Trying the Lunt Herschel wedge.

[ollypenrice]

An occasional guest called in yesterday afternoon to try his Lunt Hershel wedge (with polarising filter and neutral density filter fitted) in something larger than his own Tak FS60.

We already had a Lunt 60 double stack Ha scope on the sun so we put his Herschel Wedge in an Altair Astro 102 Triplet for a try out. This is an exceptionally good refractor, F7, which gives a textbook star test across the field.

The detail seen in the Lunt wedge was downright astounding. We went up to about 180x and had perfectly crisp seeing, allowing miniscule details in the plages of a huge sunspot to show in exquisite detail. The owner was disappointed not to see granulation because he does see it in the little Tak, so maybe for that purpose less light would be better.

This was by far the best white light view of the sun I've ever had, better, even, than a C11 with Baader film. This C11 is a one-off with custom corrector and parabolic secondary, a great scope, so I think the Lunt wedge was beating the Baader film by some margin.

The Lunt doesn't pour out heat through a grill (a recipe for igniting ties, as Brian B once said!) but has a heat sink at the rear. It worked fine. My only fear with these devices is that someone buying second hand might not be able to read the instructions. They are refractor only and need the extra filtration mentioned above at the EP.

The party ended when, quite suddenly and for no obvious reason, the seeing went down the drain.

The owner of the custom C11 then swung it onto a daytime Venus but that's another story...

Olly

[johninderby]

Yes a good Herschel wedge does beat the best solar films. I'm using a Lunt 1.25" wedge at the moment. It's not quite as good as the Baader wedge I used to have but it is a lot cheaper.

http://stargazerslounge.com/showthread.php?t=184075&highlight=lunt

John

[Merlin66]

I built my own Herschel wedge from a F2 30 degree prism and used it on the Vixen 80/910.

The views were, as you say, even more crisp than with the usual 4" and Baader film.

I've recently, more by luck than judgement, aquired a 2" Baader Cool wedge....

It's currenly sitting on the "Big Yin" - 150/1200 achromat just waiting on the clouds to clear - no "first light" yet but I'm sure the results will be spectacular!!

(The average granulation size is around 7000 Km, with a life of about 18 minutes - you need enough magnification and seeing conditions to resolve 1 to 1.5 sec arc to really pull them out)

[iwatkins]

Baader Cool Ceramic here too. Very happy with it, the views are excellent.

Also on a 150/1200 which is called Big Bertha

Still waiting for some clear sky to try it with my DMK41 but shot below is from a DSLR using EP projection on a Hyperion 8mm.

Cheers

Ian

[ollypenrice]

Hmmm, I have a 150/1200 myself and never use it. I smell a project!!

Olly

[iwatkins]

And now you've dug a nice new area, there you go, new solar observatory.

Cheers

Ian

[Merlin66]

Olly,

Now you're moving over to the "bright side" why not maximise the opportunities of your great site to do some spectroscopy? There's an ever growing strong spectroscope group in France and plenty of work for everyone.

(You'll be blown away by the WL/ wedge results on the 150!!)