21 replies to this topic

[mikeDnight]

Mars and Solis Lacus 4.5"arc through 100mm Tak and 2mm Vixen HR. April 10 2019.

 

I don't know why the images are on their side, but north is top in the prism views that were sketched at 370X using a 2mm Vixen HR eyepiece.  

north is to the right of the lower image.

Edited by mikeDnight, 11 April 2019 - 05:06 PM.

[niteskystargazer]

Mike,

 

Nice sketches of  Mars and Solis Lacus at 4.5" arc  .

 

CS,KLU,

 

,

 

Tom

[Astrojensen]

That's more detail than I usually see at opposition. I just... Wow.   

 

 

Clear skies!
Thomas, Denmark

[frank5817]

Mike,

 

These are very fine looking sketches.

 

Frank

[Uwe Pilz]

These are great sketches. Most important: Done with a moderate aperture of only 4 inch. Thank you..

[stanislas-jean]

Hi Mike,

This is a good tentative with a 100mm aperture. The contrast given on sketch are surely enhanced, not those seen at the eyepiece.

Are you sure of the UT time, 20H44 involves a planet elevation above ground of 19° at my home?

I insert a typical picture of the mars face at the time of observation for a comparison,

 

 

north at top and tilt of the rotation axis, east at left (phase side);

indeed the atmospheric events are not shown that lower the contrasts. It is for mare acidalium, liliacus lacus, eos and mare erythraeum, etc...Those features are sized substantially less than 1" of arc. For the understanding, the diffraction effect will blurr consistently the vision at the eyepiece, if seen this will create "ghost" features more than defined features with a contour.

But the brightenings may be representative of a certain actuality and may be considered.

The phase effect in spite of 0.94 ratio is noticeable by the shadowing effect from the terminator, sothat the contrast of brightnings is a little enhanced, this helps.

 

Anyway an excellente tentative for reporting, from my opinion a 5" is placed at the limit of diffraction balance, it can show according the typical but under fixed images. The 6" helps to be away the diffraction margin, this is not linear effect around the aperture instrumental limit , but it helps to merge features above the blurring effect consistently.

Stanislas-Jean

[mikeDnight]

Hi Mike,

This is a good tentative with a 100mm aperture. The contrast given on sketch are surely enhanced, not those seen at the eyepiece.

Are you sure of the UT time, 20H44 involves a planet elevation above ground of 19° at my home?

I insert a typical picture of the mars face at the time of observation for a comparison,

 

mars 10.04.19 20H44UT.jpg

 

north at top and tilt of the rotation axis, east at left (phase side);

indeed the atmospheric events are not shown that lower the contrasts. It is for mare acidalium, liliacus lacus, eos and mare erythraeum, etc...Those features are sized substantially less than 1" of arc. For the understanding, the diffraction effect will blurr consistently the vision at the eyepiece, if seen this will create "ghost" features more than defined features with a contour.

But the brightenings may be representative of a certain actuality and may be considered.

The phase effect in spite of 0.94 ratio is noticeable by the shadowing effect from the terminator, sothat the contrast of brightnings is a little enhanced, this helps.

 

Anyway an excellente tentative for reporting, from my opinion a 5" is placed at the limit of diffraction balance, it can show according the typical but under fixed images. The 6" helps to be away the diffraction margin, this is not linear effect around the aperture instrumental limit , but it helps to merge features above the blurring effect consistently.

Stanislas-Jean

Definitely 20.44 UT. I was observing from the UK, though I'm not sure of its actual angle. Approximately 20° sounds about right!

The albedo features through the telescope were not quite as dark as the image of the sketch shows them, but they did become more evident as the observation progressed. Initially the view wasnt so detailed as the first sketch shows, so to try and make sure I recorded the features as accurately as I could, I made three different sketches. The disc size even at 370X was very small but the seeing was quite steady. I thought I detected the terminator but didn't show it in the sketch as it wasn't significant enough in my mind. 

The image you attached shows Solis Lacus but Margaretifer was nowhere near as prominent visually.

The attachment below shows north at the top while the view is reversed as a prism was used, so had I added terminator detail it would be on the right of the sketch. Preceding is to the left.

As regards resolution of features, it seems to me that there needs to be a serious rethink about the resolution limits of telescopes and planetary detail, as although not immediately evident, the features viewed were solidly presented in the 100mm Tak and Vixen HR, to the point that I'd imagine they could be measured with reasonable accuracy. 

Edited by mikeDnight, 12 April 2019 - 07:21 AM.

[stanislas-jean]

Hi Mike,

I sent you a pm for.

Frankly it is not a bad document done with a perfect 100mm.

But for the aperture in cause this would need higher means on the present situation.

This is as.

Very good skies

Stanislas-Jean

[mikeDnight]

The ability of a 4" refractor to reveal subtle detail on a 4.5 arc-second disc is a challenge but far from impossible. The disc size at 370X, though small, is still sufficiently large enough to study. And, although at first glance it may appear like there's nothing to see, over time fleeting glimpses of albedo features reveal themselves. This is where the power of the pencil comes in to play, as it enables the observer to mark down the relative positions of the varying albedo markings as they come and go amidst the waves of atmospheric turbulence, and over time build up a representation of what is actually on the disc. So the detail on the finished drawing is a representation of the albedo detail seen over the course of the observation, and not at any one point during the observation. It can be likened to stacking images, as the sketch is built up as detail reveals itself.

 The sketch is a truthful rendition of the detail visible in a 100mm refractor of high quality under good conditions in the night in question. To suggest otherwise reveals your inexperience either as a planetary observer or 4" refractor user. What the self appointed experts think and what theory suggests is of no consequence what so ever. The fact remains that the sketch is an accurate representation within reason, and  as has  been proved time and again through many observations of Mars over several years while it has been sub 5" arc, the detail recorded has always been, to some degree, recognisable respecting the CM. ( I never check the LCM in advance)!  

 You mentioned in a PM that a larger aperture is needed, implying a 6" minimum aperture would be needed to reveal such detail. Though a 6" would have advantages, it is certainly not necessary! Using my 10" F6.3 Newtonian a few nights ago, the disk was easier to see but the albedo features, though detectable, were somewhat blinded by the brilliance of the image. So it's horses for courses it seems. The 100mm with its dimmer view allowed the subtle albedo markings to reveal themselves more easily in moments of steady seeing.

[stanislas-jean]

Effectively some may have enormous experience, with more than a 100mm can do.

On the pm I left you the expected image at the focus plan of a perfect 100mm created with aberrator (based on diffraction limits laws and rules).

 

 

Image at the focus plan, some degradation have to be added: the eyepiece and your own eye, so perfect.

Nothing to see with your given image taken on planet  above horizon of 20° with sensitive color aberration by the earth atmosphere.

Any optic design doesnot correct this aberration without a device which have to be perfectly constructed.

 

Your optimism is making your unexperience on an evaluation.

I imagined forums for exchanges ideas, views, diagnostics, you are not in position to ear something with consistency.

Sorry, this is not a competition here, honestly.

Your copy (images) needs to be revised, frankly.

Stanislas-Jean

 

 

[mikeDnight]

W. F. Denning over a hundred years ago made a very pertinant observation regarding observers themselves, when he said in his book Telescopic Work for Starlight Evenings   " There is little point in having a glass of large capacity at one end of a telescope and a man of little capacity at the other"! 

 

Perhaps you ought to go back to the eyepiece and learn to observe rather than just look!! (Perhaps a change of telescope is in order also)!!!

[stanislas-jean]

Impressive comments!

The results should do with the guy at the back of the opaque lens.

To-day fortunately we have some tools for evaluation rather than just words.

Stanislas-Jean

[astronz59]

Ay,caramba, este muy impresionante! I wish my notebook was so neat!  

[Asbytec]

In good skies, it's certainly possible to pick out (presumably high contrast) detail on objects as small as the apparent diameter of the Airy disc of the aperture. I've done it on Ganymede through a 150mm aperture, it should be very possible at 4.5" arc through a 100mm aperture. I've seen mars when it was that small and saw something, but not as much as the OP. Well done.

 

Simulations are useful as a resource to identify features, but they may not accurately show what we see and the way we see it. We may miss something or may very well see it differently. We sketch what we see and hope it matches nicely enough. We do not observe simulated images, though, we observe the real world dynamic image in real time. 

Edited by Asbytec, 20 April 2019 - 06:56 AM.

[paulh83]

Great work Mike!

[Achernar]

You have an eagle's eye and superb seeing along with a great telescope. I've never seen Mars like this, except at opposition through my 10 and 15-inch Dobs, and at that it requires steady seeing and at least 300X.

 

Taras

[stanislas-jean]

In good skies, it's certainly possible to pick out (presumably high contrast) detail on objects as small as the apparent diameter of the Airy disc of the aperture. I've done it on Ganymede through a 150mm aperture, it should be very possible at 4.5" arc through a 100mm aperture. I've seen mars when it was that small and saw something, but not as much as the OP. Well done.

 

Simulations are useful as a resource to identify features, but they may not accurately show what we see and the way we see it. We may miss something or may very well see it differently. We sketch what we see and hope it matches nicely enough. We do not observe simulated images, though, we observe the real world dynamic image in real time. 

Quite different: we observe and report and simulation should match, not the contruary.

Otherwise every report could be magic but with no sense actually.

I saw the galileans as you in a 150mm but the vague features noted doesnot constitute an obvious information.

[Asbytec]

Quite different: we observe and report and simulation should match, not the contruary.

Otherwise every report could be magic but with no sense actually.

I saw the galileans as you in a 150mm but the vague features noted doesnot constitute an obvious information.

Yes, Ganymede is more vague in it's detail. 

 

As to how well a simulation should match, well, simulations (from actual images) of Ganymede bore only a vague resemblance. A bright spot here, and darker albedo there. One could discern that from the sim, the detail was where it was supposed to be best I could tell. Of course, the images were of higher resolution the 150 is not capable of, so the resemblance only went so far. 

 

Simulations are static images and usually of high contrast, especially in the Mars sim program you (and I) use. The observer is observing in the real world of seeing effects where detail comes and goes or may not be visible at all. I would not look for an exact match with a sim under those conditions, but a more general one of broader features generally placed correctly. Especially in such a small disc. 

[stanislas-jean]

Very sorry but this is not like you note.

We could capture something  more or less at the eypiece, BUT this would remain to-day with tools we have on some expectations for what we aimed. Winjupos, mars previewer, aberrator, etc... we have more to-day.

I did something on daylight on mercury, some past ago with a 100ED sw. I got small contrasted features on the session.

That matched with a winjupos, for a 100mm.

I am not dreaming about results got by such apertures, I know exactly what they can do, tak, zeiss or any others, same.

I did with a simple achromat, the vixen 100mm F10 and also an istar 100F12. All did the same, a little more with istar on planets.

Any guy arguing making more than a 100mm perfect considered in any software based on diffraction rules and aberrations involvement, is somewhere a guy very optimistic, too much that the abilities, so a kind of a BIG frog of Mr La Fontaine.

Very sorry to write this here, because I was still on the way that US observers, not had, because it was, but to-day have not enough a good approach, only commercial. 

When reading this I think we will have anathesmes for, ..., against trade marks, only.

Don't hesitate to write this.

I started with a 76mm F16 Unitron at the beginning, never saw the same on mars with those to-day pseudo apochomat, even the trade marks named, comparing to-day visually, still have, in spite of the violet light hazze, slight.

Did mars, venus and jupiter with it so detailed on the 80ies.

Probably question of own eyes: but 0 chromatic aberration is not the only channel for approaching those software expectations.

Good skies.

Stanislas-Jean

[Asbytec]

Good skies, Stanislas. Not sure how to reply.

[stanislas-jean]

Software expectations are to-day on good level for showing what it is possible with an aperture and a seeing level.

Going beyond is something out of actual concern.

We could speak about experience results, long term (that some get as basis for proving), and those got by software on moments, this is also convergent and must be.

Good skies.

Stanislas-Jean

[agmoonsolns]

Wow, these are truly outstanding! I spent a lot of time looking at these, they are very good! I really appreciate the information you have added and your handwriting is so beautiful!