Eye/filter FOV

[jetstream]

I was wondering what field of view would be had if I look through a 2" filter (one eye obviously) naked eye?

[pipnina]

24 minutes ago, jetstream said:

I was wondering what field of view would be had if I look through a 2" filter (one eye obviously) naked eye?

How far away from your eye is the filter? If you hold it at glasses distance you might get 80/90 degrees out of it (My guess based on holding my 2"-1.25" converter to my eye). But if you're too close the filter will shift to different wavelengths at the edge...

Perhaps experiment, during the day using a white (or white-ish) wall: Move the filter closer and further from your eye until you find a good balance between colour and field of view? Then maybe compare what you're seeing to your views down eyepieces of known AFOV?

That's probably what I'd try to do.

Clear skies!

    ~pip

[jetstream]

Thanks Pip! I was just out there playing with the new filter (2"HB) trying to see the big faint nebs around Orion...no go,nada Doing this gave me a VG idea of the FOV- thank you for the info!

[Louis D]

Yea, you're probably going to need some sort of image intensifier fitted to a fast, wide angle lens to achieve the goal of seeing large, dim nebula in real time.  Remember, Barnard's Loop wasn't definitively discovered until astrophotography was invented.

[pipnina]

1 hour ago, Louis D said:

Yea, you're probably going to need some sort of image intensifier fitted to a fast, wide angle lens to achieve the goal of seeing large, dim nebula in real time.  Remember, Barnard's Loop wasn't definitively discovered until astrophotography was invented.

I would have a look at this: http://www.prairieastronomyclub.org/resources/by-dave-knisely/filter-performance-comparisons-for-some-common-nebulae/

He views Barnard's loop with a 100mm frac and with the naked eye using a H-beta filter. The way he's written it is unclear but it seems like he describes it as " Faint narrow glow visible both over the belt and curving down southeast along Orion’s southeastern side. Very faint, but noticeably easier to see than in UHC filter. " when he's using the filter & naked eye while describing it as "Fairly easy in 100mm f/6 scope with some vague detail although not bright." when using his 100mm frac.

With dark skies and good transparency, Barnard's loop (and probably the lambda orionis nebula as well, though the eridanus bubble probably needs a rich-field frac) is possible with just the naked eye*.

*And a filter