New Spectroheliograph construction (based on 102mm refractor)

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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

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Last edited by SunRick on Sun Jul 07, 2024 5:57 am, edited 1 time in total.


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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

thesmiths wrote: Sun Jul 07, 2024 3:30 am Was there a little more turbulence than you normally get? It looks like the features are slightly less distinct that your typical images.
Hi Doug,

Maybe so. I did not do any hi-res imaging today, so I am not completely sure. There were no hairy edges I typically have with poor seeing. But, a dip in the jet stream resulted in 60 - 70 knot winds today. Not so good. Also, there were some light cirrus clouds. That could have caused less distinctive detail due to forward scattering or some other such reason. What is your experience with cirrus clouds and SHG imaging? I probably should not have imaged!

Rick


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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

The seeing this morning was very steady.....much better than yesterday. So, these images should be sharper at full resolution. Lots of detail in the calcium image at full resolution.

Rick
Sun 7-7-24 SHG Image - h-alpha
Sun 7-7-24 SHG Image - h-alpha
Sun 7-7-24 new SHG h-alpha.jpg (2.5 MiB) Viewed 638 times
Sun 7-7-24 SJG Image - calcium
Sun 7-7-24 SJG Image - calcium
Sun 7-7-24 new SHG calcium-H.jpg (2.72 MiB) Viewed 638 times


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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by rsfoto »

Hi Rick,

Your SHG images are better then etalon made ones


regards Rainer

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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

rsfoto wrote: Sun Jul 07, 2024 6:04 pm Hi Rick,

Your SHG images are better then etalon made ones
Thanks Rainer,

I still am surprised by the calcium-H images. I have never seen one look like that with an etalon calcium filter. Those etalon calcium filters are typically 2 to 4 Angstroms wide. But, the SHG calcium-H image is 0.1 to 0.2 Angstroms wide.....over an order of magnitude narrower bandpass. There are narrow features at the center of the calcium-H line that the SHG can capture well.

For example, here is a partial single frame of a calcium-H scan. Look at the sunspot area at the right (shown by dark vertical continuum lines). Notice the tiny white details at the very center of the wide horizontal calcium line and also notice the white parts of the line with a narrow dark line at the very center. A wide etalon filter just cannot capture those narrow center-line details very well.

Rick
Partial calcium-H frame
Partial calcium-H frame
1 frame.jpg (36.93 KiB) Viewed 625 times


- 8-inch Astro-Tech RC
- Homemade Dobs of 20, 12.5, 10, several 8's, several 6's, 4.5 inches
- Explore Scientific 127 f/9.4 solar scope with Quark-C/Lunt 40mm double-stack
- Takahashi Epsilon 180ED
- Homemade 102mm spectroheliograph
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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by rsfoto »

SunRick wrote: Sun Jul 07, 2024 6:47 pm
rsfoto wrote: Sun Jul 07, 2024 6:04 pm Hi Rick,

Your SHG images are better then etalon made ones
Thanks Rainer,

I still am surprised by the calcium-H images. I have never seen one look like that with an etalon calcium filter. Those etalon calcium filters are typically 2 to 4 Angstroms wide. But, the SHG calcium-H image is 0.1 to 0.2 Angstroms wide.....over an order of magnitude narrower bandpass. There are narrow features at the center of the calcium-H line that the SHG can capture well.

For example, here is a partial single frame of a calcium-H scan. Look at the sunspot area at the right (shown by dark vertical continuum lines). Notice the tiny white details at the very center of the wide horizontal calcium line and also notice the white parts of the line with a narrow dark line at the very center. A wide etalon filter just cannot capture those narrow center-line details very well.

Rick

1 frame.jpg
Hi Rick,

Excellent. Unfortunately I can not continue with my Sol'Ex due to problems with my mounts and that is desesperating so I opted to sell it and forget about SHG imaging. Financially I can not afford new mounts in the carrying capacity I have. F...k the chinese iOptron mounts CEM 120 EC2. Sorry, Rant over. :evil:


regards Rainer

Observatorio Real de 14
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North 22° West 101°
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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

rsfoto wrote: Sun Jul 07, 2024 6:04 pm Hi Rick,

Excellent. Unfortunately I can not continue with my Sol'Ex due to problems with my mounts and that is desesperating so I opted to sell it and forget about SHG imaging. Financially I can not afford new mounts in the carrying capacity I have. F...k the chinese iOptron mounts CEM 120 EC2. Sorry, Rant over. :evil:
Hi Rainer,

I am curious what exactly your mount problem is with respect to SHG imaging. Is it a consistent scan speed or something else?

Rick


- 8-inch Astro-Tech RC
- Homemade Dobs of 20, 12.5, 10, several 8's, several 6's, 4.5 inches
- Explore Scientific 127 f/9.4 solar scope with Quark-C/Lunt 40mm double-stack
- Takahashi Epsilon 180ED
- Homemade 102mm spectroheliograph
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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by rsfoto »

SunRick wrote: Mon Jul 08, 2024 12:46 am
rsfoto wrote: Sun Jul 07, 2024 6:04 pm Hi Rick,

Excellent. Unfortunately I can not continue with my Sol'Ex due to problems with my mounts and that is desesperating so I opted to sell it and forget about SHG imaging. Financially I can not afford new mounts in the carrying capacity I have. F...k the chinese iOptron mounts CEM 120 EC2. Sorry, Rant over. :evil:
Hi Rainer,

I am curious what exactly your mount problem is with respect to SHG imaging. Is it a consistent scan speed or something else?

Rick
Hi Rick,

Inconsistent mount speed and I got tired of waiting with a standing mount so the Sun crosses by itself over the slit.

:mrgreen:


regards Rainer

Observatorio Real de 14
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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

rsfoto wrote: Mon Jul 08, 2024 2:34 pm
Hi Rick,

Inconsistent mount speed and I got tired of waiting with a standing mount so the Sun crosses by itself over the slit.

:mrgreen:
Hi Rainer,

I looked up that mount, and it is described as an observatory-class mount! It is expensive! It has a 115 lb. capacity and precision stepper motors and good periodic error. It should be way better than my 27-year old AP900 QMD mount that has worse periodic error and lower weight capacity and ancient stepper motors! My mount is not even GoTo. I am sad for you that your mount does not work for SHG. I know how frustrating that must be.
:mad:

Rick


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- Homemade Dobs of 20, 12.5, 10, several 8's, several 6's, 4.5 inches
- Explore Scientific 127 f/9.4 solar scope with Quark-C/Lunt 40mm double-stack
- Takahashi Epsilon 180ED
- Homemade 102mm spectroheliograph
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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by y3000 »

SunRick wrote: Tue Jul 09, 2024 12:56 am
rsfoto wrote: Mon Jul 08, 2024 2:34 pm
Hi Rick,

Inconsistent mount speed and I got tired of waiting with a standing mount so the Sun crosses by itself over the slit.

:mrgreen:
Hi Rainer,

I looked up that mount, and it is described as an observatory-class mount! It is expensive! It has a 115 lb. capacity and precision stepper motors and good periodic error. It should be way better than my 27-year old AP900 QMD mount that has worse periodic error and lower weight capacity and ancient stepper motors! My mount is not even GoTo. I am sad for you that your mount does not work for SHG. I know how frustrating that must be.
:mad:

Rick
The more expensive harmonic mount I recently purchased is not as effective as the Celestron CG5-SGT, which I have been using for over 20 years. The harmonic mount always produces peach shaped of a disk, not a perfect circle . :shock:


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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by rsfoto »

y3000 wrote: Tue Jul 09, 2024 8:53 am
SunRick wrote: Tue Jul 09, 2024 12:56 am
rsfoto wrote: Mon Jul 08, 2024 2:34 pm
Hi Rick,

Inconsistent mount speed and I got tired of waiting with a standing mount so the Sun crosses by itself over the slit.

:mrgreen:
Hi Rainer,

I looked up that mount, and it is described as an observatory-class mount! It is expensive! It has a 115 lb. capacity and precision stepper motors and good periodic error. It should be way better than my 27-year old AP900 QMD mount that has worse periodic error and lower weight capacity and ancient stepper motors! My mount is not even GoTo. I am sad for you that your mount does not work for SHG. I know how frustrating that must be.
:mad:

Rick
The more expensive harmonic mount I recently purchased is not as effective as the Celestron CG5-SGT, which I have been using for over 20 years. The harmonic mount always produces peach shaped of a disk, not a perfect circle . :shock:
That is exactly the same problem I had eg. I have...

:bow2


regards Rainer

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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by thesmiths »

Most mounts are not necessarily built to slew at a constant rate of e.g. 16x sidereal rate. In fact, I think heavy capacity mounts will typically gradually accelerate and decelerate, leading to a very non-uniform scan. Older and cheaper mounts are often better. Rick's old AP900 looks like one of the best I've seen. There's probably a way to build a mount with encoders that would give an extremely constant slew rate.


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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by rsfoto »

thesmiths wrote: Tue Jul 09, 2024 4:28 pm Most mounts are not necessarily built to slew at a constant rate of e.g. 16x sidereal rate. In fact, I think heavy capacity mounts will typically gradually accelerate and decelerate, leading to a very non-uniform scan. Older and cheaper mounts are often better. Rick's old AP900 looks like one of the best I've seen. There's probably a way to build a mount with encoders that would give an extremely constant slew rate.
Hi,

Taking into account what you wrote above I started to give a startup time of about 10 seconds and a rest time of another 10 seconds, eg. I let the mount slew 10 seconds before it touched the Sun and then quit acquiring video 10 seconds after Sun disappeared and the results was

NO Success...

:shock:

I do not have the patience anymore as well as not the financial means to start all over again. I am tired... :|


regards Rainer

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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

thesmiths wrote: Tue Jul 09, 2024 4:28 pm Most mounts are not necessarily built to slew at a constant rate of e.g. 16x sidereal rate. In fact, I think heavy capacity mounts will typically gradually accelerate and decelerate, leading to a very non-uniform scan. Older and cheaper mounts are often better. Rick's old AP900 looks like one of the best I've seen. There's probably a way to build a mount with encoders that would give an extremely constant slew rate.
When I push my N or S button on the hand paddle to start a 16X scan, there is typically just 1 to 2 seconds until the scan reaches the edge of the sun. I know I have inadvertently started scanning with less than 1 second until the slit hit the sun's edge.....and it still worked fine. I don't know where my limit is, but there is no benefit to finding out. Presumably, there must be some short acceleration time. 23 lb. of SHG weight at 40 inches long is a lot of inertia to overcome.

I think part of the problem is that mount manufacturers don't think there is value to a super-consistent slew speed at 16X. Typically, that would be used for manually centering an object after a go-to command......or scanning across the moon or sun while visually looking through an eyepiece. So what if it varies from 15X to 17X.....who cares? With go-to slewing, destination accuracy is important.....but not the speed consistency of slewing there.

I have to believe the rock-steady 16X slewing both N and S of my AP900 QMD mount is a lucky design accident, with the way it was made just working out that way. I can't believe that super-consistent 16X slewing was a priority for Roland at Astro-Physics 27 years ago. Maybe I'm wrong....but I'll shoot an email to AP asking them.

Rick


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- Explore Scientific 127 f/9.4 solar scope with Quark-C/Lunt 40mm double-stack
- Takahashi Epsilon 180ED
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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by y3000 »

rsfoto wrote: Tue Jul 09, 2024 4:32 pm
thesmiths wrote: Tue Jul 09, 2024 4:28 pm Most mounts are not necessarily built to slew at a constant rate of e.g. 16x sidereal rate. In fact, I think heavy capacity mounts will typically gradually accelerate and decelerate, leading to a very non-uniform scan. Older and cheaper mounts are often better. Rick's old AP900 looks like one of the best I've seen. There's probably a way to build a mount with encoders that would give an extremely constant slew rate.
Hi,

Taking into account what you wrote above I started to give a startup time of about 10 seconds and a rest time of another 10 seconds, eg. I let the mount slew 10 seconds before it touched the Sun and then quit acquiring video 10 seconds after Sun disappeared and the results was

NO Success...

:shock:

I do not have the patience anymore as well as not the financial means to start all over again. I am tired... :|
Whether using 8x low speed or 48x high speed, my harmonic mount always cannot guarantee to get the circular disk even if I reserved 10 seconds slew
before record scanning. So for the SHG scan , I have to use my old CG5-SGT mount . :roll:


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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by thesmiths »

y3000 wrote: Wed Jul 10, 2024 3:03 am Whether using 8x low speed or 48x high speed, my harmonic mount always cannot guarantee to get the circular disk even if I reserved 10 seconds slew
before record scanning. So for the SHG scan , I have to use my old CG5-SGT mount .
Is your harmonic drive mount from ZWO or another manufacturer? I have seen C. Buil use the AM5 (at 20x) to good effect.

I use an HEQ5 Pro with a belt drive upgrade. It works quite well, but I think Rick's AP900 is better.


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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by y3000 »

thesmiths wrote: Wed Jul 10, 2024 4:27 am
y3000 wrote: Wed Jul 10, 2024 3:03 am Whether using 8x low speed or 48x high speed, my harmonic mount always cannot guarantee to get the circular disk even if I reserved 10 seconds slew
before record scanning. So for the SHG scan , I have to use my old CG5-SGT mount .
Is your harmonic drive mount from ZWO or another manufacturer? I have seen C. Buil use the AM5 (at 20x) to good effect.

I use an HEQ5 Pro with a belt drive upgrade. It works quite well, but I think Rick's AP900 is better.
Not ZWO, but WD-17s.
My 20 years old Celestron CG5-SGT works well with SHG scan for me too.


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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

The seeing and transparency were both very good again this morning.....with calm winds. I finished just before the usual summer fair-weather cumulus cloud field started forming, just before 10:00 AM. Summer is great for solar imaging! Here are 2 spectroheliograms (h-alpha and calcium-H).

Rick
h-alpha SHG 102mm f/7, 7/11/2024
h-alpha SHG 102mm f/7, 7/11/2024
Sun 7-11-24 new SHG h-alpha.jpg (2.65 MiB) Viewed 234 times
Calcium-H SHG 102mm f/7 stopped to 72 mm. 7/11/2024
Calcium-H SHG 102mm f/7 stopped to 72 mm. 7/11/2024
Sun 7-11-24 new SHG calcium-H.jpg (3.17 MiB) Viewed 234 times


- 8-inch Astro-Tech RC
- Homemade Dobs of 20, 12.5, 10, several 8's, several 6's, 4.5 inches
- Explore Scientific 127 f/9.4 solar scope with Quark-C/Lunt 40mm double-stack
- Takahashi Epsilon 180ED
- Homemade 102mm spectroheliograph
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Re: New Spectroheliograph construction (based on 102mm refractor)

Post by SunRick »

There were some nice sunspot groups on the sun today. It was another morning of clear skies, very steady seeing, and calm wind (with this continuing tropical airmass). It is certainly very warm and humid when imaging.....but worth it! I just love SHG imaging as a great morning activity during my retirement. I know.....I should be golfing instead.....but what can I say.....I'm a geek! I can do that other stuff during solar minimum. :lol:

Rick
102mm f/7 spectroheliograph h-alpha 7/12/2024
102mm f/7 spectroheliograph h-alpha 7/12/2024
Sun 7-12-24 new SHG h-alpha.jpg (2.37 MiB) Viewed 136 times
102mm f/7 spectroheliograph (stopped to 72mm) calcium-H 7/12/2024
102mm f/7 spectroheliograph (stopped to 72mm) calcium-H 7/12/2024
Sun 7-12-24 new SHG calcium-H.jpg (2.7 MiB) Viewed 136 times


- 8-inch Astro-Tech RC
- Homemade Dobs of 20, 12.5, 10, several 8's, several 6's, 4.5 inches
- Explore Scientific 127 f/9.4 solar scope with Quark-C/Lunt 40mm double-stack
- Takahashi Epsilon 180ED
- Homemade 102mm spectroheliograph
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