Sky-Watcher .85x reducer fitting in my imaging train?

[oymd]

Just now, Skipper Billy said:

The sensor is 6.5mm recessed - makes it 55mm - spot on!

lol...thanks

just posted this before I saw your explanation

[Laurin Dave]

As Skipper Billy says .. and as per ZWOs guide  yes...

[oymd]

1 minute ago, Skipper Billy said:

The sensor is 6.5mm recessed - makes it 55mm - spot on!

Last question please

So, we have sorted the reducer out.

How come I was achieving focus these past days WITHOUT the reducer, using my weird reverse contraption of adapters, shown in my above pics? My original setup has an additional 55mm at least to this neat newer setup? So I was focusing WITHOUT the reducer at about 110mm from the sensor all these past days?

[Laurin Dave]

Presumably the effect of the reducer...  without it the sensor will be at the scope's native focus position, with it I'd assume it moves further in 

[oymd]

8 hours ago, tooth_dr said:

I had to go back and look through previous threads to work out the camera, think it is the right one. 

 

3 hours ago, Skipper Billy said:

The sensor is 6.5mm recessed - makes it 55mm - spot on!

 

4 hours ago, Laurin Dave said:

yes that gives the required 55mm  ...

See link..

https://astronomy-imaging-camera.com/tutorials/best-back-focus-length-solutions-55mm.html

 

I wanted to thank everyone who helped me in this thread. Your input was immense and much appreciated!

I have not bought any filters yet, and since I have a OSC camera I was advised to get:

1- UV/IR cut filter

2- CLS filter

3- Optolong L Pro (recommended by many)

I was told that 1.25” is more than enough for my imaging circle and 4/3 camera. 
 

My question is: Where will a 1.25” filter fit in this train?

Everything in my train is obviously wider than 1.25”?

[Laurin Dave]

With the camera came a threaded ring that will screw into the 21mm extender,  screw the filter into that ..  it needs to be as close to the sensor as possible to minimise vignetting ..  

[oymd]

1 hour ago, Laurin Dave said:

With the camera came a threaded ring that will screw into the 21mm extender,  screw the filter into that ..  it needs to be as close to the sensor as possible to minimise vignetting ..  

I assume you mean this one:

So, I screwed the filter I have into it. This adaptor can only screw into the 21mm extender from the SCOPE side, but the filter pokes out.

I can see you advised the filter should be as close as possible to the sensor, so I reversed it. Is this the correct way it should go in?

Ahh...I see now why that adaptor has 4 holes in it, so that you can use a pointed object to screw it in or out of the 21mm extender?

 

And here it is with the 16.5mm added on to it:

Did I get that right?

Lastly, if I go all out and invest in 2" filters, I assume they would screw into the backside of the 21mm extender just like the 2" adapter, without the need for any adapter?

Many thanks!!

 

[Laurin Dave]

That looks right although I’d turn the filter round if possible so that any anti reflective coatings are facing the right way..  as for a 2” filter I don’t  think it will work between the flattener/reducer and camera but if you look on the scope facing side of the flattener/reducer there may be a thread you can screw one in to 

[oymd]

3 hours ago, Laurin Dave said:

That looks right although I’d turn the filter round if possible so that any anti reflective coatings are facing the right way..  as for a 2” filter I don’t  think it will work between the flattener/reducer and camera but if you look on the scope facing side of the flattener/reducer there may be a thread you can screw one in to 

Just to confirm your post, and check I got this right:

You want me to reverse just the fliter, so that it is oriented like this in the imaging train:

 

BUT, with the 1.25" the OTHER WAY AROUND so that the filter is closer to the sensor, but oriented like in the picture above?

Many thanks

Edited April 9, 2020 by oymd

[Laurin Dave]

Yes like that but will it screw further down towards the sensor 

[david_taurus83]

19 hours ago, oymd said:

Lastly, if I go all out and invest in 2" filters, I assume they would screw into the backside of the 21mm extender just like the 2" adapter, without the need for any adapter?

Many thanks!!

 

If you want 2" filters you will need something like this. That one simply replaces the 21mm spacer as it's the same length. See how you get on with the 1.25" filter first. I have mounted filters the "wrong" way round before and I've never noticed any difference. Baader actual reckon you should try them the wrong way round if you get halos or reflections.