Astrodon vs... The rest.

[ollypenrice]

On 2/15/2018 at 13:10, Bukko said:

 

But as Pete said, is there strong, hard evidence to back up the narrower bands are that much better? There seems to be a lot of anecdotal evidence in posts on SGL extolling the virtues of the 3nm filters. I do not think anyone would just say that to qualify the £1000 per filter spend they made, so there must be something in it.

 

 

Gordon.

As someone who has both Baader 7 and Astrodon 3 the evidence is hard enough for me. I'm certainly not defending the ADs because I paid a lot for mine (2 inch). I've been perfectly open about expensive and bad equipment choices in the past, the most painful being the Takahashi EM200 mount I no longer own and which I sold honestly at a huge loss. The differences are:

1 You reach an acceptable SN ratio faster in the AD.

2 Stars are absolutely tiny.

3 Structural contrasts, which include the small scale contrasts we casually refer to as 'detail,' are far higher. (I shot the Jellyfish in the TEC140 at 1.8"PP and in one of the FSQ106s at 3.5"PP on the same night. There is more of what we'd call 'detail' in the Tak images. In comparable filters the TEC greatly out-resolves the Tak, however.

4 In gibbous moonlight I shot through both in the tandem Taks with the same cameras. The 7 nan data went in the bin, the 3 nan data went into the final image.

Can't comment on the Chromas though. Never tried them. The Astrodons are expensive, I know, but don't kid yourself into thinking they might not be better. They are.

Olly

[Bukko]

Thanks Oly,

So the (financial) pain sounds like it is worth the expense.

Just need to take my bravery pills and decide on the Astrodon or save a little on the Chroma version.

Like I said, I am out of the country for a while, but I am pretty sure going the extra for the narrower band filters is a good decision.

Many thanks again to all for contributing.

Gordon.

[iansmith]

On 20/02/2018 at 11:00, Bukko said:

But if you had a significant budget to spend and a full set was a serious option, would you do it ?

In my case, yes!

I didn't want a mix of Baader and others as I want all the filters to be parfocal, which the Astrodon's certainly are.

I think you also need to think about reflections from bright stars, haloes, etc. so it also depends on what you're imaging. And if (like me) you image from a light polluted town environment then 3nm filters really help. 

On 20/02/2018 at 11:00, Bukko said:

 could be argued no-one in their right mind would spend so much on a few little disks of coloured glass....

I'm not sure anyone in their right mind would do this hobby in the first place 

Cheers, Ian

[Bukko]

So.. To close out the discussion, I thought long and hard about what to do and now, several months later, I am finally back in the UK (I have spent most of the last 4 years on assignments, firstly in Saudi, then in Singapore...)

In the end, I went for the Chroma filters, NB at 3nm and then a matching set of LRGB's so I can load the SX Maxi wheel in one go and not have to mess around swapping carousels.

The exception was the Ha, which was not readiy available in 3nm so I spent the extra on the Astrodon.

I am now in the process or re-locating to the SW of France where I will build the systems up and hope for first light before Xmas.

Thanks once again to all who contributed and wish me luck !!

Gordon

[ollypenrice]

On 14/02/2018 at 15:37, pete_l said:

What I would like to see, but have never found, is some hard, graphical, evidence that shows beyond doubt that an Astrodon (or any other make / specification) of Hα or any other NB filter does actually produce a better image than other cheaper offerings.
I would also like to see evidence that a 3nm bandwidth does produce noticeably better images than (say) a 7nm filter.

Once the comparisons are there for everyone to see, we'll all be far better informed about where the cost / quality equation leaves us.

I've used both side by side in our dual rig. I don't have the results on file but this is what I found:

In gibbous moonlight the Baader 7 data went in the bin while the AD 3nm was pretty good.

Star sizes in the AD 3nm are simply minute. The downside is that it's a kliller trying to focus the AD. Getting a star capable of providing a FWHM is often not possible in the target frame so you have to go off to find one.

S/N, perhaps counter-intuitively, is a little better in the AD making exposures shorter if anything.

Structures and contrast are usually consdiderably higher in the AD. This is slightly target dependent, sometimes the difference being lesser or greater. But it's an absolute no-brainer in favour of the AD3.

In another comparison I was doing a big project on a Jellyfish widefield mosaic using the composite technique of adding high res 'areas of interest' data from the TE140 to widefield from the Tak106 pair. The TEC normally out resolves the Taks very easily with the same model of camera. (1.8"PP versus 3.5"PP.) However, the TEC had the Baader 7 while the Tak had the AD3. When blending in the high res data I found it simply didn't look high res. It was, if anything, softer than the data from the Tak, this down to the small stars and high contrasts of the AD3.

The price of the Astrodons is brutal but I'm agonizing over whether to buy the Ha and OIII in 1.25 for the TEC/Atik 460 setup. I've a shrinking feeling that says I probably will.

OIII:  I have never owned or used a decent OIII filter. I have a  2 inch Baader, a 1.25 Baader and an old model Astronimik which was a replacement for an even worse one. They are all poor, giving haloes on bright stars and not holding the stars down well at all. I can work with them when adding OIII to blue and green just by removing the stars but a NB imager would be scuppered. Tonight I'll be borrowing a new-generation Astronomik OIII from Peter Woods (thanks Peter) to try on our Cat's Eye project. It would be a relief to find it offered a satisfactory alternative to AD. I'll let you know.

So far as I can see there is little to choose in price between AD and Ccroma, no?

Olly

[wxsatuser]

I bought my Astrodon's second hand and never regretted it for one moment.

Nice that the 5nm Ha works rather well at f/2 so well pleased.

[Stub Mandrel]

On 15/02/2018 at 12:34, Bukko said:

So I guess another question:

In general, we all like the Baader filters, do a good job at a reasonable price.

When FLI advertised they will also stock Astronomik, this is what triggered me to think further on filters.

With Astronomik, there is a small improvement in NB width, but a relatively large increase in prices. The Ha will still include the NIII line. If we are struggling a little to justify the quality improvements from, say, Baader to Chroma/Astrodon, where does this leave Astronomik?

Am I missing some middle ground?

Gordon.

It depends if you feel that 'good is good enough' or that 'better is always better'.

[Adam J]

8 hours ago, ollypenrice said:

Tonight I'll be borrowing a new-generation Astronomik OIII from Peter Woods (thanks Peter) to try on our Cat's Eye project. It would be a relief to find it offered a satisfactory alternative to AD. I'll let you know.

Please do let us all know the answer to that question. I was lucky to get hold of a second hand 5nm OIII Astrodon and just got a new 5nm Ha to go with it. So although I don't need OIII it would be nice to know for SII in the future.  3nm are out of my price range, I mainly went Astrodon to do away with reflections which I cant stand.  

[ollypenrice]

1 hour ago, Adam J said:

 I mainly went Astrodon to do away with reflections which I cant stand.  

You and me both!

Olly

[steppenwolf]

I used a Baader 7nm Ha and 8.5nm OIII filter for several years to produce bi-colour images but wanted to go to the next step and I was fed up with the OIII halos so I ordered Astrodon 3nm versions of both about 18 months ago.

I was delighted with the OIII filter as it resolved my OIII halo issues but the Ha filter was not at all good and I was bitterly disappointed. I contacted Astrodon directly as my dealer was on holiday and they were incredulous that there should be a problem but I was able to prove without a doubt that the filter was indeed faulty - it was 3nm but the peak transmission was off centre! I very quickly received a replacement and I love both it and the OIII filter.

To check the replacement Astrodon Ha filter against my original Baader one, I ran a series of tests just as I had when I proved the fault in the original Astrodon by taking a series of images alternating between the Astrodon 3nm Ha and the Baader 7nm Ha. The following images show the results with sequential single subframe images:-

Baader 7nm Ha

Astrodon 3nm Ha

Hope that helps.

[RayD]

Goodness me, that is quite compelling evidence, Steve.  Thanks very much for that.

[Adam J]

28 minutes ago, steppenwolf said:

 I contacted Astrodon directly as my dealer was on holiday and they were incredulous that there should be a problem but I was able to prove without a doubt that the filter was indeed faulty - it was 3nm but the peak transmission was off centre! I very quickly received a replacement and I love both it and the OIII filter.

 

I take it that you could see the issue obviously from the poor ha sensitivity on the original 3nm filter?

I just got a 5nm Astrodon and it was plastered in dust. I think some people put this company on a bit of a pedestal but they are not perfect.

Adam

[steppenwolf]

35 minutes ago, Adam J said:

I take it that you could see the issue obviously from the poor ha sensitivity on the original 3nm filter?

I just got a 5nm Astrodon and it was plastered in dust. I think some people put this company on a bit of a pedestal but they are not perfect.

It was very obvious to me as there was less detail using the first one than on my Baader images. However, in fairness to Astrodon, they replaced my filter from the next batch and re-called the rest of my batch - this was a VERY rare event!

With regard to the dust, I don't recall whether mine were spotless or not but the fact that I am VERY fussy and that I don't recall any dust pretty much tells me that they were not plastered in dust BUT, the case they came in was naff in comparison with the Baader version and that combined with the adhesive filter label rather than an etched filter mount didn't add much to the joy of receiving such an expensive piece of optical gear! The quality of the results when actually using the filter, however, totally mitigate the lack of 'presentation'. At the end of the day, it is the performance that matters and Astrodon filters deliver in spades.

People place these filters on a pedestal because they are soooo good to use - simple as that! I have yet to find a 'perfect' company but optically, these filters come close.

[Adam J]

3 minutes ago, steppenwolf said:

It was very obvious to me as there was less detail using the first one than on my Baader images. However, in fairness to Astrodon, they replaced my filter from the next batch and re-called the rest of my batch - this was a VERY rare event!

With regard to the dust, I don't recall whether mine were spotless or not but the fact that I am VERY fussy and that I don't recall any dust pretty much tells me that they were not plastered in dust BUT, the case they came in was naff in comparison with the Baader version and that combined with the adhesive filter label rather than an etched filter mount didn't add much to the joy of receiving such an expensive piece of optical gear! The quality of the results when actually using the filter, however, totally mitigate the lack of 'presentation'. At the end of the day, it is the performance that matters and Astrodon filters deliver in spades.

People place these filters on a pedestal because they are soooo good to use - simple as that! I have yet to find a 'perfect' company but optically, these filters come close.

Well Astrodon have been sold to OSI, so things are changing. Lots of complaints of dust recently so its not just me. On the bright side they have started laser etching the logo and filter info onto the mount now as my new 5nm Ha and a friends (who had even more dust) both came with a etched logo.

[Jkulin]

Steve have you ever examined the Chroma filters or had any feedback, I know Sara has no complaints and if I am not mistaken they originally manufactured them for Astrodon.

[steppenwolf]

1 hour ago, Adam J said:

Lots of complaints of dust recently so its not just me.

There is no excuse for there being dust on your filter - this is shoddy but hopefully something that they are going to resolve and quickly. I hope it doesn't spoil your enjoyment of what is otherwise a very fine piece of glass.

1 hour ago, Jkulin said:

Steve have you ever examined the Chroma filters or had any feedback, I know Sara has no complaints and if I am not mistaken they originally manufactured them for Astrodon.

No, John, I haven't but they are most certainly on my radar as I know of several imagers (whose opinion I would trust) that are very happy with them. I can't confirm whether or not Chroma originally manufactured for Astrodon as I simply don't know!

[Demonperformer]

Baader are in the throes of bringing out a range of 3.5nm filters that look as if they are going to be very competitively priced. As to quality ... who can say? Here's the first one out of the gate. 1.25" coming and Oiii & Sii also on the way (last I heard they were due out around the end of the year).

[Whirlwind]

On 15/02/2018 at 14:48, RayD said:

Yes all agreed.  FLI does seem to attract a premium but I've not used them and generally see very little written about them, so not sure if this is quantifiable for AP.

 

If you are targeting narrow 3nm imaging then the FLI is better with regards the 16200 because the read noise is substantially lower than then competition.  Most companies values sit around 9 - 10 whereas the FLI sits at around 6e.  It might not sound a lot but gaining signal above the read noise is relative to the square of the read noise. Hence you have to observe longer on the others compared to the FLI.  However you are paying for that premium and it in no way means you can't get excellent photos with any of them.  You can partially offset this by getting a faster system for example (assuming the same focal length and hence larger aperture)

[alexbb]

2 hours ago, Demonperformer said:

Baader are in the throes of bringing out a range of 3.5nm filters that look as if they are going to be very competitively priced. As to quality ... who can say? Here's the first one out of the gate. 1.25" coming and Oiii & Sii also on the way (last I heard they were due out around the end of the year).

If you read that on Baader's site, the comments section, the Baader team replied they hoped to have them ready by the end the year 2017

[Demonperformer]

Oops!

[GavStar]

Just received a 5nm chroma 1.25 inch filter for my night vision monoculars. The filter looks very well made (as it should for the cost!) and the transmission graph is very impressive imo.

I didn’t go for the 3nm as I think it may starve the image intensifier of light too much. I hope I notice some contrast improvement on emission nebulae compared with my existing 6nm Astronomik Ha filter. 

 

[Demonperformer]

Hope it performs as you wish, Gav. It will be interesting to read your reports on how much improved contrast the extra 1nm gives you.

[Droogie 2001]

I have the Chroma Ha & O3 3nm. Purchased them from Bernard at Modern Astronomy.

https://www.modernastronomy.com/product-category/filters-wheels/chroma-filters/

Copied this from the Modern Astronmy website:

"Try the Astronomy filters professionals use at many major observatories, NASA and JPL – Chroma!
In business for 24 years and experienced in many scientific disciplines, Chroma has made filters for several US “famous name” companies, but now operates under its own banner in the Astronomy field."

Have been very pleased with them though I have never had Astrodon's to compare against.

I went for the Chromas as they offered the ability to placed them into an ASI 1600 filter wheel, whereas (apparently) you could not do this with the Astrodon's?
I think they are worth the money no halos and stars are easier to control.

 

[newbie alert]

On 01/10/2018 at 10:00, GavStar said:

Just received a 5nm chroma 1.25 inch filter for my night vision monoculars. The filter looks very well made (as it should for the cost!) and the transmission graph is very impressive imo.

I didn’t go for the 3nm as I think it may starve the image intensifier of light too much. I hope I notice some contrast improvement on emission nebulae compared with my existing 6nm Astronomik Ha filter. 

 

What was your 6nm astronomik like?.. halos on any bright stars?

[GavStar]

29 minutes ago, newbie alert said:

What was your 6nm astronomik like?.. halos on any bright stars?

I use Night Vision monoculars which create some halos on brighter stars anyway so I can’t say anything specific regarding the Astronomik filter for halo for imaging purposes.