Dismiss Notice
New Cookie Policy
On May 24, 2018, we published revised versions of our Terms and Rules and Cookie Policy. Your use of AstronomyConnect.com’s services is subject to these revised terms.

minimum size to see surface details on Mars.

Discussion in 'Observing Celestial Objects' started by kevan hubbard, Jun 5, 2018.

minimum size to see surface details on Mars.

Started by kevan hubbard on Jun 5, 2018 at 12:25 PM

51 Replies 694 Views 1 Likes

Reply to Thread Post New Thread
  1. kevan hubbard

    kevan hubbard Well-Known Member

    Joined:
    May 15, 2016
    Posts:
    532
    Trophy Points:
    43
    Not much darkness this month but luckily Mars is just slipping into our midnight skies so it'll be well positioned as the evenings draw in after the solstice. I was wondering what the minimum refractor lense size is to see surface details given no moon or light pollution and bearing in mind it is closer to us this year.I've managed just to spy clouds on Jupiter using my 25mm pocket Borg using an eye piece giving about 20x magnification.
     
    Dave In Vermont likes this.
  2. jgroub

    jgroub Well-Known Member

    Joined:
    Aug 7, 2015
    Posts:
    185
    Trophy Points:
    43
    Location:
    Denver, CO
    I don't know what the minimum is; however, I did see albedo features with my 5-inch Mak the last time Mars came round 2 years ago, when Mars was significantly smaller than this time around. However, I was using the great Baader Moon & Sky Glow filter to increase contrast. Best planetary filter out there.
     
    Dave In Vermont likes this.
  3. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    3,928
    Trophy Points:
    113
    I'd guess around 80mm. I could see detail with my 130mm Newtonian last opposition. You'll need filters though probably. The Baader Neodymium is de rigueur for Mars IMO. Although I could see as much detail with a Wratten #11. Minus cyan filters are very good for Mars. Light blue filters are good for the polar caps.
     
  4. kevan hubbard

    kevan hubbard Well-Known Member

    Joined:
    May 15, 2016
    Posts:
    532
    Trophy Points:
    43
    Yes I was thinking about things like the polar caps not things like olympus mons in fact can any earth based ground telescope pick out olympus mons?the only pictures of olympus mons I've seen have been taken from Martian orbit.
     
  5. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    305
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    You can see polar caps and surface details with a 70mm refractor.

    I was using my 70mm f/10
     
    Last edited: Jun 6, 2018
  6. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    3,928
    Trophy Points:
    113
    In that case I'd guess around 70mm then lol.
     
  7. Dave In Vermont

    Dave In Vermont Well-Known Member

    Joined:
    Jan 5, 2016
    Posts:
    3,201
    Trophy Points:
    113
    This Mars-Go-Round will provide valuable data on what filter(s) will be the best choice(s) for Mars. This will provide alot of people - like me - trying many filters. And this time we have the hard science from the 2003 Mars Opposition, which is one truly for the books, for us to really be armed for bear. The negative-green FL-D Filter is an obvious candidate and will, no doubt, be found and ready. And stacked combinations will be tried and tried again.

    And the Baader Neodymium M & S Filter is always a good choice if you can only have one filter on hand!
     
  8. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    305
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    The Baader M&S and B+W FL-D are my most used Mars/ Jupiter filters. Always good results with them.
     
    Dave In Vermont likes this.
  9. Dave In Vermont

    Dave In Vermont Well-Known Member

    Joined:
    Jan 5, 2016
    Posts:
    3,201
    Trophy Points:
    113
    I knew you'd notice this last post of mine! :p

    That B+W FL-D Is quite intriguing. I also have the Tiffen. It's turns things green while also scattering it. Bizarre! In the the image below, it's the darker one. I'm sure you recognize the B+W just by the color.



    B+W FL-D Filter & Tiffen FL-D Filter in 2-Inch b.JPG


    Have fun!

    <POIT!>
     
  10. kevan hubbard

    kevan hubbard Well-Known Member

    Joined:
    May 15, 2016
    Posts:
    532
    Trophy Points:
    43
    Yes I suspected that the polar caps would be visible with something like a 70mm refractor. I suspect that probably a 60mm might just show them too?I've seen them out of a 70mm refractor I once owned which,sadly,I gave away.I viewed it through a 50mm spotting scope a few years back but can't remember what,if any,surface details where shown. My 25mm pocket Borg using high quality eye pieces just showed it as a round disk at 13x.pushed beyond that it tends to be shaky with a very restricted field of view. Strangely at 7x you have to move your eye around the eye piece to get in the whole field of view, I think that was using a 32mm eye piece made by celestron!
     
  11. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    3,928
    Trophy Points:
    113
    Usually Martian polar caps are more visible a few weeks after opposition. I don't know why.
     
  12. Gabby76

    Gabby76 Well-Known Member

    Joined:
    Dec 16, 2016
    Posts:
    305
    Trophy Points:
    43
    Location:
    Slovakia/ Canada
    Surface detail with a 50mm would need exceptional optics and eye. Some details can be glimpsed with a 60mm under excellent sky conditions.
    It is quite amazing the difference in viewed detail between a 60mm and 70mm!

    Dave, I am quite surprised at the difference in coatings between the two. Typically a FL-D is a quite subtle filter...
     
  13. kevan hubbard

    kevan hubbard Well-Known Member

    Joined:
    May 15, 2016
    Posts:
    532
    Trophy Points:
    43
    The difference between 60mm and 70mm doesn't seem much 10mm/1cm but when it becomes seen as a circle it's a lot,10mm across the circumference of a whole circle is a substantial increase in aperture. Of course you have to factor in such things as aperture stops behind the lenses and glass quality. I was,about a year ago,looking at a gentlemans pocket telescope in the science museum in Oxford, England.it was a draw tube design and of about 45mm but behind the lense you could see a major aperture stop which must have knocked received light down to about 20mm.also it wasn't very pocket unless you where a giant!
     
  14. Dave In Vermont

    Dave In Vermont Well-Known Member

    Joined:
    Jan 5, 2016
    Posts:
    3,201
    Trophy Points:
    113
    I used the Sirius Optics' '2003 Mars' filter on Mars (duh!) during that utterly exceptional Mars Opposition. As I've written come hither & yon. And that filter is a magenta-colored filter, and I'm trying to find out what all went into these.....But the reason I'm writing this is the discussion has been hitting on the Martian Polar-Caps, and what works to get them to be more apparent - so here goes:

    This magenta-colored filter looks like this:


    Sirius Optics Mars 2003 Filter - PNG.png


    When using this it makes the light red areas and the 'green/brown' darker areas very distinct from each other. In other words, these are in sharp contrast. Remarkably so! Sharp, sharper, and sharpest! As for those often virtually invisible Polar-Caps, both Northern & Southern, to stand-out in incredible contrast and brightness. Or in the exact words I cobbled together at the time (you likely have noted - I'm quite the 'Word-Smith'- please do forgive):

    "They stood-out like two little white cotton-balls, in sharp conflict with the jet-black field of outer-space."

    So yes - these magenta-colored glass-filters work very well indeed for the Martian Polar-Caps. :cool: Now I've been busily assembling a squadron of the different magenta-bearing filters out there - both optical and photographical filters. New & used. Current-production & no longer being manufactured.

    Next Up -

    We're On a Mission to Skin an Onion! Join Us! Join Us! Come On In! :p
    Guess where I mean....?


    ps - Gabby, almost forgot! Yes, the difference in intensity between the B+W and this Tiffen thing is quite striking to my eye, too. I'm looking at the colorations coming back at me. The B+W does't seem to have any green to it, while the Tiffen does. And the old SO 'Mars 2003' does not, while the Orion Mars does. So I'm also on a quest to find out what these 'coatings' are. Speaking of the chemical-compositions of these things actually are. As an organic-chemist, if & when I find out, I'll endeavor to translate my findings into 'Everyones' English' and write-up what these are and do. So all us astro-freaks can understand what's going on. Any and all information you come by, please pass it my way?

    Thanks!
     
    Last edited: Jun 7, 2018
    Orion25 and Gabby76 like this.
  15. kevan hubbard

    kevan hubbard Well-Known Member

    Joined:
    May 15, 2016
    Posts:
    532
    Trophy Points:
    43
    They've sent a probe,can't remember who NASA, ESA one of the two,to probe into Mars's onion skin.see if it is still active down at the core.those volcanos appear either expired or dormant, I'm guessing the first.it's still got a weak but localised magnetosphere suggesting that the core may still be molten. Although Venus is a similar size to earth meaning that it probably has a molten core but virtually no magnetosphere but that could be something to do with the slow spin.spin up Venus to earth or Mars rotational speeds and hey presto a magnetosphere? Mind mercury is thought to be solid to its ferrous core yet has a stronger magnetosphere than Mars.
     
  16. Dave In Vermont

    Dave In Vermont Well-Known Member

    Joined:
    Jan 5, 2016
    Posts:
    3,201
    Trophy Points:
    113
    I was referring to Venus in the 'Onion' remark. Mars has a very tenuous atmosphere, about 1/20th that of Earth. But Venus is now being actively considered to launch full-scale explorer craft to. And has very thick atmosphere with an atmospheric-pressure about 200X* that of Earth. Not to mention a round-the-clock ground-level temperature of a bit over 800°F.

    Easy to get confused what is being done and where. We have a Mars-Opposition up very soon. And Reggie just found a really easy, simple, and inexpensive way to elucidate markings in the Venusian atmosphere. Things are amazing and coming fast!

    Might even make-up for that Monster-Winter!


    * I think it 200X, or maybe 20X? Either way - not a great place to plan for as a vacation destination (unless it's for someone else you don't care for...:p).
     
    Orion25 likes this.
  17. kevan hubbard

    kevan hubbard Well-Known Member

    Joined:
    May 15, 2016
    Posts:
    532
    Trophy Points:
    43
    I suppose all planets are onions?layers and layers except they don't make you cry when you cut into them!I haven't seen Venus for a bit due to a combined effort of evening commitments,clouds and such long days as our solstice approaches.I believe that only the USSR has landed anything on Venus but others have mooched around it's cloud tops.
     
  18. Dave In Vermont

    Dave In Vermont Well-Known Member

    Joined:
    Jan 5, 2016
    Posts:
    3,201
    Trophy Points:
    113
    Well, I cooked-up ( :rolleyes: ) the Onion-Planet analogy for Venus as it's my favorite planet and yet it remains a very mysterious world. You find out one thing about it, another mystery pops into view, and when you 'peel' away that mystery? There's another one waiting! It's like peeling an onion. You ever peeled an onion? It's endless layers - until you reach the center.

    And there's nothing there! Just a pile of peeled layers of onion all over your table.

    :eek::D
     
  19. kevan hubbard

    kevan hubbard Well-Known Member

    Joined:
    May 15, 2016
    Posts:
    532
    Trophy Points:
    43
    Didn't Winston Churchill once call Russia an enigma within an enigma? The same could be said for planets including our own.I was reading a few days back that earths spin,magnetosphere and gravity is not enough to stop the sun blowing our atmosphere away.the proposed notion was dark matter allows earth to hold onto its atmosphere. Not sure if it's true but an interesting theory.
     
    Nebula and Dave In Vermont like this.
  20. kevan hubbard

    kevan hubbard Well-Known Member

    Joined:
    May 15, 2016
    Posts:
    532
    Trophy Points:
    43
    Yes I've peeled plenty of onions as i, it's been replaced by hot,hot,Indian curry now,once had a love of pickled onions and would eat them slowly layer by layer.
     

Share This Page