12" DOB. 1.25 VS 2" EP

[IVAN TAPIA]

Hello everyone, I have a 12" dob great scope with a 1.25 5mm, 9mm, 10mm,25mm EPs and a 2" 35mm that came with the dob and feels great to look through it, I want to get some nebula filters and I would like to know if its worth it to spend on a 2" size, if so then I can get more 2" EPs, Thanks. IVAN

[swamp thing]

Hi Ivan

Nice scope

I use 2" filters as I want them to work with my longer focal length eyepieces (which are all 2" fitting).

I do have a 1.25" O-III filter as well for high power planetary nebulae observing, but it seldom gets much use TBH. I tend to Barlow my 2" eyepieces and filters instead.

[John]

My filter arrangement is similar to Steves.

Some 1.25" - 2" adapters have a filter thread on their bottom end which, with the addition of a suitable spacer such as a Baader 14mm fine tuning ring, can be used to hold a 2" filter so it can be used with 1.25" eyepieces.

[RikM]

I use an 1.25" UHC filter and 2" OIII (actually I am using an 1.25" in a 2" adaptor prior to finding a nice second hand 2" OIII). I find the OIII too aggressive for the higher magnification I get with my 1.25" EP's but the low power 2" EP is just right. The UHC doesn't give enough contrast in the 2" size but works well at the higher magnifications. This is all to do with the exit pupil given by the scope/EP combination.

It is generally easier to use 2" filters with 1.25" eyepieces than the other way around. I can just about get away with the 1.25" OIII in the 2" adaptor but eye placement is critical to avoid vignetting the edge of the field.

[Moonshane]

I buy 2" filters generally even with 1.25" eyepieces but beware of this http://stargazerslounge.com/topic/84086-novel-use-for-baader-fine-tuning-rings/

[IVAN TAPIA]

Thanks for the replies, I just took a look at the 2" adapter and it has a tread for the filters, ill be getting 2" filters then, Thanks. IVAN

Sent from my ADR6425LVW using Tapatalk

[itmo]

I have a couple 2" filters which i attach to a 1.25-2" adapter filter thread by extending them with a few empty filter rings. I got these rings for change from the local astro shop as DIY stuff. It is still not enough extension to fit my televue barlow, but I usually dont use the barlow and nebula filters together. Only thing I miss is using barlow+variable filter with moon, but that is not  a big loss.