The Quarkenscope!!

[Stu]

This has been on my mind to try for quite a while and it is now taking shape.

I have received a slightly battered SW150 f5 which has decent looking optics in it. The focuser was rubbish unfortunately so I have put the Moonlite from my 120ED on it (after a little fettling it fitted very well), requiring a change to my 'kit re-allocation programme!'

I will try it masked to 120mm to start, but have a 75mm D-ERF plus holder which I will mount just ahead of the focuser tube, a little way behind the last baffle so I can safely use the full 150mm.

Then it's just a case of waiting for some sun.

I guess the results will depend upon the quality of the optics. CA should not be an issue in either Ha or white light using a continuum filter, SA maybe but we will see. Having the larger aperture with a shorter focal length should actually work very well in terms of amount of disk visible. With the Binoviewers and Zeiss orthos, fingers crossed for some positive results.

If all works well, I will sort out the cosmetics properly, either a paint job or a wrap of some sort.

Stu

[Davey-T]

Very nice Stu , I think you should spray it all in matching red

Dave

[jetstream]

Awesome Stu! I am eagerly waiting your tests with this scope. I have heard of at least one f5 scope that the Quark excels in. Aperture for resolution + the ability to keep the mag down- great thinking!

[Stu]

Very nice Stu , I think you should spray it all in matching red

Dave

Now there's a thought..... I had been trying to decide between a somewhat unimaginative choice of....black or white, erring on the side of white currently [emoji3]

[Stu]

Awesome Stu! I am eagerly waiting your tests with this scope. I have heard of at least one f5 scope that the Quark excels in. Aperture for resolution + the ability to keep the mag down- great thinking!

That's the idea anyway Gerry. I do hope the optics are up to it!

[michael.h.f.wilkinson]

That looks great. I have future plans along similar lines with my 85mm tri-band ERF. Still need a Quark of course.

[jetstream]

That looks great. I have future plans along similar lines with my 85mm tri-band ERF. Still need a Quark of course.

Michael, what is a tri band ERF, what wavelengths are admitted?

[michael.h.f.wilkinson]

Michael, what is a tri band ERF, what wavelengths are admitted?

A tri-band ERF lets through three fairly narrow bands: one centred on H-alpha, one on the Baader solar continuum pass band, and one on CaK. Mine is a Beloptic one. I have heard there are only six of them, worldwide. My plan is for a single scope that can handle white light through a wedge, H-alpha with a Quark, and CaK with a Lunt CaK module.

[jetstream]

Michael thanks for the info, another great idea! I was wondering about why you would have one of these.... I am eagerly waiting for the results of this- the scope you use etc. Some very good info coming from this thread!

[Stu]

The Beast! It lives!

Just trying this out under not fantastic conditions, mainly just to see that everything works.

I can get focus using just the 32mm plossl, and also with Binoviewers with 25 ortho and 32mm plossls.

I'm mounting it on the Ercole, which handles it very well. Also I'm using my new (to me) catsperch observing chair which works brilliantly.

So, the views are very nice, perhaps in not getting the 'wow' because the cloud keeps coming through and it's hard to get the tuning right. I've added a polarizing filter after the Quark to cut the brightness and boost the contrast a little and for the moment am just using a UV/IR cut filter.

With a large aperture and long effective focal length I would expect this combination to need good seeing conditions, and the sun higher in the sky to really excel.

I'm going to call it a qualified success at the moment, until I can test it out more thoroughly under better conditions.

I'm getting a good portion of the disk in view, and also played around with a x0.8 reducer ahead of the diagonal, but still protected by the filter. This focused with the single eyepiece but not the Binoviewer. I guess a future development could be to cut the tube so the binoviewers work with the reducer, that would help alot. If my maths is any good, a 0.8 reducer on an f5 750mm f/l scope would take me to f4 (within Quark spec) at 600mm which is TV85 territory. Should work well, and I can aperture mask if the conditions are dodgy.

One more thing, I found binoviewing with the 32mm Plossls very awkward, the Orthos are much easier. Perhaps I should just use the Orthos when bv'ing and keep the 32 for cyclops viewing. One to consider

Stu

[michael.h.f.wilkinson]

Congrats on that first light. Looking forward to more results

[jetstream]

Awesome Stu! Do you notice any preliminary changes in detail using this scope vs the 120ED? How long does it take to tune the Quark?

[Stu]

Awesome Stu! Do you notice any preliminary changes in detail using this scope vs the 120ED? How long does it take to tune the Quark?

Very hard to say Gerry, the conditions are so variable I would have to do a side by side and I'm not sure I will get the chance before the 120 goes.

Certainly the mag is held down better with the shorter focal length. The image seemed a little soft but to be fair the sun was low and clouds kept interrupting play.

Verdict postponed for another day. It won't change my decisions though, the 120 is going regardless, for other reasons. I know the Quark is cracking in the 85 and 106 so if this works it is a nice bonus, and it's fun experimenting.

I'll tell you one thing though, it's a little chilly out there!! I was doing my normal trick of shorts, t shirt and crocs. Certainly felt it when the sun went below the roof line!!!! DOH! [emoji3]

[Davey-T]

Hi Stu, what is the problem with the 32 Plossls ? I've got some cheap Revelation bino's and a couple of 20mm Revelation eyepieces that came with them, was thinking of getting another 32mm TV Plossl to go with the one I've already got to try a pair of them.

Tried it in the Quark /100mm refractor combo but I think the 20mms are too much mag' so be interested in your views before wasting money.

Dave

[Stu]

Hi Stu, what is the problem with the 32 Plossls ? I've got some cheap Revelation bino's and a couple of 20mm Revelation eyepieces that came with them, was thinking of getting another 32mm TV Plossl to go with the one I've already got to try a pair of them.

Tried it in the Quark /100mm refractor combo but I think the 20mms are too much mag' so be interested in your views before wasting money.

Dave

Hi Dave,

It's nothing to do with the quality or magnification, it's purely a physical thing getting the inter pupil distance correct whilst still being able to get my nose comfortably between them. I have the eye guard extenders on them which may not be helping matters so I will try again without those and see if it's better. The lower mag was certainly preferable to the 25's but I couldn't get comfortable to view properly

[Dude_with_the_tube]

someone has been spending money like there is no tomorrow  

16" dob,then quarkenscope.

But if serious,i like the idea Stu and looking forward to your results.

I am still considering what to go for.Quark or dedicated solar scope in likes of Lunt60.

[Davey-T]

I am still considering what to go for.Quark or dedicated solar scope in likes of Lunt60.

I have a Quark and LS60 , if only going for one I think a Quark and a selection of refractors is the way to go, especially if you've already got a refractor.

Nice to have both though

Dave

Thanks Stu, my wife keeps telling me I've got a big nose 

Dave

[Stu]

someone has been spending money like there is no tomorrow

16" dob,then quarkenscope.

But if serious,i like the idea Stu and looking forward to your results.

I am still considering what to go for.Quark or dedicated solar scope in likes of Lunt60.

Fortunately the 150mm f5 was very cheap and I already had all the other parts.

Plenty being sold to cover the Sumerian too, unfortunately :-(

[LMC]

I await your verdict with interest.
A  quick question:
Isn't the BV a little OTT.  I've looked through a number of dedicated HA scopes, more than a few were Binoviewered, yet I could see no difference.  Could easily be my eyes but interested in your opinion.
The quark EP costs a fortune down here - about $2300 or 17'/9p in old money  - so there's not many independent reviews.
We have sun tho'.  Lots of it. 

[Stu]

So, a progress report from today. We had some unexpected sunshine for most of the day so I made the most of it and have been doing plenty of experimenting.

I have been wanting to try to get my Orion x0.8 reducer working, but previously had been unable to get it to focus. Not enough back focus. So, I tried a slightly more radical approach.

Scope

UV/IR Cut filter

Focal reducer

T to 2" adaptor

Quark

Zeiss T2 Prism

Binoviewer

25mm Orthos

The prism has a very short optical path so helps reduce the overall requirement. This configuration has the Quark in line with the scope ie before the prism.

The Denks also have a reducer switch which gives an additional method of cutting the mag.

So, first things first... It actually came to focus quite comfortably, now at f4 and 600mm focal length. With the additional Denk reducer I was getting very near to full disk views. Either way, the mag was controlled so I was able to see a large portion of the disk and maintain context to the views.

My impression of the views however was that they were a little soft and lacking contrast. I am guessing that the seeing is a large part of this. The larger aperture and overall focal ratio mean that seeing conditions will need to be excellent to make the most of this combination.

Masking down to 120mm did help, but the most telling thing I did was pop the TV85 out next to it. What a cracking scope that is, producing lovely sharp and contrasty views. With the focal reducer I was getting lovely full disk views too.

Various experiments followed, including using the 106mm and then finally got rid of the binoviewer. I need to repeat this to check the results but I do think the image was quite a lot sharper with just the single eyepiece ie no binoviewer.

Simple conclusion then. I think the seeing conditions will dictate how much aperture gives the best image. Today, either the 85 or 106 gave the best images depending on how the seeing was. I think the 150 is worth pursuing for for the best days in summer with the sun high in the sky. I can also make up some smaller aperture masks, 90mm to cut through the poorer seeing.

The jury is out on the binoviewers, I will do some more comparisons and check whether I'm right but for this application it appears that single eyepiece was sharper.

Will be back soon with more info.

[Stu]

Actually I'm assuming that the positioning of the Denks further from the Quark makes no difference to the final magnification.

I think the Quark passes a parallel light beam, like a Powermate, so the distant from the eyepiece should not affect the magnification. Am I correct?

[Qualia]

Outstanding set up and very informative thread, Stu. Thank you for putting this together

[Stu]

I made some progress with this today.

I took it all apart to see what was what.

I gave the objective a good clean with Baader fluid after a thorough air blow to get rid of any grit.

Next was flocking the inside of the lens cell.

With a bit of schoolboy geometry, I arrived at a position for the D-ERF based upon the baffle apertures and positions. This is pretty much just ahead of the focuser anyway so hopefully should be about right. I can tweak if necessary.

Used a pair of dividers to get the measurements...

Rear baffle.

Front baffle.

Mickey Mouse geometry diagram.

I drilled the hole for the D-ERF holder.

This is the tube before flocking and with the holder in place.

After a cry for help to the forum, Peter Drew rescued me with some info about which way round to install the D-ERF. Arrow marked on the side faces the sun. I found the instructions after asking the question....

Tube after flocking.

D-ERF installed, with a slight tilt.

Can you see me?? [emoji6]

Back together again for the moment.

Next steps, I've ordered some black and red vinyl to pimp up the exterior. Need to flock the inside of the dew shield and the back part of the OTA, then I'm about done.

Will update once the vinyl arrives and I've finished it off.

Will also post this in the DIY section.

Stu

[Dude_with_the_tube]

looks interesting Stu

well i managed to get my hands on s/h Lunt 60 for very reasonable price (less then the cost of quark) so i pulled the trigger on that one

[Stu]

looks interesting Stu

well i managed to get my hands on s/h Lunt 60 for very reasonable price (less then the cost of quark) so i pulled the trigger on that one

Have fun with that. I'm sure the Quark vs dedicated scope debate will continue for a long time. It's up there with 'frac vs Newt I think! [emoji6]