What is the maximum TFOV you would like for DSOs

[GavStar]

7 minutes ago, Stu said:

Yes, I’ve changed from my thick cloak to my waterproof cloak  

@GavStar I do think that perhaps going in search of another expensive scope, perhaps the simpler approach of the x3 might be just as effective if not moreso on those huge nebulae like Barnard’s loop. Worth a go first?

Stu, unfortunately the 3x lens setup vignettes a lot due to the use of 1.25 inch filters between the NV lens and the 3x lens.

To stop the vignetting I think some in the US have got custom 3 inch (or so) filters made to fit the outside of the 3x lens.

However, I agree with you - getting another expensive scope is probably not the answer.

[Stu]

1 minute ago, GavStar said:

Stu, unfortunately the 3x lens setup vignettes a lot due to the use of 1.25 inch filters between the NV lens and the 3x lens.

To stop the vignetting I think some in the US have got custom 3 inch (or so) filters made to fit the outside of the 3x lens.

However, I agree with you - getting another expensive scope is probably not the answer.

Shame about the vignetting.

What is the fitting on the front of the NV?

[GavStar]

3 minutes ago, Stu said:

Shame about the vignetting.

What is the fitting on the front of the NV?

It’s a specialist ENVIS thread - I needed to get this adapter to enable 1.25 inch filters to be fitted on the front.

https://www.rafcamera.com/adapter-envis-to-astro-1-25

At 1x the adapters and filters work great but when you stick the 3x lens on top as per these before and after photos, that’s when the problems start. 

 

[Stu]

I do wonder whether a prime photo lens could be made to work? What sort of focal length do you need?

[PeterW]

Camera lenses work, I used an old 135mm f2.8, found the focus too sensitive and the aperture is a bit more than the 2” filter diameter so I lost more light. I pop my 2” on the front of the 3x as adding thickness beteeen objective and multiplier worsens the vignetting. Also given the field of view there will be some roll off in halpha sensitivity across the view... sweeping around is best. For 1x I just pop the 2” on the front with an adapter.

Peter 

 

[25585]

Depends on the DSO. I generally like to keep a nearby recognisable star or pattern in the FOV if possible, where zooms or at least parfocal eps come in useful.

The M57 below shows 2 stars nearby, for example.