2" or 1.25" filters, which is more convenient?

[Chipela]

I'm about to buy a couple of filters to help in visual observations (at least an UHC filter). I've been contemplating whether I should buy 2" or 1.25" filters.

My eyepieces are (mostly) 1.25" so the smaller size should be enough and is cheaper too.

However, I've started to think that buying a 2" filter and screwing it to the bottom of my 2"-1.25" adapter would be convenient since I could then change magnification (by switching the eyepiece) without a need to unscrew and screw the filter everytime. But is this a major factor?

Another issue might rise from the fact that some Barlow lenses seem to be longer than my 2"-1.25" adapter so they might hit the filter but I don't have a Barlow yet so this is only theoretical.

Thanks for help,

Chipela

[D4N]

I screw my 2" UHC-S into my diagonal, then it stays there regardless of eyepiece choice.

Another thing to consider is that if you use a 1.25" filter with a 2" EP then you can get vignetting as light is being blocked from getting to the EP.

/Dan

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[Chipela]

Another thing to consider is that if you use a 1.25" filter with a 2" EP then you can get vignetting as light is being blocked from getting to the EP.

Yes, I have considered this issue. Getting a 1.25" version would mean that I can't use it with my 28mm eyepiece which is 2".

Best regards,

Chipela

[YKSE]

I upgraded my filters (UHC and OIII) from 1.25" to 2" mostly for convenience, and for framing large nebulas better.

As you know, 2" can be mounted in extension tube in a Newt, and in diagonal fn other scopes. Changing filters in cold from eyepiece to eyepiece in cold is not much fun.

Nebulas like Veil and North America are doable with your scope, providing the sky is reasonbaly dark, these are over 3° TFOV, with 1.25" filter, you can see part of them,

The downside is of course the cost.

[rwilkey]

Hi Chipela, I went with 2" and screw them into the 1.25-2" adaptor as I have both 1.25" and 2" ep's, a route you may go down later.

[brantuk]

Hi Chipela - you may find a better solution is to use a filter slide tray where you can store two or three filters (and a blank) and just slide the filter you wish to use over the focuser hole as required. It depends on the type of scope though - for dobs/newts  they're pretty cheap or easy to make - for other closed scopes you may have to buy a purpose made filter wheel or slide tray. Hth

(just google "telescope filter slide tray", or "filter wheel")

[Chipela]

Hi Chipela, I went with 2" and screw them into the 1.25-2" adaptor as I have both 1.25" and 2" ep's, a route you may go down later.

Thank you for all answers! I think I'll go the route Robin suggested. It leaves all options open and also simplifies eyepieces switching. Brantuk's idea is also interesting, I need to give it a thought.

[Dave In Vermont]

The only 2" filters I use are IR and UV-Filters, which I use in video-AP. As these filters come into play for what all I'm doing that night, it's just easier to screw these 2" ones into the nose of my diagonal. So it depends on what I'm up to.

Dave