Different Ca-K options, differences?

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Re: Different Ca-K options, differences?

Post by Bob Yoesle » Fri Jul 07, 2017 5:38 am

Just to ad my 2 cents worth, the relatively inexpensive (especially used) Synta 100ED f/9 scopes (Celestron, Skywatcher, etc.) don't do too bad at 394 nm either:
CaK hi res.jpg
CaK hi res.jpg (497.46 KiB) Viewed 2445 times
Equivalent to a 160 mm scope at H alpha BTW... Orion ED 100 f/9, 2x TeleVue Big Barlow, DS CaK home brew, PGR Chameleon.
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Re: Different Ca-K options, differences?

Post by MalVeauX » Mon Aug 20, 2018 8:25 pm

Bob Yoesle wrote:
Fri Jul 07, 2017 5:38 am
DS CaK home brew
Hey Bob,

Do you mind expanding on this double stack CaK home brew setup? I'm really starting to feel like getting into a double stack calcium system with my 6 inch refractor since the resolution would be significantly higher than an HA system and I just really like the look of calcium.

Does your system allow you to see filaments and prominences in Calcium?

I'm curious of course what your system is and how you stacked it and how you manage the thermal energy?

Thanks!

Very best,

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Re: Different Ca-K options, differences?

Post by Bob Yoesle » Tue Aug 21, 2018 3:30 pm

See related post How to DS CaK
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Re: Different Ca-K options, differences?

Post by george9 » Fri Aug 24, 2018 3:53 am

Why is the Lunt CaK stated as only for refractors and the Quark for both reflectors and refractors?

I had the Quark CaH and I could tell there was a lot of out-of-band light. My eye could see a bright blue sun with no CaH detail (old eyes). My Lunt CaK produces a very dim purple image, also with no CaK detail. I know part of the reason is that CaK is shifted toward UV compared to CaH, but the difference in not enough to explain a bright blue sun; that's just a lot of extra light coming through. I sold the Quark CaH and the new owner produced a wonderful image with it. My Lunt also seems to produce nice images.

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Re: Different Ca-K options, differences?

Post by krakatoa1883 » Fri Aug 24, 2018 7:50 pm

Actually Quark CaH is advertised for refractors only. I used it with some success with my 130mm solar reflector (dealuminised primary mirror) but I wouldn't recommend it for use with ordinary reflectors (both mirrors aluminised) unless a full aperture front ERF is employed.

Yes, Quark passes more light than an ordinary CaK module, however in my opinion it is an imaging device only. I have been able to see some prominent active regions, i.e. the bright zones around large sunspot groups, but the view was nothing compared to the details that can be imaged with the same device.
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Re: Different Ca-K options, differences?

Post by george9 » Sat Aug 25, 2018 3:23 am

I agree on imaging. I actually got the CaH to test my ability to actually see it. That will have to await a cataract operation. So I switched to the Lunt CaK for quicker startup and hope that the 2A bandpass would be better.

For now I have an R2 video, but will eventually get an ASI of some sort. More for realtime watching than processed images.

George

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Re: Different Ca-K options, differences?

Post by Valery » Sat Aug 25, 2018 2:44 pm

george9 wrote:
Sat Aug 25, 2018 3:23 am
I agree on imaging. I actually got the CaH to test my ability to actually see it. That will have to await a cataract operation. So I switched to the Lunt CaK for quicker startup and hope that the 2A bandpass would be better.

For now I have an R2 video, but will eventually get an ASI of some sort. More for realtime watching than processed images.

George
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Re: Different Ca-K options, differences?

Post by george9 » Thu Aug 30, 2018 7:26 pm

Right, Valery. Thanks. I was very impressed with the realtime image that a NEAF attendee created with his small refractor, Lunt CAK B1200, and ASI174 camera. Not sure what software he was using. Seems like in theory the pixels would be too big for a short-focal-length refractor and I don't remember seeing a Barlow. But I am in no hurry.

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Re: Different Ca-K options, differences?

Post by hopskipson » Tue Feb 26, 2019 1:15 am

Is anyone familiar with this filter? Will it show prominences?
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Re: Different Ca-K options, differences?

Post by solarchat » Tue Feb 26, 2019 10:48 am

lol. This filter is being sold by Apolo Lasky who has been booted from this forum under 3 different user names for selling unsafe solar filters. No, it will not show prominemces. stay away.
I could go on with the litany of mentally unbalanced actions this person has taken towards our forum and others but suffice it to say, I dont recommend this filter.
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Re: Different Ca-K options, differences?

Post by hopskipson » Tue Feb 26, 2019 11:17 am

Thanks for the warning!
I realize you get what you pay for especially in this niche of astronomy. What are the most cost effective and reliable ways of Ca-K observing? Is the Quark worth getting or would most agree that the Lunt is a better choice or is there another option? Sorry for the noob questions.

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Re: Different Ca-K options, differences?

Post by marktownley » Tue Feb 26, 2019 12:16 pm

Quark CaH or Lunt CaK are your only choices.
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Re: Different Ca-K options, differences?

Post by hopskipson » Tue Feb 26, 2019 5:15 pm

I have the Quark ha chromosphere and like the way it works but not sure what to expect from calcium h as opposed to k. Will you be able to “see “ prominences, does it need a telecentric or is f ratio not critical? I will be using it with a tri-band derf on a 6” refractor and a 8” sct. Would I be better off with the Lunt and what size blocking filter would you recommend?

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Re: Different Ca-K options, differences?

Post by krakatoa1883 » Thu Feb 28, 2019 8:41 pm

I have both a Lunt diagonal and the Quark H, they are different devices and I like both. The Quark calcium doesn't need a true telecentric beam to work however it performs best with a light cone slower than f/10, better around f/12 or f/15. It can be used down to f/7 but with a slight loss of contrast.

The Quark has some advantages over most Lunt CaK diagonals:
- has a large BF (23 mm) suitable for most scopes
- costs much less than a B1200/1800 Lunt module, which has a smaller BF
- can be used visually if one has enough eye sensitivity to short WLs
- can be used in both straight-through mode or inserted in a diagonal

The main cons are:
- requires a power supply for tuning
- has a larger BP, around 5A, compared to Lunt units, which means that some features (for example the supergranulation) lose a bit of contrast. In active regions, however, I did not notice much difference with the Lunt module
- can't be stacked with CaK filters or units which are the most commonly used ones in our community (actually I am not aware of anyone using the Quark in DS mode). I tried to stack my own Quark with an Omega optical CaH filter but the resulting image is too dark.

Both Quark and Lunt devices allow to image prominences although they show with less contrast than in H alpha.
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Re: Different Ca-K options, differences?

Post by MalVeauX » Fri Mar 01, 2019 4:12 pm

Heya,

So, revisiting this topic, a few months shy of 2 years later. I had gotten a chance a while back to image with PST CaK filters (2.2A to my knowledge?) and got to try them double stacked, the chroma filter, etc. But I have not tried a Lunt module.

I currently have moved my system to a C8 Edge HD for general purpose and I use it for solar. My full aperture D-ERF is tri-band (HA, CaK & Gband).

So my next exploration will be how to best add CaK to this system. Understanding an SCT mirror is not ideal.

PST CaK filters are unicorns, so I don't want to bank on this.

That leaves custom filters (uncertain) and Lunt Cak modules.

So I'm considering how best to look into a Lunt Cak module and potentially how to double stack them later if I get a 2nd filter. I'm curious the real differences between the Cak B600 & Cak B1200 & Cak B1800, etc. I realize these are simply narrowband filters, but I'm curious what is important in the module if you already have an ERF handling system (my tri-band D-ERF and a Baader Blue CCD IR block filter as the 2nd ERF) prior to the Lunt Cak module. I'm also curious about transmission with these filters, and if anything can be removed to improve transmission, knowing thermal is handled.

* Lunt Cak B600 vs B1200, etc, what are the real differences? (again considering thermal is handled)
* How to disassemble and potentially double stack two of these later?
* Reflection issues? I've encountered these before. Easy way to tilt things?

*Any thoughts on transmission difference between a Lunt Cak module and a PST Cak filter?

Very best,

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Re: Different Ca-K options, differences?

Post by bart1805 » Fri Mar 01, 2019 8:05 pm

* only difference is the size, you can compare it with the different coronado or lunt H-alpha BF's. The tube with the two filters is the same. Don't know if you still need the Baader Blue when using the triband. Valery could tellegen you.
* viewtopic.php?f=9&t=25552
* yes but not extreme with just the B600
* the PST #1 filter has a more narrow bandwith compared to Lunt.

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Re: Different Ca-K options, differences?

Post by MalVeauX » Fri Mar 01, 2019 8:43 pm

bart1805 wrote:
Fri Mar 01, 2019 8:05 pm
* only difference is the size, you can compare it with the different coronado or lunt H-alpha BF's. The tube with the two filters is the same. Don't know if you still need the Baader Blue when using the triband. Valery could tellegen you.
* viewtopic.php?f=9&t=25552
* yes but not extreme with just the B600
* the PST #1 filter has a more narrow bandwith compared to Lunt.
So the B600 is 6mm and will vignette anything with a sensor larger than that? So I would need the B1200 version to be able to use the IMX174 sensor as it's 11mm, right?

Very best,

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Re: Different Ca-K options, differences?

Post by bart1805 » Fri Mar 01, 2019 8:48 pm

Yes it will vignet, but when you are after HR imaging at 2000mm, maybe that problem is not so big. But I would buy the biggest one you can afford. And then go for the straight through version.

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Re: Different Ca-K options, differences?

Post by MalVeauX » Fri Mar 01, 2019 9:27 pm

bart1805 wrote:
Fri Mar 01, 2019 8:48 pm
Yes it will vignet, but when you are after HR imaging at 2000mm, maybe that problem is not so big. But I would buy the biggest one you can afford. And then go for the straight through version.
Hrm,

Was reviewing your thread where you dissembled the Lunt & PST Cak options. So there's nothing to the lunt other than the two filters sandwiched together? Just seeing if anything could be removed to increase transmission (like whatever is acting as the ERF for the module?). Looks like the PST filter (that yellow one) being removed would be more ideal. But, fat chance of me finding those. So there's likely no way to get just the narrowband filter from the Lunt without the sandwich stuff?

I have a 1.25" & 2.0" skybender set, so just looking at options to be able to put two filters eventually into one of them to be a CaK module that potentially is double stacked. Since the PST CaK is virtually not an option anymore, the only remaining option are the Lunt Cak filters. Or something custom. But I've yet to see anything custom with high transmission and anywhere close to 2.4A that is the same cost range as the Lunt (since Chroma didn't work out).

Very best,

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Re: Different Ca-K options, differences?

Post by bart1805 » Fri Mar 01, 2019 9:41 pm

There are two pre blockers in the nosepiece. The narrowband element consists of two pieces cemented together, you can't do anything about that.
I thought you had a chroma filter?

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Re: Different Ca-K options, differences?

Post by MalVeauX » Fri Mar 01, 2019 9:48 pm

bart1805 wrote:
Fri Mar 01, 2019 9:41 pm
There are two pre blockers in the nosepiece. The narrowband element consists of two pieces cemented together, you can't do anything about that.
I thought you had a chroma filter?
Heya,

Ahh, so are the pre-blockers necessary if we already have an ERF (Aires tri-band) and a 2nd ERF (Baader Blue CCD IR Blocker)? I'm curious if the pre-blockers in the Lunt module are significantly lower transmission or if they're high transmission? I would have no need of them in my setup. But if they're not lowering transmission much, then I wouldn't destroy the module over it.

I had the first series 1nm Chroma, but it really didn't do anything other than serve as an ERF since its too wide bandpass (10A).

Very best,

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Re: Different Ca-K options, differences?

Post by bart1805 » Fri Mar 01, 2019 9:52 pm

In the thread you started yourself there is a lot of information:
viewtopic.php?f=9&t=24974
You don't destroy the module by removing the preblockers. You can unscrew the nosepiece. When you use a triband there seems to be no need for these preblockers.

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Re: Different Ca-K options, differences?

Post by MalVeauX » Fri Mar 01, 2019 9:55 pm

bart1805 wrote:
Fri Mar 01, 2019 9:52 pm
In the thread you started yourself there is a lot of information:
viewtopic.php?f=9&t=24974
You don't destroy the module by removing the preblockers. You can unscrew the nosepiece. When you use a triband there seems to be no need for these preblockers.
Thanks,

Yea, sorry, hard to keep track of where the information goes sometimes. But seeing as you recently worked with these and took them apart, it's reassuring that it's not too difficult.

Very best,

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