Barlow to camera adaptor

[PJH34]

As I have not found an answer to my problen in the firum pages, here is my question, which I hope someone can answer.

I am using a Nikon D90 attached at prime focus to my Skywatcher EQ80 with a 3cm T adaptor. No star diagonal. Image of Andromeda very small. To make it larger I want to use my x2 Barlow.

What type of T adaptor tube will I need to bring the focus to the camera? Even the telescope maximum of 7.5cm focus distance is not enough.

[JamesF]

It is possible to get t-adaptor extensions of various sizes. Be aware though that adding a barlow will increase your required exposure time quite significantly.

I am quite surprised M31 should be so small with your current setup. Do you have an example you can post?

James

[Steve Ward]

I recently bought the ED80 Pro with the sole original purpose of shooting M31 because it fills the frame almost perfectly with my Canon1000D ( same sensor size as your D90 )

Got round to it last night , heres a 246s unguided sub to show you what you'll get .

M31 ,1000D + ED80 Pro , 246 seconds unguided single frame.

Needs a lot of long exposure to get much apart from the core i'm finding .

Happy hunting