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After many hours of fiddling round with Registax wavelet settings to process my own solar system images, I've always been curious as to how it actually works. In doing so I've put together my own image sharpening program which does something similar to Registax wavelets. For comparison, I've also added some general purpose deconvolution techniques which you'll probably be familiar with from other image processing software (like Wiener inverse filtering, Richardson-Lucy, etc). In choosing a point spread function to deconvolve with, one suprising result was that the typical stack outputs from Autostakkert work best with a Lorentz point spread function (with a minor modification). Deconvolving with a Gaussian point spread function doesn't really work. Deep-sky images seem to deconvolve best with a Moffat point spread function (which is to be expected - it's already well established that star profiles in long exposures are best approximated with a Moffat function).
On the whole, it's unlikely that you can sharpen solar system images much more in this program than you already can in Registax. You can see results from Registax wavelet (sharpening layers), inverse filtering (e.g. Wiener), and iterative deconvolution (e.g. Landweber) below. They all give very similar results. In all the techniques there's a similar trade-off between less noise but less detail vs more noise but more detail.
There are some quick start notes on the first page of the Readme here:
There are some examples of deconvolved images here (move mouse over image to see before/after):
Image credits are on the hyperlinks
The Windows download is here:
Example solar system tifs to experiment with are here:
And the project page is here (with Source code in the src folder)
If anyone finds it useful, do post here how it compares to other tools you use for solar system image sharpening.
The download and the source code are free, you can use it unrestricted for any purpose. The OpenCV and OpenCVCSharp components which my program use have licence information at the end of the Readme.pdf.
I recently spent my Xmas money on an L-Enhance filter as I have seen amazing results with this filter.
I took it for a test run on the Y Cas Nebula last night (not the best night, but when is?)
I managed to get around 43 mins of time.
I normally shoot 1 min exposures with my 1000D modified camera but I thought I'd go for 90 seconds as the filter would reduce brightness? (any thoughts on exposure times here would be great)
The results were not as great as I was hoping for - see below.
O over stretched it just to see if I had captured the 'ghost'. He's there, but it turns out really grainy and not the nice subtle wispy nebula that I see from other folks.
So my questions are:
- is this a tricky nebula target?
- What exposure times should I run?
- Is 43 mins way too little for this (or any) target?
- any other advice???
Canon 1000D - modified
Skywatcher 72ED Telescope
Skywatcher AzGTI mount (AZ mode at the moment until I can get polar alignment working with SharpCap)
Any thoughts, hints, tips greatly appreciated!
Thanks in advance!
I recently purchased my first telescope and camera, and now I want to make sure I have the correct Barlow or reducer to couple them together to achieve Nyquist sampling on the camera (or slight over-sampling). In case it’s important, I’m interested in planetary imaging—in theory that shouldn’t matter for this sampling question, but maybe there are other considerations to take into account.
I used this calculator (https://astronomy.tools/calculators/ccd_suitability) and plugged in my info:
Telescope: Celestron 8 SE
Camera: ZWO ASI462MC
Seeing: experimented with this one, but would like to get optics that allow for poor or very poor
Binning: prefer 1x1 to preserve spatial resolution, but could consider higher if SNR is a problem
I’ve seen on several forum posts that people often use a 2x Barlow to couple the two. However, according to this calculator, that will always lead to over-sampling. If anything, it says I should use no intermediate optics or even a reducer.
So my questions are:
Binning: Will I be able to see anything with 1x1 binning, or should I expect to need to bin to collect enough light?
Is there some other consideration that’s more important here than achieving correct sampling? It seems like most others are over-sampling, and perhaps there’s a good reason for this. If so, is there another formula that would let me determine the appropriate optics to buy?
Thanks in advance for any help!
In market for a good quality, reasonably priced long focal length 1.25 eyepiece to increase fov and help locate and view large objects. Celestron makes a 32mm for @$45.00. Is it any good? Price seems too good to be true. What are good quality/price options?
despite the full moon and the humid weather I could not resist to take some exposures yesterday, merely to test a couple of things, not with the intention to get something decent. I had all sorts of problems, like my ZWO ASI 120MM (mini) not being able to display any stars in PHD2, so I decided to go without guiding, and honestly, as my polar alignment was very good, I was happy with the results of my 1 minute shots.
But having taken a closer look at the subs, I noticed strange diffraction spikes of the bright stars (see attached example).; I'm using a Orion 8 Astrograph and a Canon 500D.
One of the things I modified, I attached a cooling system to the DSLR, bringing it's weight from 480g to 1080g, could that be the problem; I don't remember where, but I seem to have read somewhere that the Orion8 focuser could take up to 1300g. I know I'm close, but still.
Or is it my collimation that is not ok; I admit, I did not check it, as I collimated last week during the day and the whole setup has not been moved. It stays outside under a car cover.
Anybody any idea what's going on here?
Thanks in advance,