Which refractor for Quark

[Luke]

14 hours ago, Stu said:

That’s interesting Luke. I would have thought the 100ED may be a bit slow and long focal length for best performance with a Quark but clearly not from your experience. The problem is often keeping the magnification down to match the seeing conditions isn’t it? I had good results with a TV85 and also a 106mm f6.5 triplet.

I was surprised, Stu! I was expecting the Tele Vue 85 (F7) and Equinox 120 (F7.5) to be better with the Quark and its 4.2 Telecentric and recommended F30. But for me the view definitely "pops" best in the Skwatcher ED 100 DS Pro (F9). My wife Sarah agrees.

The least "poppy" scope for me has been the lovely little Tele Vue-60 (F6). To me the contrast is clearly a notch lower with this one versus the 85 and 120, though it's still a nice view and has served me very well - I am happy enough with it.

I give all four a big thumbs up for white light.

Is a Tele Vue or Tak overkill for h-a? Well I think I paid three times more for the Tele Vue 85 than for the ED100, never mind versus non-ED! But I like well-made things and also use my scopes for night time. It's always a joy to use the 85, and the optics are very sharp. I like using quality items!

And the 85 is built like a tank. The package it arrived in was squashed, but the scope looked in perfect nick. The ED100 is light, and I love that, but I wouldn't fancy throwing it about too much.

[Luke]

16 hours ago, Stu said:

The problem is often keeping the magnification down to match the seeing conditions isn’t it? I had good results with a TV85 and also a 106mm f6.5 triplet.

Sorry, I forgot about your point re: matching scopes to seeing conditions. From where I observed I found that the ED100 was almost always fine with the Quark (I would guess 95% plus) and that on the rare occasion it wasn't, I tended to leave it for a while and come back later, and it usually improved enough for me. Maybe my location affects things.

When the seeing wasn't okay for my ED100, it tended to be choppy and I could still see little chops at 60mm and didn't enjoy it. For imaging I remember that I did sometimes step down from the 120mm to 85mm because of seeing conditions.

Although I regularly used four scopes, for me it was not so much to match the seeing. I mainly used my scopes like this:

The Tele Vue 60 was my grab-and-go scope and saw a lot of use during lunch and on holiday. I used it for visual and imaging (undriven - letting the sun drift over the ASI174 chip). I also used the 60 for full disc imaging at home (as four tiles, I think)

The Tele Vue 85 and ED100 are my default visual scopes at home. I put them both on a dual-mount giro and start with the Quark in the ED100 and white light in the 85. Then I swap them over (capping the scopes first and pointing well away from the sun!), mainly so I can sneak in a bit closer on the sunspots in white light.

The Equinox 120 was my favourite to image with from home, being the largest aperture I could use. Here's an image with the Quark and Equinox 120:

Now that I am not imaging, I might rethink things a bit. I'm very happy with the ED100 for visual h-a, but for white light I'd ideally like to be using the Equinox 120 and the Baader Herschel wedge regularly. The problem is I think the Equinox 120 is a bit heavy dual-mounted on the giro, so I have to get the HEQ5 out, which I am a bit lazy to do for solar visual!

[Stu]

Interesting stuff @Luke. Which eyepiece did you use in the Quark? I seem to recall 32mm or 40mm plossls were order of the day to keep the mag down?

I have found giro mounts to be amazingly capable, particularly if on a decent tripod. The TV85 and 106mm triplet went on my Giro-WR with no problem. The 106mm weighed 5.5kg if I recall correctly.

I used this setup at SGL10 at Lucksall to observe the partial solar eclipse, fab views.

[bomberbaz]

On 09/04/2021 at 21:21, Stu said:

 

I’ve found 100mm to be quite a sweet spot for white light solar observing. It has enough aperture to give excellent detail whilst being perhaps less affected by seeing conditions than larger scopes, although obviously the best high power views come with excellent seeing. I would have thought the Bresser would perform reasonably well. What have the seeing conditions been like for you?

With my FC100DC it is rare that I don’t see clear granulation, and at times it can be quite startlingly sharp.

I think that on reflection I need to give it chance Stu, perhaps on the occasions I tried maybe focus wasn't quite sharp enough or seeing wasn't the best, I am not sure but I am going to try again.

I have to admit that during lockdown last year I tried on several occasions without getting the granulation detail I was looking for and this put me off so the wedge has remained in a box since may last year.

So not sure what I am doing wrong, tried at between mag 150-180 with and without continuum filter also with a UHC but no joy.

Care to share your own methods to see if I can emulate them?