Hi, I have had my setup now for a week and this is what I hope is a resonable effort for my first attempt as I am a newbie. The image was from Brisbane last night so there is a large amount of light pollution and the dew was a pain, equipment was the Celestron 9.25", a 2 x barlow and the Philips Vesta Pro. I think I need a mask as focus seems very hard to predict. This image was sent through registax at 800 frames and I used 80%, I then used scheme 5 from Peter Lloyd's web page for my linked wavelets. I am resonably happy with the end result but all my images seem to be a little redish with not a lot colour. This I think maybe be the limitation of my web cam (not sure). If any one could give some feed back good or bad (with help on how to fix) it would be great as you guys will be my only feedback options to learn from. I think I may have to join a group.
Thanks for looking in advance
Carl
Last edited by carlstronomy; 12-05-2012 at 09:44 PM.
Hi Carl,
I can't really comment on your result as I have a different setup but it is very close to my first effort with Saturn using a webcam. It really depends a lot on the "seeing" at the time as well. I am not sure if the barlow is pushing your limits on the scope. I know most of the time when I try a barlow the image is bigger (usually not much) but the trade off is a much more degraded image. I use a Bahtinov mask for stars etc but I don't know if they help with video /cam work on planets? Somebody could correct me!
Cheers
Dave
I'm new to the whole imaging thing myself, however what I have found works well with focus is to use a bahtinov mask to focus on a nearby star. Once I have achieved focus, I then lock the focusser and then slew to the planet (or deep space object for that matter). If im going to use a barlow for imaging, then I make sure the barlow is already in place before focusing with the bahtinov mask.
In Registax you can use the 'wavelets' feature to help counteract the atmospheric effects from poor seeing. plenty here on IIS with experience on using wavelets, also have a look at some of the tutorials on youtube.
I generally capture for 2-3 minutes and set the program to choose the best 2000 frames.
You might want to try Auto Stakkert too. Let it stack your data, then take the finished image and open it in Registax to do your wavelets.
I generally capture for 2-3 minutes and set the program to choose the best 2000 frames.
You might want to try Auto Stakkert too. Let it stack your data, then take the finished image and open it in Registax to do your wavelets.
Hi thanks for the reply I have downloaded Auto Stakkert and have been having a play with it to see how it goes. It stacks much better but seems to blur the image more so I will have to do more studying. Thanks for you feedback and I checked out your site, love the images you have captured. My father lives up at Yarraman I think my 9.25" SCT should do well up there with less pollution.
Hi Carl,
I can't really comment on your result as I have a different setup but it is very close to my first effort with Saturn using a webcam. It really depends a lot on the "seeing" at the time as well. I am not sure if the barlow is pushing your limits on the scope. I know most of the time when I try a barlow the image is bigger (usually not much) but the trade off is a much more degraded image. I use a Bahtinov mask for stars etc but I don't know if they help with video /cam work on planets? Somebody could correct me!
Cheers
Dave
Hi I think the 9.25" SCT should be okay with a 2 x barlow folcal ratio of 10 and focal length of 2350mm (But I too am not totaly sure). I have notice a few good shots out there with 2 x barlows and 8" scopes but the cameras used may be better too.
I'm new to the whole imaging thing myself, however what I have found works well with focus is to use a bahtinov mask to focus on a nearby star. Once I have achieved focus, I then lock the focusser and then slew to the planet (or deep space object for that matter). If im going to use a barlow for imaging, then I make sure the barlow is already in place before focusing with the bahtinov mask.
In Registax you can use the 'wavelets' feature to help counteract the atmospheric effects from poor seeing. plenty here on IIS with experience on using wavelets, also have a look at some of the tutorials on youtube.
I was wondering as the lens used to focus using a mask on the star has to be removed to fit the camera, the focus is always out so manual adjustment is still required. I would think that would negate the use of the mask? I know that when I look at saturn throught the web cam the picture is a little fussy so I am not sure if a mask can be used for the web cam. I know if I went to a star I would find it very hard to see it in the web cam but I have not tried it yet. My knowledge is low on this so trial and error is a must. But I did not want to go out and buy a mask if it would be no use.
I was wondering as the lens used to focus using a mask on the star has to be removed to fit the camera, the focus is always out so manual adjustment is still required. I would think that would negate the use of the mask? I know that when I look at saturn throught the web cam the picture is a little fussy so I am not sure if a mask can be used for the web cam. I know if I went to a star I would find it very hard to see it in the web cam but I have not tried it yet. My knowledge is low on this so trial and error is a must. But I did not want to go out and buy a mask if it would be no use.
Thanks for the reply
Okay, so what I do is find and centre the star using an eyepiece. then I pop in the webcam, and then find and centre the (currently out of focus) star in the web cam software. I then pop in the mask and adjust focus until i get the correct diffraction pattern on screen. I then know that my webcam is now properly in focus. At that point I lock the focus, and then I just slew to the planet and start the capture process.
Okay, so what I do is find and centre the star using an eyepiece. then I pop in the webcam, and then find and centre the (currently out of focus) star in the web cam software. I then pop in the mask and adjust focus until i get the correct diffraction pattern on screen. I then know that my webcam is now properly in focus. At that point I lock the focus, and then I just slew to the planet and start the capture process.
Thanks for info and explenation. I will certainly implement on my next veiwing session.
I sent the DBK21 for you to have a play with today, you will need to download iccapture from the Imaging Source website as I can't find the disk, so you may as well get that now while waiting for the camera to arrive.
I hope you enjoy the loan and post some pics!
Good first start!
Deconvolution is your friend, especially during bad seeing and longer exposure times or when averaging your frames.
Though useful to bring out scale-dependent detail in non-challenged images, wavelet-based image manipulation is not really the go-to tool to correct for bad seeing conditions or focus related issues.
The linked wavelets routine in Registax, as far as I can tell, do allow you to emulate a chain of sharpening operations that can approach a simple deconvolution operation. However, you'll get better results with less fiddling by using a 'real' deconvolution plug-in or dedicated app.
Bad focus and/or bad seeing smear (convolve) your 'sharp' image across the image plane. They way they do that differ. Deconvolution (un-smearing) can help in cases that aren't too bad and where the input image isn't too noisy.
Bad seeing scatters photons in a random distribution pattern following a Gaussian pattern. Deconvolution with a 2D Gaussian kernel can therefore fix this type of 'blur'. The worse the seeing, the bigger the pattern.
Incidentally, this is also what Registax' "Linked Wavelets" mode effectively does; deconvolution using a Gaussian kernel by sharpening, re-blurring, sharpening, re-blurring, sharpening - this has got nothing to do with Wavelets anymore (it's single scale) and in essence it's a not-so-user-friendly (you have to specify each iteration manually) reblurred Van Cittert Decon routine that lets you (incorrectly) apply deconvolution to stretched data. Don't get me wrong; 'Linked Wavelets' in Registax have the capability of improving your image somewhat when used in this capacity and it's better than nothing, but know that they will be almost always sub-optimal results.
An out-of-focus image, on the other hand, is the convolution of the real/sharp image with the shape of your scope's aperture (an evenly lit circle for a refractor, a circle with a black spot and some spider vanes in case of a Newtonian, etc.) De-convolution by the shape of your scope's aperture therefore should yield a sharp image again.
Remember to use deconvolution on a non-stretched (e.g. non-gamma corrected) input image for best results - only stretch and/or gamma correct your image afterwards. Decon only makes sense on linear data (e.g. data as it was captured by the sensor being a simple photon counter).
Hope this helps (and isn't too confusing)!
Cheers,
Ivo
EDIT: I should also say that if you'd like to use deconvolution (and you should ), it should be one of the first things you do to your image. This is for the simple reason that, the more you modify your image, the harder it becomes to model the 'blur' that your image contains. The harder it is to model the blur, the less effective deconvolution will be when attempting to reverse that blur.
I sent the DBK21 for you to have a play with today, you will need to download iccapture from the Imaging Source website as I can't find the disk, so you may as well get that now while waiting for the camera to arrive.
I hope you enjoy the loan and post some pics!
Thanks Peter, can not wait for it to arrive the sky has begun to clear today and the mud will hopefully clear by tomorrow. Cant wait to try out the camera and I will be posting images as soon as I have some.
Good first start!
Deconvolution is your friend, especially during bad seeing and longer exposure times or when averaging your frames.
Though useful to bring out scale-dependent detail in non-challenged images, wavelet-based image manipulation is not really the go-to tool to correct for bad seeing conditions or focus related issues.
The linked wavelets routine in Registax, as far as I can tell, do allow you to emulate a chain of sharpening operations that can approach a simple deconvolution operation. However, you'll get better results with less fiddling by using a 'real' deconvolution plug-in or dedicated app.
Bad focus and/or bad seeing smear (convolve) your 'sharp' image across the image plane. They way they do that differ. Deconvolution (un-smearing) can help in cases that aren't too bad and where the input image isn't too noisy.
Bad seeing scatters photons in a random distribution pattern following a Gaussian pattern. Deconvolution with a 2D Gaussian kernel can therefore fix this type of 'blur'. The worse the seeing, the bigger the pattern.
Incidentally, this is also what Registax' "Linked Wavelets" mode effectively does; deconvolution using a Gaussian kernel by sharpening, re-blurring, sharpening, re-blurring, sharpening - this has got nothing to do with Wavelets anymore (it's single scale) and in essence it's a not-so-user-friendly (you have to specify each iteration manually) reblurred Van Cittert Decon routine that lets you (incorrectly) apply deconvolution to stretched data. Don't get me wrong; 'Linked Wavelets' in Registax have the capability of improving your image somewhat when used in this capacity and it's better than nothing, but know that they will be almost always sub-optimal results.
An out-of-focus image, on the other hand, is the convolution of the real/sharp image with the shape of your scope's aperture (an evenly lit circle for a refractor, a circle with a black spot and some spider vanes in case of a Newtonian, etc.) De-convolution by the shape of your scope's aperture therefore should yield a sharp image again.
Remember to use deconvolution on a non-stretched (e.g. non-gamma corrected) input image for best results - only stretch and/or gamma correct your image afterwards. Decon only makes sense on linear data (e.g. data as it was captured by the sensor being a simple photon counter).
Hope this helps (and isn't too confusing)!
Cheers,
Ivo
EDIT: I should also say that if you'd like to use deconvolution (and you should ), it should be one of the first things you do to your image. This is for the simple reason that, the more you modify your image, the harder it becomes to model the 'blur' that your image contains. The harder it is to model the blur, the less effective deconvolution will be when attempting to reverse that blur.
Confused me never
Such a lot of things to learn a huge learning curve but great fun. I did download the Astra Image plugin for photoshop the other day and had a little play on some one elses image, as mine really up to chop with the web cam. It worked well or so I think, so I have had a small play with deconvolution. The only difference is I did it last not first so might go and have a bit of another play right now.
Well here they are image "Old" to the left is using wavelets in Registax6. Image "New" in the middle is using deconvolution in Photoshop CS. I used Registax to stack saved and sent to CS for Astra Image adjustments then did my colour adjustments etc back in Registax. Final smoothing then completed in CS for the finished product. This image was supplied curtesy of Poita image "Original" to the right in his thread in Solar System. It is not mine and I do not take any credit for the image itself thanks Poita for sharing.
So now its your turn peeps which seems better? I know which I like more and it is so much easier than wavelets, you get much more control and there is less messing around. Thanks for the tip Ivo. But much more learning to do.
Does anyone know of a free deconvolution program or plugin?
So now its your turn peeps which seems better? I know which I like more and it is so much easier than wavelets, you get much more control and there is less messing around.
The Decon one looks better, though there is not too much in it. Good color too!
Quote:
But much more learning to do.
It never stops, trust me... (even if you write the darn software )
Quote:
Does anyone know of a free deconvolution program or plugin?
Have a look at IRIS. There is also G'MIC and ReFocus (the latter is limited to Gaussian or circular profiles) for The GIMP. The GIMP only does 8-bit though, which limits you to applying decon to planetary and lunar images. There is a 16-bit+ version of the GIMP coming soon though, which should be a boon for people on a budget!
Thanks to Poita his DBK21 has arrived in the mail for loan purposes. Here are a few shots of the moon, and a very poor shot of saturn. Could not work out how to get colours in saturn with the settings on IC Capture, but I could not stay out long and play due to the wind (to cold) so I will try again hopefully tomorrow as I also now know to adjust white balance for the histograms to adjust colours(thanks again Poita)
Seeing - Poor 3-4 at best
Jetstream - 80-90 Knots
Wind ground level - Approx 10 Knots
All in all a bad night but a boy with a new toy must play
Good stuff, for the moon shots, take the settings off auto and move the gain back down to zero, (less noise that way) I also find that it is better to underexpose the moon a little with the DBK and then lighten it up later, seems to retain more detail that way.
Quote:
Originally Posted by carlstronomy
Thanks to Poita his DBK21 has arrived in the mail for loan purposes. Here are a few shots of the moon, and a very poor shot of saturn. Could not work out how to get colours in saturn with the settings on IC Capture, but I could not stay out long and play due to the wind (to cold) so I will try again hopefully tomorrow as I also now know to adjust white balance for the histograms to adjust colours(thanks again Poita)
Seeing - Poor 3-4 at best
Jetstream - 80-90 Knots
Wind ground level - Approx 10 Knots
All in all a bad night but a boy with a new toy must play
Well, I got another viewing session in on Tuesday night. The images are much better, but the seeing and jetstreams were still terrible. The weather here in Brisbane has been clouded at night since Tuesday so I have had no viewing sessions since. I set up Wednesday but got two minues viewing and no recordedings as the clouds rolled in(Thems the breaks). With any look I can get a couple of good views in before returning the camera, but already I can see that this camera on my SCT should give great results. Any comments please feel free to send them in.
), it should be one of the first things you do to your image. This is for the simple reason that, the more you modify your image, the harder it becomes to model the 'blur' that your image contains. The harder it is to model the blur, the less effective deconvolution will be when attempting to reverse that blur.
. Cant wait to try out the camera and I will be posting images as soon as I have some.
which seems better? I know which I like more and it is so much easier than wavelets, you get much more control and there is less messing around. Thanks for the tip Ivo.
But much more learning to do.
) so I will try again hopefully tomorrow as I also now know to adjust white balance for the histograms to adjust colours(thanks again Poita)
