can't seem to get a sharp image pre or post processing

[eye-to-the-sky]

been experimenting with webcam imaging for a couple of weeks now, Im consistently running into a problem with getting decent focus on the monitor screen during capture and dissapointing results after processing.

So this is the set up, please don't laugh too much

Scope is a Meade 4504 114 mil apeture GOTO, bought it years ago when I knew nothing.

Webcam is a Philips SPC880 flashed to 900 spec by Morgan's

I'm currently using VLounge as the camera operating platform and Registax 6 for processing.

I first got some mediocre results of Jupiter but was not too surprised as this was my first attempt, the seeing was probably not the most favourable, the finished image was small and pixelated.

So I waited for the moon to appear, thought big target must be able to get a good sharp image on screen, well almost but not as sharp as I wanted, post processing was dissapointing, trying to adjust the image in wavelets resulted again in a pixelated image.

Am I doing something fundamentally wrong (have tried adjusting gain, brightness gamma shutter speed et all but cant seem to get the kind of sharp images I was hoping for) or is this sort of thing beyond the capability of the scope Im using.

I also tried dropping the resolusion down a stage but that hasn't improved anything

Hopefully attached are some images of what I've produced so far, hope I can get some useful critique, thanks in advance.

Graham

Jupiter13.bmp

[terrym2002uk]

Could you tell us about your work flow?

[malc-c]

OK your scope (if it's the same spec that google thows up) is a 4.5" f8 reflector. Jupiter is not best placed at the moment, which will be why you are getting poor images when targeting it. As for the Moon, I would be pleased with that result given the equipment used, so don't put yourself down.

To really get things pin point you need to ensure the scope is well collimated (the subject has been discussed at length so I'll leave you to read up on that) and to make sure you have exact focus a Bahtinov mask is the only way to confirm this. You can but them from around £15 or make you own (again DIY Bahtinov mask has been covered on the forms). You use a bright star and your web cam and then when the diffraction pattern is correct, remove the mask and then point that at your target. Any images out of focus from that point will be down to poor seeing conditions.

[eye-to-the-sky]

Terry, I've not got into the habit of jotting down all the settings for each capture just yet, but from memory, I've been running at either 10 or 15 fps with the shutter speed adjusted to try and bring some clarity to the image whilst adjusting gain, gamma and brightness to try and clean it all up, the video runs are between 3 minutes and 5 minutes, aiming to stack as many frames as possible within 95% compitabillity of the reference frame quality.

I'm still fumbling my way around a lot of the features in registax so maybe some of it is just my ineptitude with the software.

Hope that kind of fills in what you mean by workflow.

Malc, thanks for the encouragement, the primary mirror isn't as pristine as it might be, Im considering getting it re-coated, I've recently laser collimated it and was horrified at just how far out the mirrors were, I'm surprised it could see anything !

The lower resolution picture of Palus Somni at the top of the frame is post collimation and is a still capture, so optically its still not quite what I'm aiming for.

A lot of what I'm doing here is trying to learn the craft before deciding if I'm going to commit money to a better quality scope, so for now I have to carry on with what I have.

Would a focal reducer help with eliminating pixelation or am I just expanding the field of view with one of those ?

Thanks and hopefully I'll get some more replies from yourselves or others.

[johnb]

You use a bright star and your web cam and then when the diffraction pattern is correct

I did not realise use could focus on a star and then move to the moon - must try that

John B

[Mak One]

Terry, I've not got into the habit of jotting down all the settings for each capture just yet

I'm not familiar with the capture software you mention, but if it helps, I use Sharpcap (freeware) to capture the AVI's from the webcam (Neximage - a.k.a. an SPC900). You can set it so it saves a text file of your settings at the same time as the AVI. You can try all the settings you like on a particular target and don't have to worry about "scribbling" down the right settings (in the dark) and matching them up with a whole load of AVI's later.

I've found that for lunar stuff, keeping the gain low enough so it doesn't introduce over-exposure or noise artefacts is key, whilst still leaving enough detail for registax et al to work on. Keep the exposure as high as the image will stand without burn-out of the bright bits. Saturation and gamma to zero. Brightness and contrast mid way, again high enough to give a good image but low enough to avoid over-exposing the bright bits. 300-400 frames at 5fps. If you use 30fps for focus/framing etc then switch down to 5fps for imaging, you'll have to change the settings to suit as the exposure etc for the image changes with frame rate.

Once you've got the focus right (key to whole lot) and the capture settings there or there abouts, fire away and have a play with the results in registax until you're happy. Pick a good frame, set your alignpoints and let it go...

Good luck and happy imaging!

[eye-to-the-sky]

Ash, thanks for your help, the Vlounge camera platform is what installed itself when I plugged in the 'cam so I've been plodding along with that, I'll load up sharpcap and get a feel for how that works, definately like the settings display feature you mention on that platform for keeping track of things.

cheers

Graham

[Mak One]

You're welcome Graham. One other thing - don't over do the wavelets in the final registax process. Your base image looks like it's got promise but if you don't mind me saying the next version looks a bit "overcooked". It's very tempting to push the sharpening too far in order to tease out a bit more detail, and it's a very subjective thing.

Don't worry - we've all done it. I still do.

PS. When you do hit on the right settings in Registax, remember to click on "hold wavelet settings". That way when you load up the next image, it will automatically apply the same settings when you get to that stage. Makes mosaics much easier..!

[eye-to-the-sky]

Thanks Ash, yes I agree its a bit burnt round the edges and it all boiled down to, as you said, trying to draw out the detail.

I might go way over the top, give it some wacky title, call it art and flog it to Tate Modern for millions of quids, clear off to Hawaii and buy one of the Keck's