[Edited Message Follows]

Brian - Good video.? Thanks

FYI - I use these for locking my RA on my GM811G.? All parts are from Ace Hardware.? I think the total cost is around $19.

2x each

• Plastic handle
• 3/8 - 16 stud (I think its 2" long)
• 3/8 washer (To increase contact surface area and protect the rubber washer)
• Hard rubber washer (For compression tightening of RA)?
• 3/8 washer (To increase contact surface area and protect the rubber washer)
• Fiber washer (To protect the mount finish)

EDIT - I used epoxy to secure the 3/8" studs into the plastic handle.? You can also use?Loctite Threadlocker Red 271.

Hi Tim,

As I discover more about getting better planetary images, I will give that advice freely.? ?And I do have some new things to share...??here is what I discovered:

First of all...the photo attached is surely my best final imsge.? Again, I used the C14EdgeHD ... manually focussed with the telescope focus knob (expecting a motor focusser to come in later this week).? ?Seeing was better than average that night, but not as perfect as Clear Sky Chart sometimes shows rarely.? That picture should have turned out badly on a 14 inch scope.? But it didn't....

?It was shot on the ZWO ASI224 camera (3.75 um pixel size) at f/11... With a ZWO ADC atmospheric dispersion corrector in place in front of the camera.? It was shot at prime focus with a 1.25 inch visual back...no Crayford for fine focus. A nice Crayford I have put the camera image plane too far back of the 5.75 inch recommended image plane distance.? In that scope you can be inside of 5.75 inches, but image sharpness gets worse past 5.75 inches.? It's a critical element of the EdgeHD scopes that I did not know when I bought it (used earlier this year).??

At the time of that video recording, I did not use a UVIR filter and so about 20% of the Red light was from long wavelength IR.? I only discovered that difference the following night...so use a UVIR filter to improve contrast.? I now use that UVIR in the cameras front nosepiece.

There were a few "rules of thumb" that were told me years ago when I first tried planetary imaging.? They were:

1. Rule: Only try imaging when the Clear Sky Chart shows excellent (darkest color bars) for seeing.? I find this to be wrong:? I'll explain.? The Clear Sky Chart is not able to say that there may be short windows of excellent seeing maybe 30 minutes or so, between periods of turbulent air.? It just gives the overall prediction for its time window.? Sometimes you get very lucky if you are set up and shooting... And sometimes it predicts perfect seeing and that wish does not come true either. It really is "lucky imaging."

[ See the incredible images from? Anthony Wesley of Australia....here:

Anthony Wesley explained that his best image came from a night he was not expecting great seeing, but then, the sky stabilized and...voila.? (He has a fabulous scope, a Robert Royce 16 inch Newtonian mirror...essentially flawless.? That sure helps!) ]

2.? Rule: You must use the f# that is "5x your video camera pixel um size". You are supposed to use a 2x or 2.5x (best is a Tele vue Powermate) to get the f#.? Example: on my ASI224MC camera, with it's 3.75 um pixels... this means I should be trying to get f/18.5.? so by that rule, I should have used a 2X tele to get my f11 scope to be f/22.? Yet I find this wrong too...I got the incredible image attached using that ASI224 at f/11.? ?

Why did f/11 and no 2x tele work???

When you use a 2X tele, you get 1/4th the light into each pixel.? So to get the exposure to be say 80% of full, you need 4X the exposure time.? If the seeing is so-so not perfect, the longer exposures blur out the image frame.? Using no 2X at all gives a 4X faster exposure so can "freeze" the seeing and get you clearer frames.

And for the same exposure time, say 180 sec, you get 4X the number of frames without the 2X tele.? I got 44,000 frames in each of the 180 sec exposures.? autostakkert3 (AS3) can throw out a lot of frames and have plenty to stack.

3. Don't shoot more frames than like 60 sec else the planet Jupiter will spin and the frames at the front of the video won't stack with the rotated frames at the end of the video.? No longer true: The free program WinJuPos solves this, by creating a replacement video that "de-rotates" the frames.? I do not understand yet how it performs this magic trick...but it does.? (I'll send a separate document on how to use WinJuPos.)

Last night I tried a different ASI camera.? The ASI224MC has 3.75 um pixels, so ideally (by the rule of thumb) requires f/18.5 .? The ASI178MC has smaller 2.4um pixels...so by the rule requires f/12.? My scope us f/11...that's close enough to f/12 that I don't need the 2X tele, and my exposures can be faster.

Also the ASI178 is made to use Backside Exposure.? This put the light into the pixel silicon region with no metal wiring to block the photons.? The 224 uses frontside exposure and has the metal pixel connections in the way if some of the light. The 224 is more sensitive to red and far less sensitive to blue. The 178 is more sensitive to blue than red due to the backside detection.? I have yet to process my images of last night but I think they were better.??

I used to take maybe a few thousand frames.? Now I see the benefit of taking a huge number of frames.??

Rule: use the deNoise capability of Registax wavelets:? in Registax6 wavelets, I used to only use Linear Gaussian and I was putting the DeNoise number to be 2X the Sharpen number.? What that did was to blur out the final image... it certainly denoised it, but too much.? Now I use the Default Linear wavelet setting and there is no DeNoise being applied.? For my present work that works better.

I follow up the Registax6 TIF 16 bit output with Photoshop (CS5).? Then I use the Image Size tool to expand to 200% of the original.? I use the Bicubic_Smoother selection as Photoshop says "best for enlargements." Then I copy layers,? use the Unsharp Mask at different settings like 1.7 pixel or 0.9 pixel, to gradually sharpen up the final image.? I also may have to look for noisy areas of the image, Mask them and use the noise reduction tools.??

In photoshop, after you generate your final image, flatten it. Then use the Channels tab to look at the Red, the Green, and the Blue separately as B&W images.? The blue likely has the most noise: the air scatters blue light much better than it scatters Red light.? It's why the sky is blue!? You can then use the Noise reduction tools in Photoshop to reduce noise in the Blue channel.? Likewayse examine the green and the Red channels.??

I also found that if I sharpen too much in Registax6, any colorful moons floating in the picture can become totally white and blown out.? RS6 is not smart enough to rescale the pixel intensity so it remains within the gamut.? (That seems to me a silly processing problem...should have been easy to program it to stay in gamut bounds...but it doesn't. ) So I process the same AS3 output image twice in RS6...once for the planet sharpening, on slightly less sharp for the moons process.? Then I combine the two RS6 images in Photoshop using small masks to get the colorful moons in with the sharper planet image.? ?

Hope this stuff helps you...but I need to write another document for you...showing the steps with examples...

Stay well and enjoy life and health,

Michael

On Sun, Jul 19, 2020, 8:26 AM Astronut <hg2u@...> wrote:

Hi Michael,
THANK YOU FOR THE EXCELLENT DETAILED GUIDE !!!!!
?I really really want you to know how appreciative I am that you detailed the equipment setup as well as the imaging and processing details.
Especially on the ADC, I have read what little has been published on it, but it only kinda made sense.
Your instructions are easy to follow, detailed and precise, THANKS!

I'm printing this and taking it with me as an operating guide tonight.

I also have the ASI 224 and ADC, IR Cut filter,? 2" 2x & 2.5x barlows, and a 12" LX200 GPS (F/10) OTA and am excited to try this out tonight !

We need to figure out how to make posts like yours 'sticky' to others can benefit as well...
I would have not realized the benefit to do final collimation at same target elevation, my mirror lock works ok, but just ok.
I actually switched to a small refractor for just the reason you mentioned, I was tired of fighting the seeing turbulance, and always felt I could get a little sharper image than I usually got.
Also the imaging scale change from .5"/px to 1.4"/px didn't hurt my guiding... :)

I do have another question for you, I believe you are using an extended CW shaft, I have been experimenting on the difference between using 2 21# cw's down low on the cw shaft, compared to 3 21# cw's way up on the shaft, and I kinda felt like the mount worked better with less total CW #, even though it was way farther down on the cw shaft. Do you feel the same, based on your experience ?
(I also experienced the need to make sure the legs are really tight to eliminate creep, In fact although I have the machined hand tighten optional knobs for attaching the RA to the MA?, I find I get better results when I actually use the allen wrench to make sure those are more than hand tight, especially with the 12" OTA, as well as I noticed that the tightness of the 2 RA (hold down wing bolts?) made a huge difference on my PA stability, so much that I replaced the 'handles' with the same indexable 3" long handles used on the leg adjustment of the FHD tripod. It made PA much easier with heavier loads without making my fingers sore.)

Thanks again for this excellent guide!
Astronut Tim

Hi Tim,

As I discover more about getting better planetary images, I will give that advice freely.? ?And I do have some new things to share...??here is what I discovered:

First of all...the photo attached is surely my best final imsge.? Again, I used the C14EdgeHD ... manually focussed with the telescope focus knob (expecting a motor focusser to come in later this week).? ?Seeing was better than average that night, but not as perfect as Clear Sky Chart sometimes shows rarely.? That picture should have turned out badly on a 14 inch scope.? But it didn't....

?It was shot on the ZWO ASI224 camera (3.75 um pixel size) at f/11... With a ZWO ADC atmospheric dispersion corrector in place in front of the camera.? It was shot at prime focus with a 1.25 inch visual back...no Crayford for fine focus. A nice Crayford I have put the camera image plane too far back of the 5.75 inch recommended image plane distance.? In that scope you can be inside of 5.75 inches, but image sharpness gets worse past 5.75 inches.? It's a critical element of the EdgeHD scopes that I did not know when I bought it (used earlier this year).??

At the time of that video recording, I did not use a UVIR filter and so about 20% of the Red light was from long wavelength IR.? I only discovered that difference the following night...so use a UVIR filter to improve contrast.? I now use that UVIR in the cameras front nosepiece.

There were a few "rules of thumb" that were told me years ago when I first tried planetary imaging.? They were:

1. Rule: Only try imaging when the Clear Sky Chart shows excellent (darkest color bars) for seeing.? I find this to be wrong:? I'll explain.? The Clear Sky Chart is not able to say that there may be short windows of excellent seeing maybe 30 minutes or so, between periods of turbulent air.? It just gives the overall prediction for its time window.? Sometimes you get very lucky if you are set up and shooting... And sometimes it predicts perfect seeing and that wish does not come true either. It really is "lucky imaging."

[ See the incredible images from? Anthony Wesley of Australia....here:

Anthony Wesley explained that his best image came from a night he was not expecting great seeing, but then, the sky stabilized and...voila.? (He has a fabulous scope, a Robert Royce 16 inch Newtonian mirror...essentially flawless.? That sure helps!) ]

2.? Rule: You must use the f# that is "5x your video camera pixel um size". You are supposed to use a 2x or 2.5x (best is a Tele vue Powermate) to get the f#.? Example: on my ASI224MC camera, with it's 3.75 um pixels... this means I should be trying to get f/18.5.? so by that rule, I should have used a 2X tele to get my f11 scope to be f/22.? Yet I find this wrong too...I got the incredible image attached using that ASI224 at f/11.? ?

Why did f/11 and no 2x tele work???

When you use a 2X tele, you get 1/4th the light into each pixel.? So to get the exposure to be say 80% of full, you need 4X the exposure time.? If the seeing is so-so not perfect, the longer exposures blur out the image frame.? Using no 2X at all gives a 4X faster exposure so can "freeze" the seeing and get you clearer frames.

And for the same exposure time, say 180 sec, you get 4X the number of frames without the 2X tele.? I got 44,000 frames in each of the 180 sec exposures.? autostakkert3 (AS3) can throw out a lot of frames and have plenty to stack.

3. Don't shoot more frames than like 60 sec else the planet Jupiter will spin and the frames at the front of the video won't stack with the rotated frames at the end of the video.? No longer true: The free program WinJuPos solves this, by creating a replacement video that "de-rotates" the frames.? I do not understand yet how it performs this magic trick...but it does.? (I'll send a separate document on how to use WinJuPos.)

Last night I tried a different ASI camera.? The ASI224MC has 3.75 um pixels, so ideally (by the rule of thumb) requires f/18.5 .? The ASI178MC has smaller 2.4um pixels...so by the rule requires f/12.? My scope us f/11...that's close enough to f/12 that I don't need the 2X tele, and my exposures can be faster.

Also the ASI178 is made to use Backside Exposure.? This put the light into the pixel silicon region with no metal wiring to block the photons.? The 224 uses frontside exposure and has the metal pixel connections in the way if some of the light. The 224 is more sensitive to red and far less sensitive to blue. The 178 is more sensitive to blue than red due to the backside detection.? I have yet to process my images of last night but I think they were better.??

I used to take maybe a few thousand frames.? Now I see the benefit of taking a huge number of frames.??

Rule: use the deNoise capability of Registax wavelets:? in Registax6 wavelets, I used to only use Linear Gaussian and I was putting the DeNoise number to be 2X the Sharpen number.? What that did was to blur out the final image... it certainly denoised it, but too much.? Now I use the Default Linear wavelet setting and there is no DeNoise being applied.? For my present work that works better.

I follow up the Registax6 TIF 16 bit output with Photoshop (CS5).? Then I use the Image Size tool to expand to 200% of the original.? I use the Bicubic_Smoother selection as Photoshop says "best for enlargements." Then I copy layers,? use the Unsharp Mask at different settings like 1.7 pixel or 0.9 pixel, to gradually sharpen up the final image.? I also may have to look for noisy areas of the image, Mask them and use the noise reduction tools.??

In photoshop, after you generate your final image, flatten it. Then use the Channels tab to look at the Red, the Green, and the Blue separately as B&W images.? The blue likely has the most noise: the air scatters blue light much better than it scatters Red light.? It's why the sky is blue!? You can then use the Noise reduction tools in Photoshop to reduce noise in the Blue channel.? Likewayse examine the green and the Red channels.??

I also found that if I sharpen too much in Registax6, any colorful moons floating in the picture can become totally white and blown out.? RS6 is not smart enough to rescale the pixel intensity so it remains within the gamut.? (That seems to me a silly processing problem...should have been easy to program it to stay in gamut bounds...but it doesn't. ) So I process the same AS3 output image twice in RS6...once for the planet sharpening, on slightly less sharp for the moons process.? Then I combine the two RS6 images in Photoshop using small masks to get the colorful moons in with the sharper planet image.? ?

Hope this stuff helps you...but I need to write another document for you...showing the steps with examples...

Stay well and enjoy life and health,

Michael

On Sun, Jul 19, 2020, 8:26 AM Astronut <hg2u@...> wrote:

Hi Michael,
THANK YOU FOR THE EXCELLENT DETAILED GUIDE !!!!!
?I really really want you to know how appreciative I am that you detailed the equipment setup as well as the imaging and processing details.
Especially on the ADC, I have read what little has been published on it, but it only kinda made sense.
Your instructions are easy to follow, detailed and precise, THANKS!

I'm printing this and taking it with me as an operating guide tonight.

I also have the ASI 224 and ADC, IR Cut filter,? 2" 2x & 2.5x barlows, and a 12" LX200 GPS (F/10) OTA and am excited to try this out tonight !

We need to figure out how to make posts like yours 'sticky' to others can benefit as well...
I would have not realized the benefit to do final collimation at same target elevation, my mirror lock works ok, but just ok.
I actually switched to a small refractor for just the reason you mentioned, I was tired of fighting the seeing turbulance, and always felt I could get a little sharper image than I usually got.
Also the imaging scale change from .5"/px to 1.4"/px didn't hurt my guiding... :)

I do have another question for you, I believe you are using an extended CW shaft, I have been experimenting on the difference between using 2 21# cw's down low on the cw shaft, compared to 3 21# cw's way up on the shaft, and I kinda felt like the mount worked better with less total CW #, even though it was way farther down on the cw shaft. Do you feel the same, based on your experience ?
(I also experienced the need to make sure the legs are really tight to eliminate creep, In fact although I have the machined hand tighten optional knobs for attaching the RA to the MA?, I find I get better results when I actually use the allen wrench to make sure those are more than hand tight, especially with the 12" OTA, as well as I noticed that the tightness of the 2 RA (hold down wing bolts?) made a huge difference on my PA stability, so much that I replaced the 'handles' with the same indexable 3" long handles used on the leg adjustment of the FHD tripod. It made PA much easier with heavier loads without making my fingers sore.)

Thanks again for this excellent guide!
Astronut Tim

The plate solving is part of the ASIair unit.? The ASIair plate solving ruteene is interesting in that it will do a GoTo an object. ?do a plate solve, then check it and do another plate solve to get it right on.

I find that if I make a good model with the Gemini 2 it can be used again and again until I do something to screw it up.? The accuracy of a good model places the object within about 10% of the center of the field. ? Im getting ready to start with my most recently acquired camera ? ZWO ?178 MC ? with 2.4? pixels. ?on Jupiter and the other planets. ? ?Can you center a planet using plate solving?

aruckle

Michael,

Your Jupiter image result was so nice.? I was not familiar with the ADC device until you mentioned it.

Thanks for all you comments and imaging planetary tips.?

Bob R.

?

From: [email protected] [mailto:[email protected]] On Behalf Of Michael Herman
Sent: Monday, July 20, 2020 4:21 PM
To: [email protected]
Subject: [Losmandy_users_io] A question of balance...counterweights

?

The question was asked:

?

Is it better for imaging performance to put fewer counterweights at the far end of the bar, or use more weights close to the RA axis of the mount ?

?

I am not doing deep sky at the moment, and if I bump my scope during planetary video imaging, I can see the video image jump briefly before it damps out.??

?

Therefore, you can also experiment: if you use your autoguider camera, and put it on your main imaging scope prime focus location, and point to a bright star, and give a bump to your counterweight, you can see or record on video how much the star jumps around.? The video could quantify the frequency and amplitude of the vibration.

?

Then try to adjust your weights position and give a similar bump.? Can you see a difference?? If yes...tell us what you discover!? Can you say whether there is an improvement or no real difference?

?

In terms of academic theory, this would need "finite element" modeling.? And you'd need to know something about the "bump" or driving force.? ? If it's a constant wind, it could drive oscillations of the system (think the famous Tacoma Narrows bridge).? But in the absence of any bump or wind, the only movement is the constant tracking rotation.? There are sporadic autoguiding corrections, and these if large might cause an oscillation.? I don't see any oscillations in my planetary imaging and that is getting frequent autocorrections from FireCapture through ASCOM to the Gemini-1 to the G11.

?

?

?

The trade-off is on counterweight bar flex, and image vibration. Also comes up on how heavy a scope and counterweight load can you put on a G11 before it breaks down.

?

For the vibration question...it's a good mechanics/physics question.??

?

The problem looks like this:

?

[Very Heavy Scope] ----(W1)--------(W2)----

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^

? ? ? ? ? ? ? ? ? ? ?^ is the RA axis pivot

?

What are the frequencies of this case above, versus an alternative putting more weights close to the RA pivot:

?

[Very Heavy Scope] --(W1)(W2)(W3)------

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^

? ? ? ? ? ? ? ? ? ? ?^ is the RA axis pivot

?

In general, the bottom case will have higher frequencies than the upper case.? The energy of the higher frequencies might be the same as the energy of the lower frequencies, but the higher frequency vibrations might look just like "Seeing" fluctuations.? The lower frequencies might make larger blurs if your stats.

?

This is a different puzzle for each of us, as we all have different weight scopes, cameras, and weights can vary too.? The heavier the scope the less it will move.??

?

Think of a flute or better a rope with weights on it: the holes in the flute are either open, providing a point where a sound wave can have no pressure.? On a rope with weights, the weight positions act as a null point. The rope can't vibrate there but if can oscillate between the weights.??

?

I'll say that both cases can oscillate, but if you space out the weights, you may be able to reduce the oscillation amplitude.

?

-----

Here in the top photo is my overloaded system (in the dark), showing the hollow 3 foot long counterweight shaft.? I put 3 counterweights spaced out to act as nodes to kill off some vibration modes.? The idea was to forces oscillations to go to higher frequency, which are harder for bumps or wind to create - at least that's my thinking.??

?

( By the way, finite element analysis is used in bridge design to ensure there are no harmonic frequencies like caused the Tacoma Narrows bridge collapse.? )

?

Here is a photo of FireCapture set up to evaluate the ZWO ADC atmospheric dispersion corrector.? Seeing usually appears here very severely ad the colors jump all over the place.? A bump here would make the star or planet jump all over too.? The 3rd photo is how Jupiter looked the time of the photo this week.?

?

Hope you can try some experiments to see what is optimal for your system!

And let us know what you discover!

?

Best regards and stay healthy,

Michael

?

?

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