Derotator Vs Wedge

Ric · #1 08-04-2007, 04:01 PM

Hi all, I have been reading about derotator's and was wondering about their potential as an alternative to a wedge.
From the limited reading I have done which has been mainly manufacturer's pieces it would seem that they are a viable alternative to the wedge in astrophotography as it allows you to take longer exposure images like the wedge while remaining in Alt/Az. Also I have only seen them advertised for SCT's up to 10", does this mean they are not suitable anything larger like a 12"
Does anyone know of any websites other than the manufacturer's where there would be some more info in this area. Other members thoughts on this would also be appreciated.

Cheers

nightsky · #2 08-04-2007, 04:21 PM

G'Day Ric,
I don't know much about the subject in question,but check this page out,also you can do a "Google" search you might find more
http://www.astronomics.com/main/prod...roduct_id/1220
Cheers
Arthur

g__day (Matthew) · #3 08-04-2007, 05:05 PM

If I had to choose, I'd go for a heavy duty wedge over a de-rotator any day. The wedge simplifies things, and just gives you in effect an equatorial platform. The de-rotator is one more thing to power, one more bit of technology to tune, one more set of mechanicial worm gears to tune and hope all is well, one more point of failure.

Looked at that way, in the long run a wedge stands hands and shoulders over a de-rotator.

rogerg (Roger) · #4 08-04-2007, 05:29 PM

There was a similar thread recently..
http://www.iceinspace.com.au/forum/s...ad.php?t=18696

Something else: It's hard enough to train the PE out of the RA, I wouldn't like to introduce DEC movement in to the mix also (as you would with a rotator).

Ric · #5 08-04-2007, 07:11 PM

Thanks for the input guys, definitely food for thought

Cheers

Ric · #6 08-04-2007, 07:14 PM

Just had a read of the thread Roger, very interesting.

Cheers

Ambermile · #7 08-04-2007, 07:39 PM

Well, I may be having to do something like this son once the ServoCAT goes on the the big scope. The movements do not have to be so precise as those in Alt/Az, I have been considering using at ST-7E or similar - with the guide chip deciding movement in all three axes. Very early days though...

Arthur

PS - meade derotator (or derotater as they call it on the item itself

) is up to 14" since the bigger scopes have different fittings - nothing more sinister