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How to fit a LP filter with a SW reducer/flattener

Spikey

By Spikey
in Discussions - Cameras

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Spikey

Spikey

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It's clear here so fingers crossed it will be later tonight.

Not much good for DSO's courtesy of a fullish moon.

But at least I'll get chance to try out the flattener/reducer with the LP in the chain and see if I can get focus.

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Spikey

Spikey

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I can confirm the combination I pictured does reach focus easily.

I've only got the ED80 rigged up on its own and I'm just doing a few unguided shots to try the reducer out which I will post up later.

I was worried for a while that it wasn't going to work but now I'm pretty happy :D

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Black Knight

Black Knight

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I can confirm the combination I pictured does reach focus easily.

I've only got the ED80 rigged up on its own and I'm just doing a few unguided shots to try the reducer out which I will post up later.

I was worried for a while that it wasn't going to work but now I'm pretty happy :D

Well that's really good news then ;)

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Spikey

Spikey

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I'm not 100% sure how I would check without doing a few comparison shots. I got about an hour on M1 unguided so I'll process it and put it up here for scrutiny.

Sound like I may need to get the adapter after all.

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Sp@ce_d

Sp@ce_d

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Yes it will focus, but does the flatener correct to the edge of the frame, as the spacing is now wrong?

Ahh.. I've been cropping off the edges, putting it down to PA or guiding. But the pennys just dropped it's the extra thickness of the filter in the train then.

So, either a clip filter or the adapter I guess. However, looking at the picture of the adapter if the filter goes on the other end how does it attach to the scope?

(Sry to hijack your thread Spikey but we have the same image train..)

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Black Knight

Black Knight

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Ahh.. I've been cropping off the edges, putting it down to PA or guiding. But the pennys just dropped it's the extra thickness of the filter in the train then.

So, either a clip filter or the adapter I guess. However, looking at the picture of the adapter if the filter goes on the other end how does it attach to the scope?

(Sry to hijack your thread Spikey but we have the same image train..)

I received the adapter from FLO today. Haven't had the chance to try it out yet. But I assume that instead of screwing onto the focuser tube, the reducer together with the adapter fits into the focuser tube just like a diagonal would. I assume ... :D

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Sp@ce_d

Sp@ce_d

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This may be an alternative.

My T Ring is 11mm and my SW LP filter takes up 10mm. So with the 44mm sensor to flange of the 1000D = 65mm

As I understand it we want 55mm... which is exactly what this T Ring says it will do as its only 1mm !!

Low Profile Canon EOS T Ring

Ultra slim EOS T ring, only about 1mm thick compared to the standard 11mm

Accessories @ Modern Astronomy

I'd rather be able to screw the SW reducer/flattener to the tube than have it hanging off held in just by the pinch screws. Seems there's more room for alignment errors and working loose that way.

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martin_h

martin_h

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I'd rather be able to screw the SW reducer/flattener to the tube than have it hanging off held in just by the pinch screws. Seems there's more room for alignment errors and working loose that way.

Ive just tryed the Nose Piece to reducer, rubbish! flops about too much, even with the pinch screws done up with pliers!

Oh well plan B...when I've thought of it:)

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Sp@ce_d

Sp@ce_d

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Ive just tryed the Nose Piece to reducer, rubbish! flops about too much, even with the pinch screws done up with pliers!

Oh well plan B...when I've thought of it:)

Exactly what I was afraid of. :)

I was hoping it would have worked as I'm trying to think of a way to use a filter wheel in the train too... http://stargazerslounge.com/discussions-cameras/159995-anyone-using-dslr-filter-wheel-oag.html

So far then, the slim T-Ring seems like the only option that may work for the Canon DSLR's. I emailed Bern at Modern Astro yesterday about this but still waiting on his reply.

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Sp@ce_d

Sp@ce_d

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Yea but....

If the s/w filter has 2" (M48 threads) how do you fit it to the T thread of the Slim EOS adaptor??

:) Errr... The same as I do now, with my 11mm thick T-Ring - SW filter (M48) - SW reducer ?

Or have I missed something?

EDIT.. ok just checked another T-ring I have.. hmmm I see what you mean

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Sp@ce_d

Sp@ce_d

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Sorry mate...

You must have a T thread to M48 adaptor in there somewhere?

I'm assuming we have Focuser>reducer>filter>M48 to T thread adaptor?>T thread slim to EOS>Canon body

:) You are completely right.. I am an idiot. I've got so many T-rings & adapters for Canon & Nikon it went right over my head.. doh I'm not using a T-Ring, I'm using a Skywatcher DSLR-M48 Ring adapter I got from FLO when I bought the scope... argh even worse than I thought, kinda kills that option then.. sry for the false hope folks.. :)

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martin_h

martin_h

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Ok I've come up with my plan B...

Im trying to introduce an LP filter into the "Reducer - Filterwheel - CCD" train and still keep the 55mm spacing...the answer, for me, was so simple I could kick myself. The Baader colour filters are LP cut(so they say) so its only the Lum thats going to need LP reduction........Answer = remove the Lum filter and replace with the Baader Neodymium Filter which is also UV/IF cut as well.....Doh!

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Sp@ce_d

Sp@ce_d

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Good bit of lateral thinking..

So, my missus is gonna love this then...

"Yes dear, the only way to reduce it by 10mm is to buy a CCD & filterwheel"... Oh and a bigger scope.... yeah right :)

Surely this has been done before though? Unless everyone does what I've been doing and crop off the edges? Anyway, I've asked FLO for some help working it out.

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Spikey

Spikey

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Adapter came this morning and all fitted back together again now.

Reducer is direct onto te M48 and straight onto the Canon. Adapter screws to reducer on the other end and the filter is srcewed onto the end of the adapter.

It now sits inside the focuser tube.

I reckon the earliest I'll be trying this out is at the peak star party this weekend, although I'm not expecting any LP up there - all weather permitting of course.

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