From: "doobisary" <tjp314@pacbell.net>

Date: February 6, 2010 10:21:43 AM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: Damian Peach


Mark:


I've found my 9.25" to be extremely sensitive to accurate alignment.  It's also hard to do, since I'm up on a ladder to reach the scope in my roof mount.  Compared to the f/2.5 or so f/ratio of the 9.25", collimating my 6" f/10.3 Newtonian is amazingly easy!


Planetary images will improve dramatically if you spend some time to accurately collimate an SCT.


I've used my Televue 5x powermate for planetary imaging.  It does quite well on the 9.25" with the flea 640x480 with the 7.4 micron pixels.  It's way too much magnification for the flea2 with the smaller pixels, though.  For that, I get my best results with a 2x "shorty barlow" I picked up at RTMC from Stellarvue for $20.  In fact, it was such a good price I bought two!


I'd like to try a 4x powermate, but they're 2", and my "classic" Newts have 1 1/4" focusers.  The Televues are pretty expensive, too.


Somewhere in a box I have an old Meade 3x, one of those that's about 10" long!  Picked it up from the Meade booth for $10 New about 20 years ago when they were selling off unused stock at RTMC. I used  to use it a lot on my Jaegers 6" f/10 for planetary.  But it's comparable in magnification to an old Televue 2.5x I have, too.  I sometimes use that one, but it doesn't seem quite as good as the Shortys.


-Tim.


--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:


I still haven`t attempted to perfect my collimation either using any  

of the methods at my disposal. Things seem relatively alright so far  

anyway but maybe barlowed Jupiters would show imperfections to a  

greater extent than normal..

On 06/02/2010, at 1:42 PM, Mark Gaffney wrote:


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.