Lunt LS50

[Tigger27]

Hello,

I have been observing the night sky for over 10 yrs with a 14" Meade SCT and a couple of smaller grab and go Maks (6" & 4"). Last year I bought a Lunt LS50 to try 'The Bright Side'. I have been Solar observing for about 6 months. I have just ordered a Double Stack unit and will report on this in a few weeks time . For now the report is on the single stack LS50 with standard focuser and BS600 and VISUAL ONLY, no AP

The Good Stuff

Wow, the views are stunning. The image is really crisp and clean. The Sun changes every day and the Proms can change over a few hours, so there is always some new to see everyday. 

How to use it

I have mine set up on a lightweight grab n go Alt Az tripod. Finding the sun is a doddle with the sol finder from televue. I start with an 8mm eyepiece and get the edge of the sun in focus. I then tune the pressure tuner until I can see the proms shinning nice and bright. I will then move the sun through the sweet spot. This usually brings out the fainter proms that are not visible when off the sweet spot. Next I have a quick look at the sun's surface, but the LS50 does not show much surface features ( Im sure the DS will help with this).

If there are any interesting proms, I swop to a 5mm EP and adjust the focus.

Focusing issues

The stock focuser is OK to use but lacks backfocus for my televue Radians. I have read various reports and most pull the diagonal 10-15mm out of the focuser. I tried this but felt nervous about the diagonal falling out of the scope. So instead, I have the diagonal fully in the focuser and adjust focus by moving the eyepiece out 15mm. Fine focus is achieved by using the focuser. this method works for me because the TVs pop into focus. I could change the focuser, but its £250-£450. I  cannot justify that expense so I live with the stock focuser.

Pressure Tuner

This took some getting used to, but boy does it make a difference! I find that I have to unscrew it to equalize pressure about once a fortnight. So how does it work? I find that I get the edge of the sun in focus and then increase the pressure in the PT by screwing it down until the proms come into view and you can see the 'orange peel' surface of the sun. Fine tuning of the PT brings a reward of seeing the fainter proms that are not usually picked up on amateur photos. Properly tuned the PT is a superb gizmo. 

Would I recommend it?

I read heaps of tests and reports on loads of solar scopes before buying this one. Solar astronomy is very expensive compared to nighttime astronomy, so its important to get it right first time. I did not know if I would enjoy astronomy in the warm sun; sipping a cold beer; getting a sun tan and loads of vitamin D, so I did not want to spend thousands of pounds on gear that might be used a few times and then sit on the shelf. Th eLS50 seemed the best compromise of price vs aperture. 

I love it! Yes I would recommend it if you want to try Solar

Next steps

I want better views, so I considered a bigger scope. Lunt 60 costs £2,700 Lunt 80 costs £4,000.  Lunt 60 out of reach unless I could sell the LS50, but although a better scope with a bigger light grab, its a lot of money. Lunt 80 looks a better, bigger jump but wow its a lot of money. 

I have decided on a different course and will upgrade my 50 with a Double stack filter. the adage seems to be 'once you double stack, you don't go back' so i'm looking forward to trying it out in a few weeks time and will report on its performance

[Nigella Bryant]

That's great, you'll be pleased with the better contrast and surface details with the double stack. It's like chalk and cheese. Hopefully you'll get lots of viewing of our nearest star over the spring and summer months. 

[niallk]

I hate to say it, but dual speed focusser is essential imho with the double stack 😉  there's just so much super fine detail with a DS!!  It's a good 1st world problem to have 😂

Edited April 4, 2021 by niallk

[Tigger27]

Hi Brown Dwarf,

Ouch! I was hoping to get away with the standard focuser. What focusers are you using. There seems to be 2 available moonlite & Feathertouch. Both very expensive though.

Many thanks

John

[Carbon Brush]

Hi John.  Glad to hear you are getting good views from your LS50.

When I bought my (used) LS60 it had already been upgraded to the feathertouch.
The seller left the original focusser in the box of bits.
I had a feel of it it my hands. It felt nice enough, compared to the average Synta stuff.  But compared to the upgrade it was chalk and cheese.
The feathertouch has handled different (heavy) eyepiece combinations and a DSLR, without wandering or slipping.

Slightly off topic. I was originally going to buy a different LS60 that still had the standard focusser. While waiting to buy, I bought a Baader steeltrack.
I had read somewhere on SGL that was one of recommended (or must have) upgrades.
Then when that scope purchase fell through I was left with the Baader focusser.
As it had the newt fitting kit included, I decided I would surely use it on something.
Your posts have reminded me it is still unused in a drawer.

I also spent on a Skywatcher SolarQuest mount & tripod. Which has been well used.
My solar days tend to be look, go away and do something elsewhere, then look again, then wait for a cloud to pass......
The Solarquest handles the weight of the LS60 with eyepiece, double stack, etc.
Accuracy is fine for this purpose so no need to keep chasing the sun every time I return to the eyepiece.

I have made a 3D printed lens cap. The idea being to drop it on if I am walking away for a while.
Yes it is a bit of cheap plastic instead of the nicely made and threaded original. But it goes on and off in a second.
I don't know if exposure to sun eventually degrades any of the optics, but it is my no cost way of protecting the optics.
You have probably heard about an internal Lunt filter degrading, and 'rusty' PST objectives.
Neither have been publicly explained, as as far as I know. So I'm not taking any chances.
If a bird decides to perch on the scope while I am away and c*** on the lens, the glassware is protected.
Yes I had that problem when I left a DSLR with remote trigger looking at a bird feeder 😲

HTH David.