QUARK - only operates well F/30+?

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GaborKiss
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QUARK - only operates well F/30+?

Post by GaborKiss » Fri May 27, 2016 10:27 pm

Hi,

Today I made lot of research on the Quark Chromo. My imagination was that it gives the same contrast like a double stacked Lunt scope for the following reason. I had a Lunt60 SS that was said to be 0,7 A, then I bought a 60 DS unit and that gave me 0,5 A, which was day and night visually and for me on the images as well. Then we tripled stacked it with a 50 DS unit, to be honest there was not such a big difference and some reflections made it very hard to do images. So I preferred the DS.

The Quark Chromo is said to be between 0,3-0,5A, so normally it should give the same contrast as a DS Lunt. However on forums when I read comparisons, I often run into the problem that it's not true. People say that it works more like a SS Lunt. Why?

The second thing I read was about the operating F/D. It was said, that 0,3A cannot be reached just around F45. At F20 this filter will show 0,85A only. So this means I can forget to shoot with a 0,5x focal reducer to have lower resolution as I loose the contrast?

As I want to operate the scope at the shortest possible focal length at least 50% of the time to make animations from 1/4th of the full disc, it seems impossible or I will get much worser results than with a dedicated solar scope if these information are true.

Thanks,
Gabor
Currently out of equipment, but still around to see your images! :)

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Valery
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Re: QUARK - only operates well F/30+?

Post by Valery » Sat May 28, 2016 6:31 am

GaborKiss wrote:Hi,

Today I made lot of research on the Quark Chromo. My imagination was that it gives the same contrast like a double stacked Lunt scope for the following reason. I had a Lunt60 SS that was said to be 0,7 A, then I bought a 60 DS unit and that gave me 0,5 A, which was day and night visually and for me on the images as well. Then we tripled stacked it with a 50 DS unit, to be honest there was not such a big difference and some reflections made it very hard to do images. So I preferred the DS.

The Quark Chromo is said to be between 0,3-0,5A, so normally it should give the same contrast as a DS Lunt. However on forums when I read comparisons, I often run into the problem that it's not true. People say that it works more like a SS Lunt. Why?

The second thing I read was about the operating F/D. It was said, that 0,3A cannot be reached just around F45. At F20 this filter will show 0,85A only. So this means I can forget to shoot with a 0,5x focal reducer to have lower resolution as I loose the contrast?

As I want to operate the scope at the shortest possible focal length at least 50% of the time to make animations from 1/4th of the full disc, it seems impossible or I will get much worser results than with a dedicated solar scope if these information are true.

Thanks,
Gabor
Believe me, you are flying high in the skies, Gabor. The reality is very far from these your naive fantasies.

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"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: QUARK - only operates well F/30+?

Post by GaborKiss » Sat May 28, 2016 9:46 am

Valery,

What do you mean here? Numbers are incorrect? I read experienced (as I am not) users from this and from other big forums. I didn't state nothing in my post, maybe you refer to this part "As I want to operate the scope at the shortest possible focal length at least 50% of the time to make animations from 1/4th of the full disc, it seems impossible or I will get much worser results than with a dedicated solar scope if these information are true." - but it's more like a question. As I not solely want to do closeups (then you are right with the 8"), but also similar animations like Andy Devey did with his SM90 Coronado scope, you are right. There is a not an overall setup to do both as high-res scopes are working with too long focal lengths. As I will also use the setup under average conditions and I am not experienced with the seeing conditions of Tenerife (and not willing to go up to the Teide on daily not even on weekly basis) for me the optimal solution seems to be the 4-6" range to cover a bigger area (not so high-resolution) field on the Sun.

Am I missing here something?

Gabor
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Valery
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Re: QUARK - only operates well F/30+?

Post by Valery » Sat May 28, 2016 12:39 pm

Gabor, your fantasies are: you want too much for such a limiting budget.

You can't get all in one. At least, you need to choose between two:

1. A real HR instrument.

2. A wide FOV instrument.

Junction of both is FAR out of your budget.

In the second case choice your instrument will rest for weeks and then months long during several coming years of the solar minimum. Not the best money investment for near future.

The more aperture will you get (along with a narrow bandwidth), the more sufficient for animation events will you able to find on the sun. The quitter the sun, the more aperture will you require to find something interesting and worth to catch for animation.

Of course, the Quark is the most universal device - easy to put it in to different instruments. But you are in a front with a lottery. I bet you will have a hard time to get such a good sample of Quark as Mike Garbett owns. Even if you will find it, there is no warranty that your sample will not repeat the same fate as the Quark owned by Aleaxandra, which was, FYI, a very good sample from the beginning.


Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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GreatAttractor
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Re: QUARK - only operates well F/30+?

Post by GreatAttractor » Sat May 28, 2016 4:50 pm

Gabor, one more thing:
GaborKiss wrote:Hi,
The second thing I read was about the operating F/D. It was said, that 0,3A cannot be reached just around F45. At F20 this filter will show 0,85A only. So this means I can forget to shoot with a 0,5x focal reducer to have lower resolution as I loose the contrast?
The operating focal ratio concerns only the beam that passes through the Quark. If you put your focal reducer after the Quark, you won't impact its bandwidth. However, if you happen to get a Quark with uneven transmission (e.g. due to inhomogeneous blocking filter), you'll see more of this unevenness with a reducer.
My software:
Stackistry — an open-source cross-platform image stacker
ImPPG — stack post-processing and animation alignment
My images

SW Mak-Cass 127, ATM Hα scope (D=90 mm, LS50 etalon), Lunt LS50THa, ATM SSM, ATM Newt 300/1500 mm, PGR Chameleon 3 mono (ICX445)

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Re: QUARK - only operates well F/30+?

Post by GaborKiss » Sat May 28, 2016 4:54 pm

Hi!

Thanks for the info. You make great pictures with your modified 90mm! I like it a lot, with great contrast. Do you have info about your modification?
Do you have a Quark as well? Or tried one?

Best regards,
Gabor
Currently out of equipment, but still around to see your images! :)

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Montana
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Re: QUARK - only operates well F/30+?

Post by Montana » Sat May 28, 2016 6:12 pm

Gabor, it doesn't matter if the FWHM is 0.7A or 0.3A, if the base of the curve is very broad then a lot of continuum light will get through, contrast will be low and features will not look good. You only get tight baselines with DS and triple stack etalons.
http://solarnutcase.livejournal.com/9896.html

Alexandra

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