Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

What are reasonable expectations of a 4" apo on mars this year's opposition?

  • Please log in to reply
108 replies to this topic

#76 contrailmaker

contrailmaker

    Surveyor 1

  • -----
  • Posts: 1,752
  • Joined: 02 Jan 2009

Posted 21 March 2020 - 10:44 AM

Two oppositions ago I had a great time observing Mars using an Orion 100ED.  All the mayor albedo features as well as the polar caps and, when present, clouds/dust are clearly visible with small telescopes and plenty of details with a 100mm. Olympus Mons has remained elusive with the 100mm. If my recollection is accurate, the best I have done is observing the clouds that sometimes form on top of the volcanoes using a 6” refractor. Filters help a lot with that as they are usually low contrast. Keep in mind that the duration of the Martian day is almost exactly that if a day on earth. So if one observes at the same time each evening one gets to see the same side of Mars. 

Really looking forward to the next opposition. The last one was a bust. 

 

CM
 


  • m9x18, eros312, Terra Nova and 2 others like this

#77 mikeDnight

mikeDnight

    Apollo

  • ***--
  • Posts: 1,187
  • Joined: 19 Apr 2015
  • Loc: Wild Wild West - North West England

Posted 21 March 2020 - 11:42 AM

Two oppositions ago I had a great time observing Mars using an Orion 100ED.  All the mayor albedo features as well as the polar caps and, when present, clouds/dust are clearly visible with small telescopes and plenty of details with a 100mm. Olympus Mons has remained elusive with the 100mm. If my recollection is accurate, the best I have done is observing the clouds that sometimes form on top of the volcanoes using a 6” refractor. Filters help a lot with that as they are usually low contrast. Keep in mind that the duration of the Martian day is almost exactly that if a day on earth. So if one observes at the same time each evening one gets to see the same side of Mars. 

Really looking forward to the next opposition. The last one was a bust. 

 

CM
 

Yet by observing at the same time the following night, you'll get a second pop at detecting that illusive Olympus Mons. 


  • contrailmaker likes this

#78 Brent Campbell

Brent Campbell

    Viking 1

  • *****
  • Posts: 864
  • Joined: 09 Feb 2010
  • Loc: Olympia, WA

Posted 21 March 2020 - 12:01 PM

The polar caps, Syrtis, Hellas, & Argyre should be easy in a quality 4" refractor.  I've seen clouds over / around Olympus Mons with my 3" F15 achromatic, and I've imaged Sinus Sabaeus & Meridiani with a 60mm F15 refractor.  But, I've had near-perfect planetary seeing here at The Swamp.

 

This map is good for identifying the features commonly seen:

 

attachicon.gifMars - Visual Features Map.jpg

Bomber Bob.  Where can I download a copy of that map?



#79 BillP

BillP

    ISS

  • *****
  • Posts: 20,196
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 21 March 2020 - 12:02 PM

I still remember Ken Fulton's advice about sketching an egg.

???



#80 t.r.

t.r.

    Fly Me to the Moon

  • ****-
  • Posts: 6,168
  • Joined: 14 Feb 2008
  • Loc: 1123,6536,5321

Posted 21 March 2020 - 12:15 PM

The polar caps, Syrtis, Hellas, & Argyre should be easy in a quality 4" refractor. I've seen clouds over / around Olympus Mons with my 3" F15 achromatic, and I've imaged Sinus Sabaeus & Meridiani with a 60mm F15 refractor. But, I've had near-perfect planetary seeing here at The Swamp.

This map is good for identifying the features commonly seen:

Mars - Visual Features Map.jpg

I’ve never been able to resolve the paint runs of Gomer Sinus in up to 140mm refractors...anyone lay claim to it with like aperture?

Edited by t.r., 21 March 2020 - 12:15 PM.


#81 contrailmaker

contrailmaker

    Surveyor 1

  • -----
  • Posts: 1,752
  • Joined: 02 Jan 2009

Posted 21 March 2020 - 01:47 PM

Yet by observing at the same time the following night, you'll get a second pop at detecting that illusive Olympus Mons. 

Challenge accepted, Olympus Mons will be one of my goals this year. 
 

CM


  • mikeDnight likes this

#82 Bomber Bob

Bomber Bob

    Hubble

  • *****
  • Posts: 17,505
  • Joined: 09 Jul 2013
  • Loc: The Swamp, USA

Posted 21 March 2020 - 10:59 PM

Bomber Bob.  Where can I download a copy of that map?

Can't recall where I found it, but you can save the CN copy that I posted to your PC, Laptop, tablet, or other device...



#83 m9x18

m9x18

    Surveyor 1

  • *****
  • Posts: 1,818
  • Joined: 12 Oct 2007
  • Loc: Abilene, Texas USA

Posted 22 March 2020 - 01:42 AM

???

Boiled down (pun intended), he said that you would be surprised at how many features can be found on the surface of an egg if you just look for them. Sketching forces us to be more observant. To the casual observer, the egg's exterior may appear uniform and bland. But, if we can get good at finding and sketching the minute details on an eggshell, imagine how well we could do with the things found in our telescope's eyepiece. It's just a way of training the eye as well as a method to improve our sketches.  


Edited by m9x18, 22 March 2020 - 11:54 AM.

  • EverlastingSky, BillP, payner and 4 others like this

#84 stanislas-jean

stanislas-jean

    Gemini

  • -----
  • Posts: 3,161
  • Joined: 22 Oct 2008

Posted 22 March 2020 - 05:19 AM

If you replace this famous boiled egg by Something else more evaluating like a resolution grid placed at a distance sothat some area come to a resolution limit of the 4" aperture,

this will bring a lot to you:

- quality of the optics (well characterised),

- response through the seeing,

- response to the light level of the target, testing during day, at dawn, during night, Under moonlight lighting.

The scope is not all the question but also the ability of the observer even using the best of the best scope.

Performing such, when comparing OTA with different design and construction you see quickly that with "minimal" optical acuracies fullfilled the major limiting factor is the observer equation.

 

Olympus mons is not a big concern through a 4" aperture, because possible also through a 3" aperture, when mars is 12-13" of disk and lefting the limb and the Terminator of the planet.

Stanislas-Jean


  • m9x18, Astrojensen, eros312 and 2 others like this

#85 daquad

daquad

    Surveyor 1

  • *****
  • Posts: 1,714
  • Joined: 14 May 2008

Posted 22 March 2020 - 09:44 AM

Boiled down (pun intended), he said that you would be surprised at how many features can be found on the surface of an egg if you just look for them. Sketching forces us to be more observant. To the casual observer, the egg's exterior may appear uniform and bland. But, if we can get good at finding and sketching the minute details on an eggshell, imagine how well we could do on the things found in our telescope's eyepiece. It's just a way of training the eye as well as a method to improve our sketches.  

I recall reading that sketching the full moon with the naked eye is excellent practice for sketching at the telescope.

 

Dom Q.


  • m9x18 likes this

#86 m9x18

m9x18

    Surveyor 1

  • *****
  • Posts: 1,818
  • Joined: 12 Oct 2007
  • Loc: Abilene, Texas USA

Posted 22 March 2020 - 07:46 PM

Yes, all true. Plus, we can try sketching boring things like a wall other such mundane subjects/objects. We would be sure to benefit from exercises like that as they cannot help but to improve our observational skills and sharpen our sketching abilities all at the same time. So watch out Mars, we're getting ready for you!     


  • John Huntley and daquad like this

#87 stanislas-jean

stanislas-jean

    Gemini

  • -----
  • Posts: 3,161
  • Joined: 22 Oct 2008

Posted 23 March 2020 - 04:41 AM

Better things to observe when targets to test are typically unknown, sketched then compared with the target at final.

An other game.

Stanislas-Jean


  • m9x18 likes this

#88 laedco58

laedco58

    Ranger 4

  • *****
  • Posts: 304
  • Joined: 29 Dec 2015
  • Loc: Sandstone Minnesota

Posted 23 March 2020 - 09:08 AM

I’m hoping the weather is favorable. Planetary observation through a refractor is a new experience for me. Well actually any non terrestrial observation with a refractor is a new experience for me, lol. 


  • Jon Isaacs and m9x18 like this

#89 mike bacanin

mike bacanin

    Surveyor 1

  • *****
  • topic starter
  • Posts: 1,883
  • Joined: 19 Mar 2007

Posted 28 March 2020 - 12:35 PM

After reading of Don Pensack and his experience of observing mars with the Baader Contrast Booster filter, I think i'll probably give it a try.

 

Mike



#90 Rutilus

Rutilus

    Mercury-Atlas

  • *****
  • Posts: 2,608
  • Joined: 17 Dec 2010

Posted 20 April 2020 - 02:38 PM

I found these while going through some old files today. Mars was between 12 and 13" in size at the time.

Scopes used were my 4 inch Takahashi and 120mm f/8.3 achromat.

 

Attached Thumbnails

  • Mars-x8x-cn.jpg

  • Dave Mitsky, BillP, Traveler and 10 others like this

#91 Rutilus

Rutilus

    Mercury-Atlas

  • *****
  • Posts: 2,608
  • Joined: 17 Dec 2010

Posted 26 April 2020 - 08:47 AM

The polar caps, Syrtis, Hellas, & Argyre should be easy in a quality 4" refractor.  I've seen clouds over / around Olympus Mons with my 3" F15 achromatic, and I've imaged Sinus Sabaeus & Meridiani with a 60mm F15 refractor.  But, I've had near-perfect planetary seeing here at The Swamp.

 

This map is good for identifying the features commonly seen:

 

attachicon.gifMars - Visual Features Map.jpg

Back in 2009, I purchased a vintage 76.2mm f/16.4 Achromat refractor for the grand sum of $30. The scope was made by Kenko

and is circa 1965. It came with all the bits in a long wooden box. The original mount I found to be useless for the length of the scope,

so I mounted the scope on my Vixen GP mount. Fortunately, the scope could be used with 1.25" eyepieces,via a Vixen 36mm thread

adapter that fitted into the end of the focus mount drawtube. The lens has coating issues, due to someone going over the top with

lens cleaning over the years.

Even with its lens problem the scope does give good views of Mars. Here is a set of drawings I made back in late 2009 when

Mars was between 9 and 12.5 arc seconds in size.  

Attached Thumbnails

  • Mars-76mm-cn-1.jpg

  • payner, Traveler, daquad and 6 others like this

#92 JKAstro

JKAstro

    Mariner 2

  • *****
  • Posts: 293
  • Joined: 11 Aug 2006

Posted 26 April 2020 - 10:51 AM

Earlier in this thread it was mentioned that Mars at opposition will be quite bright.  Is this then an object where having too much aperture can actually be a hindrance?

 

Elsewhere I recall never settled debates about what is the "best" planetary scope, with one camp regarding a 6 inch APO as their favorite and others a 10-12 inch Dob and a few others choosing a 7-8 inch Mak.  Would the brightness of Mars slightly tip this advantage towards the smaller and more accurate contrast of a refractor?  Or does it simply mean that the larger scope is more likely to require filters to bring the brightness down to more tolerable levels?

 

Not trying to start the "best" debate again, but just wondering if the characteristics of Mars makes it an object where aperture is less important than something like Jupiter, and that a 4 inch APO would see about as much as a larger scope because in most cases Mars doesn't have small sharp details such as the white ovals on Jupiter.

 

In the collage of sketches Bill put together, it is not clear from looking at them who used a larger scope.  I feel that with sketches of Jupiter one can fairly accurately guess the aperture used by the detail given, but less so here.  In my own experience I don't recall seeing any more detail in my VMC200L on Mars than I did with my Vixen 4 inch achromat, but on Jupiter the VMC200L wins.

 

JK



#93 BillP

BillP

    ISS

  • *****
  • Posts: 20,196
  • Joined: 26 Nov 2006
  • Loc: Spotsylvania, VA

Posted 26 April 2020 - 11:51 AM

In the collage of sketches Bill put together, it is not clear from looking at them who used a larger scope. 

The image has each person's CN handle under it.  Then in my post I listed all those CN handles and the scopes they used.  So these are who had the larger scopes:

 

Jef De Wit      305mm   Newtonian  02/04/2010

NerfMonkey      305mm   Newtonian  02/15/2010

Robert Forgacs  305mm   Newtonian  02/02/2010

 

Astroducky      318mm   Newtonian  01/27/2010

 

Sixela          400mm   Newtonian  01/27/2010

 

Erika Rix       406mm   Newtonian  02/07/2010


Edited by BillP, 26 April 2020 - 11:52 AM.


#94 Bomber Bob

Bomber Bob

    Hubble

  • *****
  • Posts: 17,505
  • Joined: 09 Jul 2013
  • Loc: The Swamp, USA

Posted 26 April 2020 - 12:07 PM

In my own experience I don't recall seeing any more detail in my VMC200L on Mars than I did with my Vixen 4 inch achromat, but on Jupiter the VMC200L wins.

 

No Mars in my VMC200L while I had, but it was great with Jupiter.  Mars is a weird one.  Close to opposition my Astro Optical 75mm F15 @ 240x can show as much detail as my 4" F15.  I'm looking forward to side-by-sides between the AO 75mm and my new AT102ED.  Not sure which one will win -- which is surprising to me.  Why?  I have no idea.

 

Thanks for the list, Bill.  Tough to argue with big Newtonians.  This apparition, I have a vintage 8" F6 Newtonian that in testing acts like a big APO, and I can't wait to train it on Mars, too.



#95 John Huntley

John Huntley

    Mercury-Atlas

  • ***--
  • Posts: 2,633
  • Joined: 16 Jul 2006
  • Loc: SW England

Posted 26 April 2020 - 01:35 PM

With it's low position in the sky from the UK, my refractors have an advantage simply because it is easier to get the darn things pointing at the red planet. It's more awkward with my 12 inch dob even if it does produce great planetary views.

 

For the forthcoming Martian opposition I will have the choice of my Tak FC-100 DL, my ED120 and my TMB/LZOS 130 F/9.2 triplet. I wonder which will deliver the best views ?. Its going to be fun finding out smile.gif


  • stevenwav likes this

#96 James Ball

James Ball

    Apollo

  • -----
  • Posts: 1,305
  • Joined: 22 Jun 2014
  • Loc: Western Kentucky

Posted 26 April 2020 - 02:03 PM

In my own experience I don't recall seeing any more detail in my VMC200L on Mars than I did with my Vixen 4 inch achromat, but on Jupiter the VMC200L wins.

 

No Mars in my VMC200L while I had, but it was great with Jupiter.  Mars is a weird one.  Close to opposition my Astro Optical 75mm F15 @ 240x can show as much detail as my 4" F15.  I'm looking forward to side-by-sides between the AO 75mm and my new AT102ED.  Not sure which one will win -- which is surprising to me.  Why?  I have no idea.

 

Thanks for the list, Bill.  Tough to argue with big Newtonians.  This apparition, I have a vintage 8" F6 Newtonian that in testing acts like a big APO, and I can't wait to train it on Mars, too.

I just ordered the AT102ED so I am also looking forward to it!  I will be doing both visual and some imaging so it will be interesting what it will show.  Anyone have an idea how much more detail I could possibly get with imaging using a 4"?



#97 Dave Mitsky

Dave Mitsky

    ISS

  • *****
  • Moderators
  • Posts: 91,878
  • Joined: 08 Apr 2002
  • Loc: PA, USA, Planet Earth

Posted 26 April 2020 - 02:40 PM

I own a 101mm Tele Vue apochromatic refractor and find planetary views through it rather lacking.

I am neither a pessimist nor a "nay-sayer".  I am merely reporting on the results of my years of observing in the above quote.

 

At a private observatory complex where one of the very few 206mm Astro-Physics Starfire EDF apochromats ever manufactured was once housed, I had a chance to view Jupiter through that telescope and a 20" classical Cassegrain housed in another dome on the same night.  Guess which view I preferred.



#98 Bomber Bob

Bomber Bob

    Hubble

  • *****
  • Posts: 17,505
  • Joined: 09 Jul 2013
  • Loc: The Swamp, USA

Posted 26 April 2020 - 02:42 PM

I just ordered the AT102ED so I am also looking forward to it!  I will be doing both visual and some imaging so it will be interesting what it will show.  Anyone have an idea how much more detail I could possibly get with imaging using a 4"?

I got this shot back in 2014 with a 60mm F15 achro using a 12.5mm Orthoscopic for eyepiece projection + an Orion StarShoot camera:

 

M4380-Mars-20140426EP06A01CP20.jpg

 

I expect my AT102ED to do much better.


  • jimandlaura26, John Huntley, eros312 and 1 other like this

#99 James Ball

James Ball

    Apollo

  • -----
  • Posts: 1,305
  • Joined: 22 Jun 2014
  • Loc: Western Kentucky

Posted 26 April 2020 - 07:40 PM

I got this shot back in 2014 with a 60mm F15 achro using a 12.5mm Orthoscopic for eyepiece projection + an Orion StarShoot camera:

 

attachicon.gifM4380-Mars-20140426EP06A01CP20.jpg

 

I expect my AT102ED to do much better.

That is about what I got with my ETX90 last time, but never could tell how good it would do since it was mostly a dust storm when I tried it.  If I can match or exceed that I will be content for this time :)



#100 AllanDystrup

AllanDystrup

    Surveyor 1

  • *****
  • Posts: 1,666
  • Joined: 27 Sep 2012
  • Loc: 56N 12E, Denmark

Posted 27 April 2020 - 02:51 AM

.

     Here's an example of a visual observation with my 3" Vixen APO from the Mars 2016 opposition. Mars was rather low (11° altitude) in civil dusk (SQM 17 ~NELM 4.6), and it was calm with an above medium (not excellent) transparency and seeing.

    

     I made the sketch at 108x magnification using a light orange filter. Several light and dark areas were clearly visible, and could later be identified as the indicated surface features:

    

MARS 2016.png

*click*

    

     -- Allan


  • payner, daquad, eros312 and 5 others like this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics