Off-centre clarity Lunt50

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04Stefan07
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Off-centre clarity Lunt50

Post by 04Stefan07 »

I have noticed with my Lunt I need to position the Sun on the far right to get the detail I need.

If I position more in the centre or left of the FOV I lose detail on the far left of the disc. The blue glass filter has been cleaned as it did fog up so it defs isn't that (thought it would have been!). Could it be the following?
- Something to do with the pressure tuning? If I tune it more maybe the detail will be more even across the FOV?
- Camera/sensor tilt issue (which I know I have but unsure if that affects it).

Attached is an example of both.
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2.JPG (68.83 KiB) Viewed 1310 times


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Re: Off-centre clarity Lunt50

Post by DeepSolar64 »

My Coronado 90 seems to on average favor the right side of the field for greatest detail. And it's tilt tuned not pressure tuned.


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Re: Off-centre clarity Lunt50

Post by marktownley »

You could try tilting the focuser to bring it back centre?


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Re: Off-centre clarity Lunt50

Post by 04Stefan07 »

The focuser itself looks ok and im not sure how it can be tilted.

Could it be something to do with the blocking filter maybe?


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Re: Off-centre clarity Lunt50

Post by marktownley »

I don't think so. I had (have) the same with my Lunt50, it is off centre.

Just image with the sun off centre...


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Re: Off-centre clarity Lunt50

Post by JochenM »

I have the exact same thing with my LS50 as well if I use it for full disk imaging. I honestly never gave it much thought, just move the disk to where I know it's fine (bottom left in my case) and call it a day.

As Mark already hinted, it can very likely be solved by tilting the focuser slighty to compensate. There's adapters you can buy to achieve that (focuser tilt adapters). But unless it's really preventing you from getting the shots you want, I wouldn't bother.


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Re: Off-centre clarity Lunt50

Post by rsfoto »

Hi,

For me both look the same sharpness but moving it from side to side has the effect that the brighter part moves over the spots and so giving more contrast and therefore it we seem to see it sharper IMHO

Wait until you have some spots on the right upper corner and move it to the left lower corner ... IMHO


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Re: Off-centre clarity Lunt50

Post by Ivan »

Hello, my Lunt50 is exactly the same. A little improvement in the image was helped by rotating the filter unit in the focuser, and looking for a more uniform area. This is a normal situation.

Ivan


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Re: Off-centre clarity Lunt50

Post by Bob Yoesle »

It looks like you have a pretty pronounced Jacquinot spot ("sweet spot") which is off-center. This off-centeredness could be from the focuser alignment, or the diagonal. You might want to try and re-orient the OTA with respect to the blocking filter diagonal to see if you can center up the spot of good on-band imaging.


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