Shywatcher Nosepiece Inner Thread

[Jm1973]

Hi. I'm pretty new to this, so apologies if I've got any of the nomenclature wrong. I am looking to incorporate some kind of light pollution filter into my imaging train, but I am not sure where to put it. I currently connect a DSLR to a T-ring, and connect the T-ring to the nosepiece (I think that is what it is called), and the this fits into the focusser. Pic below:

The nosepiece has an inner thread of around 36mm, which the eyepiece holder would screw into if I was observing.

Is this inner thread a viable place to incorporate a filter? If so, what type?

Remember.. there are no stupid questions... only stupid people. 🤣

[Jm1973]

Anyone have any idea?

[nephilim]

It depends on which camera your using. Message FLO & ask which type you'll need (Email). They're pretty quick to answer mate.

[Chefgage]

Have you thought about a clip in filter for your DSLR? I use this type https://www.harrisontelescopes.co.uk/acatalog/skytech-cls-canon-eos-clip-filter.html?gclid=Cj0KCQiAhs79BRD0ARIsAC6XpaWe5phCbxkfNit8tXskT4sv-PZJvdktHdJMhrfrDD0prSoQufeEAkIaAun8EALw_wcB

 

[Jm1973]

On 18/11/2020 at 05:48, Chefgage said:

Have you thought about a clip in filter for your DSLR? I use this type https://www.harrisontelescopes.co.uk/acatalog/skytech-cls-canon-eos-clip-filter.html?gclid=Cj0KCQiAhs79BRD0ARIsAC6XpaWe5phCbxkfNit8tXskT4sv-PZJvdktHdJMhrfrDD0prSoQufeEAkIaAun8EALw_wcB

 

Thanks for the reply. Yeah, I have thought about a clip-in filter, but I'm just trying to work out how other people do it.

I think using a filter in the nosepiece is more versatile, as I could maybe use them for visual too.

 

 

[tooth_dr]

On 17/11/2020 at 23:50, Jm1973 said:

Anyone have any idea?

It's not a bad idea, but the problem is that its too small an opening for a 2" filter, and too large for a 1.25" filter.  You could make an adapter to hold the 1.25" filter housing into that space, but it would cause severe vignetting with the DSLR crop sensor.  An EOS clip filter as suggested above is a good idea.  It's not as versatile as you have pointed out, but it does the job it's intended to do very well.   I've learnt myself in astronomy that sometimes you can kill two birds with one stone, but more often than not it involves a significant compromise.

 

[Jm1973]

25 minutes ago, tooth_dr said:

It's not a bad idea, but the problem is that its too small an opening for a 2" filter, and too large for a 1.25" filter.  You could make an adapter to hold the 1.25" filter housing into that space, but it would cause severe vignetting with the DSLR crop sensor.  An EOS clip filter as suggested above is a good idea.  It's not as versatile as you have pointed out, but it does the job it's intended to do very well.   I've learnt myself in astronomy that sometimes you can kill two birds with one stone, but more often than not it involves a significant compromise.

 

Hi there. Thanks for the clear reply. I just wasn;t sure of there was a filter size that would fit this thread. But it sounds like even if there was one it may be more trouble than it's worth to put a filter that far away from the sensor.

From what I've been reading it sounds like a clip-in filter will help with colour shift and possibly haloing as well.

The reason I've been enquiring about this is I have a NIkon APS-C which doesn;t have a lot of filters available for it. I am going to get a Canon instead, as these have a much wider range of clip ins to choose from.

[tooth_dr]

31 minutes ago, Jm1973 said:

The reason I've been enquiring about this is I have a NIkon APS-C which doesn;t have a lot of filters available for it. I am going to get a Canon instead, as these have a much wider range of clip ins to choose from.

It is possible to fit a 1.25” filter inside the camera, between the T adapter and the mirror, I’ve tried it myself and it works ok.  I used a small 3D printed holder. 

[Jm1973]

5 hours ago, tooth_dr said:

It is possible to fit a 1.25” filter inside the camera, between the T adapter and the mirror, I’ve tried it myself and it works ok.  I used a small 3D printed holder. 

That is very interesting. Especially as 1.25" filters seem to be cheaper than clip filters.

Have you had any issues with using a 1.25" filter? 

Do you recall where you got the adapter from? Or was it on Thingiverse or something?

Edited November 19, 2020 by Jm1973

[Jm1973]

Found it!

https://www.thingiverse.com/thing:4306640

Fearl0rd? Isn't that the guy who coded SharpCap?

[tooth_dr]

43 minutes ago, Jm1973 said:

Found it!

https://www.thingiverse.com/thing:4306640

Fearl0rd? Isn't that the guy who coded SharpCap?

That looks neat.  Mine was just a circle, based on a cardboard template, and you can see the filter was threaded from the back, and still just cleared the mirror.

[Jm1973]

2 minutes ago, tooth_dr said:

That looks neat.  Mine was just a circle, based on a cardboard template, and you can see the filter was threaded from the back, and still just cleared the mirror.

I think I might get that, and then buy an l-extreme 1.25". Whenever they are back in stock.

[JamesF]

1 hour ago, Jm1973 said:

Fearl0rd? Isn't that the guy who coded SharpCap?

I really don't think so.  That was/is Dr Robin Glover.  Though he could of course be "Fearl0rd" at the weekends.

James

[Jm1973]

6 minutes ago, JamesF said:

I really don't think so.  That was/is Dr Robin Glover.  Though he could of course be "Fearl0rd" at the weekends.

James

Ha! 🤣

My bad. Fearl0rd is the guy who coded the ASCOM driver for DSLRs.