New, cheapest Mars filter.

[Peter Drew]

This evening I've been viewing Mars with a 16" SCT and Baader zoom eyepiece at 500x. The higher elevation of Mars is giving a better image with this telescope now, the aperture and magnification are keeping up with the diminishing size. Even at 500x, Mars is still rather bright and rather swamps the detail, I tried several standard filters which gave little improvement. At one point I noticed that Mars suddenly appeared much more contrasty with reduced shimmering. I expected that a light cloud had dimmed it but it turned out that I had accidentally breathed on the eyepiece. I cleaned the eyepiece lens and carefully huffed on it to see if the same effect happened and it did. As the initial application of the misting evaporates, the extinction gradually decreases until full illumination is gained. During that process, a "best" level is found. The cheapest accessory currently available and worth a try.  ?

[nightfisher]

I once tried similar with Jupiter and a Tal 200K, took it from a cold cellar to outside, set it up and by time i got to the ep the primary mirror had misted up

[Louis D]

1 hour ago, Peter Drew said:

At one point I noticed that Mars suddenly appeared much more contrasty with reduced shimmering. I expected that a light cloud had dimmed it but it turned out that I had accidentally breathed on the eyepiece. I cleaned the eyepiece lens and carefully huffed on it to see if the same effect happened and it did. As the initial application of the misting evaporates, the extinction gradually decreases until full illumination is gained. During that process, a "best" level is found.

Do you think it was the light reduction or slight Guassian blurring that improved the image?  If the former, a variable neutral density filter should accomplish the same effect.  If the latter, a slightly ground clear glass (soft focus) filter should accomplish a similar effect.

I've used an apodizing mask over the front of my Dob to achieve a similar effect.  I was never convinced it improved the view, but the prismatic color effects were definitely trippy.  I still have the home-brew mask in the back of the closet.  I'll have to dig it out and try it again sometime.

[Peter Drew]

5 minutes ago, nightfisher said:

I once tried similar with Jupiter and a Tal 200K, took it from a cold cellar to outside, set it up and by time i got to the ep the primary mirror had misted up

What I've suggested trying is a very light breath misting which evaporates in a few tens of seconds, the primary optics are unaffected. The result I've seen is similar to the enhanced view you get with Ha viewing when thin cloud drifts by. On Mars I could clearly see dark markings and an obvious pole cap when misted, they were much harder to see once the mist had cleared.    ?

[Peter Drew]

1 minute ago, Louis D said:

Do you think it was the light reduction or slight Guassian blurring that improved the image?  If the former, a variable neutral density filter should accomplish the same effect.  If the latter, a slightly ground clear glass (soft focus) filter should accomplish a similar effect.

I've used an apodizing mask over the front of my Dob to achieve a similar effect.  I was never convinced it improved the view, but the prismatic color effects were definitely trippy.  I still have the home-brew mask in the back of the closet.  I'll have to dig it out and try it again sometime.

It could quite easily be either or both in combination. I have tried variable density filters before but don't recall them being so effective. Cheap enough to try.     ?

[Cosmic Geoff]

I was thinking about this the other night, when I viewed Mars with my C8 + binoviewer + x2 Barlow, seeing a satisfying amount of detail. The binoviewer also worked well on Mars with my 127mm Mak.

Possibly the good result is because the binoviewer cuts down the light reaching each eye by 50% or more, rather than because of any binoviewing magic. After all, one's eye is dark adapted while Mars is a rock bathed in direct sunlight.   By this reasoning, some neutral density filtering ought to be good. 

[Peter Drew]

I usually leave the light on in the observatory for observing the Moon and planets other than looking for planetary moons.  ?