Delos 3.5mm and Radian 3mm Saga Pt 3

[alan potts]

Delos and Radian back to the focuser

After posting yesterday with the second part of my review on the Delos 3.5mm and Radian 3mm I was encouraged to push the envelope somewhat by one or two members to include the Sky- Watcher 190mm M/N, one of my favourite scopes. The reason I excluded it from the test was that in my opinion it was just too much magnification, but some disagreed and I aim to please if at all possible.

Maksutov Newtonian 190mm

First just let me say I went to the scope with a fair range of high power glass.

Delos; 3.5mm, 4.5mm, and 6mm.

Radian; 4mm 3mm and 5mm.

Nagler 6mm-3mm zoom.

I wanted to find out just how high I could push things on a night where there was no; wind or cloud and very low humidity. For me these were the best seeing conditions I had had for some time, the only thing spoiling the night was a very large Moon which was too close to Jupiter for me, still they say Jupiter is Moon proof, we will see.

After finding the planet which was not difficult with the wonders of modern technology I started out with the 6mm Delos (X167) just to have a reference point, the planet was tack sharp to steal a phrase and I would have said it to be absolute on the money for everything. The belts of the equatorial region were sharp with some wispy detail there to be seen and the there were belts both North and South of this visible as well as clear shading of the polar regions. The four small moons were also discs and were sharp without any distortion of the shape. I always find this scope confuses me with where north and south are as it is different from my others. Next I sort of wished I had a 5.5mm something or the other but the 5mm Radian (X200) had to do as the Pentax 5mmXW was out on loan to a friend, I did checkout the Nagler zoom at an approximate setting and everything was fine, this is a sharp eyepiece up there with the best of them. The Radian was no better but it was no worse at the higher magnification and I would have said the pervious description would also apply for all aspects of the view before me

.

Now I took the bull by the horns and plugged in the 3.5mm Delos (X285), straight away this showed a visibly larger disc and there was also the two equatorial belts at well as thinner belts the north and south either side but with my eyes it was no where near as distinct as before, it lacked punch, the belt had taken on a slightly more silvery look and I could no longer discern the detail that I could around and below X200, this rather negates the reason for viewing at this level of magnification in my opinion but I concede some people may like this type view and there is a slim chance that others may have better conditions. I did find by looking for prolonged periods there were other nuances of detail that were drifting in and out but for me they were not as clear as with the smaller powers, not that x200 is small.

By now I was thinking in for a penny in for a pound, so I slotted the 3mm Radian (X330) into the focuser, much to my surprise it was no worse but it was also no better which was obviously going to be the case. I noticed deterioration in the disc of the moons at this power, though I had to move the scope slightly to see them such was the narrow field of view, in general the main body held up well but the edge of the planet was no longer crisp as before, it had a wooly look about it, for sure cashmere .

I have to conclude that unless other people have better sky conditions and eye sight than me I could not really see the point in pressing the scope to such high levels. My eyes are not all they once were but a few years ago they were absolutely excellent with almost perfect colour perception, something that was checked on a regular basis as part of my work. The other downside of high power is even the slightest breath of wind makes viewing almost impossible, I was lucky and had a still night but could not avoid knocking the scope from time to time. I  must concede, though within specifications, this mount it not really study enough for this scope. I think after I had time to consider my finding I believed the best power was provided with the 5mm Radian (X200) this was acceptable to me, the Delos 4.5mm (X222) was also very good though, I cannot see a case for going past this.

The other thing that I found I did not agree with 100% was the much used statement that Jupiter is Moon proof, for me there was a reduction in the contrast between disc and sky and as far as I am concerned this must have a small effect on the overall image you are seeing. Maybe this was not the best night to conduct this test but with the conditions I had I did anyway.

It would be nice to see some reports from other members doing something along the same lines with theirs scopes under there skies, even with other variables it would be a worth while experiment.

Alan.   

[michael.h.f.wilkinson]

Thanks for the report. As I said, I do push my C8 to 290x with the XW7 on nights of good seeing, and my best view of Saturn bar none was using the Vixen LV7 I used to have (under exceptional conditions). I do agree the contrast is reduced a bit at higher mag, but I find I can pick out more detail. On Mars the latter effect is more pronounced, and more magnification helps more. Maybe I do not experience as much deterioration of contrast due to the larger central obstruction (meaning the contrast was lower to begin with), or the fact that I have an F/10 scope whereas the MN190 is F/5.3. While TV and Pentax EPs do not break out a sweat at F/5.3, correction might still be a tad better at F/10. Besides that, EPs and magnification are notoriously personal.

[alan potts]

Michael,

I could not agree more, magnification is a personal thing and I hope that came across in the way I wrote the piece. Who am I to impose my views on others, I just try to write as i see it. You could have a point in the scope speed as well though going back to the opening line I find I like the same in my LX 200, rarely going above X200 on Juptier and about X260 on Saturn and Mars, though the Moon will take up to X500 with my sky on a good night.

Alan

[John]

Thanks for more to digest on high power viewing Alan 

Your findings mirror my own in many ways. Most of the time Jupiter ain't no friend of ultra-high magnifications, if you want to see the details at their best.

On Saturn and Mars however you might find the situation a little different perhaps ?

I'm sure there is an interesting discussion to be had on what it is about the nature and presentation of the Jovian features v's those on Saturn and Mars, that leads to their differing response to high magnifications 

[alan potts]

Interesting discussion indeed, the only thing I can see and more so on Mars is the difference in the colours . The other thing is also you could argue both need more magnification in the first place to present them eye pleasingly large enough.

Alan.