New 6nm Astronomik filters

[strongmanmike]

Just now received my new set of 36mm 6nm narrowband Astronomiks, these are a new line from Astronomik and the following tested specs are printed on each filter case:

Ha: 6nm @ 97.8% transmission, good to F3.1
OIII: 6nm @ 93.5% transmission, good to F3.4
SII: 6nm @ 97.4% transmission, good to F2.4

I'll whack'em in asap and see how they work under Moonlight :thumbsup:

Mike

[TR]

Mike,

That moonlight stuff is evil. Be carefull ;)...

Terry

[Geoff45]

Sigh! More money to be spent. Do they do a 50mm square?
Geoff

[photosinferno]

Geoff,
This is the link to the Astronomik 6nm Data page here (http://www.astronomik.com/en/fotografische-emissionslinienfilter/ubersicht-fotografische-emissionslinienfilter.html)

Looks like they do do 50mm unmounted.

John

[clive milne]

Yes

http://www.astronomik.com/en/fotografische-emissionslinienfilter/schmalbandfilter-h-alpha-ccd-6nm/astronomik-h-alpha-ccd-6nm-a-50x50mm-ungefasst.html

However, Baader do a similar filter for about 60% of the cost, and a 3.5nm filter (Ha only) for about $100 cheaper than the Astronomik 6nm.

http://www.baader-planetarium.de/sektion/s43d/s43d.htm#halfa-3-5nm

[strongmanmike]

After a quick look, part of the difference could be in the flux throughput's? I think Gerd Neumann at Astronomik has been working hard on getting a narrower band pass while maintaining a very high throughput in his new filter line? According to the Baader website the 7nm Baader Ha has a transmission of only about 87% compared to the nearly 98% of the narrower Astronomik 6nm. The Baader SII is at 8nm and only about 91% throughput compared to 97.4% for the Astronomik at 6nm, the Baader OIII is at 8.5nm and throughput of about 87% compared to the Astronomik at 6nm and 93.5% transmission. So overall around 10% more throughput from the Astronomiks with slightly narrower band pass too.

Not sure on the throughputs of the 3.5nm Baaders but I would assume they would be less again..?

Mike

[clive milne]

Being that they do not supply any information other than fwhm, I would assume so as well.

fwiw, There is also Omega optical who do a 0.7nm H-alpha in a 2" format. The transmission is around 80% and is realistically only useful in focal lengths above f/7

Here it is:
http://www.ebay.com.au/itm/Optical-FIlter-Astronomy-656-3-nm-Hydrogen-Alpha-2-inch-Eyepiece-Galaxy-Nebulea-/151221750576?pt=LH_DefaultDomain_0&hash=item233584cb30

[gregbradley]

I'm interested to see how they go. I quite like the 5nm Astrodons I have. Expensive though.

Greg.

[Paul Haese]

I had Astronomiks in both the old version and the new versions and found the reflections were a pain at fast f ratios. I wonder if these new ones will be reflection free. I am with Greg, Astrodons are great but expensive.

[Alchemy]

Also interested if they are reflection free, I have the old astronomik and have since sourced another brand. In this day and age I don't think it's acceptable to have reflections given none of them are cheap ( assuming $400 for a 50mm round filter) for what amounts to $203718 per square meter ... 200k $$$$$$

Will watch with interest your results.

[Slawomir]

I have 1.25 Astronomik 12nm filters (bought them about two years ago) and have not noticed any reflections at F5.6. Was happy with their performance until I moved very close to the city - luckily I 'discovered' Astrodon's 3nm filters - very expensive filters but do excellent job in blocking light pollution.

Mike- I am looking forward to reading your report regarding your new filters :)

[strongmanmike]

Yeah, I've used Astronomik filters for 12 years now... with a Meade 12" LX200GPS with Optec and Meade reducers, 80ED refractor raw, 200mm camera lens raw, Starfire APO with massive 4" field flattener and the AG12 with big 4 element Wynn corrector, with two different Starlightxpress cameras and two different FLI cameras and I have to say halos have never really been an issue :shrug:

For example, THIS (http://www.pbase.com/strongmanmike2002/image/131270068/original) was taken with the then new Astronomik halo free line 12nm Ha filter in my then new ProLine 16803, pretty good test I recon.

So in the end I think it really depends on your particular image train combo ie type of corrector, CCD window, chip cover slip, your coatings and filters..?

Mike

[Paul Haese]

As you say Mike it depends on the setup but some of your wider field images taken with the FLI have halos. Two examples are below. Those halo types are what made me change from Astronomiks to Astrodons. I don't get those at all now. I was getting them on two separate systems with different camera.

http://www.pbase.com/strongmanmike2002/image/158972601

http://www.pbase.com/strongmanmike2002/image/156946951

[strongmanmike]

Perhaps I was not quite clear enough here?

Yes, strangely I did see small halos around stars with the Astronomik narrowband filters when used with the PL16803 on the AG12 but not so much with the same filters and the same PL16803 on the Starfire and 4" FF that I linked to, same filter and camera but no halos. There was no halo problem when using the PL11002 and the Starfire either.

The SX H694 and AG12 system I currently use shows no problematic halos with either NB or BB Astronomiks.

So I guess what I meant was, across 12 years of using several series of Astronomik filters, with several very different optical-camera systems, halos were not generally an issue for me. If you look at all the several hundred images across my site you will not see glaring halos and where they do show I don't consider them a big problem.

Having looked at many 1000's of images over the years from all manner of imaging systems it is clear to me that any number of imaging systems can show halos (of all shapes and sizes) and the filters, regardless of brand, are not necessarily specifically causing the problem but rather it is a combination effect.

Of course how much halo and their size and intensity you are willing to accept can be a personal threshold too. That Orion nebula shot Paul linked to was a pretty popular and successful image for me actually so any halos present don't detract for everybody.

Mike

[Paul Haese]

I have no doubt that differing filters and setups contribute more or less to the problem with Astronomiks filters. The shots below of mine show what I experienced with the filters.

http://paulhaese.net/NGC6334QSI.html

http://paulhaese.net/IC2177SeagullNebula.html

On one image I have in narrow band the problem was significant. My only question is whether they have truly sorted this issue. I am not contesting whether an image is more or less successful here; just whether the halo problem they had is gone.

[strongmanmike]

And there-in lies the problem, what one particular optical system achieves with one particular set of filters another may not. There are halos in many images made with filters of other brands besides Astronomik.

[Eden]

Very keen to see your results with these, Mike. Gerd makes fantastic filters and I expect these are no exception.

I can't speak for narrowband filters but I have definitely experienced halo effect on brighter stars with some brands (Baader being the most noticeable), whereas the newer Astronomik filters are halo free.

[strongmanmike]

I am not changing anything in my system except the NB filters and they are changing from 12nm to 6nm, so yes it will be a valid test I guess as the current Astronomiks in use show all ok.

I'm just going to finish off my current project (hopefully next New Moon period :prey:) first and then I will put the new NB filters in and shoot something :thumbsup:

Mike

[Logieberra]

Hi Big Mike

Got my new Astronomik 6nm filter in the mail today from bintel.

Strangely, the filter glass is rattling around in the 1.25" housing.

Surely that can't be right?! Are yours fixed?

Struth... :(

[Slawomir]

All of my 12nm Astronomiks (3 narrowband filters) are rattling around.

[Logieberra]

Really! Is there a tech explanation why that might be?

My Astronomik LRGBs don't and my sold Astronomik 12nm didn't... how strange!

Big Mike, pls rattle that Ha 6nm :)

[Slawomir]

I don't think it matters for narrowband filters, but a rattling Lum filter could potentially cause some extra unwanted effects due to filter-glass being at a non-right angle (that would vary throughout the night with different telescope orientations) to incident rays and thus acting as a rectangular prism.

[gregbradley]

Do they need spacers? I had some 50mm square ones and they are only 1mm thick and most filters are 3mm thick. Without the spacers they rattled around in the filter wheel and got damaged.

Later Gerd sold me spacers for them once they were ready which they weren't when he sold them to me, plus they cost $100. I still haven't forgiven him for that unprofessionalism.

Greg.

[Logieberra]

Called the good people at Bintel. Sending me a replacement. Apparently they have a tool for this trick.

[Logieberra]

I don't think so Greg. Would be a right pain in the +×÷÷% if they did.

[Slawomir]

Good to know it can be rectified :)

[gregbradley]

Oh its probably the little ring that holds the filter in needs to be tightened if this is a mounted filter. They usually have 2 little slots at either side for a tool to grab on and tighten or you could carefully use a kitchen knife if you are game.

Greg.