Which filters?

[malcvtr]

Having just restarted the hobby after a 38-year break :shock: I'm assembling a new visual observing setup. I like to look at everything - DSO, planets, you name it! I've never had any filters and wonder what you blokes would recommendI buy next.

Cheers

Malc

[Whippy]

I think the two most popular filters would be a general light pollution filter like the Baader Neodymium, and a UHC filter to help bring out detail on many Nebulae. That's the two I have anyway.

Tony..

[ianporter13]

Malc,

first one I'd buy would be an OIII filter, with your CPC800, a focal reducer and a nice wide eyepiece the Veil Nebula would be nice in OIII.

as for planetary filters I've not used them so can't offer any advice there.

Ian

[John]

Hi Malc,

At the risk of contradicting the previous poster, for deep sky I would advise a UHC filter before an OIII - the OIII is effective but is rather "severe" wheras the UHC (in my case I use a Baader UHC-S) maintains enough throughput to see faintish background stars as well as increasing the contrast of nebulae, especially planetaries. That said, I also own and use a Baader OIII filter with my 8 inch dobsonian so they are both pretty useful

I have not used planetary filters so I can't comment on them.

John

[Andrew*]

I would say the most worthwhile filter is a light polution or (U)ltra (H)igh ©ontrast filter. There are loads of different ones available, but among the best are Astronomik's CLS filter, Baader's, Astronomik's or Lumicon's UHC filter and Baader's Neodymium filter.

There are also narrow band visual use filters including OIII and Hb, which isolate particular wavelengths of light that are common sources of light particularly from nebulae. Because these filters block much more light than more general purpose filters, they are recommended for large-aperture scopes.

All mentioned are available from the following sites:

http://www.iankingimaging.com/show_products.php?category=18&offset=10&offset=20&offset=30&offset=0

http://www.firstlightoptics.com/products.php?cat=11

http://www.telescopehouse.com/acatalog/Online_Catalogue_Light_Pollution_39.html

Interesting topic, actually - I'm going to start a LP/UHC-S poll now!

Andrew

[malcvtr]

Many thanks for the very helpful replies. Counting the "votes", it looks like the UHC is in first place, OIII second and neodymium third. Apologies for a dumb "newbie" question, but what does a focal reducer do Ian?

Thanks again,

Malc

[GazOC]

A UHC-S filter is likely to get more use than a O III filter IMHO. I'd get that if it was to be the first or only filter you buy followed by the OIII after that.

And for planetary filters:

http://theguidescope.com/2007/10/24/filters-for-planetary-observing/#more-18

[malcvtr]

Thanks Gaz. That's a great guide you've put together there! Very useful.

Malc

[MikeP]

A focal reducer does what it says on the tin - it reduces focal length. In effect, it is the opposite of a Barlow.

I'm sure you know that magnification = (focal lenth of OTA) / (focal length of eyepiece) and also that true field of view = eyepiece AFOV / magnification, by using a reducer, it reduces magnification and hence increases the TFOV.

Mike

[malcvtr]

Cheers Mike. Obvious really... :oops:

[malcvtr]

I've more or less decided to go for the Astronomik UHC filter, but wonder where to get it. Iankingimaging don't list it and Greenwitch want £81.99 for it, compared to Moonfish's £65. Anyone dealt with Moonfish.com before?

Thanks

Malc

[Andrew*]

Malc, look out for the results of this poll and decide once there's a clear result.

Also, make sure you're buying the correct UHC filter if you do go for the Astronomik one. I think there is a CCD one and a visual one... Teleskop Service might be a good bet for it. Their service is excellent and they'll be happy to answer any questions!

Andrew

[malcvtr]

Thanks Andrew - and thanks for the link to the poll. I shall watch with great interest!

[saturn5]

Here's a link about various filters and their uses.

http://sciastro.net/portia/advice/filters.htm

Hope it helps.

[malcvtr]

Thanks mate. Yet more helpful advice! I'm glad I joined this forum

[saturn5]

I have Lumicon UHC, light and dark shades of red/yellow/green and blue plus a Moon filter 25% which reduces the glare from a full moon(sunglasses for your scope ).

[Macavity]

For experimental(!) purposes re. COLOUR filters, I found the Antares (1.25" format) quite sufficient.

http://www.rothervalleyoptics.co.uk/categories.php?type=acc⊃=antare&sub_type=filters

The set of seven contains most... except perhaps "violet" - But I don't observe Venus that much.

[Alan53]

Here is a nice write up on filters,,, http://www.cloudynights.com/item.php?item_id=1520 .

Al

[bern]

Try "**************they have possibly the best line up of filters in the UK and know their stuff

bern

PS. There's only one version of the Astronomik UHC, a visual version which is used with an IR block for imaging.

[Ant]

Promoting yourself like this Bern is out of line.

Please do not do it again.

[malcvtr]

Here is a nice write up on filters,,, http://www.cloudynights.com/item.php?item_id=1520 .

Al

Wow! What a write up! That's what I call serious research :shock: