QHY8 and 6inch Archo

[fo.manush]

Hi Guys,

I have a 6Inch F8 Celestron Achromat and wish to get a QHY8 for prime focus imaging.

I just wish to know if the QHY8 will work fine with my telescope due to its CCD sensor having a relatively wide field of view.

Thanks

[Tandum]

Qhy8 only needs a 28mm image circle so it should be ok in any 2" focuser.

[fo.manush]

Thanks for the reply Robin.

I also heard that some people with Newtonians did not have enough play in their focusers and had issues.

Could this be a problem for me? I have never had issues focusing my D90 DSLR for imaging.

Sorry for the basic questions guys...total nood here.

[Tandum]

If it's a refractor it should be ok. You may or may not need an extension tube.

[multiweb]

I use a 5" newt with a QHY8. You'l have to use a coma corrector (I use a baader MPCC) and do flat fielding to minimize vignetting.

[Hagar]

The only problem I can see using a QHY8 with an achro is the fact that the 3 main colours all tend to have a slightly different focal point which may make your image a little out of focus or at least make the focus look a little soft. You may be able to get hold of a corrector lens which will slightly move the focal point and align all 3 colours.

[fo.manush]

Hagar,

I didn't know such a corrective lens existed. Are these freely available for purchase?

[Tandum]

Baader make a fringe killer filter to do this. Google (http://www.google.com.au/#hl=en&source=hp&biw=1276&bih=818&q=baader+fringe+killer&aq=f&aqi=g3g-v2&aql=&oq=&fp=fd1042bfdceafadc)comes back with a few reviews on them and andrews (http://www.andrewscom.com.au/site-section-10.htm)lists the 2" fringe killer at $179.

[fo.manush]

I have a Baader Semi-Apo filter which I have loved for visual use. I think I will invest in a 2inch version for Astro Photography aswell if I go down this path. Any CA that remains after this will have to be dealt with in post processing.

I also wish to know if an equivalent Mono CCD exists out there in the same price/ performance band of the QHY8?