Lunt tuning system general question

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Lunt tuning system general question

Post by David Fox »

Hi

Quick question for those in the know:

The lunt pressure tuner - do you take this off completely and reattach each session?
Any other 'best practice' advise around this be appreciated.

Thanks again,

David


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Re: Lunt tuning system general question

Post by Montana »

Hello David,

I've never used a pressure tune system but I think folk release the pressure before each session and then re-pressurise but I don't think you completely take the knob off. I think if you do it is very hard to get back on!

Alexandra


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Re: Lunt tuning system general question

Post by David Fox »

yes Alexandra can be awkward rethreading but I swear I saw somewhere that you take it off completely. Cannot recall where but I've been doing that since but I'd like to make sure case I'm damaging the tuner. 🤔

Thanks

David.


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Re: Lunt tuning system general question

Post by marktownley »

Unless you have a 'leak' there really is no reason to be messing with it once you have it tuned, just an occasional tweak.

If you keep taking it on and off you really do run the risk of killing the threads on it, which will effectively kill the scope.


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Re: Lunt tuning system general question

Post by krakatoa1883 »

I usually relieve pressure every time but I don't remove the knob completely. Lunt manuals can be downloaded from here.


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Re: Lunt tuning system general question

Post by Highbury Mark »

Apart from regreasing and (if necessary) changing the o rings, the only reason for unscrewing the tuner completely is if you’re observing from a different location with contrasting atmospheric pressure. I left mine on for months at a time, and it always held pressure effectively.


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Re: Lunt tuning system general question

Post by Bob Yoesle »

Somewhat off topic but germane.

In my limited experience with the Lunt pressure tuner I have fount it to be a little stiff at times to manipulate, which seemed to make tuning a bit more difficult due to significant image movement while tuning. Therefore being a tinkerer, I would explore a connector as used with the PC-USB to get the tuning mechanism off the scope via a second pressure tuner piston and adapter hose. Alternatively, one could explore removing the OEM piston and make (have made) and adapter to fit is its place, and use the OEM piston off-scope via connection tuning to do the same thing.

Ultimately, the Lunt PC-USB controller would seem to provide a repeatable and easy to use tuning capability, and a rather insignificant cost relative to the larger/more expensive telescopes.


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Re: Lunt tuning system general question

Post by David Fox »

Bob thanks, and for the good advise from all (I've stopped taking that cylinder off 👌)
Tempted by the USB controller now that I have the 60 but the cost 🤔 particularly this side of the pond.


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Re: Lunt tuning system general question

Post by SimonM »

I asked the same question with Lunt Support only a couple of weeks ago. They did say that there really is no need to undo the Pressure Tuning knob between sessions. The first time it resets the pressure for the altitude and thereafter it should be fine.

Simon
Last edited by SimonM on Fri Mar 19, 2021 11:55 pm, edited 1 time in total.


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Re: Lunt tuning system general question

Post by solarnoob »

The pressure tuner USB controller worked great during the Summer/Fall seasons; not so great lately because of the cold weather (T < 42F); all I see most of the time is a flat Sun no matter the pressure level. Last week, we had a day when the temperature was in the upper 50s, and it worked fine. The BF3400 filter doesn't help either.

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Re: Lunt tuning system general question

Post by torsinadoc »

solarnoob wrote: Fri Mar 05, 2021 7:18 pm The pressure tuner USB controller worked great during the Summer/Fall seasons; not so great lately because of the cold weather (T < 42F); all I see most of the time is a flat Sun no matter the pressure level. Last week, we had a day when the temperature was in the upper 50s, and it worked fine. The BF3400 filter doesn't help either.

Frank
Do you heat your blocking filter? I wrap mine in a dew heater strap when it is cold otherwise the sun is pretty much washed out.


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Re: Lunt tuning system general question

Post by solarnoob »

Thanks for the tip; I'll give it a try.

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Re: Lunt tuning system general question

Post by Genoafire »

I have the LS130 double stack setup and the 3400 internal blocking filter with both tuners connected to their own PCUSB units. It really is nice to have a precise digital readout for the exact position of each tuner when they are precisely “on band”. Being able to increase and decrease the pressure in tenths of a psi to adjust to the exact best tuner pressure with absolutely no movement of the scope/image from hand turning the knob is a huge plus. Since I don’t have an observatory, yet, I have to set up and take down my scope each time and it is really sweet to just press the buttons and get to the exact psi recorded from the last observing session. As Frank mentioned the only downside I have found with the PCUSB in my case has been when the weather is under 50° the PCUSB units will cycle up and down 1-2 tenths of a psi every 10-20 seconds until the Etalons/blocking filter warms up. Not a problem with visual, but during a sequence of video frame captures it does cause a sharpness issue. So I usually set up early and then wait until everything has warmed up enough for the psi to become stable. Not really enough of an issue for me to try to remedy, but I do like the dew strap idea.

Bob


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Re: Lunt tuning system general question

Post by Carbon60 »

Generally not necessary, but occasionally when the threads bottom out before getting on band it is necessary to unscrew until you hear the air pressure equilibrate, definitely not all the way out.

Stu.


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