Camera Options for Lunt LS80 DS

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
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AJ132
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Camera Options for Lunt LS80 DS

Post by AJ132 »

Hi All.

I am new to this forum and have been reading various post and learning a lot.

Up until recently, my Astronomy interest has primarily been imaging of deep sky objects. However, the number of clear/moonless nights I get here in a Red Zone near Houston are quite limited. Plus, imaging in the summer heat of Texas is hardly worth the effort even with a cooled camera. Therefore, I decided to give Solar imaging a try to hopefully get more opportunities to participate in the hobby. To that end, I recently placed an order for a Lunt LS80MT, Double Stack unit and B1800 Blocking Filter. Based on the research I did it seemed like this would be the best choice given my typical Seeing.

While I am waiting for the scope (currently on back order) I thought I would start to get the rest of my gear together so that I will be able to start imaging once I get the new scope setup and tuned. I read somewhere that the optimal image resolution for Solar imaging can be calculated by dividing the F# of the scope by the pixel size of the camera sensor with the best results ending up somewhere between 3.5 – 5. Before reading this, I thought I had the perfect camera for imaging the sun with ASI174MM, but quickly realized that the 174 with 5.86µm pixels will be way too large for the native F7/560 Focal Length of the LS80. Even if I use 2x Powermate to increase the focal ratio to F/14 I will still only get to 2.4 resolution. It appears that the ASI174 is not going to be my best choice. I also have an ASI78MM that I have been using as a guide camera on my night scope. The 178 has 2.4µm pixel size which would give me around 2.9 resolution at the LS80’s native F7, or 5.8 if I use a 2x Powermate. The 178 also has a smaller chip which means that full disk imaging would be out of the question, meaning that mosaics are likely in my future if I want full disk images. The 178 also has a pretty slow frame rate at around 60fps.

This then brings me here to hopefully receive some helpful and knowledgeable advice. It does not appear that either the ASI174 or ASI178 are going to be the best camera options for the LS80. My first question, is this a fair assumption? Is the “magical” 3.5 – 6 range really that critical given other limitations like Seeing? What other high frame rate camera options are available that work well with the LS80, fall within the 3.5 – 5 range, give full disk in a single frame? My guess is if such a camera exist the price is likely going to be ridiculous. If i had to choose between the 174 with a faster frame rate or the 178 with the smaller pixels, which would be the better option? I would love to hear what other folks here are using for imaging with F/7 or similar scopes and any recommendations on the best imaging setup for the LS80. I guess given that the LS80 is on back order, I could reconsider this scope for imaging. However, I would prefer to find a way to make it work as I have read many positive reviews, including and older one by Mr. Ramsden found here.

Thank you in advance for the advice. I am looking forward to reading the responses.

AndrewJ


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Re: Camera Options for Lunt LS80 DS

Post by AJ132 »

Edit:
I went back and did some more digging and it appears the range of 3.5 - 5 was for white light imaging. For H-Alpha the optimal pixel size is supposed to be the F#/2.8 giving the maximum pixel size of 2.5µm. So it does appear that the ASI178 will work OK and the ASI174 could work if I use a 2.5x Powermate. So maybe I answered my own question...

Here is my Source: https://www.cloudynights.com/topic/6120 ... esolution/


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Re: Camera Options for Lunt LS80 DS

Post by Montana »

A very warm and sunny welcome Andrew :hamster: I think there are plenty of people on the site with a Lunt 80 so I am sure help will come some :)

Alexandra


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Re: Camera Options for Lunt LS80 DS

Post by marktownley »

Welcome indeed Andrew.

You have kinda answered your own question. I use 2 cameras, one for full disks and one for closeups.

Mark


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Re: Camera Options for Lunt LS80 DS

Post by AJ132 »

@Alexandra/@Mark.

Thank you for the warm welcome. Much appreciated.

There is a lot to get my head around when switching from deep sky to solar. For Deep Sky I use a camera with 6µm pixel size with an F/7 scope, which is right in the sweet spot of 1 - 3 Arcsec/pixel. So I was a bit shocked to learn for solar that I needed a camera with less than half that pixel size for a scope wit the same F Ratio.

I am really hoping that this new Lunt L80MT will be a good scope. I was a bit nervous about buy the "new" model now that they are phasing out the dedicated LS80Tha scopes in favor of the new modular design. That said, I also didn't really want to buy a scope that I may not be able to get accessories for down the road. Hopefully the performance on the modular scopes will be as good as the classics. I searched high and low and could not find any reviews on these new modular scopes from Lunt. Fingers crossed it will turn out to be a good scope.

Now all I have to do is figure out how to use it... I am sure I will be back with more questions once I get it setup.

All the best.

Andrew


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Re: Camera Options for Lunt LS80 DS

Post by mconsidine »

Coincidentally, I recently finished some measurements of Barlows for a Lunt 60 + ASI 174mm combo. Off of eBay/Amazon I bought an inexpensive 2x cell (svbony), a 2x Bushnell adapter (from which the cell could be unscrewed), a variable projection eyepiece adapter, and a 3x Barlow cell.

All are in 1.25" format. And I have not yet had a chance to experiment with the last two.

In any case, I set these up on an old refractor and took images with the zwo of a panel on a distant radio tower. Then I measured the size of the panel in each of the pictures and compared them to its size without a Barlow.

The 2x Barlows placed in the nosepiece of the camera had an effective power of 1.85, because they were closer than their design spacing (ive inferred the FL of the Barlow is about -50mm)

Putting the camera in the Bushnell as if it were an eyepiece gave an effective power of about 2.5x, because in that case the spacing is larger.

So your spacing is going to matter slot with the Barlow and you might well be able to what you need. I will eventually try putting a Barlow cell into the variable adapter, allowing me to dial in an ideal power, if I end up needing it. Or the 3x Barlow cell directly on the nosepiece may give me the ratio I need.

Fwiw,
Matt


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Re: Camera Options for Lunt LS80 DS

Post by solarchat »

those reviews have gotten a LOT of hits.


Stephen W. Ramsden
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Founder/Director Charlie Bates Solar Astronomy Project
http://www.solarastronomy.org
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