From: "hpholcomb" <hpholcomb@yahoo.com>

Date: July 28, 2008 6:38:44 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: Jupiter with Baader filter..

Hey Mark,

Two simple, elementary really, questions:

1.  Is your scope collimated properly?

2.  How was the atmospheric turbulence at this seeing, i. e., were the

stars really "twinkling" or were they rather steady??

Those two astro viewing influences can make a big difference.  On a

night with significant atmospheric turbulence, I can hardly do any

planetary work with my 8" modified catadioptric.  Durn subject not

only jumps around like a bouncing rubber ball, very similar to your

"...dancing around..." description, but also is not sharp, which could

be due to both collimation and turbulence.

Perry

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

Hi Milton, & others, I got out last night with the 10" & 4 star  

aligned the scope.Using the 25mm eyepiece was a good bit easier for  

this process than the 20mm one. I noticed slewing was slightly off  

(10- 20 degrees) when Auto aligning these stars, I guess due to  

incomplete PA. I then rushed somewhat precipitously, to try my new  

Baader UV/IR cut filter with my DBK 21A F04.AS. Similarly Jupiter was  

out by the same amount when slewed to after the 4 star. It was also  

dancing around so much to in the camera`s FOV that refining the image  

was difficult if not impossible. In the brief time I had before the  

planet skipped out of view &  had to be re-found I noticed that the  

disk was still too bright to discern surface detail as I had with the  

4" scope. I had limited time to adjust the levels mostly shooting at   

the 33ms setting, Gamma 1.00 & moderate gains.I did also try adjusting  

the brightness & focus  somewhat.These are the settings I used for my  

movies with the 4" scope. Would these be adviseable levels for the 10"  

too? One thing I must check next time is the relative position of the  

object in the finder when discernable by the camera as this will be  

invaluable when actually nudging the image into view. With the 4" it  

was down & right of the centred eyepiece position. At least I was  

getting some form of image of Jupiter at the outward extent of the  

focuser with the nosepiece assembly out a little in it`s position in  

the sleeve. I`m pretty sure I hadn`t accomplished this before! Mark.