High Quality Moon Filter for Visual

[issdaol (Phil)]

Hi All,

Having never used Moon filters in the past I now find I need one.

I currently use Astronomiks filters for other purposes but they do not seem to offer any Moon filters.

I basically want a very high quality Moon filter to reduce glare while maintaining contrast and resolution.

Either 1.25" or 2" is ok.

Cheer and Thanks in advance

[mental4astro (Alexander)]

I'd suggest a pair of polarising filters piggy backed onto each other. These will vary the amount of light getting through according to their relative placement to eachother. Rotate one way, you get about 50% reduction. Rotate 90 degrees and you get nearly 100%.

As the Moon's brightness changes, you can then vary the amount of light getting through the filters. These filters are also good for reducing the glare of Jupiter, even Saturn.

I've got a set of these filters, and are good also when photographing the moon with a web cam. If I'm using my 17.5" scope, I have no choice but to use these filters for visual and webcaming the Moon.

These are readily avialable, and Andrews has 1.25" ones for around $20 each.

[mswhin63 (Malcolm)]

I also use double polarixing filters and are very good, I also have a continuos rotation version and with my BAADER lenses I can rotate them easily while still viewing. I just twist the eyepiece.

[issdaol (Phil)]

Hi Malcolm and Alexander,

Thanks for the advice which filter models and make are these?? so I can check them out

Cheers

[mswhin63 (Malcolm)]

Mine is Orion 2", you can get them from most astro shops.

[mithrandir (Andrew)]

Originally Posted by mental4astro

I'd suggest a pair of polarising filters piggy backed onto each other. These will vary the amount of light getting through according to their relative placement to eachother. Rotate one way, you get about 50% reduction. Rotate 90 degrees and you get nearly 100%.

How do you do that? As far as I can determine the 1.25" filters thread into the eyepiece. Doesn't that mean you have to take the eyepiece out of the focuser to change the relative orientation of the two filters?

[mswhin63 (Malcolm)]

Originally Posted by mithrandir

How do you do that? As far as I can determine the 1.25" filters thread into the eyepiece. Doesn't that mean you have to take the eyepiece out of the focuser to change the relative orientation of the two filters?

There are different orientations, I have my 2" that screw into the expansion adaptor of my Baader eyepiece directly and does not require to take the eyepices out to adjust. - mine - https://www.bintelshop.com.au/Product.aspx?ID=7168

My previous webcam, I had to take out the webcam everytime I altered the filter, really annoying. I managed to alter the exposure control better recently so I dont need to do this any more. - https://www.bintelshop.com.au/Product.aspx?ID=6612

The last option is a double Polarising filter in 2 parts, one is fitted to an adpator that fits into the eyepiece holder (of the scope) the other filter screws into the lense. The eyepice and single filter fits into the eyepice adaptor allowing it to rotate the filter without pulling it out. Although a bit fiddly it is a big improvement. This method does not work on all focusers as it extends the eyepiece further out and may not allow you to focus correctly. (That was a mouthful, hope you understood it) - Cant find a link for the one above, but i do have one myself.

[mental4astro (Alexander)]

Originally Posted by mithrandir

How do you do that? As far as I can determine the 1.25" filters thread into the eyepiece. Doesn't that mean you have to take the eyepiece out of the focuser to change the relative orientation of the two filters?

Yep! I to have a similar adaptor as Malcolm. The thing with the adaptor is it causes too much of a change in the focus travel, and it is also more stuff to get in the way. So I need to remove the EP from the focuser! Really, so what! I find it less fiddely, and the little adaptor is not in the way. Suits me. You may want to keep using the adaptor.

[issdaol (Phil)]

Hi All,

Thanks for the comments and advice it's been a great help.

Cheers

[astro744]

If you want maximum resolution forget the polariser and get the 13%, 25% and 50% neutral density filters from Lumicon. See http://www.lumicon.com/telescope-acc...ensity+Filters

[ausastronomer (John Bambury)]

Originally Posted by astro744

If you want maximum resolution forget the polariser and get the 13%, 25% and 50% neutral density filters from Lumicon.

If you want maximum resolution forget about using any filter at all. Whichever filter you use, you are cutting down the light throughput and detail. A far better option is to have some ambient light around where you observe. This will limit your pupil dilation so the moon does not "appear" so bright. Look at the moon in daylight, it isn't so bright! Observing the moon is not harmful to your sight. It takes a minute or so for your pupil to dillate back to normal after observing the moon, that is all. Remember you are observing reflected light only, coming from a surface with the colour and texture of a bitumen road.

I regularly observe the moon unfiltered in the 18" Obsession and 14" SDM, without issue.

That all having been said. my wife and son have very "light sensitive eyes" and much prefer to use a filter. However, they lose detail!

Cheers,
John B

[astro744]

Originally Posted by ausastronomer

If you want maximum resolution forget about using any filter at all.

OK, I'll give you that one. I was assuming a filter was to be used since that is what the user wanted. My experience with a polarising filter is that small craters disappear with a filter in place and are visible without any filter (C9.25).

[issdaol (Phil)]

Hi All,

Thanks for the comments and advice. Much appreciated.

Originally Posted by astro744

If you want maximum resolution forget the polariser and get the 13%, 25% and 50% neutral density filters from Lumicon. See http://www.lumicon.com/telescope-acc...ensity+Filters

Claude has kindly sent me a Lumicon ND25 to try or return so I will see how this performs.

Originally Posted by ausastronomer

If you want maximum resolution forget about using any filter at all. Whichever filter you use, you are cutting down the light throughput and detail. A far better option is to have some ambient light around where you observe. This will limit your pupil dilation so the moon does not "appear" so bright. Look at the moon in daylight, it isn't so bright! Observing the moon is not harmful to your sight. It takes a minute or so for your pupil to dillate back to normal after observing the moon, that is all. Remember you are observing reflected light only, coming from a surface with the colour and texture of a bitumen road.

I regularly observe the moon unfiltered in the 18" Obsession and 14" SDM, without issue.

That all having been said. my wife and son have very "light sensitive eyes" and much prefer to use a filter. However, they lose detail!

Cheers,
John B

John do you wear sunglasses at night???

Through my scope the Full Moon is so bright it really does hurt your eye when viewing. Detail is really fantastic but you can only look for very short time then you walk away seeing after images. In different phases the intensity is less but still powerfull.

I am not sure it's just sensitivity of my of my eyes cause my old CPC1100 did not have the same visual effect.

Maybe I need to have a couple more bourbons beforehand

Cheers

[BlackWidow (Mardy)]

This thread is interesting. Can I ask about Polarising filters please. I use a moon filter for viewing when the moon is near full. However the idea of using two palarising filters gives more scope.. My question is this.... Is it better using a Toucam Webcam to use two Polarising filters when filming things like the Moon or Jupiter, or is it better to just lower the gain of the camera. I also use an IR filter on the Toucam...



Regards
Mardy

[mswhin63 (Malcolm)]

I used to use double polarizing filter on my webcam but since I managed new drivers (not toucam webcam) I am now able to remove my double polarizing and adjust the exposure setting.

If you cannot adjust the exposure setting during recording then you may have no other option other than to use double polarising filter. They do give a big range of darkening. The other problem with using double polarising is that it may extend the focal length further and may have to fit them in a way so they don't do that, In the past I only had about 2mm of FL left before I ran-out of focus. For me it was annoying as I had to pull out the webcam everytime I wanted to adjust it.

Try to get the drivers adjustment to work before trying to use double polarising. You will save a lot of hassles.

[BlackWidow (Mardy)]

Thanks for that. I can adjust the settings on my camera, but was not sure if the filters gave a better result..


cheers
Mardy