From: Mark Gaffney <markgaffney@mac.com>

Date: July 28, 2008 7:31:50 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Re: Jupiter with Baader filter..

Hi Perry, Last I looked the scope was still collimated correctly & the stars were twinkling last night. I`ve had troubles before with turbulence & visibility & have had to give up on the whole process of set-up mid way but last night was OK I believe. It must be 4 months ago now, one night, I managed the she-bang-a boodle of 3 star, Iterative Polar Alignment & 3 star again & then had the 10 inch reflector slewing to test objects (like NGC 2516 & the Jewel Box & others) successfully with both Astroplanner & Equinox 6. I haven`t had the same success since due to not being persistent enough I guess & have mostly used the scope for viewing the moon which it seems to track reasonably well on Planetary Alignment. The new filter has enabled me to make some movies of distant trees yesterday which before were too bright. ( too much light gathering capacity on the C10-NGT I imagine). The 4SE does trees no problem! So I`ve just got to be patient & try again! I`m pretty sure the PA is still out anyway after 2 attempts at IPA in the first of which I got further away not closer. The second attempt I only completed the first steps (slewing to the alignment star & Syncing) after the previous re-adjustment of the mount controls. I was hoping the error of about 1 degree it was giving me would be good enough! Mark.

On 29/07/2008, at 10:38 AM, hpholcomb wrote:

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.

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