Discussing a possible design for a SHG with a local guy, I got thinking......
Why not "trial" a white light version just to tune the acquisition speeds/ software...could we come up with an "acceptable" white light scanned image????
The idea is pretty simple - you add a slit to the end of your favourite white light scope then image the slit gap with a camera lens/ DMK.....
As the slit scans across the solar disk you generate a series of "white light" strips - to be combined into a final image...
Hmmm sounds like a good mini- learning project.
Keep you posted...
White light non-spectrohelioscope
- Merlin66
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White light non-spectrohelioscope
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
https://groups.io/g/astronomicalspectroscopy
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
Re: White light non-spectrohelioscope
There's two ways to do this - during capture or post processing.
Post processing thoughts first:
It's possible to capture at a rate X then in software sample at a lower rate. Interpolation allows for fractional variation. This takes more imaging storage space but allows the fine tuning of the sampling rate to create a circle.
The main issue is that the earths atmosphere will change the rate as the sun rises, peaks and then retreats due to the bending of light.
Lastly - it would be prudent to image and stack the slit in realtime then assemble the stacked slit images.
Capture - guide assistance
A guider that can capture basic details - such as sun spots - can be used to provide a registration point. This could be done in a set of ways:
* FFT alignment with an updated reference image to keep up with solar changes
* FHWM of the solar disk itself - probably best to make a multi-point to cope with convection.
The resulting registration point allows the accurate positioning of the slices.
Oddly enough my own app is built for realtime processing (already has a form of FFT alignment, stacking etc)
Lastly it's possible to transform and register the spectra against known spectra.. a sort of astrotortilla but for spectra.
I think that the main issue is slit-wide resolution.. perhaps a diagonal scan is more preferable in this instance - map and then drizzle.
Post processing thoughts first:
It's possible to capture at a rate X then in software sample at a lower rate. Interpolation allows for fractional variation. This takes more imaging storage space but allows the fine tuning of the sampling rate to create a circle.
The main issue is that the earths atmosphere will change the rate as the sun rises, peaks and then retreats due to the bending of light.
Lastly - it would be prudent to image and stack the slit in realtime then assemble the stacked slit images.
Capture - guide assistance
A guider that can capture basic details - such as sun spots - can be used to provide a registration point. This could be done in a set of ways:
* FFT alignment with an updated reference image to keep up with solar changes
* FHWM of the solar disk itself - probably best to make a multi-point to cope with convection.
The resulting registration point allows the accurate positioning of the slices.
Oddly enough my own app is built for realtime processing (already has a form of FFT alignment, stacking etc)
Lastly it's possible to transform and register the spectra against known spectra.. a sort of astrotortilla but for spectra.
I think that the main issue is slit-wide resolution.. perhaps a diagonal scan is more preferable in this instance - map and then drizzle.
Re: White light non-spectrohelioscope
Ken, you could also set a scope up in the daytime and point at a distant scene and just turn on the drive to scan this scene across the slit. Hold the fast button for accelerated scans.
Chris
Chris
Chris Schur
----------------------------------
Birch Mesa Observatory, Payson Arizona
Clear Creek Canyon Observatory, Happy Jack, Arizona
----------------------------------
Birch Mesa Observatory, Payson Arizona
Clear Creek Canyon Observatory, Happy Jack, Arizona
Re: White light non-spectrohelioscope
Good point - or you could use a circular target with a lower fl scope/lens at the end of the garden. Just use a laser pointer to align the centre point.
- swisswalter
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Re: White light non-spectrohelioscope
Hi Ken
that project sounds great
that project sounds great
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE
from 7 am - 7 pm http://www.nanosys.ch
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from 7 am - 7 pm http://www.nanosys.ch
from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa
Re: White light non-spectrohelioscope
Nick wrote:There's two ways to do this - during capture or post processing.
Post processing thoughts first:
It's possible to capture at a rate X then in software sample at a lower rate. Interpolation allows for fractional variation. This takes more imaging storage space but allows the fine tuning of the sampling rate to create a circle.
The main issue is that the earths atmosphere will change the rate as the sun rises, peaks and then retreats due to the bending of light.
Lastly - it would be prudent to image and stack the slit in realtime then assemble the stacked slit images.
Capture - guide assistance
A guider that can capture basic details - such as sun spots - can be used to provide a registration point. This could be done in a set of ways:
* FFT alignment with an updated reference image to keep up with solar changes
* FHWM of the solar disk itself - probably best to make a multi-point to cope with convection.
The resulting registration point allows the accurate positioning of the slices.
Oddly enough my own app is built for realtime processing (already has a form of FFT alignment, stacking etc)
Lastly it's possible to transform and register the spectra against known spectra.. a sort of astrotortilla but for spectra.
I think that the main issue is slit-wide resolution.. perhaps a diagonal scan is more preferable in this instance - map and then drizzle.
Hi Nick!
Do you gave any info on this app? Sounds really interesting.
Cheers
Alex