After a long period of being unable to observe due to the weather and access to my telescope, I had a run of nights where the seeing was good and the moon had not risen (between easter and ANZAC day), and I was excited by the prospect of seeing Jupiter, Mars and saturn at a reasonable hour.
While I had some really lovely views of Jupiter (saw the Great Red Spot) and Io occultation, and some surface features of Saturn and it rings, Mars was just a pink, featureless disc, and very bright. This was viewing at about 50 degrees or more altitude, and with an 8mm delos through my 120mm refractor. I tried adding a 2x power mate - but the seeing was not quite good enough for that to be worthwhile. I wasn't really disappointed until I read another thread saying they could make out the polar caps easily, through an 80mm refractor at x150 magnification.
I use a red No. 23A filter on smaller telescopes and red No. 25 filter on larger telescopes to make the polar ice cap stand out. If you don't have them, you can try to improvise with any orangey sunglasses you may have, or that red translucent plastic gift wrapping stuff that you can find around the place.
Cheers,
Renato
I use a red No. 23A filter on smaller telescopes and red No. 25 filter on larger telescopes to make the polar ice cap stand out. If you don't have them, you can try to improvise with any orangey sunglasses you may have, or that red translucent plastic gift wrapping stuff that you can find around the place.
Cheers,
Renato
Hi Renato, whats the difference between these 2 filters? Is their transmission spectrum different?
I tried using an Astronomik UHC filter to increase contrast, but it just seemed to add a blue halo around Mars.
Mars is a tricky fellow to observe. Just this week I had the chance to view it through a C11 (an 11" SCT). Making out details was just a pain. Yet a few years back, same planet but this time using a much smaller C5 (a 5" SCT), detail wad certainly not lacking! No filter either. BOTH polar caps were visible, with one bigger than the other, a detailed green boarder tracing their edges, and a lot of surface features.
Three things affect seeing of detail on Mars:
1, atmospheric conditions making seeing good. Mars is tiny, so punching magnification when the atmosphere is turbulent is a no win situation, regardless of the scope you have.
2, its position in its orbit. Mars' orbit is a little more elliptical than Earth's. As a result at its opposition it can vary greatly in how close it gets to us. Right now it is as bad as it gets. In another 6 or 7 years it will be as good as it gets, but only by a small amount (remember it isn't a big object)
3, Dust storms! Yes, dust storms can rage over the planet, TOTALLY obliterating any surface detail. These also affect the performance of the surface probes that have landed on Mars, from Viking to today's rovers. From the observational reports I'm reading this week, this might be the case. I'll do some more poking around for this.
Filters can help, but you need at least point 1 above to be in your favour. After that it's just plain aperture grunt.
Hey Alex, what do you mean by right now is as bad as it gets. I've only been observing for a year so no previous years to compare but from what I've read now is the time to view mars. I've been seeing both polar caps every night for a week.
I looked up the page on planet oppositions here in IIS. I'm a little out in how "bad" things are. By bad I mean where Mars is in its elliptical orbit. When it is at its furthest point from the Sun, it is also at its furthest from us when at opposition making the angular size of Mars very small. From the info on the Oppositions page, its furthest opposition was a couple of years ago. Its best opposition will happen in 4years time:
If you have been seeing both caps this week, then it must be local atmospheric conditions that have been poor for me.
As you mentioned, now is when Mars is currently at its best - for its current orbit position. In 4years time, its opposition will also coincide with its closest approach in its orbit to the sun. Earth's period is one year. Mars' is close to two. So as the two planets orbit the Sun, when they are at opposition once nearly every couple of years, the two planets will be in a different stage of their orbit around the Sun, closer or further away and in between.
Mars can vary anywhere in size between 3.5" and 25.1". It appears largest near opposition, where the Earth is between Mars and the Sun. Right now, it is roughly 15" in diameter. For the 2016 opposition, it will be about 18" and for the 2018 opposition 24".
I have observed Mars a few times over the last month. The north polar ice cap was easily visible and at different times I have observed Syrtis Major and Acidalia Planitia, both large dark features on the surface of the planet. These observations were in my 12" Dob and also the 30" scope at Linden. In general, the features are easier to pick up in the 30" but I have had some sharp views in the 12" at 200x where the seeing was very good. You need magnification and very good seeing.
With Mars' axial tilt and current position, you cannot see both poles. The north polar cap is visible, the south polar cap is not. Earlier in April, I saw some ice cloud over Hellas Crater to the south. Maybe you are seeing some ice cloud.
The attached images are screen clips from SkySafari for Mars A (Apr 2 10pm) and Mars B (May 1 10pm). Mars A shows north polar ice cap at bottom, the large dark region Syrtis Major towards top and at top Hellas crater. Mars B shows the north polar ice cap at bottom and directly above it the dark region Acidalia Planitia.
Luke , the night of the partial solar eclipse , I had the best views or Mars this time around in my Iatar 127mm f8 at 333x showed the polar cap , lots of dark makings easily and atmosphere .
This is after looking at Mars at least twice a week for the last 2 months , yes the atmosphere has to be perfect to see good detail and your 120 ED is more that capable of showing plenty on Mars ,,, when the seeing allows .
The night before last Mars was just a pink moving sponge at any magnification , but Jupiter and Saturn were not bad , it just takes a very steady night to see Mars at its best as your scope is capable of doing .
Thanks all for that very useful and encouraging info. As a beginner, its still all bit mysterious as to whether its the equipment, the conditions, or the operator that is the cause of a disappointing view. It seems that its the operator in this example - he needs to learn about perseverance.
The thing that threw me was that I was getting some lovely moments of detail on Jupiter and Saturn and I just expected Mars to join in the party.
The thing that threw me was that I was getting some lovely moments of detail on Jupiter and Saturn and I just expected Mars to join in the party.
You have to remember that at this time Jupiter is 35" in apparent diameter and Saturn about 19" but twice that width width with the rings. Mars is only 15" in comparison. Jupiter and Saturn will be less susceptible to poorer seeing because of their size and much more easily defined features. For any detail on Mars you need very good seeing.
Hi Renato, whats the difference between these 2 filters? Is their transmission spectrum different?
I tried using an Astronomik UHC filter to increase contrast, but it just seemed to add a blue halo around Mars.
Thanks
Luke
Hi Luke,
The 23A is red, and the 25 is red but lets a lot less light through than the other one. At the time, the Celestron filter guide said to use 23A on up to 8" telescopes, and to use No.25 on bigger telescopes. Regardless, I always thought No25 was better in my C8.
Most of those UHC filters are designed to enhance the views of emission nebula, which are that aqua-green colour. So it will probably enhance something or other on Mars.
I also have a violet filter which was meant to be used for the violet clearing on Mars. I thought it was a totally useless filter, until one night after about 10 years, it actually was extremely useful after the features had all but disappeared for a few nights. But I haven't used it for a decade or more since.
Cheers,
Renato
P.S. Red cellophane wrapping was what the term I was looking for in my post below.
Also, as the others have said, other problems to viewing Mars relate to seeing and dust storms on the planet. And seeing can relate to where you live. For decades, from my suburban backyard, surrounded by houses I've easily seen the markings on Mars with my Vixen 102mm APO and even with my 80mm ED refractor.
But since I moved a couple of years ago to a place near the beach, where I am surrounded by 2/3 and one acre blocks, instead of getting the better seeing that I expected compared to my old backyard - well - things have been pretty miserable. Most of the time, 300X now delivers mushy images, whereas at my old place I could happily push 400X reasonably often.
Hopefully, you don't share my predicament - but it could be a factor.
Cheers,
Renato
Also, as the others have said, other problems to viewing Mars relate to seeing and dust storms on the planet. And seeing can relate to where you live. For decades, from my suburban backyard, surrounded by houses I've easily seen the markings on Mars with my Vixen 102mm APO and even with my 80mm ED refractor.
But since I moved a couple of years ago to a place near the beach, where I am surrounded by 2/3 and one acre blocks, instead of getting the better seeing that I expected compared to my old backyard - well - things have been pretty miserable. Most of the time, 300X now delivers mushy images, whereas at my old place I could happily push 400X reasonably often.
Hopefully, you don't share my predicament - but it could be a factor.
Cheers,
Renato
Actually, my telescope lives on some acres in a valley with steep escarpments, so I'm sure there's a fair amount of turbulence especially in summer, but there's no or very little light pollution.
I've never brought it up to Sydney to try viewing here, but maybe I should.
Is there something about the sea-land interface that leads to poorer conditions in your case?
Actually, my telescope lives on some acres in a valley with steep escarpments, so I'm sure there's a fair amount of turbulence especially in summer, but there's no or very little light pollution.
I've never brought it up to Sydney to try viewing here, but maybe I should.
Is there something about the sea-land interface that leads to poorer conditions in your case?
You have escarpments, and I live next to a gully with a small creek, and I'm wondering if this indeed has something to do with it.
I know I'm not getting what I was used to get out on rural land, devoid of neighbours's heaters and warm houses. Nor what I got in my suburban block after they went to bed.
Regards,
Renato
Valleys are not the best places to use astronomical scopes. They act as dew traps & can funnel wind and turbulence & often have reduced transparency. Notice how fog settles in valleys and the tops of the ridges are clear? And if the valley is agricultural land, dew/fog is even worse. The better place to set up a scope is up high above the fog line.
Now if you live in a valley, you might not have access to higher areas - no ones fault, but it is a small consolation to know the limitations you have.
Dark skies close to Sydney are very hard to come by that are best suited to astro. A few of us chasing sites limit possible sites to the ridge tops and plateaus of the Blue Mountains. We would have more choice if we went into the valleys, but this would work against the skies we are chasing. I mention this so you and others can understand what works best for astro and what to look for in possible astro sites.
Valleys are not the best places to use astronomical scopes. They act as dew traps & can funnel wind and turbulence & often have reduced transparency. Notice how fog settles in valleys and the tops of the ridges are clear? And if the valley is agricultural land, dew/fog is even worse. The better place to set up a scope is up high above the fog line.
Now if you live in a valley, you might not have access to higher areas - no ones fault, but it is a small consolation to know the limitations you have.
Dark skies close to Sydney are very hard to come by that are best suited to astro. A few of us chasing sites limit possible sites to the ridge tops and plateaus of the Blue Mountains. We would have more choice if we went into the valleys, but this would work against the skies we are chasing. I mention this so you and others can understand what works best for astro and what to look for in possible astro sites.
My site is half way up the valley side, with escarpments close by. There are plateaus that I could drive to that would be nice dark, elevated sites - but I like the comforts of home close by - I'm one of those lazy astronomers, not a real one.
I like the comforts of home close by - I'm one of those lazy astronomers, not a real one.
Nothing wrong with that Luke, . Main reason why I wrote my last post is so you can understand how geography affects our viewing. Site selection is not something we can all control. And if our home is already located at a dark site, it can be quite inconvenient to shift site.
A good friend of mine lives in the deserts of New Mexico in the USA. His home is located in a valley that is a bit of an oasis with water deep underground. While where his home is still at over 1500m above sea level, the surrounding ridges create havoc with the quality of seeing. To move his scopes up to the ridge tops is both difficult and not realistic for him. He's more often than not complaining about seeing, but understands the situation and does what he can with whatever the valley throws up.
Plus, it is always nice to be able to take a break from observing in the depths of winter to warm up, take a cat nap, and then be refreshed for more, with all the comfort that home offers.
If it is not too impractical for you, see about shifting your observing site to higher ground. Might be that it just becomes an occasional jaunt to higher ground rather than a regular one. All depends on personal circumstances.
Myself, you are in a more fortunate situation than I as you are already in dark sky country, despite being in a valley. My home is located in the depths of Sydney's light polluted skies, To be able to just get to a dark site is a luxury for me...
I have never seen the need to use a filter for mars, but i am only new to this hobby, as you may know the higher you go in mag the dimmer the object becomes.
I have never seen the need to use a filter for mars, but i am only new to this hobby, as you may know the higher you go in mag the dimmer the object becomes.
Filters for planetary viewing are used to enhance contrast of surface features and not so much to reduce brightness. Sometimes the features are so subtle that only a filter of the correct colour will show them.
that is the cause of a disappointing view. It seems that its the operator in this example - he needs to learn about perseverance. 
. Main reason why I wrote my last post is so you can understand how geography affects our viewing. Site selection is not something we can all control. And if our home is already located at a dark site, it can be quite inconvenient to shift site.
To be able to just get to a dark site is a luxury for me...
