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What filters to get for my 10 Inch dob?

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#1 Cloudkicker

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Posted 21 September 2019 - 01:33 AM

 I have some simple color filters but I've been looking into the more specialized filters like the OIII.   

What filters should I get and in what order should I get them?  Any recommendations on brand?   The crappy part about my eyepiece collection is my 9mm on up are 2"  and my smaller eyepieces are 1.25".    Probably middle of the pack in terms of quality would be where i'm comfortable spending.



#2 havasman

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Posted 21 September 2019 - 02:05 AM

Welcome to the forums!

 

2" filters should fit the threads on the objective end of your 2-1.25" adapter or coma corrector. So get 2" if you can swing it as you'll likely have 2" widefield eyepieces some day and narrowband nebula filters work great on lots of wide objects.

 

My faves = Lumicon UHC and Lumicon Gen 3 O-III but Televue and Astronomik are equivalent by all accounts.

 

Some really like the DGM NPB and there is a case for it. I have one in my kit and use it, but rarely as its distinguishing passband includes a frequency that yields bright red stars I do not fancy.

 

I bought Thousand Oak filters some years ago as they were cheaper. Not dirt cheap, but less $. They work. The others are better. I still use a TO H-Beta.


Edited by havasman, 21 September 2019 - 02:06 AM.


#3 sg6

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Posted 21 September 2019 - 02:22 AM

OIII is likely the best single filter, followed by a UHC - where UHC is OIII and Hb pass. Then comes UHC where the UHC is OIII and Hb and Ha pass.

 

Ha is a bit questionable as the wavelength is said to fall outside the night vision area so the scope receives it, it gets to the eye but remains as grey not a red. Suppose grey is OK, but maybe do not expect red.

 

My first would be the UHC that is OIII and Hb only.

Whose I leave as your decision based mainly on cost.

 

If you add these filters then the targets have to correspond to the filtering. Pointing (scope + OIII) filter at a Ha object will result in nothing.



#4 DLuders

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Posted 21 September 2019 - 03:06 AM

Welcome to Cloudy Nights!  smile.gif   Recommend reading this "Useful Filters For Viewing Deep-Sky Objects" article --  https://www.prairiea...ep-sky-objects/



#5 Spartinix

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Posted 21 September 2019 - 12:35 PM

UHC first I'd say. I was amazed by the difference at first use.
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#6 Starman1

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Posted 21 September 2019 - 12:40 PM

 I have some simple color filters but I've been looking into the more specialized filters like the OIII.   

What filters should I get and in what order should I get them?  Any recommendations on brand?   The crappy part about my eyepiece collection is my 9mm on up are 2"  and my smaller eyepieces are 1.25".    Probably middle of the pack in terms of quality would be where i'm comfortable spending.

Recommendations:

1) Buy a filter for your lowest power eyepiece, whatever size that is, because that is the eyepiece you'll use most with the filters.  Magnifications above 10-12x/inch of aperture aren't 

particularly valuable for most nebula filters.  Keep exit pupils at 2.5mm or larger, preferably.

2) Start with a narrowband (UHC-type) that transmits H-ß, and the 2 O-III lines.  It's sort of a "universal" nebula filter.

3) Add a good O-III filter to the mix for maximum contrast on certain nebula, like planetaries, Wolf-Rayet excitation nebulae, supernova remnants.  A UHC-type works on these as well, with a tad less contrast.

4) The "A" tier brands, currently, are Lumicon, Astronomik, and TeleVue if bought new.  If bought used, no Astronomik filters before 2016, no TeleVue before 2018, and Lumicons from 2005-2012 and 2018+.

5) The "B" tier brands, and occasionally one of these will be wonderful, currently, are Orion, DGM.  They're a little less expensive.

6) The "C" tier brands tend to not be bad filters, merely have too wide a bandwidth for maximum contrast.  They can be useful at a bit higher magnification, or in smaller scopes where the narrower filters result in too dark a field, but, and this is important to note, when you are using a nebula filter, you are enhancing the view of the nebula, not the stars, so maximum contrast is usually preferable to the wider bandwidth.  These are usually the lowest priced filters.

7) After a fair amount of experience with the above types of filters, if you have 10" of aperture or more, I also recommend an H-ß filter.  These are useful on the large faint hydrogen nebulae, like the nebula behind the Horsehead. I said 10" because I think many if not most of these nebulae are quite faint, and an H-ß filter has a very narrow bandwidth, making the field quite dark.  You need some light grasp or a very large exit pupil to use this filter well.

8) the bandwidths to look for are:

UHC type(narrowband)--22-27nm

O-III visual--11 to 15nm (must get BOTH O-III lines)

9) Here is a buyer's guide to peruse: https://www.cloudyni...s-buyers-guide/


Edited by Starman1, 21 September 2019 - 03:07 PM.

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#7 aatdalton

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Posted 21 September 2019 - 01:46 PM

Welcome to Cloudy Nights!  smile.gif   Recommend reading this "Useful Filters For Viewing Deep-Sky Objects" article --  https://www.prairiea...ep-sky-objects/

Additionally, the Prairie Astronomy Club has a very extensive list of how different filters perform on different objects. Sort of gives you a summary list of how many nebulae your filter will be useful on. (hint, UHC and Oiii very useful). 

 

https://www.prairiea...common-nebulae/


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#8 Jon Isaacs

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Posted 21 September 2019 - 02:08 PM

7) After a fair amount of experience with the above types of filters, if you have 10" of aperture or more, I also recommend an H-ß filter.  These are useful on the large faint hydrogen nebulae, like the nebula behind the Horsehead.

I said 10" because I think many if not most of these nebulae are quite faint, and an H-ß filter has a very narrow bandwidth, making the field quite dark.  You need some light grasp or a very large exit pupil to use this filter well.

 

Some large nebulae like the California and Barnard's loop are best seen with small, fast telescopes and an H-Beta filter using large exit pupils. I find an H-Beta filter useful in any scope but in general, of the three it's least used.

 

I mostly use the H-Beta filter as a tool to gauge just how much H-beta is present in a particular nebula.  I then use that information to choose between the UHC and the O-III.  The Veil has very little H-Beta so the O-III is the better choice.  The North American-Pelican complex shows quite a bit in H-beta so that means the UHC will be the more effective filter under most circumstances.  

 

As others have said, buy 2 inch filters because they will work with both 2 inch eyepieces and 1.25 inch eyepieces are filters are most effective with long focal length eyepieces.  I first purchased 1.25 inch filters to try to save some money but I soon realized it actually cost me money since they could not be used with the eyepieces that really took advantage of them.

 

Jon


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#9 Cloudkicker

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Posted 21 September 2019 - 03:05 PM

Thanks for the feedback guys, much appreciated.

@dluders   I had the link saved somewhere but couldn't find it, thanks!

 

@starman1  Thanks for the breakdown,  exactly the type of first hand info I was looking for



#10 scotsman328i

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Posted 21 September 2019 - 03:48 PM

In a short answer...ALL OF THEM! LOL.

You have enough aperture to bring out the best in planets and DSOs. All of the filters have different applications for each and every object. Think about a ND filter, UHC, OIII and SkyGlow in 2” formats, color filters I have done in 1.25” format as it’s typically those higher power eyepieces in 1.25” you’ll use to study the planets. My 2¢ worth, best of luck and clear skies!



#11 cimar

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Posted 21 September 2019 - 04:26 PM

Hi,

I use UHC, OIII and Hbeta. I especially like the Hbeta.

Astronomik offers nice filters in high quality.



#12 brentknight

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Posted 21 September 2019 - 07:09 PM

Hi,

I use UHC, OIII and Hbeta. I especially like the Hbeta.

Astronomik offers nice filters in high quality.

Just curious...  why do you especially like the H-beta?  That’s the only type I don’t have...  yet. 



#13 Mike W.

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Posted 21 September 2019 - 09:25 PM

Here's a very informative site for filter band pass graph's, sometimes this helps narrow the choice to drop cash on 2" disc.

 

Toggle the filter pass graphs on & off by clicking the box next to the filter in question.

 

https://searchlight....9d-153d7e7c0eb8

 

Knowing what happens in the glass really helps.

 

My choice new as recommended by others for a first filter, Farpoin/Lumicon UHC  2018

 

And Don, I don't think I've ever read a better put together post on filters for DSO's. waytogo.gif

 

For planetary high mag filters, if you have any funds left over, Baader Contrast Booster.

Most of your high mag eyepieces are going to be 1.25"

 

BTW, if any of you have Thousand Oaks filters you want a spectro scan done on, LunarFox is looking for more of them to add to his site.

It's Easy and it's free,except a few bucks shipping you pay each way, 

The more we participate in getting filters scanned, the greater our data base will be.


Edited by Mike W., 21 September 2019 - 09:28 PM.



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