DEEP SKY FILTERS

[bomberbaz]

I am considering one of these in a bid to improve elements of my back garden (light poluted) viewing but before I start thinking of shelling out a fair chunk of money, I really need to know if anyone has any experience with these and if they are worth the spend.

I am looking at either the Lumicon Deep Sky filter  http://www.rothervalleyoptics.co.uk/lumicon-deep-sky-filters.html which seems to have a good broad spectrum of light whilst claiming to kill other extraneous light  http://www.astrosurf.com/buil/filters/curves.htm#Lumicon Deep Sky

Or the TS Optics CLS filter which claims to be a Deep Sky filter but to me appears to be closer to a UHC-S of the Baader type http://www.teleskop-express.de/shop/product_info.php/language/en/info/p4687_TS-1-25--CLS-broad-band-nebula-filter---visual-and-photography.html (it is available in 2")

I used to do a lot of fishing and became aware the tackle manufacturers were catching me with buying new stuff all the time rather than me catching fish. SO before I get caught spending out in a similar fashion here, does anyone use one of these visually for low light reflection nebula or other viewing and what is thier experience.

Steve

[swamp thing]

Buy a tank of gas.

Dark skies first steve.

Yes I know it's inconvenient isn't it hauling that scope out to dark skies, but the truth of it is. The only way your going to see faint nebulae and galaxies is from a dark site. There are no shortcuts I'm afraid.

Nebula filters can help but even they work best from dark skies.

Ps

Reflection nebulae are not helped at all by filters unless they are reflecting emission line stars.

[NGC 1502]

If you are talking about visual observing, then for me the UHC filter is the best.   But it's not for objects like galaxies & clusters, as mentioned get out of town is the best advice.

However, for objects like supernova remnants, planetary nebula etc, the UHC works a treat.   From my light polluted back yard, the Veil nebula is no problem using a UHC with my Dob, and from a dark site with my TV 70mm refractor.    Some like the OIII best, I have both, and find the UHC the most useful most often.

The Skywatcher UHC works well, and the considerably more expensive Lumicon UHC even better.

Regards, Ed.

[ronin]

The Lumicon one will make it blue.

It passes 4500 to 5400 then cuts out from there to 6300 and so allows the Ha through just above that.

In effect from around green to red get removed.

The TS CLS one appears to block very similar.

The IDAS P2 looks a little better option as it tries to selectively block the LP wavelengths, well the commonish ones and what it passes at the red/IR end is a bit more then the IDAS P1.

If you look at the Orion Skyglow filter that appears to have a similar characteristic as the IDAS P1 and my be a little less in cost.

However remember they all remove something, so the balance is altered,

[RikM]

The Lumicon one will make it blue.

It passes 4500 to 5400 then cuts out from there to 6300 and so allows the Ha through just above that.

In effect from around green to red get removed.

The TS CLS one appears to block very similar.

The IDAS P2 looks a little better option as it tries to selectively block the LP wavelengths, well the commonish ones and what it passes at the red/IR end is a bit more then the IDAS P1.

If you look at the Orion Skyglow filter that appears to have a similar characteristic as the IDAS P1 and my be a little less in cost.

However remember they all remove something, so the balance is altered,

Quite right for imaging use, for visual observing colour balance isn't an issue.

I haven't noticed any great enhancement to the views from broad-band 'light-pollution' filters. I use Astronomic UHC and OIII filters from a moderately light polluted back garden and find them very useful indeed. I prefer the UHC in general but the OIII is a better choice for certain objects. As Swampthing says above though, dark skies make all the difference.

[John]

......I haven't noticed any great enhancement to the views from broad-band 'light-pollution' filters. I use Astronomic UHC and OIII filters from a moderately light polluted back garden and find them very useful indeed. I prefer the UHC in general but the OIII is a better choice for certain objects. As Swampthing says above though, dark skies make all the difference.

Thats just my experience too. The Astronomik O-III is my primary nebula filter and is very effective, within the limits of my skies, on certain objects. In the case of the Veil I feel it's so good that it justfies the cost of the filter on it's own

[RikM]

... The Astronomik O-III is my primary nebula filter and is very effective, ...  In the case of the Veil I feel it's so good that it justfies the cost of the filter on it's own

I met up with a few guys down on Exmoor a few weeks ago and the view of the veil in a nice dark sky with a 10" Dob, a 28mm EP and an Astronomok OIII was simply stunning. So much detail it really was 'photographic'. The filter has paid for itself already with just that one trip to the country

The company wasn't bad either

[Owmuchonomy]

+1 for the OIII especially on the Veil but I'm under a mag 5 to 6 sky here so that helps too.

[bomberbaz]

Ok cheers guys. I was hoping for something different for using in my garden. I looked at the IDAS filter on the FLO site and thought the product description was excellent and was something that I dont have that could be of use but then at the bottom was the following warning note: Note, however, that light pollution suppression filters are not a perfect substitute for dark skies.

Nuff said I think

Steve

[nicks90]

i have 2 filters at present - the skywatcher UHC and the 2" baader neaodymium and both get regular use in my 12" dob.

the UHC is brilliant at dark sites and the back garden, really makes things that are almost drowned out by LP pop out. Worth every penny, so much so that I am considering spending some hard earned on a more expensive UHC to get teh absolute most I can out of it - its that effective!

The baader neodymium is a strange one. With having bad LP in my garden I find all my widefield viewing very grey/orange and washed out. This filter doesnt make anything that is invisible suddenyl become visible - a galaxies surface brightness is fixed and so is the LP that makes is disappear into the murk... BUT, those objects that do manage to push their way through the LP do become a lot more distinct and contrasty. The sky is a proper black and the stars become proper points. This means things like globulars and clusters absolutely spectacular again. No more dull stars on a grainy grey backdrop - but proper diamonds on inky black! At a dark site its not needed.

Being a 2", it also conveniently fits over the end of my camera kit lens (held fast with a blob of blutack) and i'm just waiting for the moon to do one so I can try some widefield in my back garden without having every 30sec sub come out like an orange skittle macro shot...

but as others have said, nothing beats a dark sky site.

[gooseholla]

I only find a LP filter useful if you have an annoying orangey glow in your scope and you want to cut it. I have this when looking east, all the street lights are lined up down our road that way. Then it makes things which were impossible to see due to an orange cover seeable.

[bomberbaz]

Cheers again for all the replies,  I have both UHC and OIII filter. However the thing with these  is they both are very narrowbanded and what I was really looking for was a filter with a more natural look. I have a LP filter and tbh, I am not overly impressed with the results it gives, perhaps I need to give it some more light and see if I can train better results out of it.

So I think trying more use of my NeoD filter and the LP filter over towards my LP's areas (thats worst from NNE to S) which is a large area, so I would really like to have something that works for me. I am considering spending some money on a HUTECH IDAS P2 but I will take this on approval i think if I cannot tease something better from the other 2.

I do realise that there is no magic solution and that dark skies rule but 90% of my viewing is from the garden hence me wanting to make the most of what I have. Hope this makes sense.

In the end if I draw a blank with all these options I may consider winning the lottery and moving to Northumberland

Steve

[nicks90]

Keep trying with the neodymium filter, once you've used it a few times you suddenly realise how much a different it makes.

Except for very narrow band filters,I thInk this is the only one that genuinely cuts out the sodium lines between 5600-6000a whilst leaving the rest pretty much untouched. AFAIK generic skyglow filters just dim everything, pretty much a neutral density filter across all wavelengths, but I could be wrong.

The baader neod is also superb at pulling out details when the moon is up, M13 was pretty much exactly the same a couple of nights ago under full moon as it was 2 weeks ago with no moon present in my lp infested back garden. Definitely worth £80 in my opinion, as it has vastly improved my back garden viewing pleasure. Just need to buy a threaded 2" focuser attachment thingymebob so I can leave it permanently in place in the focuser when using a combination of 2" and 1.25" EPs.

[Don Pensack]

Alas, the so-called broadband filters are really just weak nebula filters.  In an already quite dark sky, they turn up the contrast just a bit.

But, in light-polluted skies, they saturate, meaning the amount of light reflected in between the two side of the filter glass actually causes more light scatter than if they weren't used.

For objects with full spectra, like star clusters and galaxies, there is no substitute for darker skies.  The best filter is petrol--you put it in your car and drive to darker skies.

Failing that solution, try a bit higher power.  That will darken the background sky a bit and increase the size of the object.  It works well on star clusters.

[Dave In Vermont]

Proactive solutions are also quite useful for the problem of light-pollution. Such as flocking the tubes of a telescope to minimize light-scatter, as well as finding/fashioning longer dew-caps on refractors and SCT's. And also on reflectors. Though they would look funny, a reflector with a light-shroud/dew-cap can decrease those stray photons from light sources quite nicely.

Newer "astrograph" scopes of the reflector genre with F/4 and 3.9, etc. often are showing up in the market with the focuser further back from the end of the the tube. So rather than sell-off one's current Newtonian - make a shroud, or buy such if you find one, to accomplish the task.

I have red-fluorescent lights outside my home, and also in my living-room for when I'm going outside to use my equipment. This started a dialogue with a few of my neighbors. They wondered if I was running a brothel! We had a good laugh over that after I explained about astronomy and observing and preservation of night-vision. Now most, when the see my red-lights switch on, shut off their outdoor lights.

Clear & Dark Skies - inch-by-inch,

Dave