2" filter problems

[Milliways]

I went to MC2 today to get a 2" filter for my scope.. but i have a few issues that conflict with me using one.. I have to have my camera attached directly to the focuser with my T-ring on the back of the focuser adaptor just so i can achieve focus.. there is no way that i can see to let me use a 2" filter and then achieve focus as i have to use an adaptor then put it into the 2" ep adaptor, i cant achieve focus like that as my camera is too far away from the ota. I know of a method of raising the primary mirror to achieve focus like that but i dont know how to do it and really dont want to..

Is there anyway that i can do this apart from mutilating my kit?

Cheers.

Dave.

[Starflyer]

I don't know that 'scope, but Is the inside of the focuser tube threaded? If so it should be possible to attach it to the end of the focuser inside the 'scope, ie closest to the diagonal.

If you do this, always attach it with the 'scope horizontal to avoid disaster should the filter slip from your grasp

[Milliways]

I don't know that 'scope, but Is the inside of the focuser tube threaded? If so it should be possible to attach it to the end of the focuser inside the 'scope, ie closest to the diagonal.

If you do this, always attach it with the 'scope horizontal to avoid disaster should the filter slip from your grasp

Yeah but unfortunatly we tried that and the focuser thread is HUGE, way to big for the filter :'(

[Ant]

Is there anyway that i can do this apart from mutilating my kit?

Cheers.

Dave.

Not really.

A 2" barlow would move the focus point out, I'm also certain that would enbale you to acheive focus. But even with the lens cell removed and screwed directly into the 2"adapter, it'll turn a 10" F5 into a F7 or 8ish (slower and smaller FOV).

You could buy a low profile - that night help, but get whoever it is that you buy it from to give you measurements first.

Ant

[George]

I have the same scope but a moonlight focuser, the inside of the T mount should be threaded to accept filters this is where you place your filter. AFAIK filters will have a neutral effect on your focus.

If I get a minute later I'll post a piccy of my t-mount with filter.

[Milliways]

I have the same scope but a moonlight focuser, the inside of the T mount should be threaded to accept filters this is where you place your filter. AFAIK filters will have a neutral effect on your focus.

If I get a minute later I'll post a piccy of my t-mount with filter.

Your a superstar mate thanks

[George]

The picture is self explanatory

Best I could do I'm afraid

[Milliways]

Thats great thanks!!

I did try that in the shop with the adaptor.. but it is the same distance as having the 1.25" adaptor in, and i cannot focus with the 1.25"

[George]

If you have a barlow take the lens out of the bottom and use as an extension tube.....works for me.

[gfletcher]

Is it worth imaging like this with a 2" UHC filter?

Graham

[Milliways]

Has you imaged through a 1.25" barlow?? does it degrade the image at all? as this is the only way i know of to image with a filter??

Cheers.

Dave.

[George]

Nope I use prime focus, imaging for a DSLR thru a 1.25 aperture would cause far too much vignetting better to use the 2'' aperture.

[Starflyer]

Long shot - If you can find out what the thread size is inside the focuser tube maybe a filter step-up ring will do the job.

[calibos]

A lot of focuser drawtubes are threaded as a form of baffling to reduce reflection from off axis light. A lot of people confuse this threading for filter threads. If the threading looks the same width all the way up the drawtube its baffling. If there is about 5mm of thinner threading at the end of the drawtube and then thicker threading the rest of the way up, then you've got threading for filters at the end and the rest baffling threading.