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Baader Oiii halo suggestions


MattJenko

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I have taken a couple of images now using my Baader 1.25" Oiii filter and it possesses a mightily impressive ability to create big, bright halos around the bigger stars that my other filters do not. An example is below.

Is this something that can be addressed or mitigated in any way? I have scoured this forum and the wider interweb for thoughts and the solution actioned by others seems to be a depressing one of a purchase of an Astrodon or Astronomik filter. Are these particular Baader filters just cursed, blobby glass that will force me into a processing netherworld? Everything else Baader I have owned or seen is of great quality, seems a real shame if this is the errant 500.7nm sheep of the family, and I would like to see if I can tame it before giving up on it or going mad trying to process big bright halos out of final stacks.

Thanks as always - Matt

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Matt, I have the Baader 1.25" OIII 8.5 nm filter which I use with my Hyperstar and it doesn't produce halo's except on very bright stars.  The two brightest stars in your image are HD 215907  and HD 21558 mag 6.3 and 6.4 the brightest star in my attached image is BSC 19 Aur which is mag 5.0, the image is 300 sec at F/1.9 with the OIII filter.  It looks as if you have a defective filter, I'd return it if I were you.

Mike

post-6382-0-68135400-1427898717.jpg

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Hmm, here's an example using my Baader OIII (1200s sub):

post-23751-0-20460000-1427905612_thumb.j

Not as pronounced as MattJenko's example, but also nothing like Mike Hawtin's example. Should I be looking for replacement as well?

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I feel your pain and have been let down by BOTH Astronomik and Baader in the past as both company's filters cause halos in my imaging - I feel particularly bitter about this as I was assured that the Baaders would resolve the halo issues and frankly, they haven't! In fairness to both Astronomik and Baader, the halos I get are nowhere near as bad as yours but they are NOT halo-free by any stretch of the imagination. I have also heard that Astrodons are halo-free but I'm not prepared to splash the cash to find out for myself as twice bitten etc. ..... 

Halos are also somewhat dependent on focal length - the shorter the focal length, the greater the chance of halos which is one reason for user's mileage to vary.

Also bear in mind that halos can also be caused by interactions with other optical elements in the light path and the more glass you have the greater the propensity for halos - something that I really need to thoroughly check out for myself but I JUST WANT TO GET OUT AND IMAGE, NOT FAULT-FIND ALL THE TIME - yes I am shouting ...........

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I have given FLO a headsup, but I am going to try a few things out first before giving up on it or accepting the fact that I will be getting lots of processing practice in when doing NB! Clouds need to clear admittedly, and yes, I would like to just get on imaging too, but I have some ideas.

I have done a temporary scope swap with a fellow SGLer up the road from me (thanks Rob :) ), and he has taken my 250px and I have borrowed his RC6 for a few months. It is to try it out on all the galaxies that are swinging across the skies in Spring, but I will try out the focal length theory you mention Steve and point the CCD with the Oiii at some bright stars. I was planning on native FL of the RC, so a hefty uptick to 1370 from my reduced ED80's 510. I will also do the usual, like move to a different filter wheel position, vary the filter-> chip distance, and ensure there is no filter tilt etc etc (or even try introducing some tilt) and possibly try the ED80 without the flattener. If all this still results in my monster halos, then fine, I may throw in the towel, but on the bright side, I have learnt a fair bit about how to blend images.

I will also see what FLO say, if anyone else has had problems and if there is something I can do. Thanks for the advice, and the honest assessment of my stars.

Matt

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Martin from FLO has very kindly offered to send me another Baader Oiii filter for comparison to check to see if the filter I have is defective, or if it is the combination of that particular filter in my setup.

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I found halos on my Baader [OIII] filter, but in my case I chose the nuclear option in the form of a 3 nm Astrodon. Actually I got it as part of a full set of 3 nm Astrodons  :eek:

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My 1.25" Baader Oiii halos as yours has done but my 2" is halo free so is my Astronomik Oiii. There is no guarantee that Astrodon  would not halo either as discussed on CN forum. You could try removing the stars from the image by either Noel's actions or using the dust and scratches filter on a separate layer and pasting stars from an Ha or Lum or even RGB and OSC image on to it. As NB is false colour the colour appearance of the stars is irrelevant. On a few occasions that I have done a Bicolour I decided to transfer the stars from an OSC image on to the Bicolour. I know you are using Pixinsight and using pixel math and a keen star mask this is an easy task.

A.G

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Hi AG, thanks for the info. I took Olly's advice when I imaged this target and I did a quick RGB set on the stars, so I had something to do exactly what you suggested and merged the stars in over this using PixelMath. It worked out ok and I was extremely happy with the results, but it will be a much more serious problem if the stars are over any Oiii nebulosity I may capture.

Interesting about the 2". I'll try a few things out soon, but it seems that I may be able to mitigate rather than completely solve. Ho hum. FLO are being really cool about it, so will see what pans out. I think I'll leave the full set of Astrodons solution well alone for a little while :)

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  • 2 weeks later...

Martin from FLO has very kindly offered to send me another Baader Oiii filter for comparison to check to see if the filter I have is defective, or if it is the combination of that particular filter in my setup.

I got the same effect with my Baader OIII filter matt, again on an ED80 with 0.85FR, I will follow this thread with interest

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I have managed to do some testing with both the original filter and a replacement, kindly sent by FLO. I have tried to get things in proportion, to stretch the same to show the effects.

This shows a couple of stars from a test image in the following configurations:

Row 1: Original Filter as a baseline

Row 2: Original Filter facing the inverted direction

Row 3: New Filter facing the inverted direction in different filter position

Row 4: New Filter facing the standard direction in different filter position, also in a 180 orientation

This covered a lot of possible causes and the results seem to be that the halos are simply there as part of the Oiii filter in my current setup which is : Skywatcher Reducer&Flattener - adpator - SXpress Filter wheel with 1.25 Oiii and 414ex with a few delrin spacers to ensure correct distance. These are all 10 min exposures, but by the time I had messed about, the target area was sinking into some LP in the left, but the conclusion I have come to is that while the replacement filter appears to be slightly better (which is a bit subjective), the particular setup I have just doesn't play nice with this filter in general.

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Got this O111 haloing ever since I've had the Baader flter set, quite a few years now, it's been discussed at one time or another on several forums. It's worse on 100mm refractor than 10" SCT using everything else the same.

Just have to take a separate RGB for the stars, no point faffing around trying to fix it I found.

Dave

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Yes, seems to be my conclusion as well. I had a fair bit of practice on my first proper NB image in managing them, will just have to get used to it. Will try a session without the reducer and see if that helps at some point, but I just want to gather some data now :)

Thanks for all the feedback and special thanks to Martin at FLO for sending me another filter to try, no questions asked and no pressure to resolve. Sorry I haven't 'fixed' it!

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  • 6 months later...

A bit of a ghoulish resurrection, but I just noticed this on FLO's site:

http://www.firstlightoptics.com/blog/product-recall-baader-iii-85nm-ccd-narrowband-filter-2458453.html

A product recall for the Oiii filter. I have contacted them and will see what happens. Am quite hopeful this could get resolved, although funnily enough, it has improved my processing skills immensely over the last few months, so has had a silver lining anyway!!

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A bit of a ghoulish resurrection, but I just noticed this on FLO's site:

http://www.firstlightoptics.com/blog/product-recall-baader-iii-85nm-ccd-narrowband-filter-2458453.html

A product recall for the Oiii filter. I have contacted them and will see what happens. Am quite hopeful this could get resolved, although funnily enough, it has improved my processing skills immensely over the last few months, so has had a silver lining anyway!!

Saw this yesterday too. Checked mine and it's a 2458395 so it's ok......but also means I don't have an excuse lol

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(I must have missed this first time around....) There is of course the other thread regarding Baader OIII filters, but regardless, 2-3 years ago, I was introduced to a method using a quick mask for dealing with them.   It can be a bit "touchy-feely" with the settings (and it may not satisfy a pixel-peaker) but if viewing at screen, or A4, size it can do a pretty good job sometimes...

QUICK MASK - Removing Star Reflections DENNIS.docx

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Just a quick update.

Baader recalled the defective OIII filters of 2014 and 2015.

My replacement (second one) works now perfecly. No halos. They promised to verify 100% of their stock, so none defective should be shipped anymore.

But: I have the same problem with SII and the normal Blue filter. Lets see what they say about that :)

Kind regards, Graem

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