From: Mark Gaffney <markgaffney@me.com>

Date: February 5, 2010 7:42:48 PM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: Damian Peach

My attempts to barlow (2.4x & 2x) Jupiter a while ago were very noisy & dark..I`m wondering if the seeing was working against me or whether a Televue type would work better than my cheapo Vixen etc. ones..Have you or anybody else ever used a Televue 5x barlow for instance..?

Mark.

On 06/02/2010, at 12:24 PM, doobisary wrote:

Antonio Cidadao of Portugal used to use an AO2 for keeping planets on chip with his ST5 camera. That device has been out of production for many years, though, unfortunately.

I have an AO-7 with my SBIG ST2000XM. It's great for "guiding" DSO images, but it (and devices by Orion and Starlight Xpress) can't be used for planetary for a couple reasons. First, they work at very slow rates (the AO2 did corrections many times/second). Second, they get their pointing information from an off-axis chip in the camera (SBIG) or a guide camera (Starlight Xpress, via an OAG).

I've been curious whether anyone has tried planetary imaging (of faint planets like Uranus and Neptune, in particular) using an image intensifier and really short exposures/high frame rates, to freeze the seeing that would otherwise be crippling with the long exposures required (shortest exposure I was able to use on Uranus with my 12.5" Cass was half a second).

-Tim.

--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:
>
> Hey Ray,
> Yes it`s my aspiration to become one of these "Deep Sky fiends"! I`d
> like to have my finger in several pies eventually..
>
> Mark.
> On 04/02/2010, at 3:19 AM, Ray Byrne wrote:
>
> > G'day Mark,
> >
> >
> > To my way of thinking - well for Solar System imaging the cameras we
> > use and good old AstroIIDC is in effect adaptive optics. We are
> > taking video at an incredible frame rate and then letting our
> > favourite software ditch all the crap and stack the good stuff ready
> > for us to tweak it. I don't think that an AO gadget could work this
> > fast and is aimed at the Deepsky fiends who are taking long exposures.
> >
> > Just my two penn'th
> >
> > Ray
> >
> >
> > On 2 Feb 2010, at 21:27, 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.
> >>>>
> >>>
> >>>
> >>
> >>
> >
> >
> >
>