From: Alan Friedman <alan@greatarrow.com>

Date: March 30, 2009 9:07:38 AM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: weekend solar images

Hi Alberto,

Thanks for your note. I hope you are recuperating well.

I've had the Baader FFC for some time now. I once used it for planetary imaging with the 10" scope, but decided that it's minimum FL amplification (about 3x - almost 11 meters FL ) was more than my local seeing could take advantage of... I now use one of the 2x barlows most of the time with this scope. But the FFC is very well matched for my short focal length refractors. I'm not sure if the 4 element apochromatic design is critical for planetary imaging, but it certainly can't hurt. It was less expensive when I purchased it five or so years ago than it is today. My barlow collection at present is the FFC, a Televue 2X Powermate, and an old Astro=Physics 2x barlow (mid 1990s vintage.)

best wishes,

Alan

On Mar 30, 2009, at 9:33 AM, albe albo wrote:

As usual it is always a real pleasure observing your "heart"  images.

For me it is similar: i like the image for itself  and my possibilities are not enough for "scientific" imaging.

Anyway i try not to "add" features even if the simple basic processing could be considered like a  "modification" of the original image.

In this case it would be impossible to image anything since every image is not the representation of the reality.

So what is the reality?

Should we ask about reality  to Neo/Morpheus  or to the agent Smith?

The Matrix docet so we can continue to image as always!

I'm reading about the thousand oaks Halpha filter versus PST but my ideas are still confused.

I noticed that you are using a FFC by Baader.

is ist that magic apochromatic extender-multiplier etc etc.

The last time you wrote me you listed some Barlow lens but i didn't remember this one.

Is it a recent acquisition?

Does it worth its high price?

Thank you in advance

Alberto

Da: Alan Friedman <alan@greatarrow.com>

A: Astro_IIDC@yahoogroups.com

Cc: macastronomer@yahoogroups.com

Inviato: Lunedì 30 marzo 2009, 5:06:58

Oggetto: Re: [Astro_IIDC] Re: weekend solar images

Hi Milton,

Thanks for the note. Apologies for not providing more technical info - I am really an image person at heart (but I think you already know that!).

The set-up uses the A-P stowaway (FL=450mm) and the Baader FFC with a 2.5 inch extension. I've not measured it exactly but I think the effective focal length is in 1500-1600mm range. Settings vary with each, but a good average is:

exposure: 23ms

gain: 600

gamma: .9

The captured streams are 600-900 frames in length - 100-150 frames are selected for stacking. Seeing is very poor overall, but there are a small number of sharp frames in each stream. Anticipating the dwell moments between high turbulence while capturing and then evaluating and hand selecting the data for stacking are the two most challenging parts of the process.

For those who might be interested, I will be doing a presentation on solar and lunar imaging techniques at the Mid-West Astro-Imaging Conference in June.

best wishes,

Alan

On Mar 29, 2009, at 9:15 PM, Milton Aupperle wrote:

Hi Alan;

Nice Shots..

What sort of focal length are you using? It would be nice to see some of the technical details.

TTYL..

Milton Aupperle

--- In Astro_IIDC@yahoogro ups.com, Alan Friedman <alan@...> wrote:
>
> Hi all,
>
> I had a chance this weekend to capture some nice prominences on the
> edge of the sun:
>
> http://www.avertedi magination. com/img_pages/ tsunami_prom_ 20090328. html
>
> sunny skies and best wishes,
>
> Alan
>
>
> Alan Friedman
> avertedimagination. com
>