Focus problem with LS50 DS

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Tigger
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Focus problem with LS50 DS

Post by Tigger »

Good afternoon

I am reaching out for some help.

I have owned a ls50 for about 6 months. Today I received a DS filter, but cannot get it to work.

I have done the following

1. Set up and focused the scope as normal in SS.

2. Added the DS. Tilted all the way from right to left. The ghost moved from top left to bottom middle off the sun

3. No matter where I put the ghost, the sun was just a featureless out of focus sphere.

4. Tried adjusting focus and the PT. again no effect except to make it more out of focus

5. Took off DS. Reset focus and PT in SS. Changed eyepiece to reduce mag. I use TV Radians. Used 10mm this time. Set up in SS was spot on

6. Attached DS. This time I lookedthru the ep as I screwed on the DS. The ghost moved around the sun. Tilted but again same result. Tilt is about nine pushes from right to left and you can see the filter has been tilted from the outside

I observe under a black out curtain so image is nice and bright

Please help, I’m at my wits end

Many thanks

John


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Re: Focus problem with LS50 DS

Post by EGRAY_OBSERVATORY »

You've certainly come to the right place for answers John, so welcome.

Surprised you use the 10mm E,P. rather than a 20 or 24mm EP, but none-the-less, just concentrate on any focusing without the DS on the limb/edge of the Solar-disk firstly and always even...

1. As long as the sky is fairly-well clear of even a haze-layer, you are correct in the initial setting of the PT on the scope's own Etalon,

2. So try again and then when all set-up for the first stages, retry the DS and just adjust its' Etalon on the limb-edge at first.

3. Only then is it worth slewing to surface-detail.

Proms will not be as good with the DS, but the surface-detail/granulation/porridge and filaments etc., will have better contrast with the DS...

Best Wishes
Terry


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Re: Focus problem with LS50 DS

Post by Tigger »

Hi Terry

Thank you for your reply. The problem is that I cannot achieve focus on any part of the Sun with DS attached.

In SS, no problems, focus is very sharp. 10mm EP is only 35x mag. Most days I’m using higher mag with no problem.

With the DS fitted, I cannot achieve any focus. The DS does not need more back focus does it?


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Re: Focus problem with LS50 DS

Post by marktownley »

Hi John.

So you can focus and see detail in single stack, but not at all in double stack? Sounds to me like the double stack module is decontacted, send it back for a replacement.

Mark


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Re: Focus problem with LS50 DS

Post by Tigger »

Hi Mark,

Thank you for your advice. I bought it direct from Lunt. It only arrived today. Excuse my ignorance but what does 'decontacted' mean and would this happen at the factory or could it happen in transit? the DS has travelled from Arizona to Florida where it was shipped to UK. The box was never opened and shows no sign of damage. I used Fedex. I thought if I bought it direct from Lunt it would be a good 'en. Such plans of man and mice .....

Many thanks

John


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Re: Focus problem with LS50 DS

Post by marktownley »

decontacted basically means the glass plates of the etalon are no longer connected together, so the etalon does not work... :(


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Re: Focus problem with LS50 DS

Post by Tigger »

Thanks Mark. I have told Benjamin at Lunt and they are looking into it for me


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Re: Focus problem with LS50 DS

Post by EGRAY_OBSERVATORY »

At least Mark and John your DS has come with the proper case from Lunt, so normally that would protect the DS in transit.

Could it also be that you need to pull out the BF draw-tube to say half its' length for focusing ??

I have the Lunt 60mm version and the drawtube is all part of the focusing requirement...

Terry


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Re: Focus problem with LS50 DS

Post by Tigger »

Lunt Update - They appear to have accepted that the unit is decontacted. They have been very open and honest, good to see. Not sure if I can swap with a unit here in UK or if it has to be sent back to Arizona. Bit of a bugger because I was looking forward to my first DS views. Hey ho Astronomy eh?


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Re: Focus problem with LS50 DS

Post by EGRAY_OBSERVATORY »

The nearest main agent for Lunt is Lunt EU in Germany, but if you get the instructions from Lunt U.S. to return it to themselves, I would follow their instructions..

Your comment is another example of how well Lunt treat their customers, compared to some other suppliers. They clearly want their customers satisfied and that certainly reflects with your comments...

I hope it get's sorted asa John

Best Wishes
Terry


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Re: Focus problem with LS50 DS

Post by Radon86 »

Thanks John for sharing your problems.
I would not have realised that these faults can happen.
Hope you get better luck with your 2nd DS.

Magnus


Solar: H-alpha": Quark Chromosphere filter; Baader white light filters
Scopes: Altair Astro Travel ED70mm (F 420mm, D=70mm);; Skywatcher 90mm (F 910mm D=90mm); GSO focuser;;Altair Astro 60mm guidescope (D=60mm,F=225mm)
Cameras: ASI120mm-S,ASI174mm
Mount: SW HEQ5 Pro, SW EQ3 Pro Synscan (SW = Skywatcher),Vixen Polarie tracker (portable setup)
Accessory: SW Auto-focuser
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