Quite reQuarkable! ;-)

[Moonshane]

Given the choice what would be best for the quark?

102mm f6/6 £155

90mm f5.5 £219

80mm f7.5 £219

All brand new achros or should I just save more for a used SW 80mm ED

[John]

The focal reducer must be behind the quark, both to prevent shattering under heat stress and (if a front-mounted ERF is used) due to the fact that the telecentric lens in the Quark is not optimal for Petzval and similar objective/reducer configurations.....

Good point Michael - thanks for raising it

I've found this schematic of the Quark internal layout which is quite interesting:

[Stu]

Is the 102mm f6.6 Shane?

Given that a good quality achro should be fine with the narrowband quark, I would say that the 102 should be best.

At f6.6 this gives around f28 with the Quark Barlow putting it in the optimum range.

I guess it will come down to whether the figure of the objective on the achro is decent enough. Whether it is better than an ED80 I'm not sure. The CA is irrelevant and if the figure is good enough then I would expect the additional aperture to give better resolution and brightness.

This is all based on what I've read though, no practical experience at all!!!

Sent from my iPhone using Tapatalk

[michael.h.f.wilkinson]

Given some images I have seen on Solarchat taken through a Quark with a humble ST80, I would not hesitate in using an achromat. An ED or triplet is not going to add much. Indeed, a well-figured singlet is enough (but quite hard to come by).

[Moonshane]

cheers guys. It's the Opticstar one which seems amazing value at £155. I have confirmed with them that only the finder bracket (and presumably the shoe) is plastic so it's very suited to wedge/quark use. It would also be useful as a RFT, giving about 4 degrees with my 40mm widefield in a 2" diagonal. http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_225

they say they will have stock during December.

[spaceboy]

The focal reducer must be behind the quark, both to prevent shattering under heat stress and (if a front-mounted ERF is used) due to the fact that the telecentric lens in the Quark is not optimal for Petzval and similar objective/reducer configurations. What I find curious is the fact that the tele-centric lens in the quark would be at odds with wide-angle EP designs, because the PowerMates use the tele-centric design to prevent all sorts of problems barlows can produce with SWU and UWA designs. If I get a Quark, I will first get a 0.5x focal reducer to screw into the cemara nose piece or EP, and try the MV 24 on its own; check out how this works, and only if this doe snot will I invest in Plossls. I would not buy them at first, but just ask my colleague who bought my 26 and 36mm Plossls (Vixen) if I could test them. BTW, I cannot imagine that orthos would not work. A 24 or 25mm ortho might be just the ticket.

My understanding of it is that the baffling and blackened edges on the optics of the TV plossl are far better than most on the market and hence why Daystar recommend them. Having had a look at Stu's 25 & 32mm TV plossl at PSP I now understand why they are recommended.

If Stu would be so kind as to post a picture of the lower lens and barrel of his 25mm TV plossl this might better explain why the TV plossl work as well under day time observing as they do at night.  

[spaceboy]

cheers guys. It's the Opticstar one which seems amazing value at £155. I have confirmed with them that only the finder bracket (and presumably the shoe) is plastic so it's very suited to wedge/quark use. It would also be useful as a RFT, giving about 4 degrees with my 40mm widefield in a 2" diagonal. http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_225

they say they will have stock during December.

Your not giving up on the wait for the LS50THa as well are you Shane?

[Moonshane]

Just suffering from spender's syndrome. Usually manifests itself when I have cash to spend and products are delayed. The usual symptom is a rash on the leg caused by a hole burned in my pocket.

[spaceboy]

Regards the optic star refractors Shane they look very similar to the Bresser / Meade / ES refractors and if this is the case I am almost certain the actual focuser body is ABS not metal. Would that be a problem? 

[Moonshane]

yeah, I think it would matter as plastic and solar obs don't mix well. Opticstar did confirm specifically re the plastic parts. Maybe I should just go for a tried and tested 102mm f5 skywatcher.

[Stu]

If you can confirm it is metal then the opticstar looks quite good. The focal ratio is a bit longer which should suit the Quark better than f5.

Sent from my iPhone using Tapatalk

[John]

I think bomberbaz has bought one of the Optistar 102mm F/6.6's or at least was looking very seriously at them recently. Perhaps he could confirm what the focuser is made from ?. This Optistar line looks extremely similar to the Bresser achros and also the Meades which came before them. In the 127mm and upward sizes the focuser was definitely metal but I've not owned one of the smaller aperture ones.

I guess you would want metal baffles within the tube too ?

[Pig]

Luke,

I will go for the Chromosphere  I would be stupid not to take the advice - fully digested

Stu,

Thanks for the power supply link - Much appreciated

[Davey-T]

Thanks Stu.

I have a set of TV plossls now so thats the eyepieces catered for I guess. I could always consider getting a focal reducer for the ED102 to get closer to full disk views.

I'll probably wait to see how these settle down over the next few months before deciding anything.

Just ordered one of these for my Quark

Dave

http://www.365astronomy.com/ts-05x-focal-reducer-with-125-inch-filter-thread-p-3092.html

[Stu]

Just ordered one of these for my Quark

Dave

http://www.365astronomy.com/ts-05x-focal-reducer-with-125-inch-filter-thread-p-3092.html

That looks just the ticket Dave. Might have a go with one too :-)

Cheers

Stu

Sent from my iPhone using Tapatalk

[michael.h.f.wilkinson]

I was thinking about the same one with a TS branding, should I get a quark.

[John]

Just ordered one of these for my Quark

Dave

http://www.365astronomy.com/ts-05x-focal-reducer-with-125-inch-filter-thread-p-3092.html

I've recently picked up the 32mm, 20mm, 15mm, 11mm and 8mm TV plossls. I didn't get them specifically for Solar observing as I don't currently do much of that but it's good to see that they would be useful if I get a Quark sometime. I assume the longer focal length ones would be more suitable for use with the Quark ?

[Stu]

I've recently picked up the 32mm, 20mm, 15mm, 11mm and 8mm TV plossls. I didn't get them specifically for Solar observing as I don't currently do much of that but it's good to see that they would be useful if I get a Quark sometime. I assume the longer focal length ones would be more suitable for use with the Quark ?

I think the 32 and 25 are likely to be most useful, the others will give too high power most likely. The 40 is also recommended but I can't see that adding anything over the 32 really, unless you have a longer focal length scope?

Sent from my iPhone using Tapatalk

[John]

I've owned a 40mm TV Plossl in the past. Thje quality is just as good but It does not show much, if any, more true field over the 32mm and it's not parfocal, by some way, with the other TV plossls. I believe it is generally recommended by TV to those that need to wear glasses when observing.

If my Vixen ED102 is the host scope for the Quark the 32mm would give 87x, the 20mm 139x and the 15mm 186x which seems a useful range for a 102mm aperture, unless the Quark imposes other constraints / limits that I'm not aware of.

[michael.h.f.wilkinson]

Going to low magnification (say 2mm exit pupil) can be handy in H-alpha. I used my MV24mm 68deg EP in the LS35 and was surprised to see detached proms at some distance from the disk. These distant proms have low surface brightness and show up best at low magnification.

[Davey-T]

I've owned a 40mm TV Plossl in the past. Thje quality is just as good but It does not show much, if any, more true field over the 32mm and it's not parfocal, by some way, with the other TV plossls. I believe it is generally recommended by TV to those that need to wear glasses when observing.

If my Vixen ED102 is the host scope for the Quark the 32mm would give 87x, the 20mm 139x and the 15mm 186x which seems a useful range for a 102mm aperture, unless the Quark imposes other constraints / limits that I'm not aware of.

Tried a few in my Quark and it generally doesn't seem to work very well with anything under 25mm.

It's already got a built in 4.3X barlow

Dave

[John]

Thanks Dave + Michael. Useful to know.

Clearly H-Alpa and the Quark requires us to re-examine some of our habits

[Mark at Beaufort]

I would be interested in how the Opticstar f5 80mm frac works with the Quark. Certainly in normal use its poor above 30x unless its stopped down to 60mm or 50mm - but Ha is different.

It would be good to try it out some time before considering another better quality refractor.

I know I have a 102mm f6.95 APO but I do like to view the whole solar disc.

[Davey-T]

The Quark/ barlow is optimised for 656nm, full disc up to 450mm f/l as you're only dealing with a small part of the spectrum does this not mean an expensive scope is wasted on it ?

Dave

[Stu]

My understanding of it is that the baffling and blackened edges on the optics of the TV plossl are far better than most on the market and hence why Daystar recommend them. Having had a look at Stu's 25 & 32mm TV plossl at PSP I now understand why they are recommended.

If Stu would be so kind as to post a picture of the lower lens and barrel of his 25mm TV plossl this might better explain why the TV plossl work as well under day time observing as they do at night.

Some pics here of the 32mm...

Stu

Sent from my iPhone using Tapatalk