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[GGK]

I'm still figuring out what I want to do regarding equipment for prime focus and Afocal, but regardless of what NV device I choose, I plan to use the NVD with eyepieces at least some of the time.

 

One of my wide field refractors is a 100mm f/4 flat field Petzval.  400mm focal length (easy math)

 

For those with something close to that, what is your most used eyepiece focal length and which bandwidth Ha filter will likely do best in Bortle 5 skies than will also darken to Bortle 4 or 3 at times?

 

Using the TV 55mm Plossl with 67mm adapter, the NVD will see an f/1.55 light cone at about 6X, if I did the math right. Targets are large nebula with an Ha filter.

 

From what I read, faster is better for more light, but will being that fast in a ~4" refractor cause any issues?  Would I be better with a 41mm Panoptic, or maybe something else?

 

I also question if the standard 6-7nm Ha filter is the right recommendation for a first filter since a 4" f/4 refractor isn't that common.

 

What's your experience and thoughts on using this refractor?

 

Gary

 

 

[sixela]

A Pan 41 is really good but won’t give you the same FoV or effective f/ratio as a TV67, I.e. you’ll use both.

And yes, such a setup is just perfect for really large nebulae or even groups of nebulae.

Whether you want a 6-7nm H-alpha filter, a 4nm dual band or a 3nm H-alpha will depend on how dark your skies are, what objects you want to look at, and whether you want just one filter also for handheld use at 1x front-mounted.

That refractor is pretty fast with a 67 mm or 41 mm eyepiece afocal stack, so it certainly tolerates very aggressive 3-4 nm filters.

Edited by sixela, 15 August 2024 - 03:39 AM.