blurry edge??

[coco smoko (Stephen)]

Would like to know why the edges are blurry .
Is it a lack of light on the edge???
hhhhhhhhmmmmmmmmmm
Also what is near jupiter, its not a moon.
Taken around 9:30 friday night

[Inmykombi (Geoff)]

Hi,
I dont know why the edges are blurry... but I looked up some Jupiter info and Europa was transiting about 9.30 Friday night, and Io was within about 1 Jupiter diamater from the planet about the same tim.

It may have been Io.

Geoffro.

[Paul Haese]

That is Io you have there. You might like to get Jupiter 2 as a program that tells you about moons and GRS information.

The blurry edges are onion rings. They are compression rings caused by the camera not being able to download all the available grey scale. Many cheaper webcams suffer from this problem. To minimise the problem use the histogram to expose your planet at near full histogram. You will not completely remove it but it will look better than this. Which camera are you using?

[coco smoko (Stephen)]

Hi, thanks , onion rings ok.
The cam is a color dmk21 with 3 times barlow.
I think I will capture in black and white to increase frame rate from 30 to 60 fps.

The seeing can clear things up some yeah????
Thanks for the help.............

[Paul Haese]

That is odd you are getting onion rings with a DMK. What size scope are you using the barlow and camera on? You might be under exposing. Are you using the histogram to adjust your settings?

[coco smoko (Stephen)]

Hi Paul, 12 inch dob, only 30 fps but I am going to start black and white and grab 60fps. The photos are done with no tracking in the heart of Melbourne. I think an eq6 and some country locations will help.Any tips would be very helpful....

Thanks, Steve

[coco smoko (Stephen)]

Oh, is the histogram done post or pre filming..

Thanks again. Steve

[Paul Haese]

Histogram is done during capture. It is under view in IC capture. You want the histogram to be around 250. So you need to adjust your gain and exposure to meet this target. Images that are well below half way on the histogram often exhibit onion ringing too. This is on top of those cameras that are compressing the data.

So also ensure that you are not using any compression with your capture too. You need to use the appropriate codec for your colour camera.

Let me know if you have trouble understanding this. I will try to explain further.

[iceman (Mike)]

The onion rings can be caused by bad seeing, when Jupiter is waving about like a flag.

I still get it myself occassionally when imaging in poor seeing.

Just keep trying and when you get good conditions, you'll find it's most likely gone.

[coco smoko (Stephen)]

Found the histogram on icapture
The help on this site is great
If i can get images closer to yours or mikes I would be very happy
Thanks Paul

Steve