10 replies to this topic

[Flaminging]

I have been looking at Mars with my 8 inch dob (my first telescope). For me, Mars looks like a fuzzy ball and I can't see much detail. And before anyone says anything, I collimate, acclimate, focus, etc. I also make sure to lower my magnification when the seeing isn't great (I only have access to 40x, 133x, and 400x). Going back to Mars, I occasionally see some dark markings, but nothing else. Mars getting farther from the Earth is a major factor, but I feel like I should still be able to see some more detail. I know that experienced observers have techniques that allow them to see more detail. Any tips or techniques? Anything would be greatly appreciated.

[DLuders]

Welcome to Cloudy Nights!     The "Choosing a Color/Planetary Filter" article reveals that #12 Yellow and #23A Light Red filters are best for Mars details, but others work well too.

[Dave Mitsky]

Mars is only 8 arc seconds in angular size now, which is really past the point of fruitful telescopic observing, even with large apertures. 

[Redbetter]

With Mars at 8 arc seconds and less than 90% illuminated it won't show much detail even if the seeing is quite good.  Learning to identify the larger dark markings you do see is still valuable for training your eye.

 

As far as tips go:

• With an 8" scope and Mars so small you need some high power eyepiece and/or Barlow options.  133x is midpower for an 8"--works well for an 80mm scope.  Something in the 175-225x range should be a sweet spot in anything but poor seeing.  Depending on what you end up with, something adding another 50 to 75x to that would be the next stop for nights of better seeing.  400x is likely to be either too much for your eye, the scope, or the seeing (with the seeing being the major limitation most of the time.)
• My experience is that red filters work very well for showing detail on Mars.  I prefer a #25, some prefer a #23 or #21 which move progressively from mid red to light orange.  This cuts the glare and scatter in less than perfect seeing--scatter which is dominated by bluer hues and weak in the red.  Red filters increase the contrast of the light and dark areas.

[Flaminging]

Thanks for the suggestions. I will try to get a filter and some more eyepieces to increase the number of magnifications I can use.

[nibiru711]

Svbony moon filter the lighter pink one has worked well for me. It gets rid of some of the glare but not all on my 6 inch f8 dobsonian and helps me the land mass and polar cap a lot better and it worked again last night on Mars with a astro tech ed 5mm eyepiece. Mars has gotten smaller quite a bit since September when I was even spotting the land mass and polar cap with an orion 70mm f10 achromat and a 6mm or 8mm eyepiece. I don't have any other filters right although I have had them in the past and used them on the moon juipter and saturn.

[Rutilus]

While Mars is now getting smaller, it is still possible to make out some of the larger features with

a scope of 8 inches.  I find that Mars is the planet that rewards the observer who has put a lot of time 

into it over months and even years. The experience gained really does help with seeing detail

when Mars is better placed. At the moment you may be only seeing a few dark patches, but of 

more importance is that you are gaining experience and training your eye and brain to detect subtle 

differences on the planet.

 

I always follow Mars as it gets smaller, even observing it when it gets down to 4 or 5 arc seconds in size.

Last night I observed Mars with my 6 inch f/8 achromat refractor using a power of 300x in bino-viewers.

I could make make Mare Cimmerium and Syrtis Major, along with the Hellas basin. I could not see the South

polar cap, but I did notice a slight brightening around the area where it should be located. Of note last night

was a quite large and bright North polar hood feature, along its southern edge I could see Utopia appearing

as a dark band or collar. Also seen was Trivium Charontis. I used the following filters #12 yellow and #21 orange.

[Pinbout]

I prefer to observe planets near my street light so my eyes won’t become dark adapted

 

also at 8” you could stop down your aperture to 6”  with a mask at the front of the tube

 

Edited by Pinbout, 28 January 2021 - 06:42 PM.

[Dave Mitsky]

The color filters that I find most useful for Mars are the Vernonscope CCM30 (magenta), which requires an adapter tube unfortunately, and the Wratten #21 (orange) and #80A (blue).

[gspeed]

> Observing Techniques for Mars?

 

Wait for Nov/Dec 2022 (next opposition)

[epee]

I find that a 50% Neural Density Filter, along with whatever color filter I'm using, helps cut the glare. However, I'm using a 12" so this may become too dark with your 8". Another filter to consider is the Baader Contrast Booster, a great all-around planetary filter; although it's pricey. 

 

Even so, there is no magic bullet that will suddenly make Mars look like a NASA photo. Time, experimentation with magnification, collimation, seeing and filters (even on other planets) will add up to the experience needed during the next opposition...