Filters and Diagonals

[am231058]

Firstly, when and why do you need to use filters? I understand that a very bright moon may need toning down a bit so a neutral or lunar filter would be useful but what about the other types?

Second, how much benefit is there in upgrading a diagonal? I am current using the celestron one which came with my cpc 800, but the fella at Green Witch said it may be worth getting a better one.

Finally, if I was looking to buy, can anyone recommend a reasonably priced filter(s) and diagonal.

Thanks in advance, Alan.

[NGC 1502]

Hi Alan, here is an article on filters for deep sky -Filter Performance Comparisons - Article

It's quite long, but can save expensive mistakes.

There are also coloured filters for planetary use, will

come back here if I can find a link.

Regards, Ed.

Edit - here is a link for planetary filters - http://www.meade.com/catalog/meade_4000/meade_series_4000_filters_02.htm

but as this is a manufacturers link, they would say they work. I have never used filters for planetary use, and I've heard

mixed opinion as to their usefulness. But I have an OIII and a UHC filter, and they definitely work, as long as they are used

on their intended targets, as the first link describes.

Lee at Green Witch knows his subject, and gives good advice.