Help required please - CCD with FF/FR connections

[PatrickGilliland]

Hi All,

Can anyone assist?

I have a Skywatcher Equinox 120 fitted with a new shiny Moonlite focuser.  I want to purchase a 0.85 FF/FR and the FLO adapter all of which is fairly straightforward in terms of connecting and use (famous last words, I know the theory but will wait and see what happens when it arrives!!).

However I also have a Orion All In One CCD and have the following issues/questions.

1.  Do I need to use a FF/FR with this or will it not be affected as much as a DSLR?

2.  If I do need to use how to I set up.  I have been advised "You do need to have the correct spacing between the ccd sensor and the shoulder of the reducer/flattener 56mm ( this spacing is correct when using the DSLR and M48 ring [for DSLR])"  I had hoped I could just use a 2" to 1.25" adapter and use the par focal ring to sort out the focus - but this does not appear to be the case.

I do have a C thread on the camera and its nosepiece as well as a c to CS adapter if of any use in your responses.  I have been advised of the below may solve the problem but any thoughts from those who have knowledge and have tried would be very much appreciated before I spend cash on items I may or may not need.

Find out what the thread is on the camera itself, If its T thread then my last reply will be valid, if its a C thread then you only need a C to T adapter on the camera to get to T thread, and spacing to get the 56mm
http://www.firstlightoptics.com/adaptors/baader-c-to-t2-with-integrated-125-filterholder.html

Appreciate any help you can provide.

Paddy

 

[lensman57]

The FF/FR is designed to correct the field  for large sensor cameras, DSLRs are at the limit of the correction but if the sensor on your CCD is small, up to 2/3" format then the use of the FF/FR is not strictly necessary unless you wish to widen the FOV.

The correct spacing for the SW FF/FR is between 55mm and 56mm depending on the type of filter used in front of the FF/FR ( LP filter for example ) so you need to subtract the distance that the sensor is set back from the front of the camera flange from 56mm, that information is usually supplied with he camera. You then use an extension tube of the correct size to get the back focus distance ( 55mm~ 56mm ) of the FF/FR right. I use a Baader Varilock T extension  arrangement as it is variable.

The SW FF/FR has a front thread  ( focuser side) of 56mm I think,  that attaches to your 2" adapter and a 48mm thread on the camera side so if your camera has a C mount then you'd need a female 48mm to a male C thread adapter ( please check the thread sizes before ordering stuff ) and you have to include the added distance introduced by the rear adapter in your distance calculations, the total sensor to the flange end of the FF/FR should be between 55mm~56mm.

Hope this helps.

Regards,

A.G

[PatrickGilliland]

It does help - the information will be retained but I think for now I will use only with the DSLR and ride on the wild side with the CCD  and go without.

First step will be to get some clear sky and images, then I can worry about the refinement if needed.

Thanks very much.

P

[Uranium235]

I would get the FF/FR regardless since it will improve the field for both cameras. To get the reducer working with your Orion camera, first you need to know the distance between the nosepiece thread and the imaging chip, then subtract that from 56mm, you are then left with the gap you need to fill with spacers (one will need to be an M48-T2), the previously mentioned Baader varilock is quite good for finetuning the distance (I have one), or you can use delrin spacers if you need to add a mm or two.

To get the spacing right for a DSLR is much easier, on FLO M48-EOS adaptor is all thats needed (the correct distance is automatically achieved).

Ive looked up that Orion CCD camera, except it isn't a CCD - its a CMOS based camera. Just over 1MP and OSC, so im not expecting its deepsky performance to be anything worth writing home about. It may however prove a lot more useful as a planetary camera or a guider to complement your DSLR. So to recap, for planetary - use the Orion, for deepsky - use the DSLR.

[PatrickGilliland]

_{Cheers AG that was the plan with cameras.  But nice to have the option.  I will look into the adapter mentioned and price iy all out (the fun bit).}

_{Thanks again for the feedback and insight very useful for a newbie....}

_P