I guess I need a filter?

[OzStarGazer]

Hello,

I tried to watch the moon with my telescope by daylight because I could see it clearly with naked eye, but I could not focus. Is it because there is too much light?
I guess I need a filter to watch it by daylight?

Thanks for your help! :)

[l3gendluk3]

Yeah it sounds like there is too much light. A moon filter is a filter that cuts down some of the uncomfortable glare from the moon and also contrasts the craters, making them slightly easier to see.

-Luke

[CJ]

You should be able to focus, filter or not. Check the eyepiece is slotted in correctly. Occasionally they don't (or maybe that's just me!).
NB Make damn sure you keep well away from the sun though!

[OzStarGazer]

Thanks for the responses. I will try again (not today - very dark here!), but I can focus perfectly at night and I have already tried twice with the moon by daylight... I first tried with the 10mm eyepiece for more details, then when I could not focus I tried the less powerful one, the one I use for the stars (25mm), and I still could not really focus... I wanted to watch it yesterday because I have read that the terminator looks spectacular 10 days after new moon, which was yesterday.
At night though I had a very nice viewing yesterday. It was warm and I stayed on the balcony for quite some time. :)

[cometcatcher]

The contrast is very low in the daytime, focus can be tricky.

[mental4astro]

I agree with Kevin. Daytime observation of the Moon is dreadful, and gets worse as the Moon's phase fills out. The sky is just too bright, competing with the Moon for contrast. Focus becomes really, really difficult. If you've used your scope before, AND it focused then, it ain't gonna change now. But under daytime conditions, a filter won't help. Except maybe a yellow filter as this will improve contrast a small amount, but you end up with a yellow image.

The only time I use a filter with the Moon is when I'm viewing it under low magnification instances (during the night too). Under high magnification, I find I don't need a filter. The filter I use is dual polarising filters so I can control the through-put of light.

[OzStarGazer]

Thanks for the new replies. I am glad to know it's not just me... :)
PS: Focussing itself shouldn't be a problem. The other day I saw Jupiter's moons!

[OzStarGazer]

At any rate I have put a polarizing filter on my eBay watch list. I think it can be very useful. :)

[CJ]

I've not used one on its own, or a pair of them, but from what I have read, most people use a pair. Andrews do them for $19 each. I've not seen any cheaper. My cheap $18 moon filter gets a lot of use. It feels pretty cheap though!

[OzStarGazer]

On which page are the polarizing filters? I just looked at the accessories page and found the colour filters, but not the polarizing ones. (I used Firefox "Find" button and also scrolled down). Thanks!
Also... I hope this is not a silly question... but would a polarizing filter (or two) also be good for other planets? They sell all these coloured filters for planets, but I think even if you can see certain details better the background colour spoils the whole experience a bit? I mean, I haven't tried any coloured filters yet, I am just trying to imagine. :)

[mental4astro]

Have a read through this excellent Lumicon filter guide. It will tell you what the different nebula and colour filters are best suited for. The good thing about this guide is it details how nebula filters can also be used on the planets:

http://www.lumicon.com/store/pg/15-LUMICON-Nebula-Filters.aspx

Polarising filters are pretty much neutral on colouration. They are used to reduce brightness, when used on their own, or allow for variable brightness control by using them in tandem and spining one of the filters in relation to the other.

Colour filters are used to tone down some colours so that different features become more readily visible. Just note when using colour filters on the planets, those features you are looking for won't necessarily stand out like the proverbial doggie's, nor immediately obvious. These features may become brighter or darker too. It is then upto you to be able to interpret what the image shows.

One last thing about colour filters: If you are mad keen on getting them, ONLY select two, three at most!!!! You just will not use them all that much. Nebula filters are a different beast. If your scope is under 6" in diameter, your best options are either a broad band filter or an OIII. The other filters will and do work, but the amount of light that they actually transmit is so small as to make them impractical for smaller apertures.

[CJ]

They are on the Guan Sheng page, almost at the bottom in the "special eyepiece filters" section. No pic though. Bintel do them for $19 too.

I can't speak for the planets. I've just read in few places that a pair of polarisers are all you really need, but opinion is, of course, divided!

[OzStarGazer]

Thank you, Alexander and Chris! :)

[cometcatcher]

A single polarising filter can be useful for daytime obs if the Moon is at 90 degrees to the Sun or half phase. At that angle you get the greatest sky darkening.

[OzStarGazer]

Thanks for the tip! :)

[OzStarGazer]

Well, I tried again yesterday and could focus much better (with a filter).
I even managed to take a couple of photos, although they are worse than those I took at nighttime (more washed out). But I could still see details relatively clearly, like the craters Catharina, Cyrillus and Theophilus. :)