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Planetary imaging - what am I doing wrong?


Jammy
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What am I doing wrong to get planetary images like these attached?

Or maybe I should be asking what am I actually doing right?

I've tried a few times to images planets with my QHY5L-ii mono camera through the C9.25 both with and without IR/UV block filter and get the same blurred results every time.

I've checked collimation, and focus using a star mask.  It's pretty good really, and I know the camera works fine because I've used it to get some good lunar shots.

I'm imaging thought sharpcap software and have processed the images with registax or autostakkert and get very similar results.  Is there anything obvious that I'm missing??

All suggestions welcome, thanks!

00_14_14_g4_ap21_conv.jpg

01_44_20_g4_ap12_conv.jpg

Moon_stitch.jpg

Edited by Jammy
spelling mistake
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I am definitely not an expert on this, but a few questions spring to mind:

  • Are you focussing via an image in the camera or using a flip mirror? Might help to see your imaging train.
  • Are you focussing using a star in the same part of the sky? (reducing mirror flop when you slew)
  • Are you finishing focus by turning the knob anti clockwise? (again reducing mirror flop)
  • How many frames did you take?
  • Did you look at Jupiter/Saturn visually and could you see plenty of detail?

I'm not actually sure the mirror flop issue affects focus anyway.

Rob

Edited by RobertI
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How are you focusing? You say with a star mask, but are you then focusing on a star? If so, there can be a big difference in focus point between solar system objects and stars. How did you focus the lunar images?

Also, do you use reading glasses? If so, make sure you use them when manually focussing. I made this mistake in my early days of requiring glasses. All my images of Jupiter were soft... then, when I focussed while wearing my glasses, suddenly the images were pin sharp!! The non glasses focussed images appeared sharp to me, until I processed them, with my glasses on!

Finally, what are conditions like when you are imaging? The atmosphere will completely compromise sharp focus when it is heavy and wet, such as we seem to continually have at the moment. The altitude of the planet will impact this too - when low there is even more crud to distort the image!

Good luck!

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Don't use a mask on planets, it's for Star focus at infinity when observing DSO's, also, don't get concerned regarding Mirror flop, lights and dark etc.

Focus best you can on the Planet, image then as mentioned run it through Registax and play about with the Wavelettes, your Saturn looks like it could turn out quite well even though it is quite low this year. 

Oh and if you wear glasses put them on haha

Don't forget as mentioned, the atmosphere is a main factor when imaging, especially Planets . 

Edited by 2STAR
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A couple thoughts. As other have said, planetary images come out very soft when stacked, sharpening using wavelets brings out a lot of detail. Another issue might be that it's a mono image of all visible frequencies. While the UV/IR block will help whenever I've shot planetary images I've had to manually align the colour channels which isn't possible here. You may get better results shooting through a colour filter, even if you wish to produce a mono image.

1 minute ago, 2STAR said:

Don't use a mask on planets, it's for Star focus at infinity when observing DSO's, also, don't get concerned regarding Mirror flop, lights and dark etc.

I'm not sure about that, anything further away than a few miles is 'infinity' as far as a camera system is concerned.

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9 hours ago, Jammy said:

I've tried a few times to images planets with my QHY5L-ii mono camera through the C9.25 both with and without IR/UV block filter and get the same blurred results every time.

Are you using any filters, e.g. R,G,B or L or is this without any filters, i.e. full bandwidth? Both Jupiter and Saturn are very low targets from the UK currently, particularly Saturn, so suffer from significant atmospheric disersion. The red part of the spectrum suffers least from dispersion so using the R filter (or beter still an IR pass filter) with help significantly. Better still including an ADC (atmosheric dispersion corrector) in the optical train will make a huge difference to these low altitude targets.

As others have said the focus looks a bit off so how are you focussing, e.g. do you use an electric focuser (and is that DC or stepper) or manual focus. In my experience obtaining fine focus with a DC motor focuser is superior to stepper motors for planetary imaging due to the image shake caused by stepper motors. Also it is better to adjust focus on the target (planet); using a bahtinov mask on a nearby bright star will get your focus close, but probably not accurate enough for a distended target like a planet where focus is constantly changing due to atmospheric turbulance and of course you will never get good results when atmosphere isn't very stable, so its always worth checking where the jetstream is located as it is usually not worth trying to image the planets with a fast running jet stream overhead https://www.netweather.tv/charts-and-data/jetstream

Hope this helps, Geof

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4 minutes ago, John78 said:

I had a quick look at wavelets and sharpening your attached Saturn and Jupiter - it looks out of focus....  It's much more obvious to see on Jupiter...

 

jupiter.jpg.5dd7a538cc8c81aa845bc63caf128043.jpg

I am not sure that wavelets after jpeg compression are meaningful. This can introduce a load of artefacts in my experience.

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2 minutes ago, michael.h.f.wilkinson said:

I am not sure that wavelets after jpeg compression are meaningful. This can introduce a load of artefacts in my experience.

Well sort of agree - but if I wavelet and sharpen your jpg you can see its in focus.....

jupiter2.thumb.jpg.423dd311b8b45516ec847c90e96acb94.jpg

 

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46 minutes ago, John78 said:

Well sort of agree - but if I wavelet and sharpen your jpg you can see its in focus.....

jupiter2.thumb.jpg.423dd311b8b45516ec847c90e96acb94.jpg

 

But sharpening the TIFF gets out a lot more detail. In part it may also be a situation of signal to noise. I stacked very many frames, which allows much more aggressive sharpening. Focus may be an issue, but given that the Saturn image shows the Cassini division, it cannot be far from perfect focus. I would really like to have a go at sharpening the original uncompressed image.

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1 hour ago, michael.h.f.wilkinson said:

given that the Saturn image shows the Cassini division, it cannot be far from perfect focus. I would really like to have a go at sharpening the original uncompressed image.

I agree that the Saturn image looks pretty close to focus and that it would be good to have access to the unprocessed tiff, but I couldn't resist taking a copy and having a play with the jpeg in Registax6....

SGL-Saturn-R6.jpg.8fe087e1eafc126d2af3cbdd253af8b0.jpg

not a great result, but there's definitely something there to work with.... :icon_biggrin:

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Along with the advise above I'd like to add my 2 cents worth... first how long are your captures time wise... anything too long will blur the details, longer than 1.5-2 minutes on OSC or 45-60 seconds per channel when using mono through RGB filters (time is focal length dependent).

Second is to hit the focus spot on I turn gamma in iCap to 50%, that exaggerates the contrast and focus is easier to fine tune to perfection.

Remember that the seeing will make or break an image, keep trying and never give up... took me about 2 years before I got a Jupiter I was happy with, and my best ever was captured only last February.

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14 hours ago, Jammy said:

What am I doing wrong to get planetary images like these attached?

Or maybe I should be asking what am I actually doing right?

I've tried a few times to images planets with my QHY5L-ii mono camera through the C9.25 both with and without IR/UV block filter and get the same blurred results every time.

I've checked collimation, and focus using a star mask.  It's pretty good really, and I know the camera works fine because I've used it to get some good lunar shots.

I'm imaging thought sharpcap software and have processed the images with registax or autostakkert and get very similar results.  Is there anything obvious that I'm missing??

All suggestions welcome, thanks!

Sorry that I was so brief in my earlier post, it was late so I just typed what I believed would help (I still do believe), but omitted explanation.

I guess that you are getting such images for following reasons: You are recording either in urban area, or somewhere where there are quite a bit of local air disturbances (like shooting over houses, or pavement, or anything that would emit heat).

This has as a consequence "shimmering" effect rather than blurring effect on individual frames - if you check your video you should see Jupiter jumping around and being "rippled" across rather than being stationary and blurred.

When you stack such a video final image gets blurred with Gaussian type PSF of rather large diameter, because stacking software is not able to align frames properly. What might help is using more alignment points, but also wavelet processing of the final stack - wavelets do good job of recovering high frequency signal in the image. Gaussian type PSF blurs the image by attenuating high frequency signal not by completely cutting it off like Airy PSF - hence this high frequency components can be recovered by boosting them (unfortunately noise is also high frequency so it gets boosted as well so you have to find balance). Wavelets can do this as well as deconvolution.

Here is quick example of your image run thru wavelets:

Screenshot_2.png.7496b52befd70569ba93cfb6b4d932f4.png

Mind you this is done on 8bit version, also corrupted by Jpeg compression. Much better results would be obtained when working on 16 or 32 bit stack, tiff or png (without lossy compression).

So my suggestion is to stack again using more alignment points, and then do wavelets. If you wish you can post your stack in 16bit png so some of other members can have a go at wavelet sharpening and see what is really captured in your data (if you think that you don't have enough experience with wavelets).

 

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5 hours ago, 2STAR said:

Don't use a mask on planets, it's for Star focus at infinity when observing DSO's, also, don't get concerned regarding Mirror flop, lights and dark etc.

By my calculation the focus shift between infinity and the moon at 1000mm focal length is about 2.6 nm.

For an object 384,000km away (the moon) @ 1000mm focal length

1/Focal distance = 1/384,000,000,000 + 1/1000 = 0.001 + 2.6 x10^-12

=0.00100000000026

=999.9999974mm

That's less than 1/100 of a wavelength of light, a shrew farting nearby will upset your focus more than that.  I doubt that you need to worry about using a mask to set focus using a star.

Edited by Stub Mandrel
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9 minutes ago, Stub Mandrel said:

By my calculation the focus shift between infinity and the moon at 1000mm focal length is about 2.6 nm.

For an object 384,000km away (the moon) @ 1000mm focal length

1/Focal distance = 1/384,000,000,000 + 1/1000 = 0.001 + 2.6 x10^-12

=0.00100000000026

=999.9999974mm

That's less than 1/100 of a wavelength of light, a shrew farting nearby will upset your focus more than that.  I doubt that you need to worry about using a mask to set focus using a star.

Those numbers make it sound that it's almost impossible to hit focus... 

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1 hour ago, MarsG76 said:

Those numbers make it sound that it's almost impossible to hit focus... 

Quite the opposite. Depth of field is not the same as focal distance. The website https://starizona.com/acb/ccd/advtheoryfoc.aspx  gives the theory behind this table. Even at f2 you have more than 1/100 of a mm to play with and at f8 nearly 0.2mm, which isn't hard with a decent sized focuser knob or a two speed focuser:

Focal Ratio Depth of Focus (diffraction limited)
f/2 12 microns
f/3 26 microns
f/4 48 microns
f/5 72 microns
f/6 104 microns
f/7 141 microns
f/8 184 microns
f/9

233 microns

f/10 287 microns
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