From: Dave Goodyear <dave@kb2networks.com>

Date: November 27, 2012 10:47:33 PM MST

To: "Astro_IIDC@yahoogroups.com" <Astro_IIDC@yahoogroups.com>

Subject: RE: [Astro_IIDC] Focussing issues .. need advice


I think you approached the Dawes Limit of the scope… I see other pictures on the net using a 102 and 5x powermate and they look about the same..  How’s your collimation?

 

 

 

Dave Goodyear

KB2 Networks Inc.

214 Main St. #318                            

El Segundo, CA  90245

310-933-2436

 

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From: Astro_IIDC@yahoogroups.com [mailto:Astro_IIDC@yahoogroups.com] On Behalf Of Dave Goodyear
Sent: Tuesday, November 27, 2012 9:35 PM
To: Astro_IIDC@yahoogroups.com
Subject: RE: [Astro_IIDC] Focussing issues .. need advice

 

 

I would think your seeing would have to be absolutely perfect to use a 5x powermate. 

 

I’m not sure what the equivalent eyepiece focal length value is for that CCD but if it’s anywhere around 8mm like most smaller ccd’s than, I believe, you have gone way over the maximum magnification your scope can provide with a 5x powermate..  your 700mm focal length has increased to 3500mm using the 5x powermate.   The recommended max magnification for your scope is 204x.  at 3500mm (5x700) focal length, a 8mm focal length equivalent ccd,   your pushing 438x of magnification.

 

Dave Goodyear

KB2 Networks Inc.

214 Main St. #318                            

El Segundo, CA  90245

310-933-2436

 

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From: Astro_IIDC@yahoogroups.com [mailto:Astro_IIDC@yahoogroups.com] On Behalf Of Rodolphe Pineau
Sent: Tuesday, November 27, 2012 6:37 PM
To: Astro_IIDC@yahoogroups.com
Subject: [Astro_IIDC] Focussing issues .. need advice

 

 

I have been trying to capture Jupiter using my flea2 and other cameras using AStro IIDC.
I use a Meade Series 5000 102 ED Triplet APO with a Televue 5x Powermate and a Baader UV/IR-Cut / L filter.
Not matter how stable the seeing is I haven't been able to get anything close to a sharp focus with this setup.
I've read some of Televue doc and tried adding a T-Thread spacer to get a 56mm back focus (which then match what one would have on a DSLR with the Powermate 5x and a T-Ring adapter) but it doesn't do any good in term of focussing (it only change the magnification as the sensor is now further away from the Powermate).

At this point I'm running out of idea and any advice would be welcome.
You can see the current result here : http://www.rti-zone.org/astro_planets.php

Thank you
Rodolphe
--

| Rodolphe Pineau RTI-Zone |
| http://www.rti-zone.org/ |
| Robotics / Unix / Mac OS X / Astronomy |