Pressure Tune Retrofit Report

[Sunshine]

Pressure Tuning review

Hello everyone, I figured I would write down my thoughts on my Lunt LS60 pressure tune retrofit, bear with me though, I am a solar baby and cannot talk the talk as deeply as you seasoned observers. 

 

On May 17 of this year I shipped off my Lunt for a pressure tune retrofit, it was originally a tilt tuner, I was always wondering why it had a tuner at all considering the views were great, I was able to see both prominences and disc detail like filaments and so on simultaneously which was great.

 

But the tilt tuner left me feeling like I was missing out after reading about what tuning really meant, by that I mean no matter how much I turned that little wheel back and forth absolutely nothing changed no matter how good seeing was or how steady I kept my gaze, and my eyes are good. 

 

Both Lunt and my local telescope shop whom I trust very much upon inspection assured me that it will not be a visible change, the wheel they say was to snap the etalon into band and not so much to tune through different features, on or off band and that was what it's function was I was told. 

 

Ok I was ok with that, the views were great so I didn't let it chew away at me, but a small part of me was convinced that my tuning wheel was not working properly, it turned with such ease that a stiff breath would spin it, it just didn't have any resistance at all and it bugged me a bit.

 

I decided to take the hit and ship it off for a retrofit to pressure tuning, the cost would be $500 US plus shipping back and forth, which in Canadian turned out to be $850 all said and done, i purchased the scope for such a great price that I figured why not I'd still be ahead anyway.

 

Off it went, I was nervous knowing pimple faced teen aged warehouse kids would be hurling my scope into and out of trucks, but it arrived safely and the wait was on, Lunt customer service was commendable to say the least, they assured the retrofit would be an improvement and so helpful and informative throughout the whole process.

 

Exactly two months later I received my scope, which was about 3 weeks longer than the time I was quoted but that's ok, the eclipse is around the corner here in north america and Lunt is busier than ever. I must mention that there was an issue with the feather touch focusser when it arrived, it was rough and felt like it had received a hard knock, I contacted Lunt and they offered to send me a standard focusser until after the eclipse because they had no feather touch in stock.

 

I didn't blame them for the focusser, but they were concerned and offered to take action before interrogating me and diverting blame to the shipper and that is a  commendable thing, it turns out that after some investigation by me I realized that it was my fault, I recall shipping the scope on its side within the case which left the focuser knob contacting the lid of the case , I remember having to press the lid down a bit too hard. After speaking to starlight, the focuser manufacturer, they said they've seen that before, a knock will misalign the focuser and it clearly was knocked during shipping

 

I managed to fix the focuser after all, now let's hear about the pressure tuning already right! First thing that struck me was the size of the tuning cylinder, it is larger and adds more weight than I imagined, this is great for a good grip on the cylinder (which you'll need!!) I'll get to that later, but it did throw the balance of the scope on my Grand Polaris mount way off, so much so that I was unable to move the clamshell forward enough on the bracket to offset the added weight, if my bracket was another 2 inches longer it would be ok, something I have to consider.

 

One very important factor when switching to pressure tuning is the mount, I'm using a rock solid Vixen GP, oldie but goodie, it's solid as a mountain and smooth as silk, but I'm afraid that anything less would have made for a hard time. Pressure tuning is nowhere near as effortless as turning that little wheel, i can guarantee that if you are planning on mounting one on anything less than a very sturdy mount you may be frustrated, the effort required to turn the wheel is far greater than the force required to turn any focuser.

You definitely don't want the sun to look like a dot on an oscilloscope while you're trying to find your tuning preference. 

 

I figure I'll describe what pressure tuning is from a mechanical point of view, it is as simple as a cylinder with a piston inside that forces air into a chamber inside the scope. As you thread the cylinder in it pushes air into the chamber surrounding the etalon which in turn physically affects the etalon.  

 

I have been enjoying the pressure tuner a lot lately and made sure to give it a fair chance under good seeing conditions, so far it has been a pleasure to use comparing with tilt tuning. It was explained to me that tilt tuning (this is from Lunt) is to snap the etalon into band and not for tuning back and forth during a session, I was sold it was on or off band and that's about it.

 

The pressure tuner right away showed off its superiority, i am now able to finely tune back and forth revealing different features in full detail rather than a happy mid point for all features which is where I was at with tilt tuning. Some people i understand leave their tuning point in one place  and don't touch it which is fine, but I greatly enjoyed finely turning that cylinder through its travel, ever so slightly and watching different features reveal themselves in fine detail. 

 

Being a noob in solar astronomy I cannot yet get into the hard core jibber jabber behind every features characteristics, I don't yet know if I'm seeing dilithium Crystals emitted from the flux ionic resonations within cavitation nodules but I'll get there lol. One thing I can speak of though is when I turn that cylinder I can actually see its effects whereas before I was unable to exact any meaningful change on the suns disc. 

 

One thing I was very curious about was if there would be any banding where certain sections of the disc were in tune while other parts were not, my tilt tuned model had an annoying issue where the best view was to the far right and as the disc moved detail would drop off near center. I understand this is common and can be different in every scope, I am happy to say that the disc pretty evenly detailed across its face, I've carefully watched as I moved the disc side to side looking for bad spots and with the exception of the outer edge I cannot see any detail drop off. I'm glad because Lunt says they can do their best to remedy that but cannot guarantee it won't have banding.

 

I hope this little write up can help others who may be contemplating the same retrofit, one has to ask whether a pricey retrofit is worth the cost, I myself think it was definitely worth it, aside from the advantages of pressure tuning itself I'm sure it's resale value improved a fair bit. I did notice that Lunt did change the serial number sticker on my scope.  The serial number changed from 2009920 to 0001392 which kind of gives it a whole new identity I guess, kind of like if Ford restored your car to new condition and even changed the VIN number lol.

In conclusion i would advise anyone to pack their cope carefully and make sure your scope is sitting on its belly and not sideways like i did unfortunately, and please do yourself a huge favour and insist on a signature required return from lunt. My scope was left on my front doorstep, big box sitting there just screaming to be taken, i almost lost my mind! and insist than lunt ad a bit more foam around the sides between your scopes metal case and the shipping box not just foam end caps and 2 inches of empty space all around the sides of the box, this is something that kind of upset me, lucky it was ok though.

 

Anyway, if anyone out there has any questions I'll be glad to answer them if I can, thank you for your patience regarding my lack of in depth knowledge.

 

 

 

 

 

 

 

 

[Pig]

Nice detailed report of your experiences with both sending the scope away for retrofitting and the positive difference it has made to your observations. I have only ever owned a Lunt 60 with a tilt tune and I found it to make quite a difference across its range, but maybe the extra aperture made the difference ?Either way all that matters is you are happy with what you can see and it's great you had the scope returned in time for the eclipse ?