Lunt Herschel Wedge

[Paul Haese]

Hi guys

I am planning on getting a lunt Herschel Wedge for solar white light imaging. As I understand it the wedge provides great views and is great for imaging.

Anyone have any experiences with these one way or the other? What issues do I need to be aware of. I am only planning to use this on my TSA 102 or similar scope.

I will not be getting this for many weeks yet as there is a back order.

[Dennis]

Hi Paul

Am I correct in my understanding that a Herschel Wedge should only be used with refractors and not reflectors of any type, be they SCT, Maks, etc.

I recollect reading this somewhere on the Baader website when I was researching astro solar film.

Cheers

Dennis

[Paul Haese]

Yeah its refractors only as far as I know. I think this has more to do with heat considerations than anything else.

[alocky]

I use one of these on the back end of my old 4" f15- it provides views far superior to my thousand oaks front glass. One thing to note, after being bounced from dealer to dealer I was finally advised by Takahashi Japan that they do not reccomend using these on the FSQ - but I am aware of plenty of people who use them on TV NP101s with no ill effect. I've heard anecdotally about an FSQ that did suffer damage to the rear doublet.
Obviously not a problem with your TSA- and well worth it. I would advise you to get polarizing filters for both 1.25" and 2", plus get the Lunt 2" to 1.25" adapter as there is no recessed slot in the 2" holder for a typical adapter's set screw.
Cheers,
Andrew.

[Rigel003]

I've seen some good images from these too, but it's not for the faint hearted having unfiltered solar light passing through your objective lens. I've been nervous ever since frying an eyepiece with an 8" newt when I was a lad. Try not to burn a hole in the side of your tube.

[Poita]

You will need the optional polarising filters to get decent photos, or the solar continuum filter or whatever it is called, which starts to push the price up towards the Baader wedge.

[alocky]

Actually - I've been able to get good pictures without the polariser, as the camera is much more tolerant than the eye. The polarisers are only really necessary for visual.
Cheers,
Andrew.

[Poita]

That is interesting. Which camera are you using? The Lunt I borrowed a while back gave much better results with a polarising filter, and the best results were with the continuum filter, but it could have been my camera/user or picnic error.

(Problem In Chair, Not In Camera)

[alocky]

Dmk41 worked well, I wasn't happy with the results from the DSLR owing to the difficulty in focussing accurately. You do need to fiddle a bit with the curves. I'll have a play with the polariser and see if it improves it - but either way it's necessary to see granulation visually and is a must-have accessory!

[frolinmod]

Paul, I was very happy with my ES102 triplet with 2-inch Lunt Herschel wedge and Baader Solar Continuum filter until last Saturday when I did a solar outreach event with a few other guys. One of them had a 6-inch SCT with a full aperture Baader Astrosolar film filter and a Baader Solar Continuum filter. We did a direct head-to-head comparison between the two scopes and the SCT won. The SCT showed far more detail. Fortunately I do have my own 8-inch SCT and a full aperture Baader Astrosolar filter for it. Next time we'll see who's scope shows more detail. Harumph!

[alocky]

Interesting data point. My 4" with Lunt wedge leaves my 10" newt with front glass filter for dead. The Baader film front filters must be pretty impressive to deliver results like that.
Cheers
Andrew.

[frolinmod]

The Baader astrosolar film leaves front mounted glass filters in the dust, no doubt about that. Glass filters are the worst, sorry. I was rather disturbed by how well it compared against the wedge too though. Too well for my fragile ego. Perhaps it's just that the 4" APO can't compete with the 6" SCT.

[alocky]

I think my FSQ is about to get Baader sunglasses!
:)

[frolinmod]

Oh, I forgot to mention that if you do get the Lunt wedge and you plan to do solar imaging with it, get yourself a UV/IR block filter as well, even if you're going to use a Baader Solar Continuum filter (it has an IR leak). Not an issue for visual use, of course.

For visual use you do need to cut down on the brightness. The Baader Solar Continuum filter works well. So does a polarizing filter. I use 2" filters and screw them onto a Baader 2"-1.5" adapter.

Some scopes don't have enough in focus to accomodate the Baader adapter when imaging (even though no problem for visual use). For imaging a Scopestuff 2" to C thread adapter works better. It has the appropriate threads for filters too.

If you get Baader Astrosolar film, I've seen fantastic imaging results from using it with an IRPASS filter. Check out the absolutely incredible white light images from Alessandro Bianconi on the solarchat forums.

http://solarchat.natca.net/index.php/en/this-is-solar-chat/1-wwwsolarastronomyorg-community-forum

[MortonH]

Anyone know if the Baader solar continuum filter is significantly 'better' than using the Lunt polariser? Just noticed that the Baader filter makes the image lime green!

Morton

[Poita]

Noticably better yes. Clearer granulation mostly.
Significantly better?
No. It is subtle. You can tell in images, but for visual I prefer the polariser, mainly because I don't enjoy the green colour.

[MortonH]

Good to know.

Thanks.

[dennisjames1]

I have a Lunt wedge with the ED 120 refractor and the polarizing filters. Great views and works well.

[MortonH]

Do you mean the Lunt polarizing filters? Wondering if you could just use a standard variable polarizer like the Orion model? That would keep the cost down significantly.

Think I also read somewhere that someone uses an orange filter (46% transmission) to give the view a "natural" orange colour.

Morton

[Poita]

I just use normal ones.
I think there is a long wait on wedges though.

[alocky]

The polariser and ND filters supplied by Lunt were both Baader items. There's no reason an Orion one would not work. The only consideration is that there isn't a lot of room left in the Herschel wedge for filters on the end of your eyepiece, and for obvious reasons you don't want to be putting them on the objective side of the wedge.
Cheers,
Andrew.