Lunt 152 H-Alpha dnd CaK

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MallinCam Jack
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Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

Long ago I owned a PST H-Alpha scope and severeal years ago I got a dual pressure tuned Lunt 80 H-Alpha scope. I have thoroughly enjoyed its performance and I just upgraded my permanent solar scope to a Lunt 152 mounted in tandem with a MallinCam VRC-10 on a CGE PRO. The views in H-Alpha with the 152 - received last Thursday - have been incredible. I also purchased the CaK module for this scope and to date my attempts to see anything using one of my cameras has failed. I have sent Rikki Hocking a Lunt an email regarding this, but also decided to post a question to this group.

Mainly, where does the CaK module achieve focus compared to the H-ALpha unit and will focus be achieved without the need for extension tubes?

Compared to imaging with H-Alpha, how much longer of an exposure is required to see anything on the PC screen? I know every camera's sensitivity is differentand I was using 1-2ms with H-Alpha. With CaK are we talking 20ms, 200ms, etc?

UPirs truly,

Jack Huerkamp


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Re: Lunt 152 H-Alpha dnd CaK

Post by solarchat »

Hey Jack,

I don't know what a Mallincam VRC-10 is but an online search reveals that it is an OTA? Is that also the camera you are using for CaK? Mainly, is it sensitive to 393nm wavelength #1. Then, did you buy the complete CaK module for the LS152 that replaces the rear end H-Alpha unit and looks like a diagonal Herschell wedge with a longer eyepiece tube that has a purple ring on it or did you buy a CaK diagonal that has a white body and long black tube that slides into a blank rear end assembly ? If so, the exposure would be a LOT lower than you would use for H-Alpha. Any sort of filter, like a green #58 celestron or something like a contrast booster, etc... can completely block out the CaK wavelength just in case you are using one.

If you can put an eyepiece into the CaK module and see anything you should be able to get a camera on it and focus it with either setup. A picture of the CaK setup would be helpful. I know that with the standard Lunt CaK wedge I had to have it almost all the way in to achieve focus with a short tube on a DMK51 camera.

Pedro Re' on this four,m uses the same setup, except not the mallincam and maybe he has some words of wisdom.


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Re: Lunt 152 H-Alpha dnd CaK

Post by Sunwatcher »

Good question Jack and welcome to the forum!

A CaK module arrived here last week and although it is still in the box bet the responses to your question will be a good value to me as well, Tommy


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Re: Lunt 152 H-Alpha dnd CaK

Post by marktownley »

Was it the CaK module specifically for the 152, or one of standalone diagonals?


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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

The VRC-10 is a Carbon Fiber Ricthey Cretien OTA that I have ridding in parallel with the Lunt152

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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

This is another view of the scopes:

Image

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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

The CaK Module includes the back plate, focuser and diagonal

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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

Here is the CaK Module and the H-Alpha Modules for comparison

Image

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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

Regarding the camera I was using, it is the 3MP SSI-L seen here:

http://mallincam.tripod.com/id58.html

It works extremely well on both the Lunt80 and with the Lunt152 in H-Alpha mode.

Here is a short video I obtained by just grabbing the screen on my computer using SnagIt and directly uploading the file to YouTube. I was using the dual pressure tuned Lunt80.

http://youtu.be/vKlIEM_qoZI

Regarding seeing anything through the CaK unit visually, I have not. I tried covering my head with a black cloth and trying to focus or see anything, and so far nothing. I tried placing the SSI-l camera into the CaK diagonal and varied the exposures greatly - still nothing.

Any suggestions?

Jack Huerkamp


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Re: Lunt 152 H-Alpha dnd CaK

Post by solarchat »

ok then. there is definitely something blocking the light then. You should definitely be seeing something visually and with the camera, focus or not.

1) after getting it pointed to the Sun, take out the CaK wedge completely and USING YOUR HANDS OR A PIECE OF PAPER ONLY---NOY YOUR EYES! see if light is coming through the objective and through the back of the scope.

2) look at both ends of the CaK module and make sure there isn't something silly like a plastic cap or a polarizer screwed into either side or inside the wedge.

3) with the sunlight still obviously coming through the Lunt scope, pout the wedge back on and look into the wedge without an eyepiece and see if you detect any violet light at all.

4) put eyepiece in, cover head with blanket, try to focus by coming all the way our or all the way in.
again, you are not adding anything to this setup like any sort of filter, polarizer, or weird eyepiece filter, etc.. right? just a straight up wide angle eyepiece in the 24-30 ish mm range?


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Re: Lunt 152 H-Alpha dnd CaK

Post by solarchat »

there isn't a metal cap screwed onto the objective end of that CaK rear end assembly, is there?


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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

I tried steps 1 through 4 on Wednesday.

1. The sunlight is definitely comint through the backplate and Crayford focuser of the CaK module. I passed my hand behind the focuser and could see the light on it.

2. I have taken a series of photos of the CaK module and focuser and below are the links to the images in my Photobucket album:

The backplate and focuser with CaK diagonal removed:

Image

The 1.25" aperture stop on the objective end of the focuser drawtube:

Image

CaK Diagonal End of Focuser Drawtube:

Image

Side view of the CaK diagonal:

Image

Focuser end of the CaK diagonal (with blue reflection of the wal behind me

Image

The eyepiece/camera end of the CaK Diagonal

Image

There does not appear to be anything like a plastic cap or polarizer in the light path.

3. I thought I saw a VERY faint violet light while I had my head under the black cloth and with no eyepiece in the CaK diagonal.

4. I used eyepieces from a 2" 60mm Kellner through the Lunt Zoom eyepiece and nowhere throughout the range of focuser travel could I see nothing - and no wierd stuff in the optical path - at least none that I installed.

Hopefully Rikki will get back with me because I am at a loss.

Thanks for your suggestions.

Jack Huerkamp


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Re: Lunt 152 H-Alpha dnd CaK

Post by marktownley »

Not seeing anything in CaK is fairly normal to be honest.

can you give us a few more details about the camera you are using please.


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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

That is what I have been told. That is why I tried out the camera. Here is some info on the MallinCam SSI-L

Full specs for the SSI-L sensor is available here:

http://www.sony.net/Products/SC-HP/cx_n ... 036lqr.pdf

Pixels size are 2.5 X 2.5 micron, Sensor side is 3 MP.
Maximum exposure is set to 8 seconds. The sensor can be binned.
The camera has a sealed chamber and is passive cooled.

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Re: Lunt 152 H-Alpha dnd CaK

Post by solarchat »

please don't take this as me understating the issue but, all of the actual statements that you are making imply that you just don't have the Sun in CaK centered on the chip or in the eyepiece.
I image and use CaK visual scopes almost every day and show them to over 80,000 people per year in my program so, if there's anything I know, its the reactions of people when they are first trying to find the Sun in CaK or H-ALpha. I know we don't know each other, but Im not someone who is just commenting without knowing what I am talking about.

The thing about CaK in the camera or the eyepiece is, it is absolutely pitch black until you happen upon the disk. You can sense it getting close with a histogram in the camera but only if you are very near it to begin with.

Some things that I noted in your responses are:

1) "i tried steps 1-4 the other day and it didn't work"

go try it again. :)

2) "I passed my hand under the focuser and saw the Sun's light" so I knew it was on the Sun.
Did you see a very intense, close to focus ball of light or just light in general? If your scope is centered on the Sun you should see a light circle representing the ambient light of the objective with a very bright unfocused light in the center that you can move in and out of focus with your hand. It will burn you if you focus it for more than second or two on your hand but it will also give you an idea of the focal point of the scope.


3) none of the references for the camera show its sensitivity to 393nm. It may not be very sensitive to this wavelength as it is outside the visible spectrum. It isn't uncommon for you not to see anything although I have never seen anyone that couldn't see at least a little something in a 6 inch refractor with a CaK wedge. This tells me that you just don't have it in the FOV.

4) "I saw a hint of violet in the diagonal without the eyepiece in"
This could be nothing or it could be that you were near the Sun but not on it.



do you happen to have a white light wedge or a piece of baader foil or glass solar filter you can use over the objective to get the sun centered and then quickly replace whatever you are using with the CaK wedge without taking off the entire back? This would ensure that you have the Sun in the center.

Im just trying to help. Rikki will just tell you to ship it back probably and since the images all look pretty normal, I don't think that is the issue. although the image from the objective side of the wedge does look really dark. I thought there was supposed to be a very shiny metallic erf in front of the CaK module. The one I have has it screwed onto the end of the focusing tube on the objective end of the entire rear end assembly. I own three Lunt CaK diagonals and each of them start off with a very shiny, mirror like erf. Yours looks like it has a polarizer in it, which would block the Cak light completely.
The absence of the ref would only make it extremely bright though, not darker.


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Re: Lunt 152 H-Alpha dnd CaK

Post by solarchat »

you don't happen to live near Atlanta, do you? just thought I would ask.


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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

No, I live about 40 miles NE of New Orleans. Hopefully I will get the issue resolved. I may just have to call Rikki at Lunt on Monday. The clouds are rolling in and it is not supposed to clear up until Tuesday. Nopefully by then I will have some direction.

Thanks for the offer.

Yours truly,

Jack Huerkamp


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Re: Lunt 152 H-Alpha dnd CaK

Post by marktownley »

I've not come across this camera at all before, and it's definitely not one i've seen used for solar at 393nm at all. I have had a look around but can't find a spectral response, if it has a built in uv/ir filter this may mean it can't be used at these short wavelengths.


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Re: Lunt 152 H-Alpha and CaK

Post by MallinCam Jack »

I will check with the camera's manufacturer to check into the sensor's spectral response. I have seen images taken by him with his other cameras but they use a different sensor.

Thanks.

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Re: Lunt 152 H-Alpha dnd CaK

Post by swisswalter »

Hi Jack

my money is on the UV/IR cut filter in front of the chip


Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

The manufacturer of the camera specifically orders the sensors without UV/IR cut filters and sells separate UV/IR cut filters for those who want them.

I just measured the light paths on the H-Alpha setup and the CaK. The CaK is about 1 1/2" less than that of the H-Alpha. The H-Alpha comes to focus with the 2" diagonal racked out about 1.2", so the CaK setup should achieve focus with the module racked out about 2". I will start there on Tuesday when clear skies are supposed to return.

Thanks to everyone for their assistance.

Jack Huerkamp


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Re: Lunt 152 H-Alpha dnd CaK

Post by swisswalter »

Hi Jack

good luck and fun in the sun


Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

from 7 am - 7 pm http://www.nanosys.ch

from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa ;)
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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

Well chaulk one up to operator error. :oops: This morning I set up the CaK module on the 152 and had the mount go to the Sun. I removed the CaK diagonal from the Crayford focuser and clearly saw the Sun's light on my hand behind the focuser. I put the CaK diagonal back into the focuser and added my MallinCam Xtreme instead of the MallinCam SSI-L. I saw what appeared to be an out of focus Sun and no matter what I did, I could not achieve focus. This had me baffled.

I then noticed light passing between the focuser housing and the drawtube. Obviously the light from the Sun was not being directed directly into the CaK module. I started moving the mount and found the "real" Sun. It was off to one side and I guess I was tring to focus a reflected image of the Sun.

This afternoon after a trip to New Orleans I contined to observe the Sun in CaK with the MallinCam Xtreme where I was able to use exposures between 1/30th second and 1/180th second. I switched to the SSI-L that I had originally tried to use and found that much longer exposures were required as its sCMOS sensor is not as sensitive as the CCD sensor in the Xtreme.

Today was not a good day to observe as a cold front had just passed and the trees were swaying due to extremely high winds. Hopefully conditions will be better tomorrow for further experimentaion.

Thanks to all who help try to resolve the issues with my CaK module.

Yours truly,

Jack Huerkamp


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Re: Lunt 152 H-Alpha dnd CaK

Post by solarchat »

Thats what I figured, it just wasn't on the chip. Oh well. Now you know.


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Re: Lunt 152 H-Alpha dnd CaK

Post by astrodanco »

Jack, after all that, you simply must post a CaK image for us using the camera in question. Please?


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Re: Lunt 152 H-Alpha dnd CaK

Post by swisswalter »

Hi Jack

congratulations. yes me to I wish to see a pic or two ;-)


Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

from 7 am - 7 pm http://www.nanosys.ch

from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa ;)
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Re: Lunt 152 H-Alpha dnd CaK

Post by MallinCam Jack »

I plan on doing so. Since Tuesday when I actually figured out what I was doing wrong the weather has been terrible. Today we had between 6" and 8" of rain with more coming tonight. On Sunday it is supposed to be clear and less windy, so I will attempt to grab some images and videos.

Yours truly,

Jack Huerkamp


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Re: Lunt 152 H-Alpha dnd CaK

Post by Derek Klepp »

Jack I will be interested in your Mallincam images as the camera I use The Gstar ex is very similar to the original mono Mallincam . I think they were developed independently many years ago. I have not upgraded as they are useful in so many different applications.
Cheers Derek


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