Using a reducer to image on cpc 925.

[Rumbold2010]

Hi all,

Frustrated with trying to get nice deep sky images at f10, I've considered a 5/6" newt as a second scope for this purpose. Tonight , however it occurred to me I might be missing a trick. In your much respected opinions, are there any reasons not to try and take deep sky pics while using my reducer. In theory at least, this would give me an f6.3 scope to work with, allowing my exposure times to come down a fair bit. Will using my DSLR through a T adaptor be affected by introducing the reducer in any way or have I simply been missing a solution staring me in the face? Opinions much appreciated. I hope the skies are playing ball for you all - lovely and clear tonight in Northants :-)

Andrew

[Owmuchonomy]

Well, click my link below and you can see the result of doing it that way for example my images of M27, M42 and the moon. It is certainly possible. Depends how high you want to set the bar.

[Rumbold2010]

Seem to be missing the link ( or very possibly I am ,myself , the " missing link" )

[Owmuchonomy]

It's in my signature.

[Rumbold2010]

Got it - I was using mobile version and it didn't appear. Those pics are phenomenal, I'd be over the moon with anything in that ballpark! Congrats , and thanks for the reply.

Andrew

[Owmuchonomy]

Only a few pictures are done in the configuration of 9.25", 0.63 reducer and unguided. The ones I picked out fall into that category. What mount are you using?

[Rumbold2010]

I've got the CPC mount with a wedge.

[Chris-A]

I use this configuration regularly (eg. this image http://stargazerslounge.com/topic/240512-m106/ ) but it does have a couple of issues, especially if you are using a DSLR.

a) Getting the correct reducer to chip spacing of 105mm - this is less of an issue with a CCD, but more difficult with DSLRs as the chip is itself 44mm within the camera body. Any significant increase on the 105mm will result in a tunnel effect on images due to coma.

Getting other accessories such as LP filters or OAGs into the configuration, whilst maintaining the 105mm spacing. There is a thread I found useful for overcoming these issues here - http://stargazerslounge.com/topic/52988-orion-oag-first-light/ .

[Sp@ce_d]

I use a reducer on my C925, but that's primarily to give me the FOV & sample rate I'm after rather than reduce exposure time. Have a look at these to understand why.

http://stargazerslounge.com/topic/106983-f-ratio-and-brightness/

http://www.stanmooreastro.com/f_ratio_myth.htm

DSLR's do seem to benefit greatly from fast scopes, probably somewhere around f5 native. So fast newts & DSLR's can produce some very good results from what I've seen.

With my C925 & reducer I get vignetting on the 314L+, so a DSLR will definitely suffer. Flats will reduce this although I've never bothered to try my DSLR with this scope so not sure how effective it is.