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Moon filter

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#1 nctrailrunner

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Posted 20 October 2021 - 08:56 PM

Howdy!

I tried searching this. There must be a thread about this, but... I am not good at searching, and I don't feel like pursuing it...

 

I have a 13% meade moon filter (ND96). It is not nearly dark enough to look at the full moon. I don't spend a lot of time looking at the full moon. it is not that interesting. But when it is full, I always spend a little time looking at it, as everything else is washed out..

 

What would you recommend for a 1.25 full moon filter, that will protect my eyes?

 

Thanks.



#2 wrvond

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Posted 20 October 2021 - 09:04 PM

Sunglasses.

 

Or, you could get a variable polarization filter. That would cover you for all the moon's phases.  


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#3 nctrailrunner

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Posted 20 October 2021 - 09:13 PM

Sunglasses is interesting. Combined with the filter, would probably be a good, free, solution.


Edited by nctrailrunner, 20 October 2021 - 09:14 PM.


#4 ram812

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Posted 20 October 2021 - 09:33 PM

I sometimes stack a blue visual filter with one of my moon filters and it tones it down a bit. I also have 3 different moon filters and I believe they each have a different level of light dimming power as they are all from different manufacturers. They didn't cost over $25USD each and can sometimes be found used. I bought a cheapo telescope one time and it had a moon filter with it, and it turned into my go-to light diffuser. Sometimes cheaper is better!

CS

Edited by ram812, 20 October 2021 - 09:34 PM.


#5 Napp

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Posted 20 October 2021 - 09:40 PM

Just increasing magnification will reduce the brightness.  Increase it enough and you won’t need a filter.


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#6 wrvond

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Posted 20 October 2021 - 09:50 PM

Sunglasses is interesting. Combined with the filter, would probably be a good, free, solution.

You'd be surprised. Just don't forget to take them off when you walk around! ;)


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#7 ColdestCrow

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Posted 20 October 2021 - 10:54 PM

Howdy!

I tried searching this. There must be a thread about this, but... I am not good at searching, and I don't feel like pursuing it...

 

I have a 13% meade moon filter (ND96). It is not nearly dark enough to look at the full moon. I don't spend a lot of time looking at the full moon. it is not that interesting. But when it is full, I always spend a little time looking at it, as everything else is washed out..

 

What would you recommend for a 1.25 full moon filter, that will protect my eyes?

 

Thanks.

You can go two routes, maybe both depending on your scope. I don't see that you mentioned what scope you have but try this...

For a moon filter I really like the Orion variable polarizing filter. They make it in 1.25 & 2 inch models. Orion claims you can even stack them together if you want for even greater reduction in brightness, although I've never tried it and probably wouldn't. If I found myself wanting to stack filters like that I would probably go with option 2... An aperture mask. You can purchase (or make) an aperture mask for your scope, which will substantially cut down the light coming in even before it hits the moon filter.


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#8 Dave Mitsky

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Posted 20 October 2021 - 11:18 PM

I simply use the old lunar observing trick of turning on a white light, which works quite well even when using a very large aperture.  I will also use higher magnifications when necessary.

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#9 Jon Isaacs

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Posted 21 October 2021 - 02:46 AM

I simply use the old lunar observing trick of turning on a white light, which works quite well even when using a very large aperture.  I will also use higher magnifications when necessary.

 

:waytogo:

 

To the dark adapted eye, the moon can seem very bright.  But dark adaptation is counterproductive when viewing the moon, you want to be observing the moon with your daytime "photopic vision".  This uses your cones and photopic vision has the best resolution and seeing in color.

 

The trick of turning on a white light helps maintain the photopic vision.  

 

Increasing the magnification dims the moon and at higher magnifications, it can even seem too dim.

 

Jon


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#10 therealdmt

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Posted 21 October 2021 - 03:48 AM

I tried the sunglasses trick after reading about it here on CN, but the first problem I ran into was my eyepiece (as in, my sunglasses hit the eyepiece as i tried to look into it lol.gif). Ah ha! That's why glasses wearers are always complaining about eye relief...

 

So I bought an Orion polarizing moon filter. But, being in two pieces, it's a bit of a pain to put in and adjust, and it just doesn't work well (for me) with my main eyepiece, a Baader zoom. Every time you zoom in or out, the ideal amount of dimming to be provided by the polarizer changes, but it's not so easy to change the polarizer on the fly. One could leave one half of the polarizer pair just resting on the eyepiece for easy turning, but my filter is a 1.25" while the top of the Baader zoom is sized like a 2".

 

Anyway, I've ended up just viewing the Moon while in the light of the streetlight out front so that my eye is resultingly not dark adapted/light sensitive (i.e., no filter is needed). I also time my lunar rambles to be at the end of my sessions so as not to ruin my dark adaptation for other targets.

 

I'm not saying I couldn't make the filter work for me, just that it's been easier to do without and I no longer feel the urge to use it. YMMV


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#11 maroubra_boy

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Posted 21 October 2021 - 04:01 AM

La Luna!

 

I LOVE IT.  I have spent countless hours sketching it either as a whole, whatever partial phase or wee sections.

 

Filters...

I only use variable polarizing filters if I am observing the full Moon, low magnification - it is just painful to spend two hours sketching it this way.  As has been mentioned, a pair of polarizing filters allow you to control the degree of transmission and hence level of comfort.  With high magnification I don't need a filter.

 

The only other filter I use is an 82A pale blue to improve contrast with low contrast features.  I've used pale yellow ones too, but I find the pale blue is better for me with subtle Maria features.

 

And yes, there is nothing subtle about the Moon.  Forget being dark adapted if you are observing the Moon.  As Dave and Jon have said, I too keep my observing area well lit while I am with the Moon.  It actually becomes a safety thing because your vision will be stunned by the brilliance of the Moon and if your environment is dark it is a dangerous situation - you just will not be able to competently see hazards in a dim environment.  And yes, I also use a strong white head lamp to illuminate my paper while I do my sketches.

 

Alex.

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#12 TheUser

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Posted 21 October 2021 - 04:19 AM

you can use it by combination with color filters (for example N12 or N21)



#13 GGK

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Posted 22 October 2021 - 07:18 PM

I do the same as others mention. To view the moon, I literally set up right next to the back of my house with the inside lights shining out the windows and the back outdoor lights on right near me. It’s actually very convenient viewing that way. The moon is still
pretty bright in the eyepiece, but I usually view without a filter unless viewing for a very long time. Then I might use a 25 or 50% ND filter or an 82A/contrast booster combination.

When the moon is near full to full like the past two nights, I prefer a 70 degree or wider angle with the moon being 30 to 70% of the field of view. With that and good seeing conditions, I can see a lot of detail on the lunar surface while the moon still appears as a large ball floating in space. I also prefer the background to be light enough to see any small wisps of clouds passing through the view.


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