John - not sure about the practical differences between the two. I have the ToUcam Pro II (840K) in the newer case and bought it off eBay for about AU$60 delivered. I'll be modifying it soon to try it on DSO's and wide star fields.
Here's a page you might be interested in - it's a webcam comparison table, and it outlines the differences between several cameras and rates their acceptability in terms of astrophotography:
Here is my set up with the Orion Deep Space Star Shoot on the WO 66 Petzval using the stock WO SCT to 1 ¼ inch adapter, with a WO 1 ¼ inch diagonal. The focuser is at approx 3 cms of its 6 cms overall travel.
As stated previously, focus could not be achieved using the WO SCT threaded 2 inch diagonal which is used for visual observation.
There may be some slight advantage having the camera mounted thus, as its own weight and the weight of the cables is less likely to pull it from the diagonal, compared to a straight through position?
I have a similar setup to Dennis, using the 66SD as a guidescope for my 102mm Tak. I use the Meade DSI for guiding, mounted on the 1/4" WO diagonal and it comes to focus about 3 cm out.
Thanks for that Dennis. A beautiful setup indeed. You've just cleared it up - I need the 1.25" diagonal instead of presuming that the 2" would take care of everything by itself. I take it that a cheaper GSO dielectric diagonal would work the same as the WO?
Cheers
Chris
Quote:
Originally Posted by Dennis
Hi
Here is my set up with the Orion Deep Space Star Shoot on the WO 66 Petzval using the stock WO SCT to 1 ¼ inch adapter, with a WO 1 ¼ inch diagonal. The focuser is at approx 3 cms of its 6 cms overall travel.
As stated previously, focus could not be achieved using the WO SCT threaded 2 inch diagonal which is used for visual observation.
There may be some slight advantage having the camera mounted thus, as its own weight and the weight of the cables is less likely to pull it from the diagonal, compared to a straight through position?
...Here is my set up with the Orion Deep Space Star Shoot on the WO 66 Petzval ...
Hi Dennis !
That looks the same as my setup - except the WO66 ED and ADM rings and rail in my case.
Do you use this config for guiding or imaging, and if the latter do you want to compare experiances - I have been having dramas which you may have seen in posts elsewhere tring to conjure decent sub-pixel guiding out of PHD and Maxim EE...
Chris
I’m not sure how similar the WO and GSO diagonals are so cannot really comment on whether or not the GSO would work. IIRC, the WO 66mm has 6cms of focus travel, and the WO diagonal brings the Orion DSSS to focus at 3cms, so hopefully, any minor differences between the WO and GSO 1 ¼ diagonals could be catered for with the amount of spare travel?
JohnH & JohnG
I have only used the WO 80mm F7 (560mm), ODSSS and PHD Guiding to auto guide the C9.25 at 1480mm (i.e. with F6.3 R/C) once or twice, and managed to retain approx 75% of the 5 minute sub frames. The rest suffered from some trailing.
At F10 (2350mm) I had to discard approx 60% of the 3 minute sub frames for the one attempt I made to auto guide at the native fl of the C9.25.
Using the WO 66mm, Orion DSSS and PHD Guiding combo with my Vixen 102mm f9 (918mm) refractor, I had no problem for 2 and 3 min sub frames, and that is the extent of my testing so far. I suspect I could easily go up to 10 or 15 mins with no problems at this short fl.
This auto guiding lark at 2 metres + focal length, sure isn’t easy! My next attempt will be to use the Tak 180mm Mewlon at F12 (2160mm) with the WO 66mm, Orion DSSS and PHD Guiding combo to see how I fare auto guiding at approx 400mm focal length. All this is on a Tak EM200, which in theory, should make it easier!
Picture attached - What I did to do this - took the SCT adapter off my 2" bintel diagonal - that gave me a male T thread - took a T to 1.25" adapter off my Viven flip mirror and screwed it in.
The really odd thing is if I use the diagonal I have to rack the focus all the way in - I am sure the distance from the back of the OTA to the chip is then quite a bit smaller so the tube end to mirror and mirror to chip distances musy be critical in some way I do not understand - not just the total distance...
Last edited by JohnH; 19-04-2007 at 08:59 PM.
Reason: typos
Your memory is correct - though with a Canon20D attached I use a FR to bring it back to f6.3 approx. Nice flat field free of colour problems so good for DSO but not the best of contrast is planetary is your thing....I have not got the best out of this gear yet...
