Filters - advice please.

[Skipper Billy]

I currently use Baader 2" filters for LRGB and Ha Sii and Oiii.

The Blue filter gives horrible halos on bright stars and so does the Oiii

I realise that they are entry level filters and I have decided to bite the bullet and upgrade.

First question is - is there any advantage in upgrading them all or just the two that dont play nicely??

Second question - what brand to upgrade to in a 2" mounted filter??? (I really dont want to have to change my filter wheel).

I feel that the filters are letting the rest of my rig down and I dont mind investing in quality gear but wanted to consult the group before giving my flexible friend a work-out!

Attached image is heavily cropped and uses the Blue filter.

 

 

[Adreneline]

I upgraded my Baader NB filters to Astronomik 6nm and I am very pleased with them. I have since purchased Antlia 3nm NB filters for my second rig and they are amazing - to me.

I still use the Baader RGB filters and the Blue is the weak one. I am deliberating like you as to where to go from here so I shall be interested to see what advice you get.

Adrian

P.S. The reason I moved to Antlia is they are 2 mm thick - like the Baader - so were a good match in the same filter wheel (8EFW) which is really helpful when using the 8EFW with my Samyang 135 lens.

[Stuart1971]

I think as you still use a CCD camera this may limit your options a bit, as most of the newer filters are CMOS optimised, i use Optolong with my QHY268m camera both LRGB and HSO, and find them very good, and also a very good price..the LRGB are only about £250 for the 2” version I believe, but no idea how they would fare with a CCD camera…

‘Just my twopeneth

[DaveS]

I think the "CMOS optimised" is just marketing guff, I don't see any difference.

When I specc'd my ODK rig I went for Chroma LRGB and NB, but that was before they went from pricey to stupidly expensive.

I currently have a set of Baader photometric filters in my LRGB wheel, but they have some horrid halos.

[ollypenrice]

I certainly don't regard the Baader LRGB filters as entry level and have never used anything else in the last ten years. I have processed Astrodon LRGB and not found anything very significant in their favour. However, all the Baader and Astronomik OIII filters I've tried have been downright lousy, and I've owned or used a few of each.  The Astrodon 3nm Ha is fabulous but the Baader 7nm is still pretty good. So...

That blue image you posted is incomprehensible to me. It is, obviously, a disaster. Going off your kit signature I'll suppose it's with your Tak 106? I never saw anything like that with the Baader blue in either of the Tak FSQs in our dual FSQ106 rig and I host two other Tak  FSQ106 rigs and neither of those produces anything like that either. My Baby Q, before that, was also fine.

Something is wrong. Clutching at straws, are you sure that's the blue filter? It looks very like the result I got with Baader and Astronomik OIII. You couldn't have a misplaced filter or a confused filter wheel?  Is the filter the right way round? Or, at least, have you tried reversing it?

If you are 100% sure this really is the Baader blue, I would contact them. They are a serious company from whom I think you might expect a serious answer.

Olly

 

[Xilman]

What do you want to do? Pretty pictures or photometry? The answer may differ.

[Skipper Billy]

25 minutes ago, ollypenrice said:

Something is wrong. Clutching at straws, are you sure that's the blue filter? It looks very like the result I got with Baader and Astronomik OIII. You couldn't have a misplaced filter or a confused filter wheel?  Is the filter the right way round? Or, at least, have you tried reversing it?

Thanks for your input Olly.

It is definitely the blue filter and it can only go in the EFW3 one way as its a mounted filter. The Oiii gives very similar results. I dont think Baader will be interested - the narrowband and broadband sets are about 7 years old. This is the second blue and Oiii I have had - the first set were just as bad and FLO swapped them but these aren't much better. I assumed it was because they were relatively budget end filters. Maybe it was a dodgy batch !

[Skipper Billy]

25 minutes ago, Xilman said:

What do you want to do? Pretty pictures or photometry?

Pretty pictures! Sans halos !

[symmetal]

Here are my results using Astronomik filters on the FLT-98 from a few years ago. They are using the full frame ASI6200MM which the FLT-98 can't fully correct so the corners aren't too good. 🙂 These are the raw stack outputs given an STF in PI.

Astronomik Deep-Sky RGB 2" Blue filter. The Deep Sky filters have narrower passbands than others. No halos. 😊

Astronomik OIII 6nm 2" filter. Halos are present. though not too severe. 

I had to buy new Astronomik Fast FR narrowband filters for the RASA 11 and these show no halos on OIII. Whether this is a bonus of fast scopes which also show no dust bunnies even when there's visible dust specks on the filters I don't know.

Alan

[ollypenrice]

This is an old M45 with Baader filters and a head-banging exposure time, the idea being to go as deep as possible in search of dust. The stars are not tight but there are no hard edged halos.

Plenty of hot blue stars in this Tak image as well, but still no halos.

I know so many people who use the Baader filters, including three whose gear I'm currently hosting, that I'm absolutely certain this is not typical of Baader. I've had three sets of Baaders myself, as well.

So what's left? Bad batch, certainly.

Have you tried these filters with another camera? A quick search on the 16200 produced a quote from Takman on here: There is still that classic microlensing ‘cross/star’ effect on the bright stars (like the KAF8300, but not as prominent I feel...)  I realize that this isn't the effect you're seeing but I wonder if it might be arising from the camera. The chip glass, the microlenses, whatever. Is there anything else in the optical path? I also wonder if there might be an internal reflection visible only in the blue which is, of course, the easiest wavelength to scatter.

A separate post on halos with the 16200 might be useful.

Olly

PS

12 hours ago, Xilman said:

What do you want to do? Pretty pictures or photometry? The answer may differ.

Grrrr.

[Skipper Billy]

11 hours ago, symmetal said:

Here are my results using Astronomik filters on the FLT-98 from a few years ago. They are using the full frame ASI6200MM which the FLT-98 can't fully correct so the corners aren't too good. 🙂 These are the raw stack outputs given an STF in PI.

Thanks Alan

Thats very interesting and thank you for going to so much effort.

Its looking like I have a 'Friday afternoon' filter or two !

David (aka Skipper Billy)

[Skipper Billy]

1 hour ago, ollypenrice said:

So what's left? Bad batch, certainly.

Have you tried these filters with another camera? A quick search on the 16200 produced a quote from Takman on here: There is still that classic microlensing ‘cross/star’ effect on the bright stars (like the KAF8300, but not as prominent I feel...)  I realize that this isn't the effect you're seeing but I wonder if it might be arising from the camera. The chip glass, the microlenses, whatever. Is there anything else in the optical path? I also wonder if there might be an internal reflection visible only in the blue which is, of course, the easiest wavelength to scatter.

A separate post on halos with the 16200 might be useful.

I dont have another camera sadly but it doesnt do it with any of the other filters (except Oiii which is equally as bad). I have got used to the tiny cross/star effect which is down to the camera and I actually quite like it now! There is nothing else in the optical path. 

Its nearly time to break the rig down now for the summer and will probably contact Baader to see what they say. 

I really dont want to splash out on a new set of filters to find out that the problem still exists and is therefore the result of some other cause!

Thanks again for your help.

 

Pretty Pictures = just playing at it!!! 🙂 

 

 

Edited February 10 by Skipper Billy

[Laurin Dave]

Hi David.. a couple of thoughts...  I'd suggest you try the Blue filter with a different camera eg your lodestar and see if the halos are still present,    also have you used the calculator on  astronomy.tools  to check where they are coming from..   When I got my SX46 (also KAF16200)  it had horrible halos and microlensing like an ASI1600 ...   SX had put the sensor window in the  wrong way around, easily fixed and lucky for me they are only just down the road.   If it is the Blue filter I'd have thought that Baader could supply a replacement, even if you have to pay for it it'll be a lot cheaper than a new set.   As for the Oiii ... the Antlias get good reviews and from what I've seen good results.

Dave

[Skipper Billy]

6 minutes ago, Laurin Dave said:

Hi David.. a couple of thoughts...  I'd suggest you try the Blue filter with a different camera eg your lodestar and see if the halos are still present,    also have you used the calculator on  astronomy.tools  to check where they are coming from..   When I got my SX46 (also KAF16200)  it had horrible halos and microlensing like an ASI1600 ...   SX had put the sensor window in the  wrong way around, easily fixed and lucky for me they are only just down the road.   If it is the Blue filter I'd have thought that Baader could supply a replacement, even if you have to pay for it it'll be a lot cheaper than a new set.   As for the Oiii ... the Antlias get good reviews and from what I've seen good results.

Thanks Dave

The Atik16200 is bolted directly to the EFW3 so mounting the Lodestar would be a major faff. But maybe a full strip down and investigation may be required over the summer so that coule be an option. Or I could borrow the ZWO 178 out of my all sky camera.

That calculator looks interesting I will certainly have a play with that. I was unaware that such a thing existed!

Thanks again for your helpful suggestions.

David

[Skipper Billy]

I am on my way to the airport now - visiting our grandkids in Sweden - and will have limted comms for the next few days. So I apologise in advance if people are taking valuable time to respond and I am not replying/acknowledging in a timely fashion.

[tomato]

Just to throw a bit more evidence into the mix, here is my 1.25" Baader blue filter of similar vintage on a very bright star (Esprit150/ASI178). There is a halo but it is at least centralised on the star, yours appear to be offset?

[whipdry]

As my setup is much the same FSQ-106ED & Moravian G3 16200EC only difference I use the 0.73 QE reducer plus I have 50x50mm Baader that are 3mm thick. Here's a stretched master stack of 12x120sec. using the Blue filter...

 

Peter  

[Laurin Dave]

55 minutes ago, whipdry said:

As my setup is much the same FSQ-106ED & Moravian G3 16200EC only difference I use the 0.73 QE reducer plus I have 50x50mm Baader that are 3mm thick. Here's a stretched master stack of 12x120sec. using the Blue filter...

 

Peter  

Interesting,   the Astronomy Tools calculator puts these as emanating about 4mm from the sensor...  

[whipdry]

2 hours ago, Laurin Dave said:

Interesting,   the Astronomy Tools calculator puts these as emanating about 4mm from the sensor...  

Just found that information about the KEF-16200 is still available, a pdf file showing dimensions has top of the CCD cover window as 1.51mm from the sensor surface, seems that's not the the issue. On the Moravian Instruments web site they still have dimensions for the G3 cameras but can't find anything on the camera CCD chamber window, have emailed the question... I'd be surprised to find it's as close as 4mm, guess I could be wrong!

 

Peter 

[symmetal]

7 hours ago, tomato said:

There is a halo but it is at least centralised on the star, yours appear to be offset?

Near the centre of the image the halos are concentric, but the further the star is from the centre the halos become offset towards the image edge. This is evident on my OIII posting above. This indicates the cause of the halo is away from the sensor surface.

@Skipper Billy Hope you're enjoying your time in Sweden. 🙂 You're welcome to borrow my Astronomik Blue filter try, to see if it fixes your problem. I use the narrowband filters on the RASA but if I need RGB I put on the OSC camera as it's quicker, so the RGB filters are not really being used at the moment.

Alan

[Sp@ce_d]

Weren’t there a batch of baader OIII’s that were bad some years back? I seem to remember people getting them exchanged? Mine have varied depending on what scope/camera combination but more bloat than halo but there are some. Having been going through my archive recently to reprocess I’ve had brilliant results with BXT! 
 

I got a set of Antlia LRGB & 3nm NB after the ridiculous Astrodon & Chroma price increases and I’m very happy with them. Certainly the NB’s seem to perform as well as my smaller Astrodons & not seen any issues with LRGB so far. 
 

I don’t have any blue/OIII in 2” otherwise I’d offer you a loan of them too.

[Skipper Billy]

On 10/02/2024 at 17:39, symmetal said:

@Skipper Billy Hope you're enjoying your time in Sweden. 🙂 You're welcome to borrow my Astronomik Blue filter try, to see if it fixes your problem. I use the narrowband filters on the RASA but if I need RGB I put on the OSC camera as it's quicker, so the RGB filters are not really being used at the moment.

Thanks Alan

That is an extraordinarily kind offer - thank you.

I am going to live with it until the rig gets dismantled in about 4 weeks time and just check the basics again as its taken apart. and see if I can locate any obvious problems first and if the calculator shows that the filter is the issue then I will probably contact Baader first to see if they have anything to say - its a long shot but worth an email.

Sweden was great - as usual - its a long way to go to see the grandkids - especially via Frankfurt!!

All the best

David (aka Skipper Billy)

 

 

 

[Skipper Billy]

On 11/02/2024 at 13:57, Sp@ce_d said:

I got a set of Antlia LRGB & 3nm NB after the ridiculous Astrodon & Chroma price increases and I’m very happy with them. Certainly the NB’s seem to perform as well as my smaller Astrodons & not seen any issues with LRGB so far. 
 

I don’t have any blue/OIII in 2” otherwise I’d offer you a loan of them too.

Thanks very much.

Thats more good things being said about Antlia !

When I get to the bottom of this issue I will post the findings in case anyone else has a similar issue.

All the best.

David (aka Skipper Billy)

[Skipper Billy]

Just had a quick play with the calculator and it is telling me that the issue exists 2.5mm in front of the sensor! So NOT a filter issue??

The plot thickens!

[Skipper Billy]

More testing of various images in the claculator and spending more time on it than I could at work shows the problem lies between 2.5mm and 4mm in front of the sensor. Given that the distance from the sensor to the mounting threads is ~19mm then the issue must lie within the camera.