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's the best way to increase color & contrast for the planets?

planet reflector observing accessories
  • Please log in to reply
62 replies to this topic

#1 SolarSailor

SolarSailor

    Lift Off

  • -----
  • topic starter
  • Posts: 12
  • Joined: 26 Jun 2018
  • Loc: Orlando, Florida

Posted 11 July 2018 - 07:45 AM

After being limited to binocular astronomy for the past few years I've recently begun learning to use my first telescope. The scope in question is a Celestron PowerSeeker 114AZ Reflector. So far I've been impressed with what I've learned on here about maximizing the viewing experience. Techniques like letting the telescope cool outside for an hour, staring slightly to the side of the object, waiting till the object is high in the sky, etc. So far I've found I enjoy looking at the planets the most, especially Jupiter and Saturn.

The only problem I have is I'm not getting a lot of color or contrast out of the planets. With the exception of Mars they all appear milky white, not orange (in Jupiter's case), grey (for Mercury), or yellow ( Saturn/Venus). I'm also getting a lot of false color where they shimmer blue for some reason. I can still make out details in Saturn's rings and Jupiter's cloud bands, but I have to stare at them for awhile. As hard as I've tried I also can't seem to see the phases of Venus, which shimmers too bright. I'm trying a few things to get better views right now.

I'm waiting for better atmospheric conditions and replacing the telescopes Huyghens eyepieces with a better quality Plossl. Aside from these what are the best ways to increase the color and contrast of the planets? I'm looking into getting some filters for this. I've read different color filters can bring out planetary detail, but I haven't heard many people here liking them. I did see an older thread where people recommended a Moon and Skyglow filter for Jupiter's cloudbands, and also that a neutral density moon filter could double as a planet filter.

I'm on a shoe string budget right now, so I'd have to get a filter that's under $20. Would they be worth it, or are they too cheap to make a difference? Also are their some other products or techniques I could be missing to bring out detail in planetary viewing? Any thoughts or comments are appreciated.

Edited by SolarSailor, 11 July 2018 - 07:55 AM.

  • SeaBee1 likes this

#2 dmgriff

dmgriff

    Viking 1

  • -----
  • Posts: 987
  • Joined: 20 Sep 2006
  • Loc: 30 degrees latitude, USA

Posted 11 July 2018 - 08:14 AM

Is the scope well collimated and what eyepieces are you using?

 

Good viewing,

 

Dave



#3 Tony Flanders

Tony Flanders

    Hubble

  • *****
  • Posts: 15627
  • Joined: 18 May 2006
  • Loc: Cambridge, MA, USA

Posted 11 July 2018 - 08:25 AM

The only problem I have is I'm not getting a lot of color or contrast out of the planets. With the exception of Mars they all appear milky white, not orange (in Jupiter's case), grey (for Mercury), or yellow ( Saturn/Venus).

In fact, the planets have very low contrast, and are not very colorful. Many photos exaggerate the contrast and colors, which is unfortunate.

Jupiter is in fact white, with perhaps a slightly bluish tint. Certainly not orange -- where did you get that idea? The dark belts are brownish, perhaps subtly orange. And the Great Red Spot is -- you guessed it! -- red. However, that's unusual; for most of the past few decades the GRS has been pale salmon pink.

In any case, all the colors on Jupiter are pretty subtle pastels; they're not at all deeply saturated. Good optics, good seeing, and reasonably high magnifications are you best help in seeing the colors.

Saturn does have a subtle yellowish tint, as you can plainly see with the unaided eye if you compare it with distinctly bluer Jupiter. The rings, however, are definitely white. The rings have ultrahigh contrast, but the belts on Saturn are much subtler than the belts on Jupiter, which are already plenty subtle enough.

 

Venus is white as white can be. Not surprising, since what you're actually seeing is cloud tops.


  • Dave Mitsky, stevek, lee14 and 4 others like this

#4 SeaBee1

SeaBee1

    Mercury-Atlas

  • *****
  • Posts: 2892
  • Joined: 19 Mar 2015
  • Loc: Under the DFW light barrier

Posted 11 July 2018 - 08:28 AM

You might try a variable polarizing filter for really bright targets, such as Venus and Mars, to knock some of the glare off. That will help you see the phases of Venus, and maybe some detail on Mars. Jupiter and Saturn should look pretty good in your scope, but they will be small. I can see good detail and contrast on those two with my 100mm refractor, which is not a far cry from your 114mm reflector. However, you will loose a bit of contrast due to the central obstruction of that scope. Part of what will help you comes in the form of experience... the more you look, the more you see.

 

Keep looking up!

 

CB


  • SteveNH and ZeusB like this

#5 Mike W.

Mike W.

    Apollo

  • *****
  • Posts: 1153
  • Joined: 23 Dec 2016
  • Loc: Washington State

Posted 11 July 2018 - 08:28 AM

Usally when planets are too bright it's difficult to make out much detail and your eye sees mostly the white light, reducing the amount of light will increase the detail, so on a shoe string budget instead of trying a inexpensive filters you might try covering part of the aperture of the scope.

Get a disc the size of your scopes tube and cut a hole in it, about 3" in diameter, then slowly cut it larger until the light is right for detail.

 

Color filters will help with some of the detail but cheap ones scatter so much light they are not worth using.

 

I would suggest something in a polarized filter, but then again the cheap ones scatter light and reduce detail, same with neutral density filters.

 

Save your money for now and try the aperture mask, a frisby, tupper ware container cover pie tin, even paper , or even just masking tape strips across the aperture.

The hole doesn't have to be perfect either, you're just reducing the amount of light that your scope is capturing.

 

I surprised myself the other night, while swapping out eyepieces I inadvertently left my collimating screen on my Barlow, slapped my 18 in there and had a pretty good view.


Edited by Mike W., 11 July 2018 - 08:33 AM.

  • ZeusB likes this

#6 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 70499
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 11 July 2018 - 08:30 AM

The only problem I have is I'm not getting a lot of color or contrast out of the planets. With the exception of Mars they all appear milky white, not orange (in Jupiter's case), grey (for Mercury), or yellow ( Saturn/Venus). I'm also getting a lot of false color where they shimmer blue for some reason. I can still make out details in Saturn's rings and Jupiter's cloud bands, but I have to stare at them for awhile. As hard as I've tried I also can't seem to see the phases of Venus, which shimmers too bright. I'm trying a few things to get better views right now.

 

 

Hi:

 

I think you're doing quite well.  Seeing color in the planets generally requires a larger telescope and excellent seeing conditions, amateur astronomy is almost all in grey scale.  A few comments:

 

- The blue shimmer is most likely due to the planets being relatively low, it's called atmospheric dispersion, the atmosphere acts like a lens and you are seeing chromatic aberration.  

 

- You will certainly benefit from better eyepieces.  Regular Plossls are far better eyepieces than the Huygenian eyepieces that ship with the Powerseeker 114.  

 

- It sounds like the atmosphere is somewhat turbulent, some nights are better than others.. 

 

Keep up the good work.

 

Jon


  • paul m schofield and bluesteel like this

#7 AnalogKid

AnalogKid

    Vostok 1

  • *****
  • Posts: 190
  • Joined: 12 Dec 2017
  • Loc: North/West of Pittsburgh PA

Posted 11 July 2018 - 09:27 AM

<snip>

Get a disc the size of your scopes tube and cut a hole in it, about 3" in diameter, then slowly cut it larger until the light is right for detail.

<snip>

I have used an aperture mask with great success.   I forget the ratios, but when I got my 8" Coulter dob way back in the mid 1980's it had instructions on how to make one, and what size.  I used an old piece of cardboard from when they sold pop by the 24 case.  , and still have, and use it.

 

When placing, make sure to put the opening where the diagonal bracing is NOT.

 

Scope_resize.jpg

Scope showing mask.


  • xvariablestarx, Mike W. and SolarSailor like this

#8 Mike W.

Mike W.

    Apollo

  • *****
  • Posts: 1153
  • Joined: 23 Dec 2016
  • Loc: Washington State

Posted 11 July 2018 - 10:02 AM

I'm not kidding about the collimtion screen, I noticed that everything was quite dim, being the first time I had used the Barlow cell for viewing, thought it was something on the lens, sure enough, a solid white disc with a hole in the center,,,,,,,,,,,,,,lol.gif

 

But the bands on Jupiter were quit distinct.smirk.gif



#9 epee

epee

    Vanguard

  • *****
  • Posts: 2462
  • Joined: 30 Nov 2006
  • Loc: Suh-van-nuh, Jaw-juh

Posted 11 July 2018 - 10:15 AM

I like Neutral Density filters for planetary observation. As others have said, the planets are not high contrast objects; I've compared it to spotting dirt on a lit headlamp. You might even try sunglasses when no one else is looking!wink.gif 

 

Likewise, planetary observation has also been compared to, "bird watching from the bottom of a pool". By this it's meant that the image swims in mirage and only offers moments of clarity. It's those moments that you live for. Besides sky clarity and darkness the other judge of observing conditions is "seeing"; the steadiness of the atmosphere. The better the seeing the more moments of clarity you have. Many have noticed that, conversely to expectations, very good seeing occurs when the sky sky is a little hazy or the atmosphere is foggy. This indicates "stillness" in the air. The amount of twinkle in the stars is also an indicator of seeing; less is best.

 

  

You have a nice scope, but unfortunately it falls in the category that comes with poor quality eyepieces. Plossls are an improvement and can be had for less than $30 apiece, but nowadays most around here are looking for a step up from these. Celestron X-cel, and Meade HD60 eyepieces are widely regarded as quite nice and sell for about $60 apiece.


Edited by epee, 11 July 2018 - 10:21 AM.


#10 vtornado

vtornado

    Apollo

  • *****
  • Posts: 1324
  • Joined: 22 Jan 2016
  • Loc: Northern Illinois

Posted 11 July 2018 - 10:16 AM

Hello Solar Sailor and welcome to the forum.

 

What eyepieces does your scope have?   If they are the ones I see bundled (20mm, 4mm and 3x barlow) Then none of these eyepieces are really very useful.  But your main telescope is very good.

I have the orion version.

I think the 20mm is a correct image eyepiece, which is fine for low power, but can introduce abberations at high power.   4mm is just too powerful for this scope, and the 3x barlow is not high quality.

 

I think your telescope is f/8.   (114mm diameter, 910mm focal length).

Usually for planets I find an eyepiece that gives about a 1mm exit pupil is the

proper balance between magnification and brightness.   Sometimes .8 is about right.

 

 

The exit pupil is the size of the cone of light that enters your eye from the eyepiece.

You can calculate it by this formula (eye piece focal length) / ( f ratio of the telescope).

 

For your scope, that means somewhere between a 8mm eyepiece ( 8mm / f8 = 1mm) or

a 6mm eyepiece ( 6mm / f8 = .75mm).

 

 

Peoples eyes are all different in regards for liking larger vs. small images or brighter vs. dimmer images,

which is what we are playing around with by changing the maginfication.

 

This 9mm eyepiece would work well in your scope.

https://www.amazon.c...degree eyepiece

 

There is also a 6mm in the same line that would work.  It might be a little too powerful for most nights.

and I know you are on a tight budget.

 

I do not suggest an aperture mask for the Jupiter/Saturn/Mars,   we want all the detail we can get

which means large aperture for resolution and light gathering.  It might work if you want to view

Venus, because there is not much detail to be seen, and it is very bright.

 

The only filter I have that made a difference on the planets is an 82A light blue filter.  This

help bring out the polar ice caps on Mars.  Most other colored planetary filters are too dark.  They really change the color profile, and block a lot of light.

 

You need to test the collimation (optical adjustment) of your scope.  This is very critical when viewing planets at high power.  I'm sure celestron aligns the scope in the factory, but you never know what shipping does.

 

To check alignment, find a bright star (polaris or the north star works best), but any star will do. Use your 4mm eyepiece and slightly defocus the image while keeping it in the center.  If it looks like a nice round bull's eye everything is fine.  If thinks are askew with the bullseye something needs to be done.

 

=======

 

Heat from the ground can distort an image too.   If you can look over a grassy field rather than roads or your neighbors roof.   A baseball or soccer field works well.

 

=======

 

Another thing I just remembered.   Of course having a steady mount is important too.

If you find you have problems focusing, or with wind.  make sure the mount bolts are

snug but not too tight.   If you are observing from a hard surface, either move to grass,

or you can cut some carpet squares to put under your tripod legs.  Sometimes

adding a small box of rocks, or a small dumbell plate to the accessory tray steadies the mount a bit.

 

 

 

Hope some of this is useful!

VT


Edited by vtornado, 11 July 2018 - 01:08 PM.

  • paul m schofield, SteveNH and SolarSailor like this

#11 SolarSailor

SolarSailor

    Lift Off

  • -----
  • topic starter
  • Posts: 12
  • Joined: 26 Jun 2018
  • Loc: Orlando, Florida

Posted 11 July 2018 - 11:37 AM

Thanks for the help so far. An aperture mask seems like an interesting idea. I might as well try it since it costs nothing but used cardboard. In the future I'll look for a name brand polarized or neutral density filter. I needed a moon filter anyway so I assume some of those filter types could double as one. For now though perhaps I should look into getting a telescope collimator instead. Do metal cheshire's really produce better collimation than homemade collimation caps, or is it only more convenient to use?
 

Jupiter is in fact white, with perhaps a slightly bluish tint. Certainly not orange -- where did you get that idea? The dark belts are brownish, perhaps subtly orange. And the Great Red Spot is -- you guessed it! -- red. However, that's unusual; for most of the past few decades the GRS has been pale salmon


I assumed Jupiter was at least half orange thanks to pictures like this.

Jupiter-3.jpg

Jupiter.jpg

I suppose I fell victim to NASA's false color image propaganda. That's one of the reasons I wanted to get involved with astronomy in the first place. I wanted to see what outer space looked like with my own eyes, not what it looked like on some computer screen. If Jupiter is supposed to look creamy white then perhaps I'm seeing it better than I thought it was.
 

Hello Solar Sailor and welcome to the forum.
 
What eyepieces does your scope have?   If they are the ones I see bundled (20mm, 4mm and 3x barlow) Then none of these eyepieces are really very useful.  But your main telescope is very good.


Thanks! Glad to hear the telescope itself is good quality. The eyepieces included were a 20mm Huyghens and a 4mm Symmetric Ramsden. Both feel like they are made of light plastic. I ordered a 10mm Svbony Plossl for $5 that appears to be an Orion 10mm knockoff. I'm not sure how good the quality is, but it can hardly be worse, or more unconfortable than what came included. I plan on replacing the H 20mm eyepiece as soon as I find something decent on sale.

Edited by SolarSailor, 11 July 2018 - 11:43 AM.


#12 epee

epee

    Vanguard

  • *****
  • Posts: 2462
  • Joined: 30 Nov 2006
  • Loc: Suh-van-nuh, Jaw-juh

Posted 11 July 2018 - 01:00 PM

Plossls have variable eye relief, based on their focal length. A 10mm will have 6 -7mm eye relief and, for me, that's too tight for comfort. A 25mm which will have around 13 -14mm of eye relief is much more comfortable. A barlow will increase the magnification of any eyepiece that will fit it by its designated amount (x2, x3,etc.) and preserve or even increase the eye relief. So I used to use a 17mm Plossl with a Barlow for "high" power viewing. More expensive eyepieces will feature better eye relief and, usually, a wider field of view. 


Edited by epee, 11 July 2018 - 01:01 PM.


#13 Garyth64

Garyth64

    Vanguard

  • *****
  • Posts: 2327
  • Joined: 07 May 2015
  • Loc: SE Michigan

Posted 11 July 2018 - 02:15 PM

"The eyepieces included were a 20mm Huyghens and a 4mm Symmetric Ramsden. Both feel like they are made of light plastic."

 

You should not be getting any false color with a reflector.  The blue false color most likely is from your eyepieces.

 

Depending on the diameter of your aperture mask, you will be reducing the diameter of your primary.  Your primary is about 4½" and is an f/8?.  Going to a 4" mask you will be making your system an f/9.  If you reduce it to about 3½", it becomes an f/10.  Increasing the f ratio could increase the contrast, but your resolving power to see minute details will be decreased.  It could be a trade off.  Test it your self and see what happens.smile.gif


Edited by Garyth64, 11 July 2018 - 02:22 PM.


#14 Sketcher

Sketcher

    Viking 1

  • *****
  • Posts: 550
  • Joined: 29 Jun 2017
  • Loc: A Dark Place in the Wild Wild West

Posted 11 July 2018 - 02:38 PM

As others have stated, planetary colors, for the most part, tend to be rather subtle.  It's better to not expect to see any colors!  Concentrate on what you can see.  Pay no attention to what you can't see.  Filters (among other things) reduce image brightness.  They will not make it easier to see color on a planet; though they can make features of various colors easier to see by (usually only subtly) increasing the contrast between neighboring features of differing colors.  In other words, color filters make planetary colors harder to see, while darkening (a little) some features relative to other features.

 

On your budget, I wouldn't bother spending money on filters -- and this advice is coming from someone who has 30+ filters!  At least not until you've gained more experience and improved your eyepieces -- a little.  The only effects you're likely to notice is that a red filter makes a planet look red.  A blue filter makes a planet look blue, etc.  A few decent, relatively inexpensive, Plossl eyepieces will provide you with more value for the dollar than will adding filters.

 

Contrast is similar to color in the sense that it tends to be rather subtle -- mostly.  What do you see when you look at a hen's egg?  An experienced planetary observer will see a wealth of detail on the egg's surface -- so much that if they were to sketch it, they would concentrate on only a tiny part of the egg.  There's just too much detail, for a person to sketch, on the visible face of an egg -- that is, if one expects to complete the sketch in a reasonable amount of time.

 

Planetary colors are also affected by the air quality one is looking through.  Mercury can appear white, yellow, orange, or red depending on how high the planet is in the sky and the quality of the intervening air.  Atmospheric dispersion can add a reddish tint to the planetary limb closest to earth's horizon and a bluish tint to the opposite limb.  Lenses can add 'false' colors as well.

 

The phases of Venus:  The difficulty, most likely, is due to the huge contrast difference between the planet and background sky.  There are (at least) three ways this can be improved: 1) Observe Venus before the sky gets very dark -- as soon as the planet becomes visible after sunset.  2) Use higher magnifications -- thereby spreading the intense light of the planet over a larger area -- effectively dimming the view somewhat.  3) Use a filter to block some of the brightness.  An aperture-reduction mask will also work; but most observers prefer to use any telescope (of decent optical quality) at full aperture.  Reducing the aperture will mute any colors that would otherwise be visible.  It will also reduce the resolution of the telescope.

 

I've never had to use a filter in order to see the phases of Venus; but I have used filters while observing Venus -- sometimes.  I almost never use filters while observing the moon, not with a 1-inch telescope and not with a 12-inch telescope.  The one major exception is when I choose to use a large, fast, achromat.  I'll then use a yellow filter to help get rid of the unfocused blue light.  I could get rid of all my filters without diminishing my telescopic pleasures.  Yet, they nice to have to help out a bit from time to time.

 

You're doing a great job!  Just reduce the expectations a bit and concentrate on everything you can see!


  • paul m schofield, SeaBee1 and chdr like this

#15 Eddgie

Eddgie

    ISS

  • *****
  • Posts: 22524
  • Joined: 01 Feb 2006

Posted 11 July 2018 - 02:46 PM

There are two kinds of receptors in the human eye.. 

 

The first type is the cone, and the second type is the rod.

 

There are two ways that the cones and rods differ.

 

The first is that while it is often said that rods are more sensitive to cones, this is only partially true.  Individual cones are about as sensitive as rod, but the difference is that each cone gets it own neuron, but rods share a neuron.  This means that a neuron that is connected to a cluster of rods is more likely to fire because with the greater area, it is more likely to fire because it is more likely that a one or more rods will be hit, while the chances of a cone being hit are smaller because it covers less area.

 

Because each cone gets its own neuron, while it is less likely that with a given amount of luminance a cone will fire, when you get a lot of them firing, you can resolve smaller detail than with rods because they are more neurons per area.

 

And most important to your question, the cones are not only where your best resolution comes from, but they are also where most of your red sensitivity comes from.   By comparison, the rod clusters are more sensitive to green and blue and do not really see red. 

 

Georgia State University Paper:

 

 

Current understanding is that the 6 to 7 million cones can be divided into "red" cones (64%), "green" cones (32%), and "blue" cones (2%) based on measured response curves. They provide the eye's color sensitivity.

 

What does this mean?  This means to see rich colors, you need to fire a lot of cones, and the way you fire a lot of red cones is to shine a lot of light on them.

 

And that is what happens when you use ever larger telescopes.

 

In a small scope such as yours, using 200x spreads out the energy outside of the fovea (the part of the retina that has the cones) and this means that the light that hits outside of the cones will contribute to the color perception or the resolution. 

 

In a 6" to 8" scope, the average observer will start to see many details on Jupiter as more of a brown that grey.  At this aperture, they are getting enough photons on to the fovea that enough cones are firing that they can now perceive some color, but the brown look means that the proportion of cones firing is low.

 

Move to a 12" scope though and now you will fire a very large number of cones, and as a result, the color starts to show more vividly.  Browns start to look reddish, and yellows and greens start to become very pronounced.

 

The very best resolution the eye can provide is achieved when you are firing all of the cones (daylight).   The brighter you can get the image, the more color and detail you will be able to see. 

 

There is nothing you can do to your telescope to change this.  No eyepiece or mirror coating or anything else will change this.

 

To see the colors of Jupiter as shown in many pictures, you need to have a minimum of 10" and 20" is better, and 30" is better still. 

 

Jupiter and Saturn in a 12" scope are very colorful.   Far more so than in even the best 6" Apo made.   It is all about firing cones and to fire cones, you need a lot of energy, and that is the role of aperture.  I know this because I have made this comparison, and a 6" aperture, no matter how perfect, does not give the same level of illumination as a 12" aperture.  Jupiter is far more colorful at 12" than 6".  


Edited by Eddgie, 11 July 2018 - 03:06 PM.

  • paul m schofield, bluesteel, bvillebob and 2 others like this

#16 Eddgie

Eddgie

    ISS

  • *****
  • Posts: 22524
  • Joined: 01 Feb 2006

Posted 11 July 2018 - 02:48 PM

And of course a mask or anything that reduces the aperture of the brighness of the image means fewer cones will fire.   Planetary observing is all about firing the most cones you can possibly fire.   This is where both color and resolution come from.  No perfect small telescope can show the colors of a much larger imperfect aperture.   It is the eye and not the telescope that is the barrier. 

For further reading, I recommend these sites:

 

http://hyperphysics....on/rodcone.html

 

Of particular interest on this page is Figure 250:

 

http://telescope-opt...al_response.htm

 

A pet peeve of mine is that telescope arguments (which is better for planets) almost always ignore the characteristics of the human eye.  Even a small telescope with a good camera can show wonderful colors when used to image Jupiter or Saturn, but that is because as compared to a modern CCD chip, the eye is a pretty poor sensor.  To make it work well, it has to have a bright image and that is more than anything else, a function of aperture.   High brightness on the fovea improves both the color and resolution because it fires more cones, and it really is all about the cones. 


Edited by Eddgie, 11 July 2018 - 02:59 PM.

  • paul m schofield likes this

#17 NEOhio

NEOhio

    Surveyor 1

  • -----
  • Posts: 1942
  • Joined: 12 Apr 2016
  • Loc: Cleveland, Ohio, USA

Posted 11 July 2018 - 03:13 PM

In fact, the planets have very low contrast, and are not very colorful. Many photos exaggerate the contrast and colors, which is unfortunate.

Jupiter is in fact white, with perhaps a slightly bluish tint. Certainly not orange -- where did you get that idea? The dark belts are brownish, perhaps subtly orange. And the Great Red Spot is -- you guessed it! -- red. However, that's unusual; for most of the past few decades the GRS has been pale salmon pink.

In any case, all the colors on Jupiter are pretty subtle pastels; they're not at all deeply saturated. Good optics, good seeing, and reasonably high magnifications are you best help in seeing the colors.

Saturn does have a subtle yellowish tint, as you can plainly see with the unaided eye if you compare it with distinctly bluer Jupiter. The rings, however, are definitely white. The rings have ultrahigh contrast, but the belts on Saturn are much subtler than the belts on Jupiter, which are already plenty subtle enough.

 

Venus is white as white can be. Not surprising, since what you're actually seeing is cloud tops.

Your description of Saturn is interesting. My (quite possibly flawed) mental recollection of Saturn in the 6" SCT or 8" dob is usually pretty strongly yellow, with the rings close in color to the planet. Next time I look at it will need to concentrate on the colors, might be like with double stars where different colors close to each other can influence visual color perception.



#18 SteveG

SteveG

    Fly Me to the Moon

  • *****
  • Posts: 6924
  • Joined: 27 Sep 2006
  • Loc: Seattle, WA

Posted 11 July 2018 - 03:19 PM

As others have said, filters aren't going to help you. You have the following problems:

 

1. The gas giants are very low, and will remain low as long as their in summer constellations, which is many years for both Saturn and Jupiter.

 

2. You're describing atmospheric diffraction, which is bad local seeing. Other things that degrade the view are viewing over houses or asphalt.

 

3. Your aperture is limited. A larger scope will show more contrast.

 

4. You are using low-budget eyepieces.

 

Regarding #1, I did some quick checking, and Jupiter gets lower until 2021, then climbs rapidly over the next couple of years. Saturn is at its lowest, and will stay low until 2021 when it slowly moves north in declination. Stay in the hobby, and in a few years you'll be rewarded better views.



#19 Eddgie

Eddgie

    ISS

  • *****
  • Posts: 22524
  • Joined: 01 Feb 2006

Posted 11 July 2018 - 03:21 PM

In my 14", Saturn was pretty colorful.  Many bands.

 

I agree with the "Pastel" part, but in sufficient aperture, the colors are not at all difficult to see so I think "Subtle" is a bit mild.  Delicate maybe is better, but there are plenty of colors and it is not a struggle to see them. 

 

In fact, Saturn is poster child for my earlier post on rods and cones.  The bigger the aperture, the more color one can see.   A beautifully colorful planet with more variety of color than Jupiter I think.  

There is not really anything the OP can do to change what he is going to see.  It is too small of an aperture to see anything but hints of color.  Jupiter and Saturn need a lot of aperture to start showing them even close to the colors often seen in pictures.  The more aperture you look though, the more colorful they get. 


Edited by Eddgie, 11 July 2018 - 03:22 PM.


#20 Sketcher

Sketcher

    Viking 1

  • *****
  • Posts: 550
  • Joined: 29 Jun 2017
  • Loc: A Dark Place in the Wild Wild West

Posted 11 July 2018 - 06:02 PM

In my 14", Saturn was pretty colorful.  Many bands.

 

I agree with the "Pastel" part, but in sufficient aperture, the colors are not at all difficult to see so I think "Subtle" is a bit mild.  Delicate maybe is better, but there are plenty of colors and it is not a struggle to see them. 

 

In fact, Saturn is poster child for my earlier post on rods and cones.  The bigger the aperture, the more color one can see.   A beautifully colorful planet with more variety of color than Jupiter I think.  

There is not really anything the OP can do to change what he is going to see.  It is too small of an aperture to see anything but hints of color.  Jupiter and Saturn need a lot of aperture to start showing them even close to the colors often seen in pictures.  The more aperture you look though, the more colorful they get. 

The context of the original question involved the use of a 114mm telescope.



#21 ascii

ascii

    Apollo

  • -----
  • Posts: 1135
  • Joined: 04 Jun 2016
  • Loc: Orlando, FL, USA

Posted 11 July 2018 - 06:25 PM

Definitely try a neutral density filter on Venus.  Even high magnification can be insufficient to knock back it's brightness.  About a month ago, I was having trouble making out its gibbous phase in my 100 mm refractor at 180x.  I put my 13 % neutral density filter on my eyepiece, and it made a big difference.  The shape was much crisper.

 

Part of the problem right now is that Venus is still far away and thus appears small.  This is always the case in its gibbous phase.  You get the double hit of small size and dazzling brightness making the shape hard to see.  As it gets later in the summer and into autumn, Venus should get much larger and into its crescent phase, making it easier to see the shape - filter or not.



#22 Redbetter

Redbetter

    Fly Me to the Moon

  • *****
  • Posts: 5748
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 11 July 2018 - 07:25 PM

When I was trying to get a better understanding of color indices for planets and moons I came across a 1971 NASA paper for calculating UBV magnitudes.  This had a table of values including B-V.  Here are a few below.   

  • Sun 0.63 (B-V)
  • Moon 0.92
  • Mercury 0.97
  • Venus 0.82
  • Earth 0.2
  • Mars 1.33
  • Jupiter 0.83 (remember it is a mix of colors)
  • Io 1.17
  • Europa 0.87
  • Ganymede 0.83
  • Callisto 0.86
  • Saturn 1.04
  • Titan 1.3
  • Uranus 0.56
  • Neptune 0.41
  • Pluto (before Charon was known)  0.80

In the continuum of things this mostly makes sense:  Mars and Titan have more of reddish or orange hue than anything else in the table.  Saturn is quite yellow or yellow gold.  Earth is dominated by ocean (dark blue).  Neptune is blue.  Uranus is blue green. 

 

The middle areas between that of the Sun and Saturn are more confusing.  Some of this probably has to do with how intensely bright Mercury and the Moon are.  Intense light tends to appear whiter than it might otherwise.  The Moon's color yellows as magnification is increased (as does Jupiter.)

 

Color perception is a complex and relative thing especially since the eye itself is so variable from person to person and with age.



#23 bluesteel

bluesteel

    Surveyor 1

  • -----
  • Posts: 1813
  • Joined: 24 Mar 2013
  • Loc: KILM

Posted 12 July 2018 - 12:06 AM

I will suggest for PLANETARY viewing, do something counter intuitive - observe with your outside light on. Just make sure that you are blocking the light from your telescope.  This will activate more of your colour receptors in your eye, as well as construct the pupil a bit, helping with the washed out effect that you are experiencing. Built-in neutral density filter.

 

How does the moon look in your telescope? Is it sharp, or blurry at low magnification? What about higher magnification? Make sure the stars are not twinkling when you are trying this, which indicates the atmosphere is steady, and will allow higher magnifications. If you are seeing not a sharp image, then you might want to look into collimating the scope.


  • chdr likes this

#24 sg6

sg6

    Gemini

  • *****
  • Posts: 3201
  • Joined: 14 Feb 2010
  • Loc: Norfolk, UK.

Posted 12 July 2018 - 02:54 AM

Scope look "right" as in a long tube. Mirror may be spherical is one area I am unsure of. Would reduce the overall result slightly, however not by a lot.

 

If it need collimating and if you want to think about it then do it by the least expence and make a simple collimation cap. Think there is a site by "astro-baby" that describes one and what you do. Simple description is you put the "cap" in the focuser with an 1/8 hole in it and simply put secondary and main central in the view.

 

Venus and Mercury are inside us, Mercury is a rock so no color, Venus is 100% cloud so bright but in effect a cotton wool ball that may be white or a but yellowy. Being inside us they are cresents not disks. You are not going to get much from them. Nice to see, tick off as observed.

 

Mars is a total pain, it will be a red sisk, and a SMALL red disk. Seems that people need 250x and above for anything from Mars. Have a look, see small red disk, tick off as observed, and save up lots of money for the next time it appears in 2 years.

 

Jupiter: Need say 60x to 80x for that - 15mm eyepiece, 12mm if you feel lucky. Not sure you will get much color, half the reason for that is your eye. At night the color aspect of it shuts down - night vision is mono, so your eye doesn't then register color. Odd option but Jupiter is visible around 21:00 to 22:00 when the sky is not yet dark, try an observation then. Eye is still "seeing" color and so might you then.

 

Saturn is boarder line I suspect. You need 120x for that and a 114mm scope is for my thinking going to be at its top end, a 7mm or 8mm eyepiece is required. If you know someone to borrow from for 5 minutes a 7mm eyepiece then do so. Might work. Same for 8mm.

 

For eyepieces and cost then a couple of plossls, likely not at this time worth considering say a Paradigm or X-Cel.

 

Contrast is going to be eye piece and collimation, also add in height of object in the sky - height you cannot really do much about. Check if possible the collimation and improve it if a) it needs it, and b) possible. Eyepieces comes down to borrow one or two to get an idea (good if you can), or expenditure. If you go for buying eyepiece do not think high magnifications are better, generally they are not. General being 98% of the time.



#25 Tony Flanders

Tony Flanders

    Hubble

  • *****
  • Posts: 15627
  • Joined: 18 May 2006
  • Loc: Cambridge, MA, USA

Posted 12 July 2018 - 06:35 AM

I assumed Jupiter was at least half orange thanks to pictures like this.

Jupiter-3.jpg

Jupiter.jpg

Of these two pictures, the one on the top has grossly exaggerated contrast -- presumably necessary to bring out those amazing auroras, something that to the best of my knowledge have never been spotted in an amateur scope.
 
The one on the bottom is much closer to true color and contrast, though something weird was happening on Jupiter the night this was taken. I've never seen a dark band right on the equator, as in this photo. I can't even tell if it's a northward extension of the South Equatorial Belt or if the North Equatorial Belt had drifted south. That's an important point about Jupiter; it changes a lot, sometimes even on a night-by-night timescale. It usually has two prominent dark bands, but sometimes one of those disappears entirely, and sometimes a third band can be just as prominent as the main two.

 

If you stand away from this photo, you'll realize that although your eye is drawn to the dark colors, it's the overall bluish hue that predominates. Tone the contrast down just a bit, blur the details, and this is a pretty good representation of what you would see through a really big backyard scope on a perfect night when Jupiter is high in the sky.

 

Alas, your scope is quite small even by backyard standards, perfect nights are rare, and Jupiter is fairly low in the scope for northern observers -- though nowhere near as low as Saturn, much less Mars.


Edited by Tony Flanders, 12 July 2018 - 06:39 AM.



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





Also tagged with one or more of these keywords: planet, reflector, observing, accessories



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics