From: Milton Aupperle <milton@outcastsoft.com>

Date: January 20, 2009 10:28:47 AM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] New file uploaded to Astro_IIDC (thx and AU/AF matter)

Hi Alberto;

On 20-Jan-09, at 2:09 AM, albe albo wrote:

Very nice Saturn  image.

A question for who is concerned: i have a filter reel mounted on my DMK : Baader- R, G, B, (Empty), IR-PASS.

The Saturn grabbed in IR had a strong GHOST below itself and the RED one has a weaker ghost while  G and B seems Ghost freee.

The IR and RED images are not blur or out of focus and the ghost is pretty precise so I could subtract it from the image as i currently do for the "doubled" moon imagery.

Is this ghost image consistently present when your imaging all the time? Or is it there some of the time? And does move or disappear as you move the saturn image from optical center to edge of field?

If it's a filter issues, it should be there all the time not just some of the time, as long as the position isn't moving.

And have you tried taking the IR-PASS or Red  filter out of the wheel, screwing it into the 1.25" nose piece adapter, just in case the filter isn't perfectly perpendicular to the optical axis? If it's tilted in the wheel, you could wind up with wedge refraction effects.

Now i'm wondering if the doubled moon imagery too can be cause by  such IR-pass or Red filters that i always use for the moon.

Next time i will try the green one (like Alan) even if the loss of light is  stronger than with the RED filter.

No one noticed such kind of problem? I could post the enhanced image of each channel separately.

Post it and let's have a look at it.

HTH.. 

Milton Aupperle