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Problem with New Lunt Solarscope


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I need advice on my Lunt LS50TH alpha B600. I tried it out yesterday and wasn’t impressed. I’m prepared to believe it’s user error! 

It wouldn’t focus with my ASI120MC cam. It wouldn’t even focus with the 2X Barlow. It only just focused with the 3X Barlow. There was just not enough inward travel. This is the more expensive model that’s supposed to be suitable for photography. I couldn’t see any granulation even turning the pressure tuner to its full extent both ways. I couldn’t see any prominences at all, but it could have been that the Sun was very quiet. 

My old Coronado PST can focus with a 2X Barlow and granulation is extremely clear. 

This isn’t the mind-blowing experience I was led to believe I’d have. 

What am I doing wrong?

Alexxx 

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Somethings not right, there was a very obvious prominence on display yesterday which should have shown up well.  Was this visual or via the camera?  The pressured tuned Lunts do seem to have a bit of a tuning issue now and again despite the claimed superiority over the tilt tuned versions.  Whatever the problem I'm sure it can be sorted even if it's a trip back to the supplier. 

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Thanks. It was with a camera. Even visual I couldn’t see any activity. I’ve been reading many posts about not being able to achieve focus without adapters,  extension tubes and even in one case, elastic bands! It’s ridiculous that my old PST performs much better. I’m very disappointed. Waiting for a reply from Tring Astro 

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My LS50/B600 focuses without any extension tubes with every eyepiece I've tried in it. Granulation and proms are visible if it is in focus. If it is not properly in focus then you lose details. 

Edit: having said that, focuser travel is rediculously short, and there isn't enough infocus for use with my 2x TeleXtender (plus eyepiece). 

Edited by Ricochet
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Hi,

In visual use, say 15mm EP or thereabouts: irrespective of detail, can you get a sharp limb?  I find I need to tweak focus for the sharpest views as i pressure tune.  Also, very fine touches on the focusser help - even with a dual speed focusser.   Tougher with the stock helical focusser. 

Have you fully unscrewed then re-screwed the pressure tuner piston? (Be careful not to cross thread - take your time).

The threads may just need regreasing - look and see if the grease is obvious when you unscrew the piston from the chamber.  It is required to form a seal for the pressure tuning.

My LS50 gave very good views, and when double stacked, great disc detail.  Typically always much better than on the GONG Ha site for the up-to-date Ha solar images.  Of course, the sun is quite quiet at the moment.  But you should be picking up some details like what you see on GONG.

Focusser in travel on the LS50 is indeed tight - I cant get my binoviewers to focus... a known issue.  I've had no issues with EPs and or with a Powermate. 

Edited by niallk
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Many thanks all. I did finally get it to focus. I was rushing in as my PST is so easy. I should have used an EP first, to get the pressure tuning right and see what activity there was. I did this on an 8mm EP. It worked well. I was advised to remove the EP holder from the filter diagonal and attach the cam directly to the diagonal. This worked well although I had to pull the diagonal a little way out of its holder, which I was also advised to do.

I can get focus with a 3x Barlow well now, but the exposure setting has to be pushed so far up in SharpCap that the frame rate drops down to practically nothing! I'm using USB 3.

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On 30/05/2020 at 19:04, Astrosurf said:

I can get focus with a 3x Barlow well now, but the exposure setting has to be pushed so far up in SharpCap that the frame rate drops down to practically nothing! I'm using USB 3.

Use gain to reduce exposure time and thus increase frame rate. Read noise also drops dramatically with this camera at a gain of 50. 

If possible, use ROI to only get the part you want (plus framing) and again, this will help speed the frame rate.

Have you tried stretching your images in say IMPPG? What you may consider dark, hides probably a wealth of information which can then be coaxed out in any image editing software :)

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On 30/05/2020 at 17:04, Astrosurf said:

Many thanks all. I did finally get it to focus. I was rushing in as my PST is so easy. I should have used an EP first, to get the pressure tuning right and see what activity there was. I did this on an 8mm EP. It worked well. I was advised to remove the EP holder from the filter diagonal and attach the cam directly to the diagonal. This worked well although I had to pull the diagonal a little way out of its holder, which I was also advised to do.

I can get focus with a 3x Barlow well now, but the exposure setting has to be pushed so far up in SharpCap that the frame rate drops down to practically nothing! I'm using USB 3.

An X3 Barlow is pushing it and will darken the image considerably. I find that an X3 is barely usable with my Lunt L60 in singlestack mode, never mind doublestacked. You will also need excellent seeing to use an X3

Slow down and take a step back. Make sure that your solar finder is set up correctly. Stick an eyepiece in and get used to tuning the Etalon. The pressure tuning is very precise and with practice you will be able to take the 'scope slightly off-tune into the red and blue wings to make different feature stand out. Get used to focusing as well. Precise focus is essential.
Don't underestimate the effects of seeing (both local and atmospheric). On the recent really hot days the seeing is very turbulent and often makes it nearly impossible to get precise tuning and focusing. Even more so as the day progresses and the ground heats up. Try and set up away from concrete or patios and these will drastically worsen the local seeing.

Getting camera spacing correct can be a pain as the focal plane is very narrow. Until you get really au fait with the 'scope it's easier to tune and focus with an eyepiece, then insert the camera. A shade for the laptop screen helps enormously as you can see what's happening as you manually move the camera in and out of the focuser.

Most importantly, DONT PANIC. I've seen people getting really frustrated with the views until they realise that they are looking at a ghost refection! (Again, check your solar finder is properly set up). Take your time, unless you are very very unlucky the 'scope will be perfect. It takes a lot of experimentation to get the best out of the kit, but once you do the spectacular secrets of the Sun are there for you to see.

 

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  • 2 weeks later...
On 31/05/2020 at 19:46, Solar B said:

I'm glad you have resolved your focusing issues for imaging 

I am curious to know about what surface detail you can see visually v your PST.

Brian 

I've yet to try! Go away clouds!

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On 01/06/2020 at 10:08, nicoscy said:

Use gain to reduce exposure time and thus increase frame rate. Read noise also drops dramatically with this camera at a gain of 50. 

If possible, use ROI to only get the part you want (plus framing) and again, this will help speed the frame rate.

Have you tried stretching your images in say IMPPG? What you may consider dark, hides probably a wealth of information which can then be coaxed out in any image editing software :)

I was recently told aboout ROI. O never thought about that! 'll try it once the damn clouds g away. What's IMPPG?

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On 04/06/2020 at 09:46, Zakalwe said:

An X3 Barlow is pushing it and will darken the image considerably. I find that an X3 is barely usable with my Lunt L60 in singlestack mode, never mind doublestacked. You will also need excellent seeing to use an X3

Slow down and take a step back. Make sure that your solar finder is set up correctly. Stick an eyepiece in and get used to tuning the Etalon. The pressure tuning is very precise and with practice you will be able to take the 'scope slightly off-tune into the red and blue wings to make different feature stand out. Get used to focusing as well. Precise focus is essential.
Don't underestimate the effects of seeing (both local and atmospheric). On the recent really hot days the seeing is very turbulent and often makes it nearly impossible to get precise tuning and focusing. Even more so as the day progresses and the ground heats up. Try and set up away from concrete or patios and these will drastically worsen the local seeing.

Getting camera spacing correct can be a pain as the focal plane is very narrow. Until you get really au fait with the 'scope it's easier to tune and focus with an eyepiece, then insert the camera. A shade for the laptop screen helps enormously as you can see what's happening as you manually move the camera in and out of the focuser.

Most importantly, DONT PANIC. I've seen people getting really frustrated with the views until they realise that they are looking at a ghost refection! (Again, check your solar finder is properly set up). Take your time, unless you are very very unlucky the 'scope will be perfect. It takes a lot of experimentation to get the best out of the kit, but once you do the spectacular secrets of the Sun are there for you to see.

 

Very many thanks. This is good advice. ;)

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Its definitely worth persevering.  I also had difficulties (perhaps b/c of too high expectations of how easy it would be) at the start.  Even to the point of occasionally thinking of selling it.  But now its a lovely piece of kit which I wouldn't part with (except for the helical focuser - that will be replaced one day, although perhaps a Solar Quest mount is ahead of it in the pecking order!).  I also had difficulties finding focus (ASI178MC) but various SGLers were v helpful.  I now use an ASI120MM mini (normally guidecam) and it is much easier - you do need to pull it out a bit but with the added nose that can be threaded on, its not a problem and is quite easy.  Definitely the right approach to find focus & features w an EP and then switch. Enjoy!

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8 hours ago, Astrosurf said:

I was recently told aboout ROI. O never thought about that! 'll try it once the damn clouds g away. What's IMPPG?

IMPPG is a software to do post-processing. I find it much easier and comfortable than Registax Wavelets for example. Link is here

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You will also have to "train" your vision system. I have a pet theory (probably garbage, but hey-ho) that viewing in such a narrowband of light is unknown to our ocular system. You definetley see more aftger viewing for a while, which helps with focus and tuning. After a bit of experience you will find that the details "snap" into vision.

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37 minutes ago, Zakalwe said:

You will also have to "train" your vision system. I have a pet theory (probably garbage, but hey-ho) that viewing in such a narrowband of light is unknown to our ocular system. You definetley see more aftger viewing for a while, which helps with focus and tuning. After a bit of experience you will find that the details "snap" into vision.

I agree with that theory.  Our brains and eyes are not accustomed to seeing things in one precise wavelength like that and our visual system has been trained all our lives to see in broadband.  So it is unusual and unnatural to visualise what the narrowband filter is showing us.

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Coronado used to say it will take 6 months to train your brain to 656.3 nm 

& thats Californian weather , the equivalent in the UK is approx 2 yrs

here's the thing i'm not joking.

Brian 

 

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On 13/06/2020 at 05:26, nicoscy said:

IMPPG is a software to do post-processing. I find it much easier and comfortable than Registax Wavelets for example. Link is here

Sorry if this is a stupid question, but how do I download the software on the site below? It looks very technical! I'm on W1.8.

https://greatattractor.github.io/imppg/

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42 minutes ago, Freddie said:

Click on the latest version under downloads. That will take you to github where you click on the win64 version to download the zip.

Many thanks. I've worked it out. Got a few brain cells working!

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