Another Quark Question

[astro_al]

I am researching Ha options at the moment and I like the idea of using my existing scopes so a Quark is of interest. I use a binoviewer and would like to use my Tak FC-76 F7.5 scope. I saw that @Stu has used this combination in the past so it looks like back focus shouldn't be an issue, however I do worry about stacking a binoviewer on top of the Quark - more from a height/rotation issue than weight.

My question is what are the implications of putting the Quark before the diagonal? Quark, Quark-T2 adapter, Baader prism diagonal, Baader quick change and then the binoviewer. Is it just increased magnification?

Thanks for reading.

Al

Edited February 27, 2020 by astro_al

[Peter Drew]

I think the main issue might be vignetting.  I would look into getting the best eyepiece adaptor as far as holding power is concerned.  I use a binoviewer exclusively on my solar telescope and use 4 securing screws to hold the diagonal firmly in place.             😀

[Rusted]

Having tried a number of clamping options I like the Baader ClickLock fittings.
This assumes that you can find one with the correct thread or spigot to suit your exact needs.
There are a lot of them and their adapters in different sizes. So it should be possible.
I used to tighten thumbscrews on push-in fittings until the literally creaked.
They were often very difficult to loosen but were still not firm enough to support a long PST etalon/filter stack.

[astro_al]

8 hours ago, Peter Drew said:

I think the main issue might be vignetting.

Ah. I didn’t think of that. Thanks Peter. 

[astro_al]

The diagonal connects to the focuser draw tube via a Clicklock. My main problem is that this, or more usually the diagonal’s T2 nosepiece, can unscrew if there is a shift in momentum. I don’t preload against this rotation as this makes it less comfortable with my alt-az mounts. I may end up applying some thread lock anyway but I am not sure I would get along with having the binoviewer after the Quark from an ergonomics perspective. 
 

Thanks both. 

[astro_al]

Does anyone have any details about back focus with the Quark? With a 2.6x glass path corrector in my FC-76 I have about 35-40mm inward travel left with my binoviewers. I guess the 4.2x barlow in the quark will push the focal plane further out still, but I have no idea if that is enough to accommodate the physical dimension of the Quark.

Thanks

Al

[astro_al]

On 29/02/2020 at 11:48, astro_al said:

I guess the 4.2x barlow in the quark will push the focal plane further out still, but I have no idea if that is enough to accommodate the physical dimension of the Quark.

My Quark arrived today. I reconfigured a Baader prism diagonal to use the 2” clicklock from the Baader Herschel wedge. This holds the Quark nicely. A 5mm extension was required to allow the diagonal’s nosepiece to clear the width of the clicklock. I also swapped the Quark’s eyepiece holder for an adapter to use the Baader quick changer for my binoviewer.

All in all it’s about another 135mm of additional back focus. My 76 and 100mm refractors have about 35mm available when using the 2.6x glasspath corrector with the binoviewer so that still leaves 100mm to find from switching to the Quark’s inbuilt 4.3x barlow which seems like a push. I guess we will see. 
 

 

Edited April 28, 2020 by astro_al

[Chinapig]

4 hours ago, astro_al said:

My Quark arrived today. I reconfigured a Baader prism diagonal to use the 2” clicklock from the Baader Herschel wedge. This holds the Quark nicely. A 5mm extension was required to allow the diagonal’s nosepiece to clear the width of the clicklock. I also swapped the Quark’s eyepiece holder for an adapter to use the Baader quick changer for my binoviewer.

All in all it’s about another 135mm of additional back focus. My 76 and 100mm refractors have about 35mm available when using the 2.6x glasspath corrector with the binoviewer so that still leaves 100mm to find from switching to the Quark’s inbuilt 4.3x barlow which seems like a push. I guess we will see. 
 

 

 

Hi there

I have the same scope, a Tak FC-76DC, and am very keen to see how you get on with configuring the lightpath for your Quark.  Good luck, and I look forward to hearing more!

Cheers, Simon

[astro_al]

There was an unexpected break in the clouds this morning so I set the Quark and binoviewer up on the Porta II to check on the back focus situation. I was fully expecting to be disappointed but.... it almost came to focus on the first try . There wasn't enough outward travel! Apologies for doubting those posts online that said it wouldn't be an issue.

In the end I added the shortest adapter that comes with the FC-76DC ahead of the Baader clicklock and could reach focus easily. It may work with just the Tak 2" adapter, although I may just add a longer T2 extension to the diagonal so I can swap in the Herschel wedge without re-configuring. This will also work in the FC-100DC and the FS-152, although not planning on using the latter.

The Quark came up to temperature while I was sorting this out and I could see surface detail and what looked like a prom at about 11 o'clock. Focusing was hard at almost 100X on the Porta but not impossible. After the lime green of the continuum filter I am loving the rich red of Ha.

Looking forward to getting this setup on the pier-mounted AZ-EQ6 when there is a longer spell of sunshine so I can experiment with the Quark's settings.

FOV was as expected based on the 4.3X amplification, not quite a full disk. Once the astro funds are replenished I may get a pair of Tak 30mm LEs to drop the magnification a bit despite the vignetting.

All in all a nice surprise and looking forward to spending more time in the sun.

 

Edited April 29, 2020 by astro_al

[Chinapig]

4 hours ago, astro_al said:

There was an unexpected break in the clouds this morning so I set the Quark and binoviewer up on the Porta II to check on the back focus situation. I was fully expecting to be disappointed but.... it almost came to focus on the first try . There wasn't enough outward travel! Apologies for doubting those posts online that said it wouldn't be an issue.

In the end I added the shortest adapter that comes with the FC-76DC ahead of the Baader clicklock and could reach focus easily. It may work with just the Tak 2" adapter, although I may just add a longer T2 extension to the diagonal so I can swap in the Herschel wedge without re-configuring. This will also work in the FC-100DC and the FS-152, although not planning on using the latter.

The Quark came up to temperature while I was sorting this out and I could see surface detail and what looked like a prom at about 11 o'clock. Focusing was hard at almost 100X on the Porta but not impossible. After the lime green of the continuum filter I am loving the rich red of Ha.

Looking forward to getting this setup on the pier-mounted AZ-EQ6 when there is a longer spell of sunshine so I can experiment with the Quark's settings.

FOV was as expected based on the 4.3X amplification, not quite a full disk. Once the astro funds are replenished I may get a pair of Tak 30mm LEs to drop the magnification a bit despite the vignetting.

All in all a nice surprise and looking forward to spending more time in the sun.

A great result - very pleased for you.  Phew, always good when a "will it work like this" plan comes together!  When the rain clears, hope you have a load of fun with this set up.

I've certainly been very impressed with the white-light views with the Tak 76, but so far haven't been able to reach focus with the Quark, although that was the 1.25" components.  I now have a Tak-friendly Baader 2" clicklock adapter and, from your tests, looks like this should give me that wee bit of extra focus leeway.  Once the sun comes out again, I'll give it a try.

All the best, Simon

[Davey-T]

Good result, I had a brief foray into using a "cheap" binoviewer with my Quark and various scopes but abandoned it, don't think my eyes are suited to bino' viewing but may give it another go.

Whereabouts are you in Kent ? I'm near the Dartford Crossing.

Dave

[astro_al]

1 hour ago, Davey-T said:

Whereabouts are you in Kent ?

A few miles south of Gravesend - so not far from you. 

[astro_al]

1 hour ago, Chinapig said:

I now have a Tak-friendly Baader 2" clicklock adapter and, from your tests, looks like this should give me that wee bit of extra focus leeway.

Yes, I think that will do it. Good luck. 

[BGazing]

On 28/04/2020 at 20:39, astro_al said:

My Quark arrived today. I reconfigured a Baader prism diagonal to use the 2” clicklock from the Baader Herschel wedge. This holds the Quark nicely. A 5mm extension was required to allow the diagonal’s nosepiece to clear the width of the clicklock. I also swapped the Quark’s eyepiece holder for an adapter to use the Baader quick changer for my binoviewer.

All in all it’s about another 135mm of additional back focus. My 76 and 100mm refractors have about 35mm available when using the 2.6x glasspath corrector with the binoviewer so that still leaves 100mm to find from switching to the Quark’s inbuilt 4.3x barlow which seems like a push. I guess we will see. 
 

 

Which adapter did you use? I see only Baader quick changer up there, obscuring whatever is beneath...

Not sure why there was talk of vignetting, 21mm at the top is mighty small to vignette.

[astro_al]

1 hour ago, BGazing said:

Which adapter did you use? I see only Baader quick changer up there, obscuring whatever is beneath...

Not sure why there was talk of vignetting, 21mm at the top is mighty small to vignette.

The adapter is this one: https://www.firstlightoptics.com/adapters/astro-essentials-adapter-for-daystar-quark-to-t2.html

I believe the field stop of the 30mm LE is 27mm which is larger than both the Quark and the binoviewer's clear aperture (25mm). Currently I am using TV 25mm Plossls which have a 21mm field stop so no vignetting.

[astro_al]

I managed another session with the Quark this morning. The thin cloud was building so viewing deteriorated but while it was clear I got a chance to experiment with the tuning on the Quark. All the way to the right and I could easily pick out a sunspot group, closer to the white light view I am used to. The prom that was visible when the dial was straight up was nowhere to be seen. Switching the dial all the way to the left the prom was super clear. I could still see the sunspots now I knew where to look, but their appearance was noticeably different. I settled on two steps in from the left until the cloud came in.

I had added another 25mm to the diagonal via a T2 extension so the draw tube on the FC-76's focuser was racked nearly all the way in. Maybe this helped as I didn't find focusing as tricky to day on the Porta today. All in all really pleased with this as a grab and go setup.

[BGazing]

2 hours ago, astro_al said:

The adapter is this one: https://www.firstlightoptics.com/adapters/astro-essentials-adapter-for-daystar-quark-to-t2.html

I believe the field stop of the 30mm LE is 27mm which is larger than both the Quark and the binoviewer's clear aperture (25mm). Currently I am using TV 25mm Plossls which have a 21mm field stop so no vignetting.

Thank you!

Yes, no point in going wider than 21mm, I use Vixen 25mm and Baader 32mm plossl (which is a bit narrower than others but still not vignetting...I think).

Re settings, have you found 'the one' or use different settings for different views? I find the latter impracticable, the 'best' setting for me is -4 or -5 (CCW), but I never have the chance to properly compare which one is clearly better as the seeing changes for the worse (sun going up) and turning it to the right just makes everything go bland on the disk and the proms disappear. Both in Borg with FTF focuser and in the Tak so the focusers are also out of the question...

Someone wrote (somewhere) that 'the best' setting may vary due to pressure and location but I have not found that to be the case (going up a mountain and the pressure is still the same).

[astro_al]

2 hours ago, BGazing said:

Re settings, have you found 'the one' or use different settings for different views?

I have only had about an hour with the Quark so far so not enough time to be conclusive. However so far I would say that close to fully CCW is the best - just as you have found. 

[Davey-T]

2 hours ago, BGazing said:

Re settings, have you found 'the one' or use different settings for different views? I find the latter impracticable, the 'best' setting for me is -4 or -5 (CCW), but I never have the chance to properly compare which one is clearly better as the seeing changes for the worse (sun going up) and turning it to the right just makes everything go bland on the disk and the proms disappear. Both in Borg with FTF focuser and in the Tak so the focusers are also out of the question...

No two Quarks appear to be the same in my experience, interesting post here from a while back but I've never succeeded in getting one, tried a few ( 6 at the last count ) to do this.

Dave

 

[steveex2003]

5 hours ago, astro_al said:

I managed another session with the Quark this morning. The thin cloud was building so viewing deteriorated but while it was clear I got a chance to experiment with the tuning on the Quark. All the way to the right and I could easily pick out a sunspot group, closer to the white light view I am used to. The prom that was visible when the dial was straight up was nowhere to be seen. Switching the dial all the way to the left the prom was super clear. I could still see the sunspots now I knew where to look, but their appearance was noticeably different. I settled on two steps in from the left until the cloud came in.

I had added another 25mm to the diagonal via a T2 extension so the draw tube on the FC-76's focuser was racked nearly all the way in. Maybe this helped as I didn't find focusing as tricky to day on the Porta today. All in all really pleased with this as a grab and go setup.

May i ask, once the Quark is on-band at its first setting, what is the wait time when altering dial position? Do you also need to refocus?

Thanks.

[BGazing]

1 hour ago, Davey-T said:

No two Quarks appear to be the same in my experience, interesting post here from a while back but I've never succeeded in getting one, tried a few ( 6 at the last count ) to do this.

Dave

 

Yes, I remember reading that before I purchased my Quark. To really really nail the subtle difference between the shortlisted positions one has to do imaging, I guess. You tried six times or you tried this with six Quarks?

[BGazing]

1 hour ago, steveex2003 said:

May i ask, once the Quark is on-band at its first setting, what is the wait time when altering dial position? Do you also need to refocus?

Thanks.

Around 5-10 minutes. No need to refocus. Frankly, you are better off doing center first, then going one way for about 3 positions, e.g. 9 o clock. If it is better, then you figure out whether it gets even beter going to -5 or dialing it down. If it was worse to start with, you go the other way...

[Davey-T]

2 minutes ago, BGazing said:

You tried six times or you tried this with six Quarks?

Six different Quarks over the years.

Dave

[BGazing]

6 minutes ago, Davey-T said:

Six different Quarks over the years.

Dave

Oh yes, I remember there was a horror story or two in there...

Looks like they are not THAT bad recently.

[Davey-T]

3 minutes ago, BGazing said:

Looks like they are not THAT bad recently.

Got one here supplied new last year waiting for the present situation to sort itself out before returning it as it no  longer lets any light through.

Dave