm, 11mm & 8mm Televue Plossls.  I found the eyepiece that required the most front focus and put a small pencil line on the focuser tube.  I then found the eyepiece from the range that required most back focus and drew another line on the draw tube.  The entire range of all these plossls were only around 2-3mm.  I know they are supposed to be parafocal so it was not surprising the range is small, but this 3mm range sits right in the middle of the draw tubes overall range.  

In comparison to my 7.5mm Tak LE, this required focusing right on the edge of the range of the focusers draw tube.  In some cases a different eyepieces required the B600 diagonal tube to be moved outwards to create a longer light path.  Although there is plenty of tube length in the diagonal to do this be careful & avoid crashes to the floor ! 

The knock on problem here was that the eyepiece intended for the extra back focus worked lovely, but when switching back to another make this made the travel between focal points more extreme, and in some cases no longer even in the range of the draw tube. 

I think that finding a set of eyepieces of the same make & design and sticking to them gives the most pleasurable viewing with this scope, I found myself messing around far to much when trying out 4 different makes of eyepieces as well as a few different designs in a single viewing session. 

This morning viewing was spectacular btw, clear steady and crisp detail up to the 11mm.  Even the 8mm was on it which is saying something. 

[JeremyS]

Interesting experiment jabeoo1 - thanks for sharing. Indeed. sounds best to stick with one eyepiece set. Or use a zoom - assuming it reaches focus in the first place..

I agree that this morning's H_alpha view was spectacular - more activity than I have seen in a while, with some detailed prominences and an impressive filo-prom. The seeing was pretty steady for a change, which makes all the difference.

[paulastro]

The other thing I noticed today which I haven't before is that surface detail - which is obviously less of a feature with single stack set ups - is suddenly more apparent when light cloud starts to roll in. It's only transitory - but it seemed to me that the dimming of the surface helped improve contrast and depth.

This is a very common and well known phenomena to observers using solar scopes regularlly.  Some poeple try to imitate the effect by using verious filters like NDs.  Filters can improve the view a bit as they cut out the glare as thin cloud will -though filters never seem to work as well as clouds do! 

[Highburymark]

More useful information jabeoo - thanks for posting.

[Highburymark]

This is a very common and well known phenomena to observers using solar scopes regularlly.  Some poeple try to imitate the effect by using verious filters like NDs.  Filters can improve the view a bit as they cut out the glare as thin cloud will -though filters never seem to work as well as clouds do! 

This forum has been so helpful to a solar newbie - thanks for posting Paul

[jabeoo1]

Here's mine on LS60 in matching Lunt red, purchased direct from Ron, great service and communication.

Dave

LS60-Moonlight.jpg

What is the knurled knob on the underside Dave ?   I guess the other one is a lock out. 

[Highburymark]

In case anyone's still checking this thread and is interested in getting hold of replacement grease for their pressure tuner, Lunt recommend 100% silicone grease. I checked out a couple of hardware stores near me, but the stuff they had was only 90% silicone - it's quite difficult to track down on the high street, so have ordered mine online. Several brands to choose from.

[jabeoo1]

Lunt recommend 100% silicone grease. 

Excellent, ordering some soon.  Cheers for finding that out. 

[mog3768]

You asked about the pressure tuner. I found when I first got my LS60 that to be able to view  prominences I had to wind it in very nearly all the way 

But have found after nearly a year of use it only needs to go in two thirds to bring proms into view. I always wind it out after use to take the pressure

off. Don't know if this is the right thing to do just seems right.  

[Pete Presland]

I also thought that was the sensible thing to do as well, despite reading it wasn't necessary.

Sent from my GT-N7100 using Tapatalk

[Highburymark]

You asked about the pressure tuner. I found when I first got my LS60 that to be able to view  prominences I had to wind it in very nearly all the way 

But have found after nearly a year of use it only needs to go in two thirds to bring proms into view. I always wind it out after use to take the pressure

off. Don't know if this is the right thing to do just seems right.

This is really useful mog3768 - thanks for posting - because there's a real lack of technical information out there. Much as I love the telescope the official "manual" is minimalist at best - with no real guide to troubleshooting - and there's not yet a great amount of advice on the web. So it's great to hear that sort of feedback. I have to screw the tuner literally all the way in until it won't go any further to view prominences, but on inspection I found the cylinder and piston of the pressure tuner were lacking in grease. I now have some replacement grease which I've applied (no chance to test the scope out yet - thick cloud for past few days) .

I also found out as I opened up the PT that the piston only had one (red) O-ring (pic attached, with Louis the King Charles spaniel looking on disinterestedly) - whereas other Lunt scopes appear to have two - yet there are two 'grooves' on the LS50 piston with space for another o- ring (again see pic), so I'm wondering if I added an extra o ring would it increase the pressure in the cylinder and improve the performance of the tuner? But first things first - waiting to see if the new grease has improved performance so I don't have to screw the tuner to its limits. Then if that doesn't work I'll call Lunt and ask about adding an o-ring. But your post above gives me hope that things might improve anyway.

[Highburymark]

Sorry - photo didn't attach to previous post - here it is .

[Pete Presland]

This is really useful mog3768 - thanks for posting - because there's a real lack of technical information out there. Much as I love the telescope the official "manual" is minimalist at best - with no real guide to troubleshooting - and there's not yet a great amount of advice on the web. So it's great to hear that sort of feedback. I have to screw the tuner literally all the way in until it won't go any further to view prominences, but on inspection I found the cylinder and piston of the pressure tuner were lacking in grease. I now have some replacement grease which I've applied (no chance to test the scope out yet - thick cloud for past few days) .

I also found out as I opened up the PT that the piston only had one (red) O-ring (pic attached, with Louis the King Charles spaniel looking on disinterestedly) - whereas other Lunt scopes appear to have two - yet there are two 'grooves' on the LS50 piston with space for another o- ring (again see pic), so I'm wondering if I added an extra o ring would it increase the pressure in the cylinder and improve the performance of the tuner? But first things first - waiting to see if the new grease has improved performance so I don't have to screw the tuner to its limits. Then if that doesn't work I'll call Lunt and ask about adding an o-ring. But your post above gives me hope that things might improve anyway.

This video shows the PT taken apart and does show two black O rings https://www.youtube.com/watch?v=Hx5abAO0ctc

[jabeoo1]

That missing O ring would make all the difference.  No wonder you are not seeing consistent detail, and having to compensate by winding the tuner right to the top. Once you have the chamber air tight the views will improve no doubt.  

[Highburymark]

That missing O ring would make all the difference.  No wonder you are not seeing consistent detail, and having to compensate by winding the tuner right to the top. Once you have the chamber air tight the views will improve no doubt.

Does your pt. definitely have two o rings then Jabeoo? Because there are other owners on other forums with just one - so I thought maybe every LS50 had just one o ring because the piston is smaller than the LS60 pt?

[Highburymark]

Ok - added a second o-ring to the tuner piston and applied grease. Now just waiting for the clouds to part.......

[Highburymark]

This video shows the PT taken apart and does show two black O rings https://www.youtube.com/watch?v=Hx5abAO0ctc

Yes thanks Pete - have seen this - it seems to be the only video on YouTube providing guidance on the pressure tuner.

[jabeoo1]

Does your pt. definitely have two o rings then Jabeoo? Because there are other owners on other forums with just one - so I thought maybe every LS50 had just one o ring because the piston is smaller than the LS60 pt?

I just looked and mine only has the red o-ring, the same as the position in your image.