Hi from Surbiton, land of night lights, UK

[nytecam]

Thanks Nytecam....... Another observation is that surely the apparent movement and other diffraction effects of turbulence could lead to resolution enhancement. Turbulence a benefit. Shock Horror! .....

An interesting comment that is generally dismissed as illogical. However many many moons ago when I used a 60mm Dixon refractor [we all start "small"] to observe Mars at a very favourable opposition I was convinced, on odd occasions, that the scope "punched above its weight" to reveal detail that should not have been visible and assumed atmospheric turbulance was in play !

As Peter states Registax freeware has solved the problem of moderate turbulance to create remarkably sharp lunar/ solar and planetary images usually beyond what is visible at the telescope

[zotric]

An interesting comment that is generally dismissed as illogical.

As Peter states Registax freeware has solved the problem of moderate turbulance to create remarkably sharp lunar/ solar and planetary images usually beyond what is visible at the telescope

It seems to me quite plausible that, for example, diffraction by turbulence causes sporadic lensing and other effects on a small scale. That might explain your occasional sense of more detail being present. There are other less exciting explanations, of course! I will take another look at Registax. Looking around the literature this afternoon, I think we need something called the aptly, but un-informatively, named 'non rigid image registration'. The actual maths is too hard for me to work out an algorithm right now but it does seem like a reasonable way forward and perseverance is probably the key.

[JamesF]

Registax serves a number of different purposes. The first is to select a number of "best fit" frames from the source data when compared to a given reference frame. Stacking these frames reduces the amount of noise in the image and whilst it may make detail easier to see on it's own the real benefit is that given a low-noise image it's then possibly to apply the sharpening algorithms to allow more detail to be seen.

There are other algorithms that can be used to extract more useful data from the capture too, such as using drizzle on undersampled images.

"The Handbook of Astronomical Image Processing" covers much of the theory and maths behind this sort of processing. It's not cheap, but an interesting read if you're interested in that side of things.

James

[JamesF]

Whilst on the subject, AutoStakkert!2 attempts to select the "best" frame from a capture sequence automatically. I believe it does this by modelling the "sharpness" of the transitions between dark and light areas in the frames on the grounds that those with the sharpest transitions are the best quality. I may be entirely mistaken there though.

James

[zotric]

Autostakkert will make a big difference.

I think it did. Impressive. Here is my original picture with Autostakkert and unsharp masking. A bit more 'layer' detail on the crater rims possibly? By having tracking marks the program appears to do much of what is needed for 'Non rigid image registration' (as I believe it is called). This sidesteps the need for a complex algorithm that would correlate unspecified features as they move about. Thanks very much, Peter, for the information.

[zotric]

Welcome to SGL.

That looks like a reasonable image from the Toucam. The Moon is tricky to get focus perfect on, so I think you've done a good job. Assuming it's the same camera sensor as the SPC900 it's well worth hanging onto the camera because there's little to beat it for planetary imaging unless you're willing to spend hundreds of pounds.

It's worth considering using a DSLR for wider field if you have one, at least to get started.

James

Hi James. Thanks for the comments. Yes it is the same CCD chip. Here is a modding article: http://home.zonnet.n..._Y/spc900nc.htm. Focussing is definitely a big issue for me. Made harder because the telescope vibrates like crazy when I touch the focuser, though this rack focuser is pretty good in itself (not much backlash) and the EQ3 mount is pretty stable. It may be possible to track down and perhaps add weights to damp these oscillations. Anyways I've been looking at whether it is feasible and/or worth the effort to fit a non-standard electric focuser. The telescope is a Meade 'starter' 114/900 bought in 2003. It seems OK optically so I think I could get a lot more out of it yet.

[zotric]

Registax serves a number of different purposes. The first is to select a number of "best fit" frames from the source data when compared to a given reference frame. Stacking these frames reduces the amount of noise in the image and whilst it may make detail easier to see on it's own the real benefit is that given a low-noise image it's then possibly to apply the sharpening algorithms to allow more detail to be seen.

There are other algorithms that can be used to extract more useful data from the capture too, such as using drizzle on undersampled images.

"The Handbook of Astronomical Image Processing" covers much of the theory and maths behind this sort of processing. It's not cheap, but an interesting read if you're interested in that side of things.

James

Thanks James. Quite a lot of 2nd hand copies around. Took pot luck and ordered one subject o the software CD being included.

[JamesF]

Hi James. Thanks for the comments. Yes it is the same CCD chip. Here is a modding article: http://home.zonnet.n..._Y/spc900nc.htm. Focussing is definitely a big issue for me. Made harder because the telescope vibrates like crazy when I touch the focuser, though this rack focuser is pretty good in itself (not much backlash) and the EQ3 mount is pretty stable. It may be possible to track down and perhaps add weights to damp these oscillations. Anyways I've been looking at whether it is feasible and/or worth the effort to fit a non-standard electric focuser. The telescope is a Meade 'starter' 114/900 bought in 2003. It seems OK optically so I think I could get a lot more out of it yet.

I bodged a Skywatcher motorised focuser to fit my 127 Mak. It made imaging so much easier. Well worth the effort, I'd say.

James

[JamesF]

Thanks James. Quite a lot of 2nd hand copies around. Took pot luck and ordered one subject o the software CD being included.

To be honest I've never even looked at the software. My interest was really to get an understanding of what was going on at the theoretical level. It did stretch my ability to remember maths learnt thirty years ago, I have to admit.

James

[zotric]

To be honest I've never even looked at the software. My interest was really to get an understanding of what was going on at the theoretical level. It did stretch my ability to remember maths learnt thirty years ago, I have to admit.

James

Hi James. Me too; but I do have a wish to find or write software that will remove the effects of turbulence from images. Step one, I am considering, is to remove geometric distortion as mentioned above. I've just been looking at the C++ CImg template library - it has interesting examples.