H-Alpha August 10th Lunt 152 - feedback wanted!

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Bojan
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H-Alpha August 10th Lunt 152 - feedback wanted!

Post by Bojan » Fri Aug 10, 2018 6:24 pm

Hey all,

I have been using my Lunt 152 for the past few months and learning how to use it.
I am really impressed by the pictures everyone is taking here on the forums and am looking for some guidance on how I could improve the views (and photos) through the 152.

One things I struggle with is the surface detail in the Lunt is VERY difficult to extract. What I mean is I can barely make anything out visually. Only once I put on a camera can I see any detail. Is this normal? I see more surface detail through my SolarMax40, however proms and spicules do come through better in the Lunt. The disk through the Lunt is almost featureless with next to no detail.

I spoke to Lunt about this and supposedly these etalons benefit from a bit of darkening in the form of "ND between .5-.8 on the front of the feather touch focuser." I have also sent in the etalon to be tuned up (there was an air leak and we replaced the orings.)

In short, I am in awe by what I imagine you all see through your scopes (from the pictures posted here using the Schmidts/pst mods) and am wondering if that may be a better route than the lunt. I tried building my own PST stage 2 mod but that etalon is too finicky for me and I'd prefer something that is more robust.
I really want to be wowed visually, and am not so concerned with photographic performance. Pictures were taken with a Neximage 5 Monochrome camera.

Thanks!
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Pre-Meade Solarmax40
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Re: H-Alpha August 10th Lunt 152 - feedback wanted!

Post by gabrieli » Sat Aug 11, 2018 12:43 am

Hi, Bojan

My Lunt 152 arrived back in summer 2010. I used the scope visually only briefly since my interest was mainly imaging. To my eyes, the image (very bright) showed more surface and prom detail if you looked for a while. I can understand why Lunt recommended neutral density filters. Imaging required quite a bit of processing to enhance the contrast. By the way, the images that you see posted are far beyond what you will see visually. Although not usually stated, most people process their image into what you see posted here. I doubt that anyone ever gets a visual view near what processed images display.

I found that using the Lunt 152 to get good high res images required fairly good seeing and that using it for lower power imaging was difficult because of hot spotting which could not be reduced by tuning.
After a couple of years, I reached the same point you seem to be in now where I wasn’t that impressed.

This all changed when my Quark Chromosphere(not Quark Combo) arrived. I attached the Quark to the scope to “double stack” it and I was amazed at how the view and especially the images changed, full of contrast and detail. I also noticed that there also was a noticeable calming effect on the seeing. This effectively gave my a new scope . My Lunt 152 with the Quark used only at 3800 mm are my main imaging setup.

I also have a large ERF I mount on a C9.25
with a Quark Combo Chromosphere but, so far, the seeing has not been cooperating for this high res setup. I’m still testing different etalon combinations. My impression is that I will not be getting a lot of use out of this setup for now.

If you were interested in getting images like the ones posted here, I would recommend a larger format (2/3” camera). If your camera has adjustable gamma that can also help with visual contrast.

The following were taken with a Lunt152 + Quark on a Blackfly S(2/3” sensor). They required extensive processing to improve the contrast and detail.

http://solarchatforum.com/viewtopic.php?f=4&t=24792

Lou

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Re: H-Alpha August 10th Lunt 152 - feedback wanted!

Post by Bojan » Thu Aug 16, 2018 1:30 am

Thanks for the feedback. So all you're saying is throw some more money at it and it'll be better :) ?

How does your Lunt+Quark perform visually?

Thanks,

Bojan
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Re: H-Alpha August 10th Lunt 152 - feedback wanted!

Post by TheSkyBurner » Thu Aug 16, 2018 4:40 am

This is the first time i have ever heard of lunt, suggest the placing of a neutral density filter in a hydrogen alpha scope.

That would destroy the chance of high magnification imaging!

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Re: H-Alpha August 10th Lunt 152 - feedback wanted!

Post by marktownley » Thu Aug 16, 2018 7:10 am

Hey Bojan.

For me what I see when I look at the images, and easier to see on the last 2, is the sweetspot - that is you top centre of the image it is brighter, then it is surrounded by a smile shaped darker band, then the bottom left and right corners are brighter again. This annulus is the sweetspot. The 152 is only really designed for hi-res images - there is an article somewhere on this all about it on the Lunt blog / website (i'll see if I can find it), I think your image is more medium-res in terms of scale, and, I think because you are imaging at this wider scale is why you are seeing what you are. Same applies visually, the sweetspot on the 152 is smaller than the disk, whereas with the 40 the sweetspot here is larger than the full disk which is why you prefer the views.

I think if you're just interested in visual then I would get a double stack Lunt60, maybe a DS coronado 90, either way try before you buy!

Mark
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Re: H-Alpha August 10th Lunt 152 - feedback wanted!

Post by marktownley » Thu Aug 16, 2018 7:22 am

Can't find the original article, not sure it remains, but Bob Yoesle copy and pasted the (blue) text I was looking for into this discussion on cloudy nights. I think it explains what you are seeing. It's Andy Lunts words from the Lunt blog.

https://www.cloudynights.com/topic/5988 ... -opinions/
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Re: H-Alpha August 10th Lunt 152 - feedback wanted!

Post by Bojan » Fri Aug 17, 2018 12:19 am

Thanks Mark I appreciate that.

Being in Ottawa Canada our weather is attrocious so the high magnification views are few and far between.

Could you help me understand the technical reason why a larger aperture scope is more susceptible to poor seeing than a small one? Is it as simple as the big scope being able to register smaller purturbations in the atmosphere so views are more affected?

I am considering selling the lunt and stepping down, and reclaiming some of those funds for better visual views.
Pre-Meade Solarmax40
Lunt 2" Wedge on ES 127mm Apo
Some photos and hobbies at:
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Re: H-Alpha August 10th Lunt 152 - feedback wanted!

Post by Montana » Fri Aug 17, 2018 9:37 am

You are correct in your thinking, that is why all the large aperture telescopes are all situated on high mountains or volcanoes around the world.
I am sure if you are more into visual a good double stack 60-80mm would do you much better.

Alexandra

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Re: H-Alpha August 10th Lunt 152 - feedback wanted!

Post by pedro » Fri Aug 17, 2018 10:36 am

Hi Bojan

Mark is absolutely right, the LUNT152 was designed for high resolution imaging. I almost never use mine for FD imaging. Having said this the LUNT152 is a wonderful instrument, I have been using one since 2011. Visually it is a pleasure to use (mine was hand picked by Markus Ludes, not sure if this means anything...). Lou is also right, you should use a better camera, CCD camera if possible (avoid CMOS). The LUN152 can only be used when you have good seeing conditions. When the seeing is not great Full Disk imaging is the way to go. Hope this helps.

I also have a few tutorials that can help (solar imaging)

http://re.apaaweb.com/image_processing.html

http://re.apaaweb.com/imaging_the_sun_PRe_2015.pdf

http://re.apaaweb.com/IMAGING_SUN_2012_small.pdf

(...)

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