T-ring adapter + DSLR: filter?

[deanm]

Hi folks,

I have a DSLR mounted at prime focus (6SE) via a T-ring adapter.

If I wanted to put in a Ha or OIII filter, where would it fit? In the T-ring?

Cheers!

Dean

[En1gma]

You would screw it onto the nosepiece that threads onto the tring.

Would either be 1 1/4" or 2"

[deanm]

Many thanks for speedy reply, En1gma!

2" should do the trick.

Dean

[h0ughy]

hotech adapter - see myastroshop - swear by it - as for the filter it it threaded for the 2" filters - get a CLS CCD 2" from Bintel

[deanm]

hOughy - is this the creature?

http://www.myastroshop.com.au/products/details.asp?id=MAS-055B

dean

[h0ughy]

yep, but if you have a refractor i reccommend getting the hotech field flattener

[alistairsam]

Hi,
to use a DSLR at prime focus, do you need a T-ring and a T-ring adaptor, or just the T-ring adaptor? I found both when searching the net.
just a bit confused with whats required to mount a Nikon to a 2" focuser on a reflector.

if I get this, http://www.ozscopes.com.au/celestron-t-ring-for-35-mm-nikon-camera.html , how do I fix that to the focuser as the threads are on the inner side.?
also wanted to get an OIII or UHC filter.

this site explains male and femail T2 adaptors http://www.telescope-service.com/accessories/start/adaptors.html what would I need for a DSLR?

[En1gma]

Hey alistairsam,

Generally you would need both, unless the focuser has a m42 thread to which you can screw directly onto.

So in your case you would go : camera - tring - m42 to 2" adapter - focuser.

If using a reflector, you should also consider a mpcc.

For filters, the 2" adapter will accept the 2" filters

Rob

[alistairsam]

thanks. mine is an F6, so was told I'd need longer exposure times but will have less issues with Coma. still to try it out.

the focuser is a standard 10:1 2" crayford focuser and it has the 2" barrel to accept 2" lenses or adaptors. but that barrel can be unscrewed. so would the T-ring thread fit the focusser thread? I'm guessing not.

if so, I might get the T-ring and the 2" adaptor with the thread such as this. https://www.bintelshop.com.au/Product.aspx?ID=7403
issue might be that it would increase amount of infocus travel required to reach focus.

[En1gma]

What reflector do you have, as generally you would need to move the mirror up to achieve focus anyway.

With regards to the tring adapter, it would only add an extra 6mm which would be negligible if you move the mirror up.

[alistairsam]

its a bintel 8" F6 reflector. was going to change the collimation bolts to longer ones so I can move the mirror up.
I might need to post this to a different thread, but any suggestions on a general light pollution filter?

I'm in melbourne, about 14 k from the cbd and there's significant LP. will the OIII or UHC filters help?

[En1gma]

I live across from Anz stadium so my lp is crazy.

But for general broadband imaging. I use a baader uhc-s. This works very well and can get an easy 10 minute sub during a footy match.

For narrowband imaging. I will be using a baader 8.5nm OIII and 7nm Ha.

Just make sure you have a look at the spectrograph of the filters in question to ensure they Are suitable for your application.

But all astro dealers should guide you in the right direction and assist with your choise based on your budget.

Since using a dslr, don't bother with 1 1/4"