From: albe albo <richter1956@yahoo.com>

Date: December 18, 2008 4:40:11 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] New file uploaded to Astro_IIDC-Puzzling Problem


Thank you Milton and Alan.


You both know that i'm trying and trying to find alternate or complementary  way for aligning/processing.

I applied de-warping to those mosaic images but when I did the first version of Copernicus something was strangely wrong and i didn't understand WHAT.

My eyes were puzzled by something unusual.

Since i'm pushing the focal to high values i'm noticing a strange blurring that it is not possible to improve with normal convolutions.

After exhamining carefully the images i noticed that the more contrasted features seemd to be doubled approx 5-6 pixels far from their originals.

I guessed that there was a "ghost" image that "directionally" messed up the overall sharpness even if the image itself is not clearly visible.

So i did an attempt duplicating the layer and subtracting a properly shifted layer (properly means experimenting the best  position) set to 20% transparency on a black background layer et ..voilà i had the confirmation of the 2nd image exhistance!

Please check the attached images (zip file).

I suggest to select the images and open them at once in preview so you may perform a quick toggle between them.

The image numbered 1 is the original one the images numbered 2 are NOT sharpened or processed but the only process i did was the ghost subtraction, nothing else.

This mean that there was a single precise ghost messing up the sharpness.

The white arrows shows (on the images N.1) the whiter rims external to the craters that puzzled me.

I have this problem both with C8 and LX10 OTAS.

It is NOT due to processing (alignment, stacking or deconvolution).

The ghost is present in the movies too and appears as a quick shift of the feature due to the seeing but i'm wondering: why that quick shift moves straight and directionally?

Usually the seeing should move random generating a circle of confusion...not a ghost shifted image.

Maybe a partial deflection due to the red /ir filter into a not perfectly aligned optical path?

The OTA is pretty well collimated (the resolution of the details confirms that)

Now i will check again all my mosaics including The 4 rimae.

The improvement is very noticeable and i'm happy that i can recover some images that i considered as lost.

Someone knows why the ghosts do exist?

Maybe they are poltergeist craters?


Cheers!

Alberto





From: Alan Friedman <alan@greatarrow.com>

To: Astro_IIDC@yahoogroups.com

Sent: Thursday, December 18, 2008 10:52:10 PM

Subject: Re: [Astro_IIDC] New file uploaded to Astro_IIDC


Thanks for pointing out Alberto's post - I missed it first time around. That is an excellent image and the wide field adds much interest beyond the famous Copernicus. Great work!


best,

Alan




On Dec 18, 2008, at 4:43 PM, Milton Aupperle wrote:

Very stunning Copernicus and area, Alberto. Even though I'm on dial-
up at 2600 baud, it was well worth the 40+ second download time.

I really like the view around the "Domezilla" area to the west and
north. The ash deposits around it are really nicely defined (striped
area).

Thanks for sharing..

Milton Aupperle

(PS - it was -32° centigrade here last night and unlikely to get
above -25°C at night for the rest of the week).

On 18-Dec-08, at 10:24 AM, Astro_IIDC@yahoogro ups.com wrote:

>
> Hello,
>
> This email message is a notification to let you know that
> a file has been uploaded to the Files area of the Astro_IIDC
> group.
>
> File : /Lunar/081208- Copernicus- Region-V4. jpg
> Uploaded by : richter1956 <richter1956@ yahoo.com>
> Description : Copernicus, Eratosthenes & Friends...
>
> You can access this file at the URL:
> http://groups. yahoo.com/ group/Astro_ IIDC/files/ Lunar/081208-
> Copernicus-Region- V4.jpg
>
>




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