Do I need a Focal Reducer?

[NeilW]

Hi,

I have a SW ED80 with a Pentax K5 DSLR which has a sensor size of 23.7mm x 15.7mm. Do I need a Focal Reducer with this setup?

Thanks,

[DJ N]

Hi Neil,

In my opinion, absolutely (not necessarily a reducer, but definitely a field flattener). The two flatteners that I have had relative success so far with is

i. Hotech SCA Flattener (no reducing factor)

http://www.iceinspace.com.au/forum/s...ad.php?t=80765

ii. William Optics III 0.8x Flattener/Reducer

http://www.iceinspace.com.au/forum/s...ad.php?t=86746


I have used both the above with my ED120 and ED80 and both are keepers!! I did have a play around with the William Optics P-Flat IV, however, I could not get any decent results with the ED120.

The other option, of which I have heard favourable results, is the Skywatcher/Orion 0.85x reducer. These work quite well, however they thread directly on to the draw tube and require a M48 ring to attach the camera to.

http://www.skywatcher.com/swtinc/pro...1=5&class2=512

Hope this helps,

Cheers,

Daniel

[NeilW]

Excellent, thanks for that Daniel. I was looking at the Orion version of the 0.85x from Bintel

http://www.bintel.com.au/Astrophotog...oductview.aspx

By the looks of things you can't get the wide T-adapter for Pentax.

Don't suppose you're in ASSA's DSI group by any chance?

[DJ N]

Hi Neil,

I have not yet joined up with ASSA...... starting to run out of excuses . I have been to a couple of meetings in the last couple of years, and keep meaning to join up.................

It would be good to meet others in Adelaide who all share the same passion errr obsession.



Cheers,

Daniel

[stardust steve (Steve)]

good info fellow Adelaideans. I am thinking much the same about joining a local assc. Would like to get out to a star party aswell as i need to look through some different scopes and view equipement setups. I continually read about all different setups but nothing beats seeing them in action 1st hand. Good luck with your imaging Neil and Daniel

[NeilW]

Guys, once you join ASSA you can then join their Deep Sky Imaging group. An excellent arena to share and develop skills.

By the way, I've just noticed Orion's field flattener:

http://www.bintel.com.au/Astrophotog...oductview.aspx

Quite a bit cheaper than the flettener/reducer unit, and it looks like a standard T-adapter thread too. Any thoughts?