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Have an APM/Lunt Hershel Wedge: Need Filters.


LukeSkywatcher

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I just found this translation online. Its the German instructions i got with my wedge translated into English: Clears up any questions i had about which order to stack filters in.

Instruction Manual
APM/Lunt White Light Solar Wedge
The APM Herschel-wedge is a professional tool to observe the sun for the serious amateur astronomers. It requires careful and safe use. For photo or visual observations it requires additional filters and must be used with the ND3 filter which you can directly screw in the eyepiece and an additional Top Pol or Solar Continuum Filter.  At the eyepiece tube side of the wedge, only ~5% of the sun light leaves. This is not very hot anymore, but can be very bright light and must be reduced to less than 1:100.000 with the correct filters.
How to use the APM White Light Wedge?
Point your telescope away from the sun.
Place the White Light Wedge into your 1.25” focuser.
Install the filters into your eyepiece or camera adapter. ND3 filter closest to the wedge and polarizing filter closest to your eyepiece or camera.
Point the telescope at the sun and focus your telescope as usual.
The 1.25” Herschel wedge has no place for a screw in filter, so all filters have to be screwed at the front end of the eyepiece barrel or camera adapter.
The sequence is as following:
Telescope Focuser > Herschel-wedge > ND 3.0 Filter > Top Pol Filter >Eyepiece/Camera.
The ND 3.0 Filter as first after the Herschel-wedge is blocking most of the 5% light leaving the wedge, now all safety risk is past, but the image is still very bright.
Imagers will welcome such bright image for very fast exposures. By using an additional neutral density Filter or Top Polarizing Filter, the Imager can adjust the brightness corresponding to the exposure time they wish to get.
For Visual observers the image will still be too bright for comfortable observing. Therefore we recommend an additional filter after the ND 3 filter to dim the image. By using a Top Polarizing Filter between ND 3.0 and eyepiece you can adjust the brightness by rotating the eyepiece. Rotating the eyepiece with the Top Polarizing Filter changes the polarization between the Top Polarizing Filter and Herschel-wedge.  This makes it easy to dim or brighten the image and adjust for your favorite view.
At higher magnification you might want to brighten the image to gain enough light for high power observations.
Optional Accessories:
Baader Planetarium Solar-Continuum Filter:
The new Baader Solar Continuum filter is designed to enhance the visibility of solar granulation and sunspot details.  By transmitting a specific spectral region around 540nm, free of emission and absorption lines, the Solar Continuum filter is able to boost contrast and reduce the effects of atmospheric turbulence.   With the Solar Continuum filter in place, images snap to focus, and granulation becomes regularly visible.  Details at the limit of visibility become easier to hold, and image motion reduced.
The sequence for imaging use is as following:
Telescope Focuser > Herschel-wedge > Solar-Continuum Filter >ND 3.0 Filter > Eyepiece/Camera.
Warning !!!!
-Never use the Herschel wedge without an ND3 and Top Pol or Solar Continuum Filter!!! Otherwise permanent damage of your eyes may occur!!!
- Never leave the telescope unattended while it is pointing to the sun.
- Never use the Herschel wedge on a Newton telescope, catadioptric telescope like Maksutov or Schmidt-Cassegrain, the optics and the telescope can be destroyed.
- Never screw filters in front of the Herschel wedge. (Filters should never be between the telescope and Herschel wedge) The filters will crack and you risk damage to your eyes. Always place the ND3 Filter behind the Herschel wedge.
- The APM Herschel wedge has a heat trap integrated. The heat is directed from the prism to the rear end of the Herschel wedge. The rear red disc absorbs the heat. Caution, do not touch! The side vents to circulate cool air.
So it seems that the continuum filter really is the only optional extra which you can either buy or not buy. Glad i did buy one because it would be nice to be able to see some granulation. Is that possible when observing in white light?. Does anyone have any images of the Sun taken through a wedge and using the SC filter to see granulation?.
Would it look anything even remotely like this?, but on a smaller scale etc. 
Cheers
Paul                                
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I should point out that i know i wont see proms or filaments. I am just wondering about the level of granulation visible.

It very much depends on the seeing conditions Paul.

Which scope are you using?

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I thought you could see proms in white light you just needed a total eclipse to do it due to the glare from the sun ????

I couldnt tell you to be honest. As you can tell, i am a complete novice when it comes to solar observing. The eclipse on 20th Mar it seems will be 94% of totality from my location, so it might be a good time to really give the wedge and filters a good test drive. I just dont want to be faffing about too much with the scope etc on the day and miss the event. I have always assumed that proms etc are visible when using H-Alpha filters or Cak.

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Under great seeing white light can give photographic like visual images, https://www.flickr.com/photos/alexandra4/15276627726/in/photostream/  This is Montana' image- I hope she ok with me posting it...she is among the best solar imagers out there and this picture represents closely what I see under great skies with my 120mm @ 240x in the summer, in the morning. The granulation will look like "pepper" at low mags and as mag increases it takes on a "cellular" appearance.  The penembral filaments will look like eyelashes. Quite amazing really.

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I dont plan on changing anything on my solar set-up. For a few quid more, i probably could have just bought a bog standard PST. Not sure if they come with all the vital filter though.

Most likely not.

I bought a 46" flat screen LCD smart tv (Sony) about 3 yrs ago and believe it or not..................the plug was sold as a separate accessory.

I mean seriously.................selling a tv without a plug?.

The world has gone bonkers.

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Psts are plug in a standard eyepiece and play.

So all the filters needed to stop you going blind are in place when you buy?.

As they really should be.

Dont worry. I'm not about to start asking questions about PST's. 

I dont think i can rule one out further down the line. I'll see how i get on with my wedge and filters. If the bug bites me with solar observing.............who knows.

But for now..................couldnt be further from my mind.

You all have been very patient with me over the last couple of weeks regarding my venture into solar observing and i cant thank you all enough. I'm sure at times many of you have felt like telling me to shut up and go away (probably not the first time this thought has crossed your minds).

You didnt. Thats what makes SGL such a great place.

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Not at all mate. If we are talking astro, it's all good.

I'd suggest a quark or Lunt 50 rather than a pst by the way

Stop putting evil thoughts into my mind. You do know that i am now going to go and google a quark and Lunt 50.

No harm in looking. I'll just cut up my credit card first.

Thanks Shane............NOT. 

I was going to ask if i could in the future add a H-Alpha filter to my solar set-up. The Quark appears to answer that question.

I didnt even look at the price. Is it more a plug and play camera/eyepiece rather then a filter?.

Not interested. Now to google a Lunt 50.

*edit*

Not gonna have a Lunt 50 either.

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Now i have the filters at hand,they all make sense as well as your photos. I put the nd filter at the bottom of eyepieceadapter and the other two attach to the EP i use. I only need to use the top part of polarising filter as the wedge prism already polarises the view.

Correct?

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Yes that is correct. Assuming you can screw the next into the bottom of

the eyepiece holder and leave it, that's good. I screw on the top pol to the eyepiece and the baader SC into the top pol.

Upload some pics if you want confirmation.

Yep all of the filters are threaded on both ends and work the same as any other 1.25 filter ive ever used on any scope. To save me time while observing i plan to leave the filters in place in the EP adapter, so the only thing ill have to swap out is the ep i use.

To clarify.........ill be leaving the ND screwed into the bottom of the EP adapter which inturn screws into the wedge. At the top end of adapter right where the ep goes, ill be screwing in the Sc filter and polarisinf filter. This means every time i use the scope, all i have to do os screw in the ep from above and then tighten the retaining screw. Basically by doing this, i am safe and cant make the mistake of forgetting to put in place any of the 3 filters.

I had thought about screwing the ND filter directly into the wedge,just below the EP adapter instead of atthe bottom of the adapter tube. Im sure this wouls also be fine as the adapter could then be screwed into the top threads of the ND.

Im amazed at the psolarising filter. Its a case of now you see me.......now you dont. Its like some kind of wizardry

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