Use of achromatic barlow with colour CCD

[Vince G]

Hello all,

Can anyone tell me if an achromatic barlow will affect the colour of a 80mm ED 'scope and a one shot colour CCD camera.

Any advice appreciated.
Regards
Vincent

[dannat]

what brand/type of barlow is it? In my limited experience a good brand barlow (eg televue) should be okay, but a cheap barlow (no-name) could adversly affect the image you are getting - the ed-80 should be giving a clear image, & the barlo could distort the image

[Vince G]

I hadn't decided on a brand. I just wanted to know if an achromat affected the image colour.

Vince G

[[1ponders]]

Yes it will unfortunately. You have a couple of options;

You can put a minus violet filter between the camera and the barlow
You can buy a good quality ED Barlow
You can buy a Powermate

A quick question. What are you hoping to shoot with your oneshot colour ccd camera? If you are hunting planets then a webcam?LPI (which I see you have) would be a better option. If you are hunting DSOs then adding a barlow/powermate will increase your f/ratio by the factor of the barlow. eg for 2 x barlow f7.5 becomes f15. That might seem like a good thing except it will increase you exposure time by a factor of 4 :eyepop:. 2.5x powermate will increase it by a factor of 6.25 etc.

[Vince G]

Thank you Paul,
Now I know what not to buy ;)

I do have a video camera and a mono CCD with colour filters as well, so I should be able to grab most of the objects.

Regards
Vincent