Jupiter 290910

[Virgoman]

Hi all,

Just attaching an image of Jupiter taken with an SPC900, which started out as an SP880 received from Morgans. This is an early image, have a quite a few more to process but am reasonably pleased. Have the dreaded onion rings unfortunately. As usual taken with an C8 SCT, and a x2 TAL barlow. Seeing was reasonable. Thanks for looking!

Best regards,

Ralph:)

[Virgoman]

OOPs Image Here!

Best regards, Ralph

[omneferuss]

Looking very good.. better seeing and/or improved focus next stop.. and refinements of processing and it'll be a world-class winner !

[gfletcher]

What causes that onion ring effect ?

Is it caused during the processing in Registax etc ?

Graham

[Space Cowboy]

Onion rings is caused by gain setting beeing too low. I had this problem when I was going below 50% gain. Its a fine balance as too high gain can cause image noise.

[bus_ter]

This is a great shot, what scope did you use?

@Space Cowboy: Interesting comment about the gain. In my images I tried to keep the gain as low as possible and the exposure as high as possible. My theory is that increased expsoure is allowing more light to hit, but the gain is just amplifying a low light image and produces more noise, much like increasing the ISO on a camera.

My next run I'll experiment with less exposure and more gain..

[Virgoman]

Thanks for taking the time to reply guys. Yes, omneferuss focusing is always a challenge, never consistent and sometimes you wonder if its the seeing or or your own crappy focussing. Compounded somewhat by a lower resolution screen which can make images appear sharper than they are - boosting your confidence. As for world class.....nice comment but.....thanks anyway:)!

Yes, Graham constant battle between putting the gain high enough to avoid the onion rings and not too high so as to burn out detail. I think the imaging source cameras allow you to crank the gain up much higher than the lowly webcam without detriment. Not sure about this, as I have never used one of these, but I have read comments to this effect.

The scope bus_ter was a Celestron C8 SCT.

Once again thankyou all for your comments, and clear skies (with good seeing!) to all.

Best regards,

Ralph:)