From: Mark Gaffney <markgaffney@me.com>

Date: February 2, 2010 3:52:39 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Damian Peach

SBIG have an adaptive optics guider for $795 USD which will work with some of their cameras. Orion have an AO guider which corrects the guidance at up to 40 times per second for $1799 USD compared to 10 times per/second for the SBIG one I think & will work with usual type CCD cameras. They operate by having a lens inside the guider that rotates independently of the whole assembly of scope etc. which has to be moved otherwise. Usual autoguiding is done at much slower rates per second I understand...

I guess not what you`d be using for your usual planetary imaging though...

Mark.

On 03/02/2010, at 8:27 AM, Mark Gaffney wrote:

By the way Ray, 

I assume you`re talking about amateur scopes?! The REALLY big earth based scopes (one called the European Extremely Large Telescope at 42 metres is the next largest on the books!) have adaptive optics now which compensate for atmospheric turbulence. Apparently earth based telescopes will now rival (or exceed) the Hubble & it`successors for clear pictures & although astronomically expensive they`re a fraction of the price of sending these scopes into space & maintaining them!  They shoot lasers at the sky to create artificial guide stars which enable these adjustments. I think for a great price you can get some sort of adaptive optics for your backyard scope now as well..

Mark.

On 02/02/2010, at 1:07 PM, Ray Byrne wrote:

Hi Mark,

He now uses a C14 mounted on a G11 and transports that to Barbados with another guy who uses a C11 on an EQ6. Damian personally told me that he thought the C9.25 all round was better than a C11 when I was considering them both, he probably meant in the UK generally - but on Barbados the C14 would be king because if seeing allows - aperture rules. 

The aperture rules bit has its limits though for planetary imaging as even the largest scopes in the world can only resolve to the limit set by us looking through the atmosphere. In the book "High Resolution Astrophotography by Jean Dregesco he felt that 16" was the upper limit and any more aperture than that was pointless. I must point out that this book was published pre webcam imaging and his comments may not be relevant, I'd be interested to hear any comments on this 16" rule.

BTW Damian still uses the C9.25 as the C14 will not always perform that well as often as the C9.25 in the English seeing. There are some contemporary Saturns that are C9.25 on his site and the C11 he sold may the one his mate uses in Barbados but I'm not sure (he said the C11 was a great scope).

From my experience tonight my C9.25 is a great scope - out in up to -17c at one point. And my EQ6 just did the business after several months in the same situation flawlessly tracking at nearly 400x mag. - wonderful gear

ATB

Ray

On 1 Feb 2010, at 18:52, Mark Gaffney wrote:

> Hi Ray,
> Last I heard Damian had given up his C11 for a C9.25 for his
> excellent imaging of the planets. Is this still the case do you
> know, that he uses a C9.25? I know he travels by plane regularly to
> the Bahamas or Canary islands (with the scope in the cargo) to get
> the best results with turbulence & jet streams..!
>
> Mark.