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#1 groverro

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Posted 17 July 2018 - 11:21 PM

What sort of filters should I have in my case for a successful observing? I was hoping to start with something small and build a collection.

 

Please recommend!

 



#2 nicoledoula

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Posted 17 July 2018 - 11:34 PM

A UHC and an O-III  That much everyone agrees on. See Starman1's posts.


Edited by nicoledoula, 17 July 2018 - 11:35 PM.

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#3 havasman

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Posted 17 July 2018 - 11:48 PM

https://www.prairiea...ep-sky-objects/

 

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

 

David Knisely wrote these informative articles for his club. His posts are also very valuable. 

 

+1 for a UHC and an O-III.



#4 groverro

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Posted 18 July 2018 - 11:38 AM

Thank you!



#5 Starman1

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Posted 18 July 2018 - 05:43 PM

Actually, unless you live in a fairly light-polluted spot, or specialize in the viewing of planetary nebulae (where an O-III filter stands out),

I'd advise saving a few $ (if money is even an issue) and getting a really nice "UHC-TYPE" narrowband filter.

I don't know what size scope you own, but a UHC-Type is a sort of "universal" nebula filter.

It transmits the hydrogen emission AND the oxygen emission in nebulae while blocking other light, so the nebula (no matter what type) shines through, but against

a much darker background.

Some examples of the type (certainly not the only ones): TeleVue Bandmate II Nebustar, Lumicon UHC, Astronomik UHC, DGM NPB.

 

For use:

--keep magnifications low for best effect (say 10x/inch of aperture and lower)

--be dark adapted first, i.e. 30-45 minutes outside away from lights before you use the filter

--try to observe the nebula high in the sky, like when it culminates, or crosses the N-S meridian.  That way you look through less air.

 

The nebula filters work on emission nebulae.  For reflection nebulae, or dark nebula, low powers and NO filter will be best.  For all other objects--no filter.

And nebula filters work well in dark skies as well.  Viewing in dark skies is a profoundly better experience if you can get to one within a reasonable distance.

Sometimes, just getting out of town is all you need to do.

 

Since a UHC-type filter transmits the O-III spectral lines, the improvement made by using an O-III filter on a target suited for it is a small increase

in contrast over the slightly wider bandwidth of a UHC-Type filter.  That's why a UHC filter is a "universal" nebula filter.

 

Of course, if you can afford both, there's no harm in having both.


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#6 groverro

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Posted 19 July 2018 - 11:41 AM

Actually, unless you live in a fairly light-polluted spot, or specialize in the viewing of planetary nebulae (where an O-III filter stands out),

I'd advise saving a few $ (if money is even an issue) and getting a really nice "UHC-TYPE" narrowband filter.

I don't know what size scope you own, but a UHC-Type is a sort of "universal" nebula filter.

It transmits the hydrogen emission AND the oxygen emission in nebulae while blocking other light, so the nebula (no matter what type) shines through, but against

a much darker background.

Some examples of the type (certainly not the only ones): TeleVue Bandmate II Nebustar, Lumicon UHC, Astronomik UHC, DGM NPB.

 

For use:

--keep magnifications low for best effect (say 10x/inch of aperture and lower)

--be dark adapted first, i.e. 30-45 minutes outside away from lights before you use the filter

--try to observe the nebula high in the sky, like when it culminates, or crosses the N-S meridian.  That way you look through less air.

 

The nebula filters work on emission nebulae.  For reflection nebulae, or dark nebula, low powers and NO filter will be best.  For all other objects--no filter.

And nebula filters work well in dark skies as well.  Viewing in dark skies is a profoundly better experience if you can get to one within a reasonable distance.

Sometimes, just getting out of town is all you need to do.

 

Since a UHC-type filter transmits the O-III spectral lines, the improvement made by using an O-III filter on a target suited for it is a small increase

in contrast over the slightly wider bandwidth of a UHC-Type filter.  That's why a UHC filter is a "universal" nebula filter.

 

Of course, if you can afford both, there's no harm in having both.

Thank you! I have a 12" SkyWatcher and do observe in Light Polluted area. I will try seeing if my local store can let me borrow the UHC filter to test out before purchasing. Do you have any specific recommendations for planetary filters?



#7 Starman1

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Posted 19 July 2018 - 02:53 PM

Planets?

Well, most observers say no filter at all, but, taking the planets visible now:

Venus--a dark blue or purple filter reduces the brightness and sharpens the image.

Jupiter--consensus says a light to medium blue enhances the belts and bands the most.  Many like the Moon & Sky Glow filter of neodymium-doped glass.

Saturn--a light yellow filter enhances the rings sharpness, but the same blue filter as on Jupiter would be used for the bands on the planet.

Mars--due to the dust storm, pretty much nothing works right now, but I like the Baader Contrast Booster filter for general viewing of all features.

There are specific filters that enhance certain details:

--ice caps and limb clouds--light blue #82, blue #80A in larger apertures, or magenta #30

--dust storms--dark yellow #15 or orange #21

--dark maria--red/orange #23A or red #25 in large apertures or magenta #30

--light colored markings--yellow #12 or deep yellow #15

 

All that said, many people prefer to not use filters on planets because low light features are often suppressed by filters.

My best view of every one was without a filter--except Mars, where I see more details (when the dust storms are absent) with a Baader Contrast Booster filter.


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#8 chdr

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Posted 19 July 2018 - 06:00 PM

Planets?

Well, most observers say no filter at all, but, taking the planets visible now:

Venus--a dark blue or purple filter reduces the brightness and sharpens the image.

Jupiter--consensus says a light to medium blue enhances the belts and bands the most.  Many like the Moon & Sky Glow filter of neodymium-doped glass.

Saturn--a light yellow filter enhances the rings sharpness, but the same blue filter as on Jupiter would be used for the bands on the planet.

Mars--due to the dust storm, pretty much nothing works right now, but I like the Baader Contrast Booster filter for general viewing of all features.

There are specific filters that enhance certain details:

--ice caps and limb clouds--light blue #82, blue #80A in larger apertures, or magenta #30

--dust storms--dark yellow #15 or orange #21

--dark maria--red/orange #23A or red #25 in large apertures or magenta #30

--light colored markings--yellow #12 or deep yellow #15

 

All that said, many people prefer to not use filters on planets because low light features are often suppressed by filters.

My best view of every one was without a filter--except Mars, where I see more details (when the dust storms are absent) with a Baader Contrast Booster filter.

 

 

Actually, unless you live in a fairly light-polluted spot, or specialize in the viewing of planetary nebulae (where an O-III filter stands out),

I'd advise saving a few $ (if money is even an issue) and getting a really nice "UHC-TYPE" narrowband filter.

I don't know what size scope you own, but a UHC-Type is a sort of "universal" nebula filter.

It transmits the hydrogen emission AND the oxygen emission in nebulae while blocking other light, so the nebula (no matter what type) shines through, but against

a much darker background.

Some examples of the type (certainly not the only ones): TeleVue Bandmate II Nebustar, Lumicon UHC, Astronomik UHC, DGM NPB.

 

For use:

--keep magnifications low for best effect (say 10x/inch of aperture and lower)

--be dark adapted first, i.e. 30-45 minutes outside away from lights before you use the filter

--try to observe the nebula high in the sky, like when it culminates, or crosses the N-S meridian.  That way you look through less air.

 

The nebula filters work on emission nebulae.  For reflection nebulae, or dark nebula, low powers and NO filter will be best.  For all other objects--no filter.

And nebula filters work well in dark skies as well.  Viewing in dark skies is a profoundly better experience if you can get to one within a reasonable distance.

Sometimes, just getting out of town is all you need to do.

 

Since a UHC-type filter transmits the O-III spectral lines, the improvement made by using an O-III filter on a target suited for it is a small increase

in contrast over the slightly wider bandwidth of a UHC-Type filter.  That's why a UHC filter is a "universal" nebula filter.

 

Of course, if you can afford both, there's no harm in having both.

thanks starman1 / don  great explanation  and suggestions i will take your advice with the baader moon and skyglow been looking into this filter for a while now  i have the celestron UHC/LPR  filter and didn't see much improvement (lost detail )  is a 6" sct too small for this filter  (not enough light gathering potential in a 6" SCT ) ???? in a light polluted city the reason for the purchase 

cheers

chdr


Edited by chdr, 19 July 2018 - 06:01 PM.


#9 Starman1

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Posted 20 July 2018 - 01:09 AM

The Celestron UHC/LPR filter is a broadband filter with a fairly wide bandwidth (around 60 nm), so it is not like the nebula filters being discussed.

The UHC in its title is a misnomer (as is the UHC in the Baader UHC-S and Astronomik UHC-E and others with an extremely wide bandwidth).

Broadband filters have a fairly subtle effect because they remove so little of the light passing through them.

And, in a city where there are many sources of lights, light pollution can be at many wavelengths passed by the filter.

In addition, such filters may increase scattered light, making the glow of the background even brighter in the eyepiece.

The place for such filters, in my opinion, is under already quite dark skies to simply turn up the contrast a tiny bit, such as when the nebula is

already very bright (like M42) and doesn't need much help.

 

The problem wasn't the 6" size of the scope, but the expectation there was a filter that would allow you to see everything better in a light-polluted city.

There are filters that allow you to see emission nebulae better (like the narrowband and line filters like the UHC-types and O-III), but not much of anything else.

As my signature states--driving the scope to darker skies is the way to see more.  You said you didn't see much improvement.  That implies you saw some but the amount

of improvement was very small.  Such is the case with broadband filters.  LPR is a poor acronym.




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