Filters for astrophotography

[rcheshire]

I hope to be the owner of a TMB80SS (price came down several hundred dollars on Astronomics) very soon and want to buy a 2" filter for use in moderate light pollution - nebula photography - this article (http://www.knoxvilleobservers.org/dsonline/tips/lprfilters.html) was very helpful, but what is the experience of others, should I go Broadband or Narrowband - Orion Ultrablock, Lumicon UHC or an O-III?

I understand that Thousand Oaks have a sharper filter gradient. Is that really a significant advantage - should I ask this question in the advanced astrophotography section.

Is there any real advantage to the Baader Fringe Killer - does it really make that much difference to inexpensive achromats, as they claim here (http://www.myastroshop.com.au/products/docs/fringe-kill.pdf).

So many claims?

[dugnsuz]

I use a broadband Hutech LPS2 light pollution filter. Works very well. Although I'm imaging from reasonably dark skies, there is a limit to exposure time dictated by skyglow and the small amount of light pollution from town lights. The Hutech filter allows me to easily double my exposure times and some! I routinely take 10min RGB subs but have pushed it to 15mins on occasion.
http://www.sciencecenter.net/hutech/idas/lps.htm

For narrowband stuff I use more specific filters.
Astronomik EOS clip-in filters - 12nm Ha and 12nm OIII filters.
I'm pretty happy with these too considering I'm using them on a DSLR.
Here's the Tarantula Nebula region I imaged with these filters...
Ha version...
http://s327.photobucket.com/albums/k461/doug-robertson/?action=view&current=25-1.jpg
OIII version...
http://s327.photobucket.com/albums/k461/doug-robertson/?action=view&current=26.jpg

Product info...
http://www.astronomik.com/en/eos_clip-filters.html

But, obviously 2" filters are available for both of these filters.

Hope some of my waffle helps!!
Doug

[Insane Climber]

hello , a fring killer is only for uncorrected refractors. be sure what your buying filters cost $$$$$$

[rcheshire]

Thanks Doug. The Astronomiks and Hutech sites are just what I'm looking for. Those clip-in filters are brilliant. I'll take my time looking over the options. I see the point with different filters - brilliant shots - a really nice library. What scope are you using?

Insane Climber - point taken - I was over filters at that stage, befuddled by the variety.

I'm hoping the TMB will perform as expected, so filter selection should just be a matter of how it suits viewing conditions and application.

For wide field a broadband filter will do, but if I want to photograph nebula with a degree of light pollution I will need a narrow band - that's pretty much how I understand it.

[dugnsuz]

Thanks most of the images on my photobucket page (just a few exceptions) are done with a Canon 70-200mm f4L lens and a 300mm f4L IS lens.
Doug

ps...The clip in filters work for me as I've no other place to put a filter in the imaging train due to the fact that I'm using lenses. Just had a look at the Bintel site - the clip ins are a fair bit cheaper than the equivalent 2" versions too!!

[astrospotter]

What great pinpoint stars in those 2 shots of Tarantula Neb. Great shots!
Thanks for the jpeg examples in O3 and Ha as they offer a real concrete example of what the two filters can do to complement each other.

Sadly I will not see Tarantula Nebula again for a very long time unless I start to rent time at the deep south astrophotography sites but that is expensive. I did spend a lot of time soaking in that and gobs of other LMC objects visually last month. Very kewl skies down there.

I wonder if anyone has tried 3-filters where the third is Si2 (guess I will read the full thread next). To me the lines for Si and Ha are so close that I question if a colorspace mix using these three (along with O3) can really do justice to the colorspace.

Ordered the Astronomik O3 and Ha only a few weeks ago but too late
for a proper Orion imaging run. I plan on Veil and North American neb
with these filters in a few months. Am at +36 dec up north here.

[dugnsuz]

Thanks for the kind words re my images.
There is an Astronomik 12nm SII EOS clip-in filter I would like to try eventually, but I've read that it's a bit of a lost cause on a DSLR for the reasons you stated - still I like to try these things out for myself (I was also advised not to try Ha or OIII filters with a DSLR, and that didn't turn out so bad!!;)).
I've tried combining the Ha and OIII images to form a Synthetic RGB.
Ha=Red channel, OIII Green=Green Channel and OIII Blue=Blue Channel. I like the method, it produces quite visually striking results on some objects. Here's the Synthetic RGB of the Tarantula region using the 2 Ha/OIII images...
http://s327.photobucket.com/albums/k461/doug-robertson/?action=view&current=27.jpg

Cheers
Doug:thumbsup:

[rcheshire]

Doug. I'm really amazed by the quality of your photography using camera lenses. I'm truly inspired, I didn't think that possible. Definitely need a good tracking system and the right filters - but is it worth it with cheap lenses?

I have an old Tamron 70 - 210 telephoto with a T-ring adapter and a standard 55 - 250mm canon telephoto. It seems to me that unless I try these lenses with appropriate filters I wont really know whether they are worth persisting with - the clip-in is really the only solution and they can be used in other configurations different lens and telescopes.

[dugnsuz]

My camera is a modded Canon 40D on a HEQ5 Pro mount - so nothing out the reach of the amateur. Imaging through cheap lenses is ultimately frustrating. A decent L lens like the 70-200mm f4L zoom I use can be picked up for around $785 new and approx $500-$600 2nd hand.

I tried the kit 17-85mm Canon lens that came with the 40D and it was no match for the L lenses I have now.
Photozone review gives your Canon 55-250mm lens quite a decent write up...
http://www.photozone.de/canon-eos/194-canon-ef-s-55-250mm-f4-56-is-test-report--review
...So it might be worth trying out some widefield work with that lens.
Not too sure about the Tamron:shrug:
BUT (and it's a big but) - you can't use clip in filters with the EF-S range of Canon lenses!!!! The back of the lens goes too far into the body of the DSLR where the clip in filter sits.

Frustrating hobby ain't it!!??:P

But, you've got that beautiful TMB 80 on the way so I wouldn't be worrying too much!!!!
All the best
Doug:thumbsup:

[joseph]

Agree, Hutech LPS2 light pollution filter is the most common and useful filter. I think you will not get any wrong to use it.

[rcheshire]

Thanks All! Yes it is frustrating when starting out, but I think I'm on the right track now.

[pin3appl3]

Doug those photos are awesome. Im getting into astrophotography and have a canon 50D and a skywatcher ED80 pro. I enjoy terrestrial photography as well so I dont think (yet anyways :P) ill get a CCD so filters seem the way to go to bring out the colour. Ive been looking on the bintel website, which filter/s would you recommend starting out? Cheers mate

[dugnsuz]

Cheers, probably best to start with a decent light pollution filter - especially if you're imaging from suburban Brisbane. This will allow you to push your exposures past the point where they might normally be "fogged out" by the light pollution from your area. A 2" filter would sit in your imaging train nicely.
The Hutech LPS2 is thought of very highly - perhaps a bit more pricey than others, but well worth it.
http://www.sciencecenter.net/hutech/idas/lps.htm
Occasionally come up in the classifieds here.

From there you could expand into Ha filter imaging - for those high contrast B&W images you see posted. These can be blended in with your normal colour shots to bring out very nice detail in nebulae.

I own 3 filters - Hutech IDAS LPS2 light pollution filter, Astronomik 12nm Ha and OIII filters.

Cheers
Doug:thumbsup: