The moon....What have I done wrong?

[pianorealm]

Hi all.

Hope someone might be able to point me in the right direction here. I tried imaging the moon a couple of weeks ago with...well to be honest awful results!

I used a ms lifecam cinema webcam....adapted using Gary Honis' tutorial.

Sky watcher 130p motorised.

Sharpcap set at 10fps and 1280x720 res

About 3 mins per capture

The original video images are not good. I'm not sure if the focus wasn't right...although I tried for ages to get it spot on. Also...in the video the image is 'shimmering'.......moving around an awful lot?

Once processed it it registax 5 the resulting image was even worse than the original! I've attached the processed image.

I realise it might be helpful to post an image from the original avi file but I can't work out how to grab a screen shot of that?

Any ideas please?

Regards, Howard

[Leveye]

Looks like a focus issue to me. Just slightly off. Gonna be great when you nail it i bet!

[Ant]

I agree, the focus is the main issue. 

But have a play with the quality setting in R5, increase the percentage till you get to around 800-1000 accepted frames and re-stack. If that doesn't improve increase the percentage some more and try again. 

You *might* find that there are a some rogue fuzzy frames getting through that is throwing the final image out.

Although I do think that focus is the problem here.

What I used to do was get focus as close as I could and take an AVI, then adjust the focus very slightly one way and re-take the AVI, adjust the focus slightly the other way and re-take. All your wasting is a little time and some HDD space.  When I say slightly one way I mean exactly that - pretty much the smallest adjustment you can do with your hands.

Ant

[pianorealm]

Looks like a focus issue to me. Just slightly off. Gonna be great when you nail it i bet!

Thanks Leveye....I hope so! Trouble was.....every time I tried to focus....the image started shaking around....had to wait quite a few seconds for it to steady then try again. I know I wasn't using the best set up.....but do most people use an electric focuser for imaging?

[pianorealm]

I agree, the focus is the main issue. 

But have a play with the quality setting in R5, increase the percentage till you get to around 800-1000 accepted frames and re-stack. If that doesn't improve increase the percentage some more and try again. 

You *might* find that there are a some rogue fuzzy frames getting through that is throwing the final image out.

Although I do think that focus is the problem here.

What I used to do was get focus as close as I could and take an AVI, then adjust the focus very slightly one way and re-take the AVI, adjust the focus slightly the other way and re-take. All your wasting is a little time and some HDD space.  When I say slightly one way I mean exactly that - pretty much the smallest adjustment you can do with your hands.

Ant

Thanks for your reply Ant. Yes, I'll try fiddling in registax.

Please forgive my ignorance here....but when you say you adjust focus as close as poss....take an avi then another two avi's adjusting focus very slightly either way.....do you then process all three avi files or just the best one?

Thanks, Howard

[Ant]

I process them all separately. It gives you three bites of the cherry - each one at a slightly different focus point and one of he three will be closer than the other two - so may give a better result.

But the key is because of atmospheric distortions - you won't know which one was best focus till afterward...

Cheers

Ant

[pianorealm]

I process them all separately. It gives you three bites of the cherry - each one at a slightly different focus point and one of he three will be closer than the other two - so may give a better result.

Cheers

Ant

OK....that makes sense thank you.

[Leveye]

Thanks Leveye....I hope so! Trouble was.....every time I tried to focus....the image started shaking around....had to wait quite a few seconds for it to steady then try again. I know I wasn't using the best set up.....but do most people use an electric focuser for imaging?

Even though i don't see any motion blur here wind can sure be an issue with larger scopes like yours especially if you have a dew shield on. Like a sail! Temperature fluctuations will make scope housings, lenses and mirrors move around and defocus so check focus often! You may want to take the pictures using a timer to give the imaging scope and mount some time to settle before taking the shot.Timing is everything just wait for some calm time. I take lots of safety shots when i'm out there cause i stack them so if i need 20 shots i usually take 100 and pick the best of the best. haha. Have fun out there!

[cgarry]

I realise it might be helpful to post an image from the original avi file but I can't work out how to grab a screen shot of that?

Any ideas please?

PIPP will let you grab frames from your video to post.  Drop your video file onto PIPP's 'source file list' and hit the 'Test Options' button.  Then on the image window that opens you can save the frame with the 'Save Image' button.

Cheers,

Chris

[pianorealm]

Thanks Leveye. I'm using a webcam so start the capture from the laptop so hopefully the scope will not be unsettled. I am having fun...honestly....although being new to all this I imagine some might think by trying to image I'm attempting to run before I can walk........... and they might be right!

[brucen]

It is certainly much easier with an auto focuser as there is virtually no vibration. I have one on my 130P but I don't think that it fits older 130P's without modification. Have you tried not fully extending the legs and putting a weight on the tray to improve stability? I found this was ok for moon shots and only really need the auto focuser for use with the webcam combined with a barlow where any movement is too much movement.

[pianorealm]

PIPP will let you grab frames from your video to post.  Drop your video file onto PIPP's 'source file list' and hit the 'Test Options' button.  Then on the image window that opens you can save the frame with the 'Save Image' button.

Cheers,

Chris

Thanks for that link Chris, will download and try to post an original screenshot.

Howard

[pianorealm]

It is certainly much easier with an auto focuser as there is virtually no vibration. I have one on my 130P but I don't think that it fits older 130P's without modification. Have you tried not fully extending the legs and putting a weight on the tray to improve stability? I found this was ok for moon shots and only really need the auto focuser for use with the webcam combined with a barlow where any movement is too much movement.

No, I haven't tried a weight on the tray and I usually fully extend the legs.....duh! Thanks for your advice brucen....seems obvious now, but there's so many other things to think about too. Not sure how old my scope is...it's mid to light blue in colour.

Howard

[glowingturnip]

if you've got a lot of shimmering in the video, that's atmospheric turbulence ('seeing') that's affecting it, and that will affect focus too, it'll be in focus in one frame and out the next frame.  Try again on another night, hopefully you get quieter conditions.

[pianorealm]

if you've got a lot of shimmering in the video, that's atmospheric turbulence ('seeing') that's affecting it, and that will affect focus too, it'll be in focus in one frame and out the next frame.  Try again on another night, hopefully you get quieter conditions.

Thanks....yes....it really was shimmering in the video. I'm using the telescope out at the back of our house....do you think warm air currents would cause this effect? I suppose the best way to find out is to take the scope somewhere else further away?

[long_arms]

Before I upgraded to the autofocuser, I would clip a regular clothes peg onto the focuser knob. 
Whilst watching the laptop screen for focus you can just touch the top of the peg which allows you to make smaller adjustments with less vibration. Worked well for me anyhow. 

Dan   
 

[pianorealm]

Before I upgraded to the autofocuser, I would clip a regular clothes peg onto the focuser knob. 

Whilst watching the laptop screen for focus you can just touch the top of the peg which allows you to make smaller adjustments with less vibration. Worked well for me anyhow. 

Dan   

OK......that's a good idea...and cheap too!   I'll give it a try, Thanks.

[glowingturnip]

Thanks....yes....it really was shimmering in the video. I'm using the telescope out at the back of our house....do you think warm air currents would cause this effect? I suppose the best way to find out is to take the scope somewhere else further away?

yes, could do, if you've got heat coming from boiler vents and the like.  thermals can do it (not really a problem at this time of year) eg over large expanses of concrete, or over water, but also it's weather - fast moving airstreams high up can cause it

[Pete Presland]

all good advice above, but sometimes the "seeing" is very poor. there are not many times when i am trying to focus with the webcam in position that i can see a stable image, the advice that Ant gives about three sets of AVI's is a good idea.the more imaging you do, the more familiar you will become with where and what the focus point on your set up is and looks like throught the webcam.

[brucen]

No, I haven't tried a weight on the tray and I usually fully extend the legs.....duh! Thanks for your advice brucen....seems obvious now, but there's so many other things to think about too. Not sure how old my scope is...it's mid to light blue in colour.

Howard

I don't think that the auto focuser will fit straight out of the box on the blue ones. I did look around before buying one and found this which might help if you want to try one.

http://stargazerslounge.com/diy-astronomer/175240-skywatcher-auto-focuser-sw-explorer-130p.html