"Imaging Sunlight - Using a Digital Spectroheliograph"

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"Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

The "Imaging Sunlight - Using a Digital Spectroheliograph" book should be available next month.
Final cover.JPG
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This 290 page book covers everything from a historical review of solar observing, commercial filters available to the amateur, white light and narrowband solar imaging as well as extensive details on the construction and use of the SHG. Construction details and results from all the current SHG's from around the world are discussed, as well as the historical SHS.

I believe with the advent and application of fast frame cameras that the SHG will be able to replace the $$$$ commercial solar filters in the near future.

I acknowledge the help and assistance given by solar amateurs around the world in making this such a comprehensive book - especially Fred Veio who kept the dream alive.
(It is also dedicated - In memory of Walter Koch (Swisswalter) in acknowledgement of his contribution to amateur solar astronomy -"Only stardust in the wind")

I hope you find it interesting and informative.


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"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by solarchat »

OUTSTANDING!

Please allow me to advertise this book when it becomes available to our 70,000+ social media followers. I am overjoyed to read this.


Stephen W. Ramsden
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Founder/Director Charlie Bates Solar Astronomy Project
http://www.solarastronomy.org
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

Stephen,
Thanks for that!
I'll confirm when it's available - Springer says next month.....(it's been a looong wait, the final manuscript was submitted in Early Oct 2015)

Unfortunately there was one significant omission....the fantastic work of Walter J Semerau didn't make it to the final cut.
Semerau built various SHS and SHG's in the 1940 through the 1960's and his articles are mandatory reading:
Scientific American, April 1958
Sky&Telescope: (volume/page)
17/368
18/679
18/643
34/329
36/51

I'd be very interested to know what happened to him....
The last known address was in Zimmerman Blvd, Kenmore, NY.
Ken


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"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Derek Klepp »

Ken I look forward to it .I have seen a few friends and even family compile specialist books related to their hobbies/obsessions and know that it is a labour of love.Just pre-ordered it on Amazon so I won,t forget
Well done.


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by grimble_cornet »

Sounds great; you must elated to see the fruits of your hard work.
I love the dedication to Walter whose contributions and humour are greatly missed.


.

.



.


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by marktownley »

Superb, I will definitely be getting a copy :)


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by ham »

terrific ! hope to get your new book soon.


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

great!! cant wait until I get it

Ken as far as W J Semerau
I have one of those original S&T 1959 articles
I was 5 at the time
so
Im in my 60's now
if you assume he was in his mid twenties at the time
he would be in his 80's by now

you may want to contact Buffalo amateur astronomers (NY)
he was a member and I believe a board member at least until 1980's
they may know
your a known name in the AA field

I know address stated in 59 article was sold in the 2000's
that's a matter of public record in NY state


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Spectral Joe »

Walter passed away in November, 1996. Quite the craftsman, anyone who builds a Lyot filter gets a tip of my hat.


Observing the Sun with complex optical systems since 1966, and still haven't burned, melted or damaged anything.
Not blind yet, either!
Light pollution? I only observe the Sun, magnitude -26.74. Pollute that!
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by DSobserver »

:hamster:


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

well that solves the W J S mystery


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Carbon60 »

Congratulations, Ken. Looking forward to reading this.

Stu.


H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Wah »

Congratulations!


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Montana »

:hamster: :hamster: :hamster:


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

https://www.amazon.co.uk/Imaging-Sunlig ... g+sunlight
It now looks like the book will be available from the 9th June.....
I'll post a complete contents listing as soon as I can.
Enjoy!


"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
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Bojan »

Looking forward to this!


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by marktownley »

Excellent!


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

I've extracted the list of contents to give you and idea of the range of subjects covered:
Contents
1.0 Brief history of solar observations​
1.1 Early telescopic observations​
1.2 Solar Eclipses​
1.3 The Sunspot Cycle​
1.4 Photography​
2.0 Safe filters for solar imaging​
2.1 Glass Filters​
2.2 Neutral Density (ND) and Optical Density (OD)​
2.3 Multi-coated filters​
2.4 White light solar film filters​
2.5 Herschel Solar Wedge​
2.6 Chromosphere Filters​
2.6.1 Lyot Filter​
2.6.2 Fabry-Perot (F-P) filter​
3.0 The Sun and its atmosphere​
3.1 Our nearest star​
3.2 Measuring positions on the solar disk - Heliographic Coordinates​
3.3 Imaging the Photosphere​
3.4 The Solar Surface – the photosphere features​
3.4.1 Limb darkening​
3.4.2 Granulation​
3.4.3 Faculae​
3.4.4 Active areas and sunspots​
3.5 The chromosphere - an introduction​
3.6 Imaging the chromosphere​
3.6.1 Imaging the chromosphere - Hα filters and telescopes​
3.6.2 CaK filters​
3.6 3 Digital spectroheliograph (SHG)​
3.6.4 Chromosphere imaging terminology​
3.7 The solar atmosphere - chromospheric features​
3.7.1 Spicules​
3.7.2 Mottles and fibrils​
3.7.3 Plage​
3.7.4 Filaments and Prominences​
3.7.5 The Chromospheric network​
3.7.6 Ellerman bombs (Moustaches)​
3.7.7 Morton wave​
4.0 Solar observations using Spectroscopes​
4.1 Early spectroscopy​
4.2 Identification of elements using the spectrum​
4.3 Early use of spectroscopy in solar observing​
4.4 Spectrographs and Spectroheliographs (SHG)​
4.5 Persistence of vision​
4.6 Spectrohelioscopes (SHS)​
4.7 The digital spectroheliograph (SHG)​
5.0 The solar spectrum​
5.1 Spectral features in the solar spectrum​
5.2 Formation of the absorption lines​
5.3 Atlas of Solar lines​
5.4 Doppler and other spectral effects​
5.4.1 Doppler Effect
5.4.2 Zeeman Effect​
5.4.3 Magnetography and magnetograms​
5.4.4 Evershed Effect​
5.4.5 Severny Moustache (Flares and Ellerman Bombs)​
6.0 The Digital Spectroheliograph (Digital SHG) – Design basics​
6.1 The telescope​
6.1.1 Airy Disk, FWHM and PSF​
6.1.2 Telescope design and energy rejection filters​
6.1.3 Solar diameter vs. focal length​
6.1.4 Surface (Spatial) resolution vs. seeing conditions​
6.1.5 Focus tolerance​
6.1.6 Mounting​
6.1.7 Summary - telescope​
6.2 The spectrograph design options​
6.2.1 Classical Design​
6.2.2 Littrow​
6.2.3 Ebert-Fastie​
6.2.4 Czerny-Turner​
6.2.5 Summary –spectrograph optical arrangements​
6.3 The entrance slit​
6.3.1 Setting of the slit gap​
6.3.2 Measuring the Slit gap​
6.3.3 Length of the slit gap (Long slits)​
6.3.4 Field lens compensation​
6.3.5 Summary – entrance slit​
6.4 The collimator​
6.4.1 Summary - collimator​
6.5 Gratings​
6.5.1 Grating theory​
6.5.2 Mounting the grating​
6.5.3 Using the grating in 2nd Order and above​
6.5.4 Summary - gratings​
6.6 The imaging system​
6.6.1 Imaging camera​
6.6.2 CCD Chip size​
6.6.3 Pixel size​
6.6.4 Bayer matrix​
6.6.5 Surface (spatial) resolution​
6.6.6 Quantum efficiency​
6.6.7 Spectral Dispersion and Resolution​
6.6.8 Camera exposure times​
6.6.9 Frame rates/ Scanning rates​
6.6.10 Aspect Ratio and distortion​
6.6.11 Bandwidth selection​
6.6.12 Summary – imaging system​
7.0 Construction of a digital SHG – Two examples​
7.1 Final assembly checks for the SHG​
7.2 Calibration and spectral resolution​
7.3 Taking the AVI video​
8.0 SHG Processing Software​
8.1 Flats​
8.2 SpecHelio Bas​
8.3 IRIS​
8.4 Virtual Dub/ ImageJ​
8.5 Spectral Line Merge​
8.6 BASS Project​
8.7 Other Software​
9.0 Amateur digital SHG instruments​
9.1 Rondi​
9.2 Rousselle​
9.3 Poupeau​
9.4 Defourneau​
9.5 Zetner​
9.6 Smith​
9.7 Mete​
9.8 Chagniard​
9.9 Bartolick​
10.0 SHG Images and science achievements​
11.0 The Spectrohelioscope (SHS)​
11.1 Cœlostat, Heliostats and Siderostats​
11.2 Amateur SHS instruments​
11.2.1 Veio​
11.2.2 Slaton​
11.2.3 Higgins​
11.2.4 Bartolick​
12.0 Future solar imaging developments​
Appendixes​
Appendix A​
Summary of important solar wavelengths​
Fraunhofer lines​
Major Solar spectral lines​
Suitable target lines for Zeeman effect​
Appendix B​
SimSpec and SimSpecSolar design spreadsheets​
Appendix C​
Suppliers of components of interest to the amateur​
Appendix D​
Useful Solar/ Spectroscopy Forums​
Other websites​
Appendix E​
Selected bibliography​
Yahoo Technical Support Group​
Glossary of terms​
INDEX​

Hope this helps.


"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
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Montana »

My goodness! that looks like the most comprehensive solar book I have ever seen!

Alexandra


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

I hope so ;)


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http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by marktownley »

Excellent! Time to order a copy :)


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Carbon60 »

Looks to be very comprehensive indeed.

Congrats.

Stu.


H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by DSobserver »

Just bought it yesterday :band


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

I hope you find it interesting, informative and useful.
There's lot's of good useful stuff for all solar observers and imagers.


"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
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by marktownley »

Mine arrives tomorrow :)


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Derek Klepp »

Over here in Oz Mark it will be a while for me even with a pre order.


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

well its here for me
here is shot below my German Sonne lithograph :D

Nice tribute to SwissWalter
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by [whrudey] »

Congratulations Ken - just ordered my copy from Amazon.com

Bill


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

some positive comments over on CN....
Any feedback/ comments from the members??


"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
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by solarscope180 »

Great book, i have been reading it with great interest.
Ralph


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

chapter 8 (software) makes it all worth it to me
i also like the historical images (has any one tried to build an image by memory only?)

but i would not give a review until i absorb more (completion)


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Montana »

I have it but not read it yet :)
Alexandra


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Spectral Joe »

Particularly for those interested in building one of these, and also for explaining the nature of these to the unfamiliar, this is a well written overall view . The details necessary to construct a working instrument are there, the theory and history are explained and examples are given. One of the unfortunate things I have seen over the years is that people underestimate the magnitude of these projects and get frustrated after starting, when they realize that success isn't coming overnight. The process is laid out here in sufficient detail that the mystery is swept away and prospective builders can launch into the effort pre-informed. Even if you are not interested in building one of these it is worth reading, so as to have a more complete understanding of the "other" way of doing monochromatic imaging. Well done, Ken!


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Not blind yet, either!
Light pollution? I only observe the Sun, magnitude -26.74. Pollute that!
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

i like to try 6.7.13 to reproduce days of old

is 100u slit wide enough ?


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

Huggin's method was to find a prominence using a narrow slit setting, probably around 30 micron and then open up the slit gap, tangential to the disk to >1mm.
I've tried this, using the PST to locate the prom and then positioning the SHG (pre-tuned to Ha) slit to match.... fiddly but achievable.


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https://groups.io/g/astronomicalspectroscopy  
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by thesmiths »

I just received my copy today from Amazon. What an amazing amount of time and dedication to detail to produce such an impressive volume. I have copies of Ken's other two books on astronomical spectroscopy, which I bought and read mainly to understand solar spectroscopy (despite their being mainly oriented towards night-time work).

As Ken points out, the part of the SHG that is evolving the quickest today is the camera (due to continued advances in semiconductor technology). Ideally, a camera should have small pixels, a large chip size, excellent noise characteristics and very fast frame rate. This allows building smaller and lighter instruments with comparable resolution and faster scan speeds.

My SHG work was done with the ZWO ASI 120MM, a USB 2.0 camera with 3.75 micron pixels and 1280 pixels wide sensor. Although I have not done any SHG imaging in the last year, I would definitely look to upgrade my camera to something like the newer ZWO ASI 290MM, a USB 3.0 camera with 2.9 micron pixels and 1936 pixels wide sensor. This would probably allow a reduction by at least a factor of two in the data acquisition time. Also, the ASI 290MM, because of its back-illuminated CMOS image sensor, claims to have "two or more times the sensitivity in the visible-light region and three or more times the sensitivity in the near infrared light region" than previous Sony sensors.

The other area of SHG design that I think deserves more attention is better slit design. I used a Thorlabs 3mm long, 5 micron wide fixed stainless steel slit. The main problems with this choice are: 1) a bit too short [better if they were more than 5mm long]; 2) they easily get dirty and are difficult to clean; 3) there does seem to be some gradual damage to the metal from the intense solar radiation after long usage. Perhaps a better solution is a custom-made lithographically defined slit (e.g., chrome on quartz). These are often used now in night-time spectroscopy [chrome on quartz masks are used in semiconductor processing and hold up well under intense radiation]. This could either be a transmission slit or perhaps even a reflective slit. Such slits would be more uniform and more stable.


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

Douglas, thanks for the comments.....
I agree the SHG needs good quality long (>5-6mm) slit assemblies.
There are varying opinions as to whether or not they need to be fully adjustable - to maximise the usage across different telescopes/ focal lengths, spectrograph magnifications and camera pixel sizes.
Making a DIY slit assembly can be time consuming, but the results can also justify the effort.
I tried with the Spectra-L200 to offer the alternative of a rotary multi slit reflective slit plate. This provides a range of 6mm long slits from 19 to 100 micron. These are produced by etching the slit gap on a chrome plated glass (1.5mm thick) substrate. This arrangement works well for conventional spectrographs but does, I admit, have some restrictions for the SHG. I don't know if it is possible to replicate this design on quartz disks, but I can at least investigate.....


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"Astronomical Spectroscopy for Amateurs" and
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Carbon60
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Carbon60 »

Arrived in the post today. :)

Nice job, Ken.

Stu.


H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
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More images at http://www.flickr.com/photos/solarcarbon60/
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

going thru some software links
Wah!'s spectral line merge not listed in links??


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

Wah!, hasn't given a direct web link to his software...it exists as an email link...
I can however send anyone interested a copy from my files.
Let me know.


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"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

it would be nice if a link existed in this forum or this forum had a download section
or a section of links of all needed software collected in one point


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by marktownley »

highfnum wrote:it would be nice if a link existed in this forum or this forum had a download section
or a section of links of all needed software collected in one point
Start a thread with the info you want then we can sticky it at the top of the page :)


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by p_zetner »

Finally got my copy. A very nice read, Ken and a sorely needed, up to date, compendium of amateur achievements.

Cheers.
Peter.


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

ok


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Sungrazer »

Where is the best place to buy it and your other book in Sydney please ??


PST Double stacked usually on an EQ3, ZWO174mm, DMK21AU, QSI683wsg, MeadeLX200, ED80 on an EQ6, and some other stuff
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

Good question!
Honestly don't know, you'd have to check around.
I think most of the members have been purchasing from Amazon...
I'll be back in Oz next week, if you still have problems let me know - I can probably help..


"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
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

Sitting around a saltwater pool
In NJ I'm reading thru 7.5 about how to take avi sequence. Nice job on how to use eq mount setting to set up for sequence.

An idea poped in my head


Instead on turning off tracking before actual sequence set slew speed to a low value and then force tracking to that speed to shorten time it takes the sun
To run across slit


Would that work or introduce ugly things???


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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Merlin66 »

Yes, you can certainly use the fast slew rates of your mount to speed up the solar scan.
Wah! uses x2 or x4 sidereal rate.


"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
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by Spectral Joe »

The only limitations are exposure time (getting enough light) and how fast your camera can acquire the data. My instrument scans the solar image across the slit internally while the telescope is tracking. A full disk is done in 6 seconds.


Observing the Sun with complex optical systems since 1966, and still haven't burned, melted or damaged anything.
Not blind yet, either!
Light pollution? I only observe the Sun, magnitude -26.74. Pollute that!
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Re: "Imaging Sunlight - Using a Digital Spectroheliograph"

Post by highfnum »

Thx

Cool I gotta try at first opportunity


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