Moon Filter?

[Squidie]

Hi every one, well the good news is that I got to see Jupiter and 4 of the moons..Awesome!!...after the clouds cleared for a little bit. I do have a question though...I have a moon lens and I figure its for looking at the moon, I saw the moon on this night also and ... WOW the craters. I did not use the moon filter and it was still super clear, what does it actually do and where does it go? I Twisted the lens apart and saw something similar ...but not really the same, do I put in a Barlow lens? because I did and it went straight through like a coin in post it tube. Looking forward to an answer but no hurry because its cloudy for the few nights again.

Thank you from

Squidie

[cloudsweeper]

Squiddie - 

Glad you enjoyed Jupiter - it is something all right!

The Moon filter screws into the nosepiece of the eyepiece - or you can screw it into the diagonal (the bit between the 'scope and the EP) so it is in use with any EP.

The purpose of the filter is to reduce the glare when the Moon is bright.

HTH,

Doug.

[DRT]

31 minutes ago, Squidie said:

I Twisted the lens apart and saw something similar

Hi,

I'm not sure what this means but it sounds like you disassembled your eyepiece. That is not a good idea as the lenses could easily fall out and it would be difficult ensuring that they were put back together properly.

What equipment are you using?

The only reason to use a Moon filter is if the Moon is so bright through the eyepiece that it becomes uncomfortable to look at. As Doug says the filter simply reduces the brightness. If you didn't feel any discomfort looking at the Moon there is no need to use the filter.

Derek

Derek

[Dave In Vermont]

As above. Most of these generic Moon-Filters are rated at 13% light-transmission. This to dim the Moon a bit when it's near to full, or approaching same. If you like them, you'd like a polarizing-filter better. These are a set of 2 filters which, when you rotate them with one behind the other, give you a variation of dimming from 40% down to about 3% light-transmission. They are also useful on other bright targets, such as the planet Venus and the brightest stars - like Sirius (a-Canis Majoris), the Dog-Star south of the constellation of Orion.

Many other types of filters are available for many different applications. But describing such would be a very long post. As you find your way about the nighttime sky, you might ask for some literature on such - it's a fascinating sub-field of observing unto itself. Take your time - you'll get there in due course!

Have fun -

Dave

[RT65CB-SWL]

Hi 'Squidie' and welcome to SGL. 

+1 for Doug's 'cloudsweeper' and Derek 'DRT' comments above. Do not start disassembling/unscrewing your eyepieces.

The filter simply screws into the nosepiece. I use a variable Lunar/Moon polarising filter. Basically they are two ND filters that rotate in a cell enabling you to adjust the amount of photons reaching your eye; (ie between 13-40% depending on make/coatings etc). The one I use includes an adaptor. (my one is for 1.25"). What I do is...

1. screw one of the filters to the adaptor nosepiece that accommodates the eyepiece.

2. screw the other one in to my star diagonal. (note: only applies if using a Mak, SCT or refractor).

3. leave the eyepiece filter free - undo the small captive locking screw - hold the eyepiece with one hand and twist the adaptor with your free hand to adjust the brightness. That way you do not have to remove the filter when you change eyepieces.

If you are using a Newtonian telescope on an Alt-Az, Dob' or 'EQ' mount then you use both filters screwed in the adaptor or eyepiece. The only downside is you have to remove the adaptor completely from the focus tube to change the brightness or remove completely when changing the eyepiece.

BTW - the Barlow lens goes between the focus tube of your telescope and the eyepiece.

[Knighty2112]

Depending on your telescope you may not have a thread in the diagonal supplied with you telescope. None of the 1.25" diagonals I got supplied with some of my telescopes have this thread at all. But my 2" diagonal that I use does have a thread that will allow 2" filters to be screwed in it, so you may only have the option to screw your moon filter into your EP if you want to use. One thing I do to limit the light coming in also when observing the moon & Venus is to sometimes leave the main telescope cap on, and only take off the smaller aperture in the cap. All my telescopes do have this smaller aperture in the lens cap to limit the light coming in too, so your telescope should also have this too hopefully.

Photos attached show the smaller aperture in the lens cap, and the moon filter screwed into one of my EP's. The internal thread in the EP is clearly seen in the image before the moon filter is screwed in.

[Knighty2112]

Actually, just checked my two 1.25" 45 degree diagonals I have (which I rarely ever use) and they do have a thread  for filters in them, but my 1.25" 90 degree diagonal that I normally always use on my smaller refractors doesn't have a thread for filters at all. 

[Squidie]

Thank you all for your help...after playing with the lens and fitter this afternoon..with your help. I have found the filter only fit's on my 20 mm lens. I'll play with it tonight to see the difference with filter on while I wait for Mars and Saturn to pop up. We have a full Moon tonight and clear sky again wooooot! The Polarizing filters sound interest...I'll just play with what I have at the moment though... but very interesting.

Thank you all again

Squidie

[Knighty2112]

31 minutes ago, Squidie said:

Thank you all for your help...after playing with the lens and fitter this afternoon..with your help. I have found the filter only fit's on my 20 mm lens. I'll play with it tonight to see the difference with filter on while I wait for Mars and Saturn to pop up. We have a full Moon tonight and clear sky again wooooot! The Polarizing filters sound interest...I'll just play with what I have at the moment though... but very interesting.

Thank you all again

Squidie

The best way to observe the craters on the moon is to view the terminator area during the waxing and the waning phases of the moon. Whilst the full moon does look dramatic through any telescope, with the sun directly overhead at full moon (or close to full) a lot of the finer details in observing craters and features are lost. Here's a couple of images to show the difference when observing features near the terminator at first quarter, and again at full moon. More detail can be seen a lot easier in the terminator area on the 15th, then when on the same area when at full moon on the 23rd of this month.

 

[Squidie]

Hi guys

WOW!! that's awesome Knighty, the difference is really astonishing and I would never have thought to look at the different phase of the moon other than full or near full. I'll try it very soon.  I did try my Moon filter and it turn the Moon Blue, very nice to look at but it did not have as much detail as my first night.

So to update ...I now have seen Mars (disappointing)...it was very very blurry and apart from being red/orange I really could not see anything at all. So I then turn my attention to Saturn...At first I thought some one had come along and drawn on my mirror ... but after a few seconds I realized that it was the tilt of the rings (maybe) or Planet, that made it look like a cartoon. After I realized, the awesomeness of it sunk in and I spent hours just following Saturn through the sky.

Thank you all for your replies and help

Squidie

[cloudsweeper]

3 minutes ago, Squidie said:

Hi guys

WOW!! that's awesome Knighty, the difference is really astonishing and I would never have thought to look at the different phase of the moon other than full or near full. I'll try it very soon.  I did try my Moon filter and it turn the Moon Blue, very nice to look at but it did not have as much detail as my first night.

So to update ...I now have seen Mars (disappointing)...it was very very blurry and apart from being red/orange I really could not see anything at all. So I then turn my attention to Saturn...At first I thought some one had come along and drawn on my mirror ... but after a few seconds I realized that it was the tilt of the rings (maybe) or Planet, that made it look like a cartoon. After I realized, the awesomeness of it sunk in and I spent hours just following Saturn through the sky.

Thank you all for your replies and help

Squidie

Yes, Mars is often rather disappointing!  Great to see it nevertheless.  Whilst observing Saturn, did you notice a small spot below and west of it, namely its largest moon Titan?  Averted vision can help to notice faint objects like that.

Glad you're enjoying our wonderful pastime!

Doug.

 

[Grotemobile]

http://www.firstlightoptics.com/moon-neutral-density-filters/variable-polarizing-moon-filter.html

This I what I use. It was good on Jupiter, the other night.

Steve.

[John]

Mars varies a lot in size and clarity depending on where it is in it's orbit in relation to the Earth. Mars apparent size will grow as it approaches it's opposition on the 22 May this year so it's worth observing it for a few weeks either side of that date.

With the transit of Mercury on the 9 May, May looks an interesting month for planetary observers

 

[Paz]

With regard to moon filters I've got a variable filter but I've found that it's main use is it making it more comfortable to look at the moon quickly which is really bright when your eyes are dark adapted.

But when it comes to seeing as much detail as possible I find it better without a moon filter - it is just a case of slowly going up to the eyepiece and letting your eye adapt slowly to the brightness (is there such a term as "light adapted"?!) as it is painful and dazzling if you don't.  Once I'm adapted to the brightness it's no problem and I can see more than with a moon filter.

[Sme4969]

The filter I have Is a O -111..like looking at a mirror on both sides but is green when looking through it on the scope 

but it is different to the moon filter on my other scope which is green to look at and through... 

[Squidie]

On 27/03/2016 at 18:54, cloudsweeper said:

Yes, Mars is often rather disappointing!  Great to see it nevertheless.  Whilst observing Saturn, did you notice a small spot below and west of it, namely its largest moon Titan?  Averted vision can help to notice faint objects like that.

Glad you're enjoying our wonderful pastime!

Doug.

 

No I don't think so Cloud ...well maybe I did, I am not sure. I did see 2 very tiny star like objects that looked like the moons of Jupiter. 1 was close south west  and the other was far east and only just fit into my view, I was not sure if they were moons or just other stars very far away. But Now you have perked my interest again in what I did see your didn't see, I'm setting up again tonight to look again. 

On 27/03/2016 at 19:55, John said:

Mars varies a lot in size and clarity depending on where it is in it's orbit in relation to the Earth. Mars apparent size will grow as it approaches it's opposition on the 22 May this year so it's worth observing it for a few weeks either side of that date.

With the transit of Mercury on the 9 May, May looks an interesting month for planetary observers

Thanks John that's really good to know about Mars, and I should have thought of it myself ....after all the Planet Documentaries I have watched. Although I have only just got my new toy and I am not thinking that  I have to think like that yet, at the moment..so I can not be to hard on myself (I did slap myself in the for head after I read your note... ha ha ouch) 

I would love to know more about the Transit of Mercury...is it lunar, solar, planetary? Never mind what... I'm in, 9 May and 22 May are in my calendar.

Saturn should be clearing the tress soon so I got to go.

Thank you all again

Squidie

[John]

16 minutes ago, Squidie said:

....I would love to know more about the Transit of Mercury...is it lunar, solar, planetary? Never mind what... I'm in, 9 May and 22 May are in my calendar....

It's a solar event so requires solar viewing equipment. Either white light full aperture filter, a herschel wedge or a specialised hydrogen beta solar scope. The black spot of Mercury's disk will creep across the Sun's disk from around 12:00 am (BST) until it leaves the disk just before 8:00 pm.

I expect a lot of astro societies will do public outreach type events to view this - I know that my own, Bristol AS, is.

[cloudsweeper]

@Squidie - using Stellarium is a great help in identifying what you see.  As for Jupiter's moons, you can usually see three or four very clearly, depending on where they are, and the giveaway is that they - and the planet - are often (but not always) in a straight line.

Doug.

[Squidie]

22 hours ago, cloudsweeper said:

using Stellarium is a great help in identifying what you see.  As for Jupiter's moons, you can usually see three or four very clearly, depending on where they are, and the giveaway is that they - and the planet - are often (but not always) in a straight line.

Doug.

I do have Stellarium on my tower (upstairs and inside) and I am just learning how to use it. Really I could just sit and play with it for hours...but I want to see the real things fist. Thanks for the tip though.