SolarChat!

Hi, Ken Harrison,

I'm Toshio Ohnishi. I'm old amateur Spectrohelioscope maker.
Recently, I made short spectroheliograph. This is not completed yet.
I have some trouble about IRIS of C.Buil.
I using AZW174MM as CCD.I do't know to use ROT2 command.
What can I should do to ROT2 command? ROT command is OK.

Toshio Ohnishi

Toshio,
Welcome to the group!

I have limited experience with IRIS but will investigate the ROT2 command for you.
I would recommend that you download Wah!'s SLiM (Spectral Line Merge) program from the library section; it's much easier to use and is very effective.

Can you give us more detail of your SHG.

Welcome Toshio! I always admire your SHG images on facebook, glad you found your way here

Mark

welcome Welcome Toshio!
I also saw your recent post on daystar filters FB

Yes a lot of us use Wah! merge program

Toshio,
Looking at the command line structure of ROT2.....
Command: ROT2 [IN] [OUT] [XC] [YC] [ANGLE] [NUMBER]
where
[IN] - generic name of the sequence of images to be treated (e.g. Solar_in)
[OUT] - generic name of the rotated images (e.g. Solar_out)
[XC], [YC] - the pixel coordinates of the centre of rotation (e.g. 150, 400)
[ANGLE] - the applied rotation in degrees (e.g. 8)
[NUMBER] - the number of images in the sequence (e.g. 25).

Example
ROT2 Solar_in Solar_out 150 400 8 25

Thank you all.

Telescope 80mm FL=910
Collimator(Camera) 70mm FL=700
Grating 1800L/mm 5000A Brazed
Slit width=20micron
CCD ASI174mm

The SLIM is not work in my windows10.
When I push Merge button,it shows 'System.NullReferenceException'.

Toshio,
Hmmm
I think that means your AVI is larger than the 2Gb limit.
You need to use VDub to rope around the line of interest to reduce the file size.
Your SHG looks very impressive!!

Thank you Ken,

Even if 451MB,I got an error in SliM.
I do'nt understand this error message.

OK !
VDab-> SliM I could make 1 frame!
How can I save this frame?
I'm a beginner in this procedure.

I found out the new one in same old.avi folder.
I should become aware of saving method. So sorry!

SliM auto creates a TIFF file with same name as avi that went in - should be in same directory

Thank you highfnum.
I waiting for next clear morning.

I saw you are using binoviewer in optical path -- what is it for?

The binocular device is used to facilitate optical axis adjustment.
In order to use it as a spectrohelioscope, a littrow type optical system is not appropriate.
Off-axis light causes distortion.

Toshio,
I have a similar set-up using a 100/1300 scope an a 70/900 Littrow 1200 l/m grating spectrograph.
The only distortion is the slant of the absorption lines within the spectrum which is easily fixed. A similar system is used by Fulvio Mete (http://www.lightfrominfinity.org/Hirss% ... scopio.htm)
Do you have other distortions??

No, I have not other distortion.
My aim is to make a telescope to observe the sun by my eye.
But I have not succeeded yet.

Toshio,
Understood.
Which 20 micron entrance slit do you use - Thorlabs?
A SHS needs vibrating slits or Anderson prisms - see Fred's book (files area of the Yahoo Astronomical Spectroscopy group) or Chapter 11 of "Imaging Sunlight" (http://www.springer.com/gp/book/9783319248721)

My Hale vibrating slit made by razor blade.

H-alpha photo by old SHS is as follow.

Toshio,
Well done.
It looks like you understand the design requirements.
Look forward to seeing your future results.

Wow! fabulous image

Alexandra

that photo with SHS how was that taken
that's NOT using a merge program - correct?

My old SHS is as follows,
I need not use 'merge' soft.

Wow impressive!
So the 2 slits spin around I assume
To build image?

Kind of like mr Hale did way back when

John,
The small pin on the motor in the slot "oscillates" the two slit plates back and forth. See "Imaging Sunlight", sect 11.2.1 for more details.

Toshio,
Very nice results from a very nice SHS. Impressive!
Well done.

What is rate that slits vibrated

John,
Around 30-40 oscillations per second is needed for persistence of vision, p 66-67.

Maybe,for visual using oscillations is 20-30 per second vibration and for graphical using is 5-10 per second.
For photo it need not make vibrate so fast. Conposite procedure is useful for smoothing.

Hi Merrill55,
I am sorry that the SLiM has some problem to process the avi files because it is using an external library to decode the avi format.
If you use the mono 8bit or 16bit SER file format to capture the video, it should be able to support without problem (I hope)
I was too lazy to implement the code for 16bit SER vertical mode, please make the spectral lines horizontally while using 16bit SER.
Also, using ROI function to reduce the video resolution can help improving the processing speed and also the capturing frame rate.
Thanks!

Thanks Wah.
I'm beginner in SHG. So I must learn more about dogital procedure.
ROi is helpful for me.
I tried Vdub and SLim recently.
I Try to more experience about DigitalSpectroheliograph.

Thank you.

Toshio,
You may find the new book "Imaging Sunlight -using a digital spectroheliograph" useful.
It has a whole chapter on the various processing software currently available and how to use them for the SHG.

Trial h-alpha photo.

Very poor image.

Wow! that's a great close up, well done

Alexandra

Thanks Alexandra.

I will try to get more detail the solar surface.

Toshio

Toshio - do you know of any other SHG or SHS in Japan (amateur)

I know one amateur. His name is Takashi Sakae. He is a teacher of high school.

I don't know any other amateur without him.

Very nice

Ken - guess you have to update total counter

John,
Already done!!
I'll look at translating the documents.

My Christmas solar image is as follows;
Somewhat blur image.

Wow!! some lovely filaments, well done and Merry Christmas!
Alexandra

Merry Christmas all.
Have a nice holy night !!

Toshio (a part of HYLOV P.233)

Picture improved
Enjoy

Trial h-alpha photo by short SHG. 2016_12_31

Much better
Focus improvement is noticeable

Yes, it's shaping up. I see two immediate issues. First, there's a lot of stray light. This can be due to misplaced reflection traps, but in your case it's likely back reflections from the binoviewer. Second, there is noticeable vignetting in the direction along the slit, usually the result of not having the telescope objective imaged onto the grating. It's a common problem, fixed by using a field lens at the entrance slit. Overall, though. this is a very good start.

This is a massive improvement, that is a tremendous image
Alexandra

Bartolick;

Yes,I should pay attention to stray light. I recognize it.
Littrow lens cause a strong ghost.(Acromatic lens cause four goast)
The binoviewer cause a strong ghost of the slit shape.
Therefore I block it using red filter (R64) in the lower part of the binoviewer.
When I use other wavelengths, the use of the color filter corresponding to each will be necessary.

The serious problem is not good quality collimator lens which light passes twice.
I must exchange on an apochromatic lens.
Probably I think that the image becomes a little sharper.

Hi all;
Recent my SHG image.
Low contrast !!

Very nice prom in the south east
Alexandra

Very good!