From: albe albo <richter1956@yahoo.com>

Date: February 6, 2010 2:40:03 AM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] new filter wheel...!

Ok Mark,

the 6.3 is a lot more "forgiving" allowing longer extensions and experiments while the 3.3 is a wild beast LOL.

Now you make me curious to test the 6.3 in order to understand how much it can be "pushed" with acceptable results.

For example i pushed the 3.3. > to 2.8 and seems to work (the focus knob of the scope is almost completely turned CCW)  but the vignetting increased a lot. 

Unfortunately i have no clear sky since long time so i couldn't do a true session with dark frame, flat field etc.

It is almost one year that i don't do any DSO. (i'm lazy too i confess)

Regarding the focals i can check them on a building that is placed exactly at 1,5 km from my house.

By the way....I wanted to measure the exact point where the C11 gives the "nominal" focal length (2.800 mm).

Putting the visual back + nose i realized i had only 2.652 mm !

So i did some tests: did I published them already on this group?

http://dl.dropbox.com/u/1094920/ASTRO/100130-MisurazioneFocale.jpg

Cheers

Alberto

Da: Mark Gaffney <markgaffney@me.com>

A: Astro_IIDC@yahoogroups.com

Inviato: Sab 6 febbraio 2010, 01:42:44

Oggetto: Re: [Astro_IIDC] new filter wheel...!

Alberto, 

I`ve taken the extender tube off the Scorpion camera (just the shorty nosepiece here) & put on the Antares 6.3 x reducer (just for the photo!) & I`m getting 9 cms or about 3 1/2 inches between camera sensor & back of reducer...The Antares may be the best alternative unless I can get my Mogg`s to work..The difference between our set-ups is of course the CRG OAG...Mark.

On 06/02/2010, at 7:22 AM, albe albo wrote:

Yes, the TIS AS can reach an hour of exposure but practically i nevew went beyond 3 or 4 minutes because it's difficult to manage the noise.

Most of my DSO images are about 1 minute or 2.

Now i link the pic of my Atik f. 3.3 setup... i gues you are veeeery long unless you have some hidden trick.

http://dl.dropbox. com/u/1094920/ ATIK-DMK- F33.jpg

Cheers

Alberto

Da: Mark Gaffney <markgaffney@ me.com>

A: Astro_IIDC@yahoogro ups.com

Inviato: Ven 5 febbraio 2010, 16:15:24

Oggetto: Re: [Astro_IIDC] new filter wheel...!

By the way Alberto, 

I was wondering how you got by the "time exposure" problem with your TIS cameras. Don`t you have to open the shutter for an extended time when doing your pictures of DSO`s? PGR cameras have this option but I thought TIS ones didn`t..?

Mark. 

On 05/02/2010, at 9:54 PM, albe albo wrote:

Wow, nice assembly.

In my experience the f3.3 reducer doesn't allow those long  extensions.

I have the same atik wheel and the same 3.3 reducer but, in order to use the DMK camera with the 3.3 reducer, i had to attach the camera practically directly on the wheel in addition even the pipe between the reducer and the wheel had to be minimal.

If i remember correctly the total length from the back of the reducer and the camera (including the wheel) had to be approx. 45 mm otherwise the reducer becomes useless.

Do i miss something?

if i understood correctly you didn' test it on the road.

Please let us know!

Cheers

Alberto

Da: Mark Gaffney <markgaffney@ me.com>

A: astro_IIDC@yahoogro ups.com

Inviato: Ven 5 febbraio 2010, 08:12:46

Oggetto: [Astro_IIDC] new filter wheel...! [1 Attachment]

Here`s a picture of my set-up with the new Atik filter wheel..
(perhaps?) I`ve yet to get the LRGB filters, probably a couple of
months away. I had enough T-thread adapters with the 2 different sized
ones that came with my Meade f3.3 reducer & those provided with the
filter wheel to perform basic connections at least. As to how things
work optically..we` ll see! I know with the Meade reducer it took a
good deal of screwing & unscrewing connections in the dark when I
first imaged with it (taking the moon) to get it to work at all. I
also have an Antares f6.3 reducer as well as the Mogg 0.3x to play
with & am pondering whether I should get another Mogg one? At least
they will attach to the camera`s nosepiece independently. The picture
shows the Scorpion 20SO at back..a Mogg adapter which takes the
cameras nosepiece etc. (I forget the serial number)..one of the Meade
T-thread adapters..an Atik one before the filter wheel..the FW..a ring
which came with the Atik another Meade t-thread..the Celestron Radial
Guider, then the Meade f3.3 reducer..I`ll have to write this all down
so I know what goes with what..!
Mark.