Q. about My Eyepieces & Filters

[Fermenter]

I don't currently own any filters but am planning to pick up at least one up before this star party I'm throwing on Thursday.

I have a question though about my Meade 4000 Super Plössl 26mm eyepiece.  I never really paid attention before but this has a filter on it by default, an ND96 (0.9) filter.  When doing normal viewing, would it be advisable to sometimes remove this filter? Or when is it advisable to use this and when is it not?

Now, I'm used to letting my eye adjust to the brightness of lunar observation through my telescope, but since these people are all first timers, and a big part of the party is going to be viewing the meteor shower taking place, I want to use a filter for the moon.  That way I'm not desiring their vision for the meteors.  I'm debating between picking up a Meade 4000 color filter set including #15, 25, 58 & 80A, and the Baader Planetarium Moon & Skyglow filter.  I would use the #80A for the moon that night, but I think the Baader would be useful as a LPR filter in general after the event since I live in Atlanta.  Honestly, I may pick up both options, however between the two what do you think is best for the event?

Also, when using one of these filters at the event, should I stack on top of the ND filter, or remove that before attaching whichever moon filter I end up using?

In addition to the Meade EP, I also have a Celestron X-Cel LX 7mm, which did not come with any filter attached.  Would it be good to use the ND filter on that as well?  I'm guessing there is a reason the Meade 26mm came with an ND filter and the Celestron 7mm did not, probably something to do with greater magnification having reduced brightness.  With the moon & color filters however, I think they'd be useful on both eyepieces, perhaps not equally and when to use them might differ for each EP.  I have a bit to learn and practice with filters.

One thing that is a bit frustrating is that my Barlow T-mount adapter does not have threads for the filters to screw on.  Do people have a solution to be able to use these filters when photographing via prime focus? Thanks!

Cheers,

Fermenter

[Putaendo Patrick]

I'm a bit confused. As far as I know the Meade 25mm doesn't come with a default filter. If you have this filter, it is an accessory although it might have come supplied in the box if you bought the telescope new. The ND96 reduces the quantity of light (I think the transmission is 13%) and this can be very useful when observing the Moon especially in its brighter phases (and occasionally other targets such as double stars). Obviously it should be removed for other observing.

Some people like Moon filters, others don't use them. Perhaps some people's eyes are more sensitive to light, and some people like to observe just the Moon while others like to switch targets and don't want to lose their night vision. At the end of the day, it's personal preference I guess.

If your telescope has a cap with a smaller secondary hole in it, you can reduce the aperture and thus the brightness of the Moon using the smaller hole. This might be a lot quicker than changing the filter all the time.

Coloured filters are, however, much less dramatic in their effects when used for visual observation of the planets. Don't expect to see big differences (in fact many people really see very little difference at all). I quite like filters and on an extended and concentrated viewing of a planet I will often try a filter or two to see if I can tease out a little more visual information.

However, for a star party, the hassle (and danger of dropping one, or worse an EP!) of changing filters and the time spent fiddling around against the slight benefits they may (or may not) have on a particular night, for inexperienced observers really all suggest to me that colour filters would be a waste of time and only add to the impatience of guests waiting their turn!

[Fermenter]

I got the telescope new, and like I said I never paid attention to it before, so that filter has been on there since I got it.  It must have been part of the package I got or something, but that was 13 years ago so who knows at this point.  And you're about the 13% transmission of light.  The ND96 is pretty much a moon filter, so I guess I really already have one.  But, I still want to grow my filter collection.

At the star party, I wasn't planning on constantly changing the filters, just adding one of the moon filters an leaving it on for the night.  So using it shouldn't be a big issue in terms of holding people up.  I'd decide when setting up the telescope whether or not it improved the image, reduced the intensity a bit, and the just go with my decision for the night unless someone complained.

After more reading, I see nothing but praise for the Baader neodymium filter (the Moon & Skyglow filter), so I am almost certainly picking that up for myself in the long term.  This filter just seems so useful, a jack of many trades and it does those things well.  Now, for myself, I just need to decide if I want to get the color filters as well.  I think for the time being I will pass and spend more time learning and researching the various brands and their offerings.  I don't want to rush picking up a bunch of filters when I'm only going to be using one at the event.

I won't be making any purchase until Sunday though, as it won't be shipped until Monday anyways.  So if anyone has anything to say between the neodymium and the #80A, I'd love to hear it.

Cheers,
Fermenter

[ronin]

The ND filter is not necessary, it is simply there for possible comfort, some people can find the moon to be a bit too bright, others like myself do not care. Partially dependant on the scope, having viewed the moon through a 6" scope it was sort of on the edge of comfort/discomfort without a filter. I would remove it from general use with the eyepiece as it is reducing the light throughput by a lot.

They are not usually a standard accessory so I guess you were lucky or it was part of an offer at the time. Sounds like a filter has ended up in the eyepiece by chance and then you have received it. But it is certainly not a requied item in the eyepiece.

Generally you do not stack filters. They are really not intended to work stacked. In simple term and also in "perfect terms" if you stack a red and a green you should get nothing. The Red would block Green and Blue, then the Green blocks Red, result being nothing.

The 7mm may have a filter put into it, if you want to. Again depends on the filter and the use that you are putting it to.

Filters are not necessary items, after 15 years I do not own a filter of any sort. MAybe one day if I get bored I might try one but so far never felt the need. I suspect that the first I will consider is a UHC filter. Since my scopes are generally smallish diameter I doubt that I will fry my brain by looking unfiltered at the moon. However I will carry on trying to since the child in me loves having the residual image of the moon on the retina. I just find it amusing.

For a star party I would not bother with a filter at all. No reason to add to the complications, just keep it simple. If the 6" is aimed at the moon then try it without the filter and if too much put it in BUT tell people that there is an ND filter in the eypeice and that this is making the moon significantly dimmer. Otherwise you could get people mumbling about the moon being dim and that it is brighter in their binoculars.

Cannot help with the barlow and diagonal. I think that some are threaded and others are not. Any thread will (should be)  be at the sort of objective end as otherwise there is the chance of whatever is inserted into the diagonal or barlow hitting the filter. Mention this just in case you have only checked one end (doubtful however). A diagonal may take 2" filters.

 

[Fermenter]

Thanks for the info.  Yeah, in photography I never stack filters.  I've seen people who, because they refuse to ever take their protective filter off a lens, and then get the filters fused together and cannot separate them without some serious effort and sometimes tools.

My main reasons for wanting to filter the Moon at the star party were, 1) because this will be the first time looking at the Moon through a telescope for most people, if not everyone, and 2) because the meteor shower is the reason for having the event that night, and as fun as the retinal burn may be it's not the best thing to experience when trying to spot meteors and other stars with the naked eye.  I'll be teaching the kids some basics, stuff like how to find Polaris via Cassiopeia, etc.

Edit: but I'm also interested in filters just for my own personal use after the event.  And looks like I may have been lucky to score a free filter, or not. It was so long ago that I no longer have the receipt and cannot remember what the price was.  I just can't believe how unobservant I've been to not notice I've had three filter on the eyepiece, though that comes as no shock to my fiancée.

[Pig]

Hiya, I think the above post have said all there us to say about filters... I also do not use a filter when observing the Moon..... when using Moon and coloured filters inline with a Barlow you simply leave the filter screwed into the eyepiece as you normally would.

[RT65CB-SWL]

Hi 'fermenter' and welcome to SGL. 

With regard to your question about the 80A & neodymium filters. I believe the 80A is a pale blue and is mainly used when observing Jupiter & Saturn. I do not own any other color filters except a #47 and a few Lunar/Moon filters.

Personally I would go for the neodymium. I like to think of it as the 'Swiss army knife' of filters.

[Fermenter]

4 hours ago, Pig said:

Hiya, I think the above post have said all there us to say about filters... I also do not use a filter when observing the Moon..... when using Moon and coloured filters inline with a Barlow you simply leave the filter screwed into the eyepiece as you normally would.

Well, I'm not using an eyepiece with my Barlow, I'm using my camera.  My Barlow is also a T-adapter.  I may be able to use the Barlow with an eyepiece as well, but I've never tried as I just got the thing for taking photos using prime focus.

 

1 hour ago, Philip R said:

Hi 'fermenter' and welcome to SGL. 

With regard to your question about the 80A & neodymium filters. I believe the 80A is a pale blue and is mainly used when observing Jupiter & Saturn. I do not own any other color filters except a #47 and a few Lunar/Moon filters.

Personally I would go for the neodymium. I like to think of it as the 'Swiss army knife' of filters.

Yeah, that's what I've been reading.  The neodymium enhances color, brings out detail in Jupiter, amazing on the Moon, reduces light pollution, everyone that has one seems to really like it.

[Pig]

So at your star party your going to have your camera hooked up !!! bit of a waste  you might as well buy everyone a book.

[Fermenter]

35 minutes ago, Pig said:

So at your star party your going to have your camera hooked up !!! bit of a waste  you might as well by everyone a book.

No, not hooking up the camera, not using the Barlow at all.  This thread is about using filters with my gear.  Some of it is about using filters at the star party, some of is about using filters for the long term.  Sorry for the confusion.

Edit: Although the last time I invited people to come take a look at the scope, I did hook up my camera.  But it wasn't a star party.  I was out there with another photographer shooting the transit of Mercury and posted on the neighborhood FB page to invite anyone who wanted to come take a look.  Several people came out and I just pulled the Barlow out and popped in an eye piece, set the focus and then let them see the Sun and Mercury, explaining what to look for.

[Pig]

ok