New CaK etalons from Solar Spectrum

[Bob Yoesle]

It's now official.

Solar Spectrum has announced the availability of CaK etalon filter systems with FWHM's less than 1 Angstrom.

K Line Solar Spectrum SM.png (170.85 KiB) Viewed 2116 times

Solar Spectrum.


Due to the limitations of even the most modern interference filter hard-layer depositing, reliable CWL uniformity and bandpasses below 1.5 A have been essentially unobtainable, and just as with H alpha, CaK etalons offer the only filter technology that can reliably achieve sub-angstrom performance and high angular resolution.

While there is the availability of DayStar K line etalons, like the rest of DayStar's current offerings, the Quarks seem problematic as far as CWL and uniformity, and their better quality CaK Quantums are insanely priced: ~$18,000 USD for a 2.0 A FWHM.

While I don't know the exact prices, Mark said his CaK filters will be similarly priced to his H alpha offerings, which in reality makes him the only affordable source for a quality < 1 A CaK optical filter system.

Mine's ordered

Bob

[marktownley]

That's exciting! I hope he has a lot of them

[christian viladrich]

Exciting news Bob !

I wonder what is the peak transmission of these filters. Do you have any data on this ?

[Bob Yoesle]

Hi Christian,

I'll have to make an inquiry with Mark, not sure he has a cleaved piece of mica yet. It will be an ~ 0.5 A RG18 etalon in a Housing I have left over from a previous 2 A DayStar CaK T Scanner (and possibly heated if not TEC controlled). It has hard coated blockers from Alluxa.

I'll post an answer when I hear back.

[hopskipson]

That's exciting! I hope he has a lot of them

While I don’t know how many systems he has on hand I know he sourced a few different sized blocking filters for future orders. With Mark, you have to be patient. I have been waiting for over a year (now that he has sourced a lot of the materials wait time should be shorter) and emails are not answered right away but I know it’s going to be a quality product and the price is reasonable.

[Dennis]

Interesting. Hopefully the design is done in mind for 100% imaging and according light throughput for the blockers and polarizers. Otherwise im out.

[Bob Yoesle]

Hi Dennis,

I'm confused by the statement "hopefully the design is done in mind for 100% imaging." Do you mean as opposed to visual? Camera sensors are generally much more sensitive than retinas with yellowed eyeball lenses, so that would seem to imply you want less throughput for the blockers and polarizers.

However, these filters incorporate new hard-coated Alluxa blockers with a very high ~ 80% transmission. Additionally, Mark has received some very transparent uncolored mica that makes - in combination with the high T blockers - the less than 1 Angstrom bandpasses practical.

My original DayStar ATM 0.7 A filter from 1976 had such a muscovite mica, and the view was brighter and more uniform than almost any I viewed through since. I really regret having sold it. That's why I'm getting one of these etalons now before that mica becomes less available via incorporation into the Baader / Solar Spectrum H alpha filters. Who knows when more of this high-quality mica will become available again. None will likely be coming out of Russia for quite some time, and that coming out from India and elsewhere is reportedly hit or miss.

Bob

[Dennis]

Hi Dennis,

I'm confused by the statement "hopefully the design is done in mind for 100% imaging." Do you mean as opposed to visual? Camera sensors are generally much more sensitive than retinas with yellowed eyeball lenses, so that would seem to imply you want less throughput for the blockers and polarizers.

However, these filters incorporate new hard-coated Alluxa blockers with a very high ~ 80% transmission. Additionally, Mark has received some very transparent uncolored mica that makes - in combination with the high T blockers - the less than 1 Angstrom bandpasses practical.

My original DayStar ATM 0.7 A filter from 1976 had such a muscovite mica, and the view was brighter and more uniform than almost any I viewed through since. I really regret having sold it. That's why I'm getting one of these etalons now before that mica becomes less available via incorporation into the Baader / Solar Spectrum H alpha filters. Who knows when more of this high-quality mica will become available again. None will likely be coming out of Russia for quite some time, and that coming out from India and elsewhere is reportedly hit or miss.

Bob

Hi Bob,

what i meant was that i hope that the transmission of the system is as high as possible and not compromized (by design) for to make it safe for visual use.
80% for the blockers sounds already very good. Info about the aproximate absolute system transmission will be of help to determine exposure times / signal strength for imaging purposes. Yes, the camera sensors are more sensitive then the human eye, but it doesnt tell me if i can saturate the pixel full well of a certain sensor in a good time.

Apart of this i think this is exciting news and im sure it will be a fine product.

Dennis

[Ljungmann]

I can confirm the very high transmission in my 0.3Å SS filter. Amazing views! My old Del Woods 0.6Å ATM filter (Quantum house now) has an extremely high transmission. Probably a good old high quality clear/light Muscovite. If I compare a newer SE 0.4Å filter and my 0.3Å filter, The SE filter have a low and "boring" transmission. Looks like 50% of the transmission of my SS filter. Looking forward to the new CaK filters.

[Bob Yoesle]

I wonder what is the peak transmission of these filters. Do you have any data on this ?

Hi Christian,

Per Mark:

"The ones we checked went from 15% to 5% . This was caused by the difference in shade of the mica. With all mica, the darker it is the lower T and broader Hw with the same coating design. With the high T blockers, I'm thinking there won't be that much difference in transmission than a Ha filter. Outside from the fact that we can't see k-line. So visibly, it may seem dimmer... We are using a UV Polaroid with a wave plate to make a circular Polaroid. So that's the same as an Ha filter."


Bob

[galaxie427]

However, these filters incorporate new hard-coated Alluxa blockers with a very high ~ 80% transmission. Additionally, Mark has received some very transparent uncolored mica that makes - in combination with the high T blockers - the less than 1 Angstrom bandpasses practical.

My original DayStar ATM 0.7 A filter from 1976 had such a muscovite mica, and the view was brighter and more uniform than almost any I viewed through since. I really regret having sold it. That's why I'm getting one of these etalons now before that mica becomes less available via incorporation into the Baader / Solar Spectrum H alpha filters. Who knows when more of this high-quality mica will become available again. None will likely be coming out of Russia for quite some time, and that coming out from India and elsewhere is reportedly hit or miss.

Bob

Thanks Bob for posting this new offering from Mark Wagner and I just want to say that the above insights you shared are also much appreciated.
I'm glad I saw your post since I was considering Mark's CaK filters a while back and now must move forward.

Thanks again,
Luka

[Dennis]

5%-15% is a good value, thx for the info.

[hopskipson]

Just got an update from Mark, my filter is complete and awaiting testing. Of course, he is dealing with lots of rain. My weather hasn’t been favorable either but spring is coming! I have fingers crossed to have it by the end of the month.

[Dennis]

Just got an update from Mark, my filter is complete and awaiting testing. Of course, he is dealing with lots of rain. My weather hasn’t been favorable either but spring is coming! I have fingers crossed to have it by the end of the month.

Lucky you, i didnt even get a reply to my email 4 weeks ago, asking how much one would be

[hopskipson]

Just got an update from Mark, my filter is complete and awaiting testing. Of course, he is dealing with lots of rain. My weather hasn’t been favorable either but spring is coming! I have fingers crossed to have it by the end of the month.

Lucky you, i didnt even get a reply to my email 4 weeks ago, asking how much one would be

Hopefully you won’t have to wait over a year for delivery like me. Try to pm him here or send him another email.
According to Mark they will be similarly priced to the RG H-alpha filters but don’t quote me on that.

[Dennis]

Just got an update from Mark, my filter is complete and awaiting testing. Of course, he is dealing with lots of rain. My weather hasn’t been favorable either but spring is coming! I have fingers crossed to have it by the end of the month.

Lucky you, i didnt even get a reply to my email 4 weeks ago, asking how much one would be

Hopefully you won’t have to wait over a year for delivery like me. Try to pm him here or send him another email.
According to Mark they will be similarly priced to the RG H-alpha filters but don’t quote me on that.

well that would be just too long for me : )
i was just curious, so you yourself dont know the price yet for yours?

[DavidP]

You might contact Bob at Alpine Astronomical about availability

[hopskipson]

You might contact Bob at Alpine Astronomical about availability

When I tried to order my H-alpha directly from Mark, he didn’t respond to my email until about a month after I ordered it from Alpine. So it took mark about 6 weeks to respond. The H-alpha took a little over the 12 weeks I was quoted for delivery. The price at that time was $3500 plus $400 for the telecentric and the cost of shipping. It was about a third of what Daystar had listed for a similar filter.

[Dennis]

You might contact Bob at Alpine Astronomical about availability

When I tried to order my H-alpha directly from Mark, he didn’t respond to my email until about a month after I ordered it from Alpine. So it took mark about 6 weeks to respond. The H-alpha took a little over the 12 weeks I was quoted for delivery. The price at that time was $3500 plus $400 for the telecentric and the cost of shipping. It was about a third of what Daystar had listed for a similar filter.

Thanks for the info.

[GeorgeIonas]

Good to hear that Mark as some clear mica. My order for a 0.3 angstrom Ha filter placed through Alpine Astro is coming up to 2 years of wait time.

[hopskipson]

Good to hear that Mark as some clear mica. My order for a 0.3 angstrom Ha filter placed through Alpine Astro is coming up to 2 years of wait time.

Ouch! That’s a little concerning.

[Bob Yoesle]

I know Mark had some production issues with a coating machine needing parts and the like. And he refused to turn out products that ultimately would end up coming right back. Sometimes you just have to bite the bullet and wait - try an Astro-Physics refractor for example, where the wait time is also usually measured in many years. While not perfect, these companies generally emphasize quality vs. quantity.

On the other hand, you can roll the dice on quantity over quality - and may pay the price in the end.

[hopskipson]

I got a call from Mark today! The filter is ready but his weather has been very bad for testing. So if you know anybody in Chico, please have them dance for sun and stop dancing for rain!

[hopskipson]

I wish I could report that I have been testing the filter out but as of today I have no idea of what is going on with the filter. I talked to Mark on 2/27 and he said it was ready for testing but his weather was making it difficult. I emailed him 3 weeks later, 2 weeks after that, another week later and last week but he hasn’t responded.

Has anyone heard from him lately or placed an order? I know he’s done this before and eventually he responds but from the phone call I got, I thought it was almost ready for shipping.

[Dennis]

I wish I could report that I have been testing the filter out but as of today I have no idea of what is going on with the filter. I talked to Mark on 2/27 and he said it was ready for testing but his weather was making it difficult. I emailed him 3 weeks later, 2 weeks after that, another week later and last week but he hasn’t responded.

Has anyone heard from him lately or placed an order? I know he’s done this before and eventually he responds but from the phone call I got, I thought it was almost ready for shipping.

With new products you never know.. might have not passed his final quality/performance check, but i hope for the best.

[hopskipson]

I wish I could report that I have been testing the filter out but as of today I have no idea of what is going on with the filter. I talked to Mark on 2/27 and he said it was ready for testing but his weather was making it difficult. I emailed him 3 weeks later, 2 weeks after that, another week later and last week but he hasn’t responded.

Has anyone heard from him lately or placed an order? I know he’s done this before and eventually he responds but from the phone call I got, I thought it was almost ready for shipping.

With new products you never know.. might have not passed his final quality/performance check, but i hope for the best.

Yeah I get that but a simple reply to one of my emails over a month and a half is not that much to ask. I don’t mind waiting it’s the lack of communication that makes me feel uncomfortable. Or am I being unreasonable?

[Dennis]

I wish I could report that I have been testing the filter out but as of today I have no idea of what is going on with the filter. I talked to Mark on 2/27 and he said it was ready for testing but his weather was making it difficult. I emailed him 3 weeks later, 2 weeks after that, another week later and last week but he hasn’t responded.

Has anyone heard from him lately or placed an order? I know he’s done this before and eventually he responds but from the phone call I got, I thought it was almost ready for shipping.

With new products you never know.. might have not passed his final quality/performance check, but i hope for the best.

Yeah I get that but a simple reply to one of my emails over a month and a half is not that much to ask. I don’t mind waiting it’s the lack of communication that makes me feel uncomfortable. Or am I being unreasonable?

I dont think you are unreasonable.

[Montana]

I haven't heard about mine for 18 months, even my vendor never replied to me either. I wonder if mine is lost forever

Alexandra

[hopskipson]

I haven't heard about mine for 18 months, even my vendor never replied to me either. I wonder if mine is lost forever

Alexandra

Don’t loose hope! I just got an email from Mark that the filter is ready to ship. Keep emailing them to get an update or PM Mark.

I haven’t had much time for imaging but as soon as I get this I will post an update and hopefully some images

[hopskipson]

Over a week, about 4 emails and no response from Mark, if I didn’t own a Solar Spectrum filter I would be very worried. The waiting continues