Can you use 1.25” filters with a 2 inch eyepiece?

[Olli]

Hi

i have two 1.25 “ filters however as mentioned in another post I am looking to upgrade my eyepieces and some of the ones I am looking at are 2”. I was just wondering is there an adapter I can buy or is it not possible to do this?

 

Many Thanks  

[dobbie]

I not aware of any reducing adapters , i really dont see any point? If your going to invest in 2" eyepieces then buy 2" filters otherwise there's no point in getting them . John 

[orion25]

Even if it exists, a filter reducing adapter wouldn't be practical. You would want to be able to fully enjoy 2" experience. So, take the plunge, my friend; you're on another level now. Start investing in 2" filters!  

Reggie

[Star101]

https://www.365astronomy.com/365Astronomy-2-to-1.25-Filter-Adapter.html

[Stu]

18 minutes ago, orion25 said:

Even if it exists, a filter reducing adapter wouldn't be practical. You would want to be able to fully enjoy 2" experience. So, take the plunge, my friend; you're on another level now. Start investing in 2" filters!  

Reggie

Actually if you position the filter at the correct place in the light path, you dont get any vignetting! I successfully tried this out a while ago, will try to find the post.

[Mark at Beaufort]

I have used the adapter from 365 Astronomy for many years. Although I have 2" EPs and 2" filters my H.Beta filter is only 1.25". I have used this 1.25" filter in my 20mm 100 degree 2" EP and it does work OK. I am not aware of any major vignetting.

 I am going to a star party tomorrow night and I will check again and report back before you commit to any purchase of 2" filters

[Charic]

2 hours ago, Olli said:

I have two 1.25 “ filters however .... eyepieces are 2”..........just wondering ?

I have just one two inch eyepiece which I don't filter.  I could  possibly hold the filter between the eyepiece and my eye! The only issue here is that it's possible to make contact between the metal frame of the filter housing and the eye lens, not so good, however, eyepieces with a smaller eye lens than the filter itself would  not have the same issue.

If you're investing in several 2" eyepieces, it could be worthwhile considering beforehand the costs involved creating a larger sized filter set and something to hold them, instead of screwing them in individually.

 

[Mark at Beaufort]

Tomorrow I am NOT going to screw the adapter into the 2" EP. I will either screw it into the 35mm extension tube or the 2"/1.25" eyepiece adapter depending which size of EP I use. I will be using a Skywatcher 150P Newt. Doing this way will enable the use of multiple EPs without having to screw the filter each time I change the EP.

Clearly placing the adapter/filter into the bottom of the extension tube will allow both sizes of EPs to be used. The 2"/1.25" eyepiece adapter (not the filter adapter) goes into the extension tube.

[Olli]

5 hours ago, Mark at Beaufort said:

I have used the adapter from 365 Astronomy for many years. Although I have 2" EPs and 2" filters my H.Beta filter is only 1.25". I have used this 1.25" filter in my 20mm 100 degree 2" EP and it does work OK. I am not aware of any major vignetting.

 I am going to a star party tomorrow night and I will check again and report back before you commit to any purchase of 2" filters

Thank you mark appreciate it. Hope the weather will be alright, raining all weekend so far ..

[Stu]

I found my post...

 

[orion25]

34 minutes ago, Stu said:

I found my post...

 

Wow! I didn't think this could really work well. You learn something new everyday! Thanks, Stu  

[orion25]

7 hours ago, Star101 said:

https://www.365astronomy.com/365Astronomy-2-to-1.25-Filter-Adapter.html

I stand corrected!  

[rwilkey]

I started with 1.25" filters but suddenly realised I needed to convert to 2" filters as I had a number of 2" eyepieces, which are better for looking at extended nebulae such as the Veil at low power.  The good thing is that you can use the 2" filters with 1.25" eyepieces by placing the filter in another part of the optical chain, such as on the bottom of the 1.25" reducer (adapter) or on the end of the diagonal.  With Baader you can even place the filter between the 2" body and the 1.25" nosepiece.

[Mark at Beaufort]

Here are my findings using the 2"/1.25" adapter.

Telescope - Skywatcher 150P f/5

Eyepieces - Revelation 30mm FOV 70 degrees, Myraid 20mm FOV 100 degrees. I did not use my 13mm Ethos or the 9mm Myraid because the 1.25" is built into the EP.

Firstly I placed the adapter into the EP itself. Secondly it was then placed into the bottom of the Revelation 35mm extension tube.

Result - no vignetting and the field stop and the FOV appeared to remain the same. No apparent lose of contrast.

I must admit that I do have a 2" OIII and a 2" UHC filter and will use these in the bottom of the extension tube. My H.Beta filter is only 1.25" and has limit objects that can be used with it. In this respect I won 't be buying a 2" H.Beta so this filter will be screwed into the 2"/1.25" adapter.

Hope this helps.

[Olli]

4 hours ago, Mark at Beaufort said:

Here are my findings using the 2"/1.25" adapter.

Telescope - Skywatcher 150P f/5

Eyepieces - Revelation 30mm FOV 70 degrees, Myraid 20mm FOV 100 degrees. I did not use my 13mm Ethos or the 9mm Myraid because the 1.25" is built into the EP.

Firstly I placed the adapter into the EP itself. Secondly it was then placed into the bottom of the Revelation 35mm extension tube.

Result - no vignetting and the field stop and the FOV appeared to remain the same. No apparent lose of contrast.

I must admit that I do have a 2" OIII and a 2" UHC filter and will use these in the bottom of the extension tube. My H.Beta filter is only 1.25" and has limit objects that can be used with it. In this respect I won 't be buying a 2" H.Beta so this filter will be screwed into the 2"/1.25" adapter.

Hope this helps.

Thank you mark I appreciate that a lot.

[Moonshane]

I agree with Mark. I actually have 2" in Oiii as those objects need max field usually but I have 1.25" in Hb and UHC as these objects can usually be accommodated in a 1.25" eyepiece field. I use them with the above adapter.