AFOV & Brightness ?

[Charic]

Constriction of the pupils will vary depending on the ammount of light received. Does this explain therefore, why the image from my 72° afov EP appears darker than my 60° afov EP? whilst looking  directly at the  bright Moon
Is it simply the fact that my eye is getting more light from the wider field of view causing the pupil to constrict even further, in comparison to the 60° afov, giving the impression that the image is darker?  I would have thought more field, more light, providing a brighter image?

So bright was the Moon, I could not see my way around the garden with the constricted pupil lol 

[John]

I've been viewing the Moon tonight with 70 and 110 degree eyepieces of around the same focal length (5mm and 4.7mm). It seems the same brightness with both to me ?. I don't think a wider field of view (true or apparent) makes an object brighter or dimmer as long as the aperture and the magnification stays the same

Mind you different eyes can see things different ways and there could be other factors at work. Maybe one eyepiece has coatings that control the glare from the Moon a little better than the other one ?

It's been nice switching between the Moon and nearby Jupiter where the GRS has been making it's way across the disk. Best views of the gas giant this year for me

PS: Callisto is just starting to show as a bright "bump" on Jupiters N hemisphere. Nice !

 

 

 

 

 

 

[Charic]

I was comparing 8mm 150x power, but the Moon and Jupiter were not high enough for me tonight, the higher, the better at my location.

I believe that the issue tonight was simply down to my pupil shutting down due to the brightness, but my 60° seemed to be the brighter of the two EPs when swapping quickly between each EP. Even the Mrs could just make out the banding on Jupiter tonight, but the seeing was not too good here tonight.

I hear what you say about better coatings reducing glare, will just have to wait on a Moonless night to further compare these two EPs.

[John]

A contracted pupil is good for planetary observing. I've heard of folks who stare at illuminated white cards to reduce the pupil to a minimum before observing the planets.

It's just the opposite of what you need when you are hunting faint deep sky objects of course. Not that there was any of that going on tonight with such a bright moon in the sky !

Hope you had some enjoyable viewing - it's so nice to have a clear night for a change