New Askar Colourmagic filters D1 & D2 (Ha/OIII and OIII/SII)

[Adam J]

23 hours ago, StuartT said:

Steve (I'm the person who emailed you about this), while the primary responsibility clearly lies with the manufacturer, I am rather disappointed in the seemingly relaxed attitude FLO seems to have about this. After all, as someone on Cloudy Nights pointed out (in a very similar discussion to this one) "If I paid for a 750mm scope, but got a 600mm scope instead, I'd be pretty angry about it no matter how good the images look." In general, I think FLO provide an excellent service and I have always been extremely happy with the considerable amount of gear I have bought with them. So I am inclined to agree with @Lee_P that FLO should consider bench testing the more expensive filters (as they do with scopes).

I have also written to Askar to ask them if they are prepared to test my filter. It is perfectly possible mine is as advertised (and I very much hope it is), but clearly some examples are not, so I think it's a reasonable enough question to ask.

When I started (not that long ago really) if you wanted filters you had some choices:

 

Baader - Good Budget 

IDAS / Astronomik- Mid Range

Chroma / Astrodon - High End

 

But now you also have: ZWO, OPTOLONG, ASKAR, ANTLIA

I would say that ANTLIA and ASKAR are trying to position themselves as mid - High end,  Optolong Budget / Mid range and ZWO Budget. 

But the reality is that very little has changed for me despite the new players on the market, if you want the best filters, with assurance that they will hit their specification or better then you should be going for Chroma / Astrodon.  I still cant imagine that I will be swapping out my 5nm Astrodons for a 3nm from any of the newer, companies for many reasons. If you want to take a chance and roll the dice then you might get a fine filter at a third the cost of Chroma or Astrodon, but you might also get something with (at the extreme) 50% peak on band transmission and 4nm as opposed to 3nm and never know which sample you got. 

Its also the reason I shudder at the thought of imaging at F2 because you see so much variation in the apparent signal collected in OIII mostly but sometimes also Ha using these high speed duel narrowband OSC setups that I can only conclude that the delta in signal between one image and another is caused by how well the filter is meeting its specifications. I have seen some people with long integrations at F2 and images that don't live up to what you could do with an F5 refactor.

 

Ignorance is Bliss....

 

Adam 

 

 

 

Edited February 15, 2023 by Adam J

[FLO]

On 14/02/2023 at 11:58, StuartT said:

Steve (I'm the person who emailed you about this), while the primary responsibility clearly lies with the manufacturer, I am rather disappointed in the seemingly relaxed attitude FLO seems to have about this. After all, as someone on Cloudy Nights pointed out (in a very similar discussion to this one) "If I paid for a 750mm scope, but got a 600mm scope instead, I'd be pretty angry about it no matter how good the images look." In general, I think FLO provide an excellent service and I have always been extremely happy with the considerable amount of gear I have bought with them. So I am inclined to agree with @Lee_P that FLO should consider bench testing the more expensive filters (as they do with scopes).

I have also written to Askar to ask them if they are prepared to test my filter. It is perfectly possible mine is as advertised (and I very much hope it is), but clearly some examples are not, so I think it's a reasonable enough question to ask.

Stuart is both emailing and posting, so to avoid confusion, I'll also post our latest response and position here. 

We like to help, but currently, we do not check the specification of the filters we sell (I am not aware of any retailer that does). We trust manufacturers to QC their filters. 

This is a popular filter, and Stuart is still the only customer to have expressed concern. He is happy with his filter's real-world results. His concern is based only on a negative report posted by someone on a US forum. 

We monitor all product returns. If we notice a problem requiring us to equip our workshop for onsite testing, then we will. I.e. we installed an optical-bench back when we noticed problems with some triplet telescopes. But, all indications (positive feedback and zero customer returns) suggest the filter performs well. Customers, including Stuart, are pleased with the results obtained using this filter.

We have already offered to accept Stuart's filter back for a full refund. 

We can also replace the filter, if he wishes, for his peace of mind. 

HTH, 

Steve 

[AstroGS]

On 05/02/2023 at 05:37, Lee_P said:

Not sure about consensus, but I’m happy to share my opinions about the Askar D1 D2 filters. I reviewed them here, and now have even more experience with them. Important caveat: as has been flagged earlier, it appears that not all of these filters are made equal, so there may be an element of “equipment lottery” to be aware of.

I think it’s best to split my opinion about the filters separately. I think that the Askar D1 (Ha/OIII) is fine, but a bit expensive for a 6nm filter. It’s not that much more to buy an Optolong L-Ultimate, which is a decent step up but still, as I’ve discovered, plays nicely with the Askar D2.

The Askar D2 (SII/OIII) works really well to add extra data to your dualband images, and I’ve been having a lot of fun using it. Here are the three images I’ve produced so far incorporating the Askar D2. More details here and  here and here. They’ve got better colours, and I think are just more interesting and nicer to look at, than my attempts using Ha/OIII data alone.

 

 

“But given the price, I do wonder if there's any advantage left over using a mono camera & FW.”
I think this depends on whether you will do purely SHO imaging, or want RGB as well. If you’re only ever going to do SHO then my advice would likely sway toward going mono. But if you want RGB as well; either to image broadband targets, or to add RGB stars to narrowband data, then data acquisition is still much simpler with OSC plus Ha/OII and SII/OIII filters (considering that no filters gives you RGB). This is my approach and I’m just using a filter holder, rather than an electronic filter wheel.

“The downside of OSC + dual band is that without processing wizardry, the images produced by the dual band filters are not as good as SHO images from a mono camera”
You need good processing wizardry to produce decent images regardless of what your setup is, so I don’t personally consider this to be a downside. Processing with Ha/OIII plus SII/OIII filters is a bit trickier than just regular dualband, but it’s OK really. I plan on writing a processing guide when I’ve time.

Finally, without wanting to rehash all the usual mono vs OSC arguments, my viewpoint is that which option is best is dependent on the individual astrophotographer and what they’d find most fun to use. I’ve used mono before, but currently have more fun with OSC. Maybe in the future I’ll switch back to mono. It’s often said that mono produces better quality images, but I honestly can’t tell the difference when looking at final, completed pictures. I rarely look at a completed picture of mine and think “drat, I wish I had a mono camera as that would have produced a better image”; but I regularly think “I’m glad it was straightforward to collect that data.”

These are some absolutely fantastic images - congrats!

It seems indeed that the filters are doing a great job. And loving your reviews @Lee_P

[AstroGS]

On 08/02/2023 at 07:12, StuartT said:

 

Interesting discussion.

I recently bought an Askar D2 to add in some Sii signal to my L Extreme images. I like the L Extreme very much (despite the halos) as I live in town and it's great at cutting out the bright sky or the full moon. So I was keen to try the D2 as well, but I am very alarmed to see the spectroscopy reports - clearly the Askar QC is pretty abysmal. So far, I've only managed two images combining both filters to make SHO the Rosette and the California. They're ok, but I am not yet convinced I prefer them to the plain old HOO ones I get with the L Extreme (here and here for comparison).

As to the question of mono+FW, I have been thinking about this too. Spending more and more on OSC, duobands etc is probably a bit wasted when I could just take the plunge and do mono (where you have far more control, higher definition etc). I'm still cogitating, so useful to have this thread. Thanks!

Does anyone know where I can get a spectroscopy report on my filter, by the way?

I absolutely love both your Rosette images…. Not sure why but, each one holds on its own. Good job!

[StuartT]

On 08/02/2023 at 10:15, 900SL said:

I've just bought an ALP-T as I trust Antlia more than Askar for QC   

The highspeed version has some bad halos apparently. Are you using the regular speed one? Are you getting a problem with halos?

[900SL]

1 hour ago, StuartT said:

The highspeed version has some bad halos apparently. Are you using the regular speed one? Are you getting a problem with halos?

Regular Antlia ALP-T, no halos in this first test run. It seems to be doing a decent job, this was less than 2 hrs in Bortle 7+. I also have the IDAS NBZ, which is a wonderful filter albeit a bit wide for my bortle at the moment. I do wish IDAS would release an updated matching NBZ for Oiii Sii.. I do trust IDAS, they wouldn't try to fudge specs like Askar have done..

I did question Lukomatico about the halos on the high speed Antlia version he tested, as halos can be due to a bunch of reasons including reflection from the camera glass. Cuiv however also had halo issues.

Bought from Flo of course

 

Edited February 21, 2023 by 900SL

[licho52]

8 hours ago, StuartT said:

The highspeed version has some bad halos apparently. Are you using the regular speed one? Are you getting a problem with halos?

The picture of the Jellyfish he seems to be so proud of is actually a perfect illustration of "newb-with-5k-RASA-setup" so I disregard his highly smug and opinionated tone.  Yes the filter has some halos but I don't think they're are excessive.  In any case he'd need to put a lot of time into learning processing before halos become the limiting factor in his astrophotography.

Sorry for harsh tone but I found the clip highly disagreeable and detached from the reality.

Edited February 21, 2023 by licho52

[rnobleeddy]

On 21/02/2023 at 22:14, licho52 said:

The picture of the Jellyfish he seems to be so proud of is actually a perfect illustration of "newb-with-5k-RASA-setup" so I disregard his highly smug and opinionated tone.  Yes the filter has some halos but I don't think they're are excessive.  In any case he'd need to put a lot of time into learning processing before halos become the limiting factor in his astrophotography.

Sorry for harsh tone but I found the clip highly disagreeable and detached from the reality.

I'd suggest you watch his other videos. They're very good and I put a lot of faith in his reviews.

[900SL]

On 21/02/2023 at 15:26, StuartT said:

The highspeed version has some bad halos apparently. Are you using the regular speed one? Are you getting a problem with halos?

Something I noticed btw.. I have my filter drawer about 10mm or so from my camera using a spacer. No haloes with the ALP-T.

I tried it reversed with the filter drawer mounted directly to the camera, and have a very faint halo after a hard stretch and poor SN. In this case the halo may be coming from a back reflection from the 533MC glass sensor cover

 

 

[StuartT]

2 hours ago, 900SL said:

Something I noticed btw.. I have my filter drawer about 10mm or so from my camera using a spacer. No haloes with the ALP-T.

I tried it reversed with the filter drawer mounted directly to the camera, and have a very faint halo after a hard stretch and poor SN. In this case the halo may be coming from a back reflection from the 533MC glass sensor cover

My filters screw in to the drawtube adapter and my OAG is then between that and my camera. So there is prob at least 15mm between filter and sensor. Despite that I get terrible halos with the L Extreme. Never thought about it being possibly related to spacing though. Interesting.

[The Admiral]

4 minutes ago, StuartT said:

halos with the L Extreme

I thought that this is a common issue with this filter, irrespective of placement. I can imagine though that the size of the halo might be different for different optical arrangements.

Ian

[StuartT]

9 minutes ago, The Admiral said:

I thought that this is a common issue with this filter, irrespective of placement. I can imagine though that the size of the halo might be different for different optical arrangements.

Ian

yes indeed. It's a widely reported problem with the L Ext. But @900SL was suggesting that longer spacing might help, so I was just saying it doesn't seem to with this filter. There was a thread on CN suggesting that reversing the filter might help. But it doesn't.

[BarleyIsCool]

On 09/02/2023 at 14:00, The Admiral said:

It's worth noting that Altair do this on their expensive filters.

https://www.altairastro.com/altair-dualband-ultra-4nm-certified-cmos-filter-2-w-test-report-11468-p.asp

You get a wide spectral print-out apparently. Anyone got one and care to comment?

Ian 

I have the Altair Sii/Oiii and I use it along with an L-Ultimate for Ha/Oiii.  They do send a spectral response chart with it and it shows the exact mid-band and width. The width is just under 4nm and the midpoint is about 1nm higher than spec.  That is my specific filter, your's may be different when you get it.  

I use a 2600MC-Pro camera and I split off the red from each filter as the Ha and Sii respectively.  Then I average the G+B from each filter to create the Oiii.  I then process the three images as if they came from a mono camera and three filters.  The nice thing is that you get double the Oiii to for improved SNR in that channel which is typically much weaker than the others (depending on target of course).

Here is the HorseHead colored as HSO with about 4 hours of exposure on each filter, so 4 hours of Ha and Sii and 8 hours of Oiii. This is with a WO-Z81 scope.