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Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Wed May 13, 2020 12:00 am
by realflow100
Could be just really bad seeing or something?
telescope is collimated to the best of my ability using a laser collimator (The laser itself is not out of collimation its accurate. I tested that before using it.)

Venus looks razor sharp in comparison with some mild but noticeable "ripply water effect" around the edges of it. No CA or anything. only mild stretching of the image near the edge of the field. but not blurry or out of focus

Saturn looks really weird. like if I move my eye around it warps and shows faint double images and strange warping effects. but I can see the rings. and possibly a moon around it? not sure?

I'm not sure if i'm doing something wrong. or if thats just how it is sometimes?
They were reasonably high in the sky. just before morning.

jupiter's cloud bands are just barely visible. looks very low contrast. a bit fuzzy. it's moons look a bit glitchy if that makes sense? like pixelated and blocky/glitchy. Stars look fine though.
its hard to tell when the image is in focus unless I use a bright object like the moon or venus or another bright star first.

terrestrial objects look absolutely RAZOR SHARP though.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Wed May 13, 2020 12:32 am
by realflow100
Venus looks something vaguely like this to my eyes. (The little sliver above venus seems to rotate with my eyes orientation. not the telescope or eyepiece) this is just an example of close to what venus looks like to me.

Also I see some pretty epic diffraction spikes too. they arent bad or distracting. just epic looking. like a bunch of venuses fading out in line with the diffraction spikes lol.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Wed May 13, 2020 3:12 am
by Refractordude
Wish I could help. Someone will be along soon that could.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Wed May 13, 2020 3:24 am
by Lady Fraktor
The higher the magnification the more you will notice the atmospheric turbulence. (rippling)
I would say with the double image your collimation is still off a bit or something is slightly out of alignment.
If terrestrial targets are sharp but planets are not you are using to much magnification for the sky conditions.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Wed May 13, 2020 10:38 pm
by realflow100
only 133x being too much? wow it must be EXTREMELY bad sky conditions then.

the double image i think is caused by my eyes because it rotates with my eyes. and not the telescope or eyepieces just a bit distracting is all.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Wed May 13, 2020 11:19 pm
by Bigzmey
For your scope 100x (1 mm exit pupil) will be close to the highest productive power under good seeing conditions. Above that is empty power and loss of sharpness and contrast.

Under poor seeing the image will degrade much faster. Judging from what you described that was the case. Did you try lower powers? It is always better to have smaller but steadier image than larger and boiling.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 12:05 am
by realflow100
Yeah but its too bright and small to see any details on jupiter then. and saturn is just a hair too bright. i can still see the rings on saturn but i can't really see the bands on jupiter anymore at a lower power. not enough magnification
Venus looks great at any magnification really. even 5x is enough to see the phase of it nice crescent shape

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 12:37 am
by Bigzmey
realflow100 wrote: Thu May 14, 2020 12:05 am Yeah but its too bright and small to see any details on jupiter then. and saturn is just a hair too bright. i can still see the rings on saturn but i can't really see the bands on jupiter anymore at a lower power. not enough magnification
Venus looks great at any magnification really. even 5x is enough to see the phase of it nice crescent shape
You can resolve major bands on Jupiter even at 30x. Make sure your scope collimated. You may also need filter to control the glare.

Here are a few tips for planets

viewtopic.php?f=94&t=4016

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 12:45 am
by realflow100
what 30x no way! its way too small looking. its just a small bright white dot with some moons for me at that kind of magnification.

I am very limited in ability to collimate my scope. can only get it "close" but not perfect. because the primary is completely fixed in some plastic housing with no adjustments. I had to cut slots in the 3 screw holes to be able to adjust it at all
and I have to "eyeball" the center point of the mirror with the secondary to get it even close.
Theres no center circle dot or hole in the mirror its just a plain mirror. Not meant to be adjusted.

the steps in magnification i have access to with my barlow and eyepieces are
133x 6mm + 2x barlow
89x 9mm + 2x barlow
67x 6mm
53x 15mm + 2x barlow
44x 9mm
40x 20mm + 2x barlow
27x 15mm
20x 20mm

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 3:22 am
by StarBru
realflow100 wrote: Wed May 13, 2020 10:38 pm only 133x being too much? wow it must be EXTREMELY bad sky conditions then.

the double image i think is caused by my eyes because it rotates with my eyes. and not the telescope or eyepieces just a bit distracting is all.
Lady Fractor and Bigzmey are giving you excellent advice! If it were me, for the highest magnification on your scope, I would use the 9mm Expanse with the 2x Barlow giving 89x and an exit pupil of 1.1.

I have an 80mm f/5 refractor giving me the same focal length as your scope (400mm), and the highest magnification I can use on it is 100x using a 4mm TV Radian with an exit pupil of 0.8. I usually prefer a clearer view using a less powerful eyepiece.

Sky conditions are key. As you keep looking into the eyepiece you will see moments of clearer views and that is what we all are waiting to see. What it all boils down to is what you are most comfortable with, it's a trade-off. More power is less clear after a certain point.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 3:44 am
by realflow100
I tried lower but I still saw the most and best detail at 133x
its just too bright and small going lower than that for me.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 7:17 am
by realflow100
Not my picture but I see roughly this amount of detail on jupiter at 133x. and it looks kinda like this.
but way smaller. not to scale.
its still smaller. about the size of your pinky nail on an outstretched arm. maybe slightly bigger or smaller. hard to tell when its just floating in space. i cant really put a ruler to measure it.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 1:19 pm
by Baurice
My centsworth:

That photo of Jupiter would be good for a 100mm F4 reflector. Your short focal length is great for deep sky objects, such as open star clusters and the closer galaxies. However, it is not a good planetary 'scope and I'm sorry to say that it won't get better. Venus is as good as it is because it is exceptionally close to us now but, for most of its orbit, is quite difficult. Jupiter and Saturn are near the horizon from the northern hemisphere, so are not well-placed for observation. "Rules" about maximum magnification suggest that you can use up to 200x magnification but, for an F4 'scope, that is very optimistic. I have an F12 Maksutov and, even with that, planets near the horizon are not clear and, under poor viewing conditions, seem to "dance" in the eyepiece.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 3:17 pm
by realflow100
Yes im seeing the dancing your talking about. Venus had it especially bad when it was full phase. but now as a thin crescent its not even an issue for some reason.

Mars also looks like a disco ball. multiple clones of it floating and swirling all around it. hard to tell where it really is. or even achieve proper focus. I have to focus on the moon or a bright star or something in order to focus properly for mars.
mars is a small dot/disk at 133x for me. too small to see details. but it is a nice orange color

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 3:33 pm
by Baurice
realflow100 wrote: Thu May 14, 2020 3:17 pm Yes im seeing the dancing your talking about. Venus had it especially bad when it was full phase. but now as a thin crescent its not even an issue for some reason.

Mars also looks like a disco ball. multiple clones of it floating and swirling all around it. hard to tell where it really is. or even achieve proper focus. I have to focus on the moon or a bright star or something in order to focus properly for mars.
mars is a small dot/disk at 133x for me. too small to see details. but it is a nice orange color
Mars is tough at any time. It will be better in October when it reaches opposition. When it was at opposition in 2018, the weather on Earth and Mars meant that I never got a decent photo.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 3:46 pm
by sdbodin
Seeing is one aspect of amateur astronomy that is not really appreciated until experienced. I will not be pointing my scopes at Saturn or Jupiter for about 5 years, not worth it. Looking straight up, thru 60 miles of atmosphere is OK at best, looking horizontal thru 500 miles of atmosphere is an exercise in frustration. Planets never look as good as those pictures on the outside of the box in the store.

Steve

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Thu May 14, 2020 7:39 pm
by Harmonious
I empathize, sympathize and adivze too. You are in part describing one of the reasons I switched over to a camera for EAA, though I still like the EP experience. For planets 12mm is is about the best I can use regularly. In scopes from 4" to 11" a 20mm was and is my most used EP. As for Mars, at the very best it was either Syrtis Major, a hint of polar cap or dust storm even with an 11" SCT .

A 6mm + 2x Barlow would be a disappointment 99.9% of the time in any of the scopes I've used. The seeing where I live is rarely good enough. In fact the only time I've ever had a crisp view of Saturn with a 3mm EP was in the high desert at about 4400'. We had an 85mm APO and a 5" SCT and it was the one and only time that we were able to use a 3mm Nagler zoom.

You might find the field of view tool at AstronomyTools] useful to get an idea of the image size with with various combinations of scope, EP, Barlow or reducer for planetary and DSOs. The image scale not the quality.

To get some idea of seeing conditions at your location check out --metoblue astronomical seeing for Orangeburg.

https://clearoutside.com/,

https://www.windy.com/ has a very good display of winds aloft by altitude/flight level. A good indicator of seeing.

https://www.cleardarksky.com/csk/prov/S ... Orangeburg

There is still a lot to see with a 100mm scope.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Fri May 15, 2020 1:20 am
by Rainmaker
Unfortunately 133x in a non-collimatable reflector is not going to get you sharp images of Jupiter or Saturn unless you have perfectly still air and a bucket full of luck. There are times when even my 4” Takahashi is limited to less than 133x .

Fortunately there are many other targets that you can enjoy that scope on, open clusters, the Moon, some of the bright doubles....

I’m not a Barlow user as I haven’t found one yet that outperformed an eyepiece on its own, maybe keep that scope at 80x or less for more pleasing views...

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Fri May 15, 2020 3:55 am
by realflow100
the moon looks great at 133x for me. still looks sharp and detailed.

I'm limited to stars and objects objects brighter than about magnitude 4 naked eye.
and with a telescope the faintest DSO I can see is orion nebula and andromeda galaxy. and just barely
otherwise im limited to just a few clusters and mostly stars like pleiades is really bright and easy to see stars with my telescope at lower magnifications. cant really see any other galaxies or DSO.

Re: Jupiter looks soft/fuzzy at 133x in 4" parabolic reflector?

Posted: Sun May 17, 2020 1:27 pm
by Baurice
sdbodin wrote: Thu May 14, 2020 3:46 pm Seeing is one aspect of amateur astronomy that is not really appreciated until experienced. I will not be pointing my scopes at Saturn or Jupiter for about 5 years, not worth it. Looking straight up, thru 60 miles of atmosphere is OK at best, looking horizontal thru 500 miles of atmosphere is an exercise in frustration. Planets never look as good as those pictures on the outside of the box in the store.

Steve
Just imagine what they're like at the moment from 51.4 degrees north! I will certainly do regular shots of the Galilean moons and could catch Titan on a good night. I will do odd images of the planets but will not be following them as avidly as I do when they are higher in the sky. I won't wait 5 years, though. There's a 10% chance I'll be brown bread by then.