Focusing problems

[Kevdan]

Hello All,

How do I overcome the problem of unable to get focus with my dslr when using a T mount and 1.25 adapter so it goes into the eyepice holder,

When using a 2x barlow I can focus easily but this is obviously due to focal length shift.

Problem is when using the direct attachment to the scope I can not use any filters such as Light polution or uv/ir as there is no way of attaching them.

would a 0.5x focal reducer work or would that shorten the focal length too much.

Kev

[steppenwolf]

would a 0.5x focal reducer work

Unfortunately, a focal reducer would be a disaster on a reflector!

Inward travel issues are common with Reflectors - the fitting of a low profile focuser can often resolve this issue.

[Kevdan]

Thanks,

I had a feeling that would be the case and as I'm going to upgrade soon to a 10" I'm not going to spend over £100 on a low profile focuser.

So now to desing a T mount adapter to hold Filters and screw into the direct fitting.

Kev.

[steppenwolf]

You could consider getting a Baader MPCC (multi-purpose coma corrector) as this has two advantages:-

1. It dramatically reduces coma on just about any Newtonian Reflector

2. It gives you an extra 10mm of backfocus BUT it is a 2" fitting so you would ideally want a native 2" eyepiece holder. The MPCC has a 2" filter thread at the front.

[Kevdan]

Looks like a better option and I can use it with the new scope when I upgrade.

Kev