Any interest in a Spectroheliograph build?

[Merlin66 (Ken)]

Now I've committed to buying an ASI174MM camera (fast frame, ROI), I can get "serious" about the folded telescope/ Littrow spectroheliograph (SHG) build.
Is there any interest locally in discussing the design and construction?

Just a reminder - the SHG is capable of providing solar images at very narrow bandwidth (<0.2A) with the image wavelength anywhere in the visible spectrum - CaH/CaK, Fe, Mg, Na, Hbeta/Halpha etc. etc.
The total construction cost is less than the price of a large ERF (!) never mind the costs of the various etalon/ blocking filters.
Feedback welcome.

[rally]

Ken,

Any chance of a bit more detail in what is involved, skills, dollars, specialised extras etc

Rally

[Merlin66 (Ken)]

YRally,
Fulvio Mete has a pretty neat Littrow design based on a couple of small refractors:
http://www.lightfrominfinity.org/Hir...elioscopio.htm

Also Daniel Defourneau's very (very!) basic arrangement using "spare" bits and pieces.....
http://www.astrosurf.com/cieldelabrie/sphelio.en.htm

The attached image shows a basic SHG using a Skywatcher ST80 scope, feeding a Classical spectrograph (See: http://www.iceinspace.com.au/63-339-0-0-1-0.html ) and using a DMK41 to image the spectrum.
Summary:
A small refractor around 100mm aperture, no filters!
A hi-res spectrograph - around 500/600mm focal length with at least a 1200 l/mm grating
A fast frame camera as large and fast as possible! The ASI 174MM working in ROI seems close to ideal.
Costs?
If you have a suitable refractor and EQ mount then the additional cost is only the construction of the spectrograph (basically two lenses + entrance slit + grating) - say approx. $250 -$400.
Then use any video camera (AVI files) you have.
Processing software is readily available.
Hope this helps.

Some results from Peter Zetner (he uses photographic lens in his design)
http://www.pbase.com/p_zetner/spectr...graph&page=all

In the new book I examine ALL the current digital SHG designs from around the world and give full construction details as well as examples of the available software for processing.

[seaker78]

I wonder if anyone has obtained a L200 from JTW astronomy.
I have had an order and paid early June 2015 and have only received promises in more than 6 months.

[Merlin66 (Ken)]

Seaker78,
PM sent.

[Maurice]

Hi Ken

You've piqued my interest....
Can we talk via PM?

cheers
Maurice

[Merlin66 (Ken)]

Sure,
Just drop me a PM, or email to:
kenm(dot)harrison(at)gmail(dot)com.
Ken