Jupiter, Trouble Getting Sharp View

[Skiddins]

I have watched Jupiter a few times now, but around 100-140x I have real trouble getting sharp focus and clearly defined edges for the planet.

At lower mags it seems very sharp and bright.

I can see the equatorial belts at all the mags I've tried but not much else.

The scope is properly collimated.

Is it because it's a bit low in the sky at the moment for truly clear viewing?

I do have a lot of light pollution etc but I'm sure I managed sharper views of Saturn.

Skiddins

[LeeB]

Hi Jupiter can sometimes seem out of focus as it appears to dim at the edges,In addition pushing the mag on bad nights will not help, I live with bad conditions alot and sometimes even 130x with my 10" pushs it. For sharper focus try 80x if its ok then its down to conditions if that still won't focus check collim again, allow more cooling time or get someone local with a scope to observe with you it will give you a second view to compare.

[hemihaggis]

hi there , i used to have a 130 as well , as its a newtonian scope it will not exell at planet views. you will not be able to crank up the magnification too much(like you could with mak ) unless at a proper dark sky site with great seeing .

[Space Bat]

Viewing planets can be hard when seeing is poor...

OK visibility may be good - but if there has been a lot of wind-which we have had recently this will pay havoc with seeing conditions.

I have had some of my best views planets during fog or misty nights - may sound daft - but fog accumulates when there is very little air movement and this will increase seeing of planets and massively improve contrast and sharpness of image.

[Moonshane]

as its a newtonian scope it will not exell at planet views. you will not be able to crank up the magnification too much(like you could with mak ) unless at a proper dark sky site with great seeing .

I don't agree with this. some of the best planetary scopes in the world are newtonian in design. more aperture gives more resolution and more focal length gives more power per mm of the eyepieces.

I have a 6" f11 newtonian which gives excellent planetary views, and on nights of good seeing so did my 12" newt.

It's more the size of the secondary as a percentage of aperture that matters as bigger = more contrast.

I would agree though that a smaller aperture fast newtonian is not ideally constructed for higher power observing. decent views can be had though, although not anywhere near as good as with an 8" or 10" newtonian and even an average 4" APO refractor would not give the resolution available to a 10" (or possibly even an 8") newtonian.

all that said, people like the different views provided by different scopes and I'd repeat that keeping the 8" dob and getting a small refractor would give more options than selling and just having a 130mm newt.

[cotterless45]

Jupiter was very high at 4.30am. Seen through my 8" dob the bands were clear and i spotted 2 darker areas on the N band. This was at x240 using a 5mm Explorer eyepiece.

Although I use Dobs 99% of the time for Dsos , it's just fun to look at planets when they pass. I would say that f5 is harsh on eyepieces and x100 gives a smaller, but better defined view. Dobs are light catching buckets, ideal for the faint objects.

[Capricorn]

Just looked up the scope, Sherwoods.

What I see is that it is f/5 so fast and will need to be kept collimated for the best views, going out of collimation will cause a fair drop in performence.

What I don't see is mention of the mirror being parabolic. If the mirror is spherical then at f/5 the image quality will be poor.

Equally I have the idea that celestron mirrors are parabolic but if so I am equally sure that it would get a mention.