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Lunar first light and improvement advice


DaveHKent

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After owning a ZWO ASI120MC for a while, I finally put it to some use and I'm fairly pleased with the first results. Taken through a Celestron NexStar 90 SLT.

23243107156_99d42935ca_b.jpg22_11_15_lunar_plato

Any tips for improvement on that, the picture looks a bit on the soft side? Conditions were not great, as it was still windy and I only give my scope around 10 minutes to cool. There is also quite a lot of muck on the sensor I need to find a way of cleaning.

I could not get anything useful out of RegiStax but found Avistack very quick and easy to get going with. Any views on the best stacker for lunar imaging?

Is there anything I can do in post processing which will sharpen the image up?

One tip for anyone getting started with these cameras, put the USB lead at the bottom of the eyepiece slot. I had it coming out at the most convenient angle, meaning that pressing up on the GoTo control moved the image diagonally, giving that extra level of confusion.

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Hi Dave, first off, that's a nice image. A lot of people don't use Registax as there 'go-to' stacker. Autostakkert! 2 (AS!2) seems to be favourably recommended. You could try putting your final image into Registax and using the wavelets function to improve the sharpness. It is better to do lots of small adjustments rather than one or two big ones. Just play around and see what you get. As long as you work on a backup copy of your image there is no danger if you go too far. When you are happy with the result click 'do all' and then save the new image.

HTH & clear skies!

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Impressive first result, well done!

Try and let it cool down for as long as recommended, but sounds like you are aware of cool down time already?

Stacking-wise, I have used AVIStack, Autostakkert and Registax for lunar and solar imaging. They can all do a fab job so I would suggest try them all when you get time and take your pick. I use Autostakkert almost all the time these days.

Your image can definitely be sharpened up. It was not obvious to me when I started stacking, but expect your stacked image to be a little blurry, more so than some of your sharpest frames in the capture. Stacking massively reduces the noise in the image which allows you to apply strong sharpening without the image falling apart.

To sharpen, some ways are to use Smart Sharpen if you have Photoshop (set Remove to Lens Blur, try something like 500% strength and radius of 1.0), or you can use wavelets in Registax as already suggested by Bryan. I also use a program called Astra Image, which is not free but I think a very fair price for what it does, you can trial it, site is:

http://www.astraimage.com/

Have fun with the lunar imaging!

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nicely done, you've got Valles Alpis at the bottom there.

+1 for AS!2, I use it all the time now.

I think you've got a little bit of colour fringing going on, visible at bottom left, which is quite normal, caused by differing atmospheric refraction for different wavelengths.  Registax has a tool to fix that - load the stacked tiff into Registax and since it's a still image it will skip all the stacking tabs and go straight to the wavelets page, there's a tool on there called RGB align, use that, draw a box round a significant feature, click 'estimate' then 'apply all' and save.

Lunar images respond really well to deconvolution tools if your processing package has one.  Van Cittert deconvolution in Pixinsight is simply amazing in what it can bring out. 

High Pass sharpening works well.  There are probably ways of doing it in various software packages, but in Photoshop you would duplicate a layer, Filter/Other/High Pass, use a scale of somewhere between 4 to 6 pixels (adjust to taste), and change the blending mode to either overlay (strong effect) or soft-light (more subtle).

Wavelets in Registax as others have said - you probably want a bit more on the first layers, but be careful not to amplify noise, and successively less on subsequent layers.  Subtlety is key though, it's very easy to overdo, and many lunar images out there have been over sharpened.

Symptoms of over-sharpening are a gritty look to the picture, overly-white bits on crater rims,and a bright ring round the limb where it meets outer space- if you see those, back off till they're gone, and you should be good to go.

Do please post up how you get on !

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