Seeing was pretty well identical to last night (yuck) so this time I dropped back on the image scale; 2X barlow & 1 extension tube. A better result I think.
You've both done a great job in pretty poor seeing. I had a go last night when Io was transiting but didn't end up with anything worth keeping. Well done.
for your responses. Mike I like your processing skill, and agree once I saw mine next to your image, that the colour difference stood out. You have also bourght out more detail. Thanks again.
Yeah I know it looks like the cut end of a sushi roll, but it is big
This was taken right at the tad end of the imaging session loooong after I should have given up, shooting about 20 deg above the roof of the house, (I guess the house isn't as thermall insulated as I though )
Positive eyepiece projection on the 8" meade sct using a 15mm celestron Ultima eyepiece, FL approx 14.6 m, F/73, 300/1200 stack. I guess if I hand sorted I'd find some decent ones but at 00:30 who cares
480X480 pixel crop, using Virtual dub and the fantastic PCFE to covert to bmps and center and crop.
Feel free to chuckle at the quality, but mines the biggest
Oh and I had to use a hell of a lot of gain at 1/25 sec which is why it's so grainy
They are going through Virtual Dub as we speak, though I'm not holding out much hope for them. Don't know if you saw the jet stream over SEQld last night
I was just being silly with trying to see how big an image I can get with a give setup.
Normally I would use a 2X barlow (negative projection) to get a bigger image than just using a toUcam straight in the focuser (prime focus). To get an even bigger image Mike, Dave Asi et al use an extension tube after their powermates/barlows (still negative projection). My barlow is pretty achromatic and the dreaded blue rim becomes very objectionable. By using an eyepiece to positive project (hopefully less chromatic aberation) and then extending the ToUcam back from the eyepiece I can get rediculously long focal lengths and image scale if I want. The reason my image is so fuzzy is because I exceeded the limit of resolution for my scope and I was imaging through very turbulent air coming off the roof of my house. I can actually vary the distance the ToUcam chip is from the eyepiece to vary my image scale to make the most of what the seeing will allow on any given night. I can also adjust it by varying the eyepiece fl as well. If I really wanted to by using say a 4 mm eyepiece I could probably get the GRS to fill the field of view but you probably wouldn't be able to recognise it.
For example, if I use a 32mm eyepiece I can reduce my scope focal length from 2000mm down to 500mm and reduce the f/ratio from f/10 to f/2.5. Now if I switch to a 4mm eyepiece and extend out to the max that my extender will allow I will get a FL of 60.5 meters and an f/ratio of about f/303. Pretty useless but I can get any ratiation inbetween to suit the conditions of the night, and using a good eyepiece have very little CA.
I'll post some images later once I've done the processing so you can see the difference in sizes using the different techniques.
Last edited by [1ponders]; 06-07-2006 at 12:29 PM.
AAAHHH!!
Well done! 
![[1ponders]'s Avatar](../vbiis/customavatars/avatar45_9.gif){kind=avatar}
) 
and extend out to the max that my extender will allow I will get a FL of 60.5 meters and an f/ratio of about f/303. Pretty useless but I can get any ratiation inbetween to suit the conditions of the night, and using a good eyepiece have very little CA.
