my attempts at SHG images continued

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my attempts at SHG images continued

Post by highfnum »

still fighting with post image processing
but captures are getting better and cleaner

caH
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Re: my attempts at SHG images continued

Post by highfnum »

CaK
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Re: my attempts at SHG images continued

Post by highfnum »

caH orig
hey if anyone wants to process for comparisons be my guest
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Re: my attempts at SHG images continued

Post by DSobserver »

hello

you look t get a good slit.

Where did you get it?


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Re: my attempts at SHG images continued

Post by highfnum »

From merlin66


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Re: my attempts at SHG images continued

Post by DSobserver »

here is my contribution

Image

I would say that youhave to improve focus from the collimation lens : this is why the edge are focus but the surface is not as sharp.

I also would suggest you to try first Ha shot : indeed due to wavelenght, focus is easier


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Re: my attempts at SHG images continued

Post by highfnum »

So you say that prime image of sun on slit is a bit off?

MERCI for image!


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Re: my attempts at SHG images continued

Post by Wah »

Good clean slit and no de-banding is needed!


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Re: my attempts at SHG images continued

Post by DSobserver »

highfnum wrote:So you say that prime image of sun on slit is a bit off?

MERCI for image!
no, the focus of the lens after the slit. Indeed it is the most sensitive one.

How do you currently manage this ?


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Re: my attempts at SHG images continued

Post by highfnum »

Manually
just once without scope attached


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Re: my attempts at SHG images continued

Post by p_zetner »

The focusing does seem to be off. My technique: Before taking instrument into the field, adjust collimator and camera lens (without telescope in place) to get sharp spectral lines from an emission spectrum source (Ne, Na, Hg lamp, etc.) placed near the slit. Remaining focus, to be done in the field, is largely the telescope, with minor (repeat: minor!) tweaks of camera and collimator lenses. As Vincent mentions, the collimator is often the most sensitive adjustment.

Peter.


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Re: my attempts at SHG images continued

Post by highfnum »

thanks all for advice
did some tweak today

this may take several tries
before I get good feel for it

I hope I now qualify for entry into the SHG club
even at low tier


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Re: my attempts at SHG images continued

Post by marktownley »

Interesting to read your progress!


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Re: my attempts at SHG images continued

Post by DSobserver »

Here my advice base on friends advice and experience for a good focus :

1- I take my camera (450D) + long lens (400mm) a manage to get infinit focus to a mountain for example.
2- remove from your shg the telescope and the camera lens
3- oriente the SHG to the sun
4- through my 450D+400mm infinit, I manage to get a perfect slit image focusing the collimator (f/8 like this I avoid any specular light from the slit)
5- place again the camera lens on your shg and focus properly the spectra on the wavelenght you want
6- place the telescope and focus it in order to get a sharp spectra edge (in fact sun edge...)
7- adjust/finalise focus with camera lens

The longer the wavelenght the easiest it is to get a good focus....


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Re: my attempts at SHG images continued

Post by highfnum »

Ok
I think I understand
The slit edge should look sharp
As well as edge of sun within slit
space


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Re: my attempts at SHG images continued

Post by highfnum »

Marktownly your next!


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Re: my attempts at SHG images continued

Post by highfnum »

oversampling error
too many frames

then when i fixed clouds rolled in!

got two partials

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Re: my attempts at SHG images continued

Post by highfnum »

part with no clouds
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Re: my attempts at SHG images continued

Post by Merlin66 »

That's looking good, mate!
Keep it up.


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