Getting to know the Lunt LS60

[Highburymark]

New o rings arrived - speedy service from Simply Bearings in UK - with different cross sections to try out the next time the clouds part.

[SkyGibbon]

18 hours ago, Highburymark said:

How would you describe what you can see single stacked? Are proms, filaments and active regions all clear? How do they compare to double stacked views? It would be interesting to know. While certain differences are to be expected from scope to scope, it may be that buying tilt tuned is a more sensible option if you don't intend to add a second etalon?

Based on my experience of two Lunt pressure tuned scopes, both have been disappointing single stacked, both have required the tuner to be tightened to the very end of the brass cylinder - and both are capable of great views double stacked. Trouble is not everyone can afford that. And if single stack views are poor, does that mean the double stack views I'm getting could be better? I'd like to find out.

In single stack mode, I can make out everything that the DS shows, just brighter, with less contrast (if that makes any sense). It is like the features are more pronounced in DS mode, but all features still visible in single stack. (maybe a small prom or filament visible in DS mode only).

 

As stated above, sometimes I have to turn the DS stack a bit to get the best view and no 2 days ever seem the same without adjusting something with the etalon.

 

I usually let the single stack warm up at least for 30 minutes before I throw the DS on. I always adjust best view with single, add DS etalon, wait another 15 min, and start making minor adjustments with it ( minor tilt adj/etalon turn.) I am more of a surface detail person, so I usually am adjusting the proms out of it to get those nice surface features.

[Highburymark]

Very interesting - makes perfect sense. You clearly have a well developed routine. Have seen a couple of reports recently from solar observers who say warming up time is important. This is something I've not really done properly yet. Thanks for replying - all adds to the bank of intelligence.

[Davey-T]

My LS60 DS with pressure tuner refused to tune a while ago after I hadn't moved the tuning for some time, I took the tuner apart and cleaned and reassembled it using red brake grease cos I already had some and it seemed to have a high temperature operating range and be nice and sticky.

Obviously this is not the recommended grease but it has been working OK for 6 months since.

On the screwing right in question, mine has always required screwing nearly right in, the instructions from Lunt are a bit confusing as they say to start fully out and wind in slowly until tuned which wastes a considerable amount of time as every one I've seen has required screwing nearly right in.

Dave

[Highburymark]

26 minutes ago, Davey-T said:

My LS60 DS with pressure tuner refused to tune a while ago after I hadn't moved the tuning for some time, I took the tuner apart and cleaned and reassembled it using red brake grease cos I already had some and it seemed to have a high temperature operating range and be nice and sticky.

Obviously this is not the recommended grease but it has been working OK for 6 months since.

On the screwing right in question, mine has always required screwing nearly right in, the instructions from Lunt are a bit confusing as they say to start fully out and wind in slowly until tuned which wastes a considerable amount of time as every one I've seen has required screwing nearly right in.

Dave

Thanks Dave. The instructions could certainly be improved!

Btw - I think the recommended grease is 100% silicone. But sounds like you've found a suitable alternative.

[Highburymark]

Not enough clear sky today to try single stack with new o-rings. Only had a few quick glimpses as the sun disappeared behind the trees, so kept the double stack filter attached. Focused. Ramped up the pressure tuner. And the views were glorious. 

The massive prom that has been dominating the solar disc for the past few days was still showing beautiful detail. Lovely filament - like egg white in hot water - but darkly contrasted against the background chromosphere.

Frustrating to have such little observing time. But really fantastic views today - with TV plossls and Fujiyama orthos. I will continue to experiment - and report back when I've tested different o-rings. But the more I use the scope double stacked, the happier I am. It suggests that the original o-rings are working properly, and that its underwhelming single stack performance does not diminish DS views. 

 

[GavStar]

Double stack filter arrived today together with the rotator as recommended by Alan. Hoping for lots of sun this weekend to try out the double tilt tune approach.

 

Edited October 23, 2017 by GavStar

[Highburymark]

5 minutes ago, GavStar said:

Double stack filter arrived today together with the rotator as recommended by Alan. Hoping for lots of sun this weekend to try out the double tilt tube approach.

 

Congratulations Gavin. Very much look forward to hearing how it performs.

[Highburymark]

Just a quick update on progress - which because of weather and work has been slow. Attached pic shows the two o-ring sizes I bought - with 4mm and 5mm cross sections. The 5mm one is too big for the LS60 pressure tuner - impossible to reattach the piston . The 4mm is very close - if not identical to the stock o-rings. Had a brief session today with a new 4mm o-ring fitted to the first groove on the piston. May have been a marginal improvement in single stack views - would need longer and more thorough test to be sure. Also added a Baader ND filter which slightly increased contrast. Double stack views continue to be very good indeed. 

Have to say I am loving this telescope. It allows me to use binoviewers and zoom EPs up to 75x with amazing sharpness under good seeing conditions. So it feels like a more substantial upgrade than I was expecting. 

[Highburymark]

After 12 different sessions with this telescope, some conclusions:

- From this experience, it is possible to have disappointing single stack performance, yet excellent views double stacked. I only presume that this is because my external and internal etalons are very well matched. 

- With my previous Lunt, the tuning of the external DS filter improved definition and sharpness of filaments and surface features, but on this scope, it has transformed them. Getting the tuning right on the external unit has been the single biggest contributor to the improvements I've enjoyed over the past couple of months. 

- Having to screw the pressure tuner all the way in is not ideal, but I'm used to it now. The main thing is I'm able to go through the bandwidths - from white light to proms and surface detail. I do wonder, though, if some tuners fail to deliver sufficient pressure to see the full range of solar features. I don't think the new o-rings, by the way, have made any difference to pressure levels with this scope. 

- The (old model Newtonian) Baader Steeltrack focuser is a great upgrade for anyone who intends to image or binoview with the LS60. The stock Crayford is ok, but not robust enough to carry heavy loads.

- I've been so impressed with how much magnification this scope can take. Enjoying great views at 77x cyclops with Pentax XF zoom, and slightly higher with binoviewer. 

Finally, I hope this thread may be of interest to others considering a LS60. I'm very happy with mine.

 

Edited November 22, 2017 by Highburymark

[Davey-T]

Glad you're enjoying you LS60DS Mark I've had mine since they first came out and always been pleased with the views.

My tuner is also screwed right in nearly.

Tried bino viewers but can't get on with them, I think it's my eyes.

On the O ring subject they're probably imperial size being made in the USA.

Dave

[Highburymark]

44 minutes ago, Davey-T said:

Glad you're enjoying you LS60DS Mark I've had mine since they first came out and always been pleased with the views.

My tuner is also screwed right in nearly.

Tried bino viewers but can't get on with them, I think it's my eyes.

On the O ring subject they're probably imperial size being made in the USA.

Dave

Thanks Dave - good to know they are as enduring as they are well built - how long is it since they came out? 10 years?

[Davey-T]

4 minutes ago, Highburymark said:

Thanks Dave - good to know they are as enduring as they are well built - how long is it since they came out? 10 years?

Probably, time flies when you get to my age 

I did have a problem recently with the B1200 BF going misty in the front but this was fixed FOC in a couple of weeks.

Dave

[niallk]

Great to hear your happiness with the Lint 60mm DS 

-Niall

[nfotis]

So, I guess that a single stack LS60 won't be adequate?

The financial step up is quite steep... you could say the the single stack LS60 is like a gateway drug 🙂

(I am more of an imagine/photography guy)

N.F.

 

Edited July 6, 2020 by nfotis

[Highburymark]

5 hours ago, nfotis said:

So, I guess that a single stack LS60 won't be adequate?

The financial step up is quite steep... you could say the the single stack LS60 is like a gateway drug 🙂

(I am more of an imagine/photography guy)

N.F.

 

I’ve had two double stacked Lunts (50 and 60), and now a Solarscope SF70 DS o my 85mm frac, and honestly none of the single stack views were particularly impressive. In each case it was vital to add a DS filter to see surface detIl. The difference is night and day.

[Merlin66]

You've got about three years to save up for the double stack....by then Cycle 25 should have kicked in bringing some sunspots etc.

In the meantime enjoy what you have. I have a DS SM60 but at the moment mostly use it SS to view and image the occasional proms.

Single stack is much better for the proms, the wider bandwidth suppresses the Doppler shifts.

The DS definitely improves surface contrast (when there's something to see   )

 

 

[Nigella Bryant]

I've a Lunt 60mm DS, love it and it's my most used scope, lol. Used solely for imaging. I had to change the O'rings and blue filter beginning of the year, but brilliant now. Recent image's with my DS.

[keramos]

Hello everyone,

Can someone advice where I can purchase O rings for Lunt LS60, and how many rings are needed to be replaced?

Thanks in advance,

[Highburymark]

31 minutes ago, keramos said:

Hello everyone,

Can someone advice where I can purchase O rings for Lunt LS60, and how many rings are needed to be replaced?

Thanks in advance,

You should contact Lunt - if you’re in Europe they are imported by Bresser in Germany. They will sort you out. I think you need two o-rings for the LS60 if my memory is correct.

[Oddsocks]

5 hours ago, keramos said:

Hello everyone,

Can someone advice where I can purchase O rings for Lunt LS60, and how many rings are needed to be replaced?

Thanks in advance,

Hi Nihal

You can order replacement O-rings direct from Bresser DE (in Germany), you need two rings for the LS60 Tha pressure tuner but be aware that during production of the THa series Lunt changed the size of the barrel and depending on the version you have you may need the O-ring with size;

Internal diameter 32mm, external diameter 40mm:

https://www.bresser.de/en/Astronomy/Solar-Astronomy/Accessories/LUNT-O-ring-32mm-for-Pressure-Tuner-at-MT-THa-solar-telescopes.html

Or,

Internal diameter 34mm, external diameter 42mm:

https://www.bresser.de/en/Astronomy/Spare-parts/LUNT-O-ring-34mm-for-Pressure-Tuner-at-MT-THa-solar-telescopes.html

You will also need to clean the old grease from the barrel and piston and replace with fresh Lithium-Teflon grease:

https://www.bresser.de/en/By-Manufacturer/Lunt-Solarsystems/LUNT-Grease-for-Pressure-Tuner-at-MT-THa-solar-telescopes.html

Here is the instruction document explaining how to exchange the rings and the different sized rings and their Bresser part numbers:

https://www.bresser.de/out/media/4bdcac812d37f790b5f779b21fd0fa76.pdf

HTH

William.

P.S. If you find that the Bresser DE website won't accept your order for shipping to the UK, as many European businesses are refusing to register as unpaid UK VAT collectors and are unwilling to ship direct to UK customers, then contact FLO to see if they will order them for you.

Edited June 13, 2023 by Oddsocks
Added postscript re EU business now unwilling to ship direct to UK customers.

[keramos]

12 minutes ago, Oddsocks said:

Hi Nihal

You can order replacement O-rings direct from Bresser DE (in Germany), you need two rings for the LS60 Tha pressure tuner but be aware that during production of the THa series Lunt changed the size of the barrel and depending on the version you have you may need the O-ring with size;

Internal diameter 32mm, external diameter 40mm:

https://www.bresser.de/en/Astronomy/Solar-Astronomy/Accessories/LUNT-O-ring-32mm-for-Pressure-Tuner-at-MT-THa-solar-telescopes.html

Or,

Internal diameter 34mm, external diameter 42mm:

https://www.bresser.de/en/Astronomy/Spare-parts/LUNT-O-ring-34mm-for-Pressure-Tuner-at-MT-THa-solar-telescopes.html

You will also need to clean the old grease from the barrel and piston and replace with fresh Lithium-Teflon grease:

https://www.bresser.de/en/By-Manufacturer/Lunt-Solarsystems/LUNT-Grease-for-Pressure-Tuner-at-MT-THa-solar-telescopes.html

Here is the instruction document explaining how to exchange the rings and the different sized rings and their Bresser part numbers:

https://www.bresser.de/out/media/4bdcac812d37f790b5f779b21fd0fa76.pdf

HTH

William.

Hi William,

Thank you for the links and detailed information, I’ll remove the rings, measure and order them.

thank you once again

[andre2]

Hi, some are saying that the proms looks even better ( Lunt 60 + 50DS)  with the DS unit , the background is darker but you have to put a black cloth over your head and let your eyes get somewhat dark adjusted . Is this true?  And 2) is it worth to save your bills for the 60 mm DS instead for the ( for me about € 1300 cheaper)  still available older 50 mm model?   Is it also true that the DS 50 is a bit less sensitive for seeings ? I have the tilt telescope, don't know if that matters.    Thanks.  

 

Edited April 14 by andre2

[Nigella Bryant]

1 hour ago, andre2 said:

Hi, some are saying that the proms looks even better ( Lunt 60 + 50DS)  with the DS unit , the background is darker but you have to put a black cloth over your head and let your eyes get somewhat dark adjusted . Is this true?  And 2) is it worth to save your bills for the 60 mm DS instead for the ( for me about € 1300 cheaper and with the money for the DS 60 I can buy a brand new and probably better Lunt 60 MT ) still available older 50 mm model?   Is it also true that the DS 50 is a bit less sensitive for seeings ? I have the tilt telescope, don't know if that matters.    Thanks.  Every tip is welcome. 

 

If you're going for a 50mm double stack unit you might as well buy the 50mm lunt because you'll lose 10mm. 

I've got the 60mm double stack as mentioned b4 and not looked back. I do use a tilt unit but that's only for imaging. Yes some people do use a black cloth over the scope and head. Double stack is really for better surface detail rather than prominences. 

[andre2]

Hi, If the prominences are just OK and the views of Surface detail almost 2x better...than I will go for it.  One thing about the tilt 60 and 50DS in comparison with an 50 mm Lunt scope, while the aperture is going down to 50 mm, the sweet spot of the 60 is not changing according to other forum's. You are right I have a 60 mm scope, I should save for the 60DS. The images are stunning! Thanks.

Edited April 15 by andre2