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Bringo

beginner question about observing Jupiter

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Hello!

I am a beginner astronomer and just purchased my first telescope: Celestron Astromaster EQ130. I decided to start "small" with an entry level scope and learn the trade as I progress. I could easily afford one of the more advance computerised scope but I want to learn the basics firsts... also the night sky isn't going anywhere so I guess I have time.

I am currently located at latitude 33 degrees approx.

The first thing I decided to observe was Jupiter being an easy target well lit... so I aligned my scope and balance it and then point it towards Jupiter. It took me a good 20 minutes to be able to zero it on my 20mm eyepieces and thanks to proper setup I was able to follow it through the RA knob only.

now what I saw was a shiny yellow dot with 3/4 moons next to it. I increased the magnification with a Barlow x2 and switched to a 10mm eyepiece. Honestly I though I would see it much bigger but it was still a slightly bigger dot with the moons. I couldn't make the bands appear. Thing is that I presume it is due to the strong flashing luminosity glaring at my eye that make it impossible for me to see the details on the planet. Is my understanding correct? Do I need to apply some sort of filter in order to discern the bands? Or is my magnification simply not enough? What are some tips to get a better more detailed view of the planet?

please note that Saturn appears like a small yellowing bulb with its rings clearly visible and Mars is just a small red dot with no discernable features.

Thank you!

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Hi Bringo, you did the right things, but don't rush, it takes more experience in observing to tease out the details of the cloud belts on Jupiter.  It's all about seeing and accustomizing your eyes which comes with observing experience and lots of patience.  Planets will always look like a pea in most telescopes.  The smaller they are the sharper the detail.  Jupiter excels at about 150x.  You do not need to use any special filters to observe planets.

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I have the same scope as you (although I never use it now as it has been superseded by other better scopes). On the telescope end cap to reduce the glare from Jupiter (and the moon too when you observe it) you can just take off just the smaller aperture cap that is built into the larger exit cap to help view Jupiter to reduce the glare. You can also use blue number 80 filter too to tease out detail in the bands too (which you screw into the end of your EP's). I use them quite regularly, but you'll find some people use them, and others don't as they don't see any benefit to them. For normal seeing conditions I do find you can make out details better mostly, although when the seeing is good you can make details out without the help of the filter. :) 

Edit: photo below shows main lens cap with smaller aperture cap removed.

image.jpeg

Edited by Knighty2112

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Hello and a warm welcome to the SGL. You should be able to see the equatorial bands at the very least. Make sure you are properly in focus. The moons should be star-like points of light and the planet will be at its smallest diameter. Jupiter and the other planets will always be small in your telescope, but details should be visible. Of course this will always depend on your skies. When the seeing is not good you will have difficulty in getting a steady image. There may be moments when the views improve and with practice these will become more apparent.

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Although using just the small aperture in the end cap will reduce the glare, it will also reduce the resolution, you are far more likely to see detail with 130mm aperture than around 50mm. Higher madnification or filters would be a better bet.

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13 minutes ago, Peter Drew said:

Although using just the small aperture in the end cap will reduce the glare, it will also reduce the resolution, you are far more likely to see detail with 130mm aperture than around 50mm. Higher madnification or filters would be a better bet.

Hi Peter, just to say that when I used to use this scope (which I don't anymore), on most nights there was very little difference between the quality of the image from Jupiter apart from the glare when using the smaller aperture as opposed to the full aperture. In theory yes there should be a difference. In practice (for this scope at least), it really only did reduce the glare, and any loss in quality of the image was very minimal.

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Perhaps I shouldn't have presented my post so "black and white" :icon_biggrin:. There are several resons why, at the time, the reduced aperture can give a more pleasing view. Reduction in glare is the obvious one and the reduced effect of seeing on smaller apertures being another. In an entry level telescope which might not have the best of optics or received collimation, the smaller sample of the main aperture can mitigate the result. All things being good and equal, the full aperture should win out.

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My opinion is that you are going to need an additional eyepiece. The supplied items are usually not really that good, that includes the barlow. In effect a poor eyepiece and a poor barlow do not produce the image that is expected.

The scope if f/5 and a 5mm of reasonable quality should produce a fair image, you will get 130x with a 5mm. I would suggest that you go for a little less and locate yourself an 8mm to give 81x, which will be adaquate on Jupiter.

Another option should be a 6mm to deliver 108x, good for Jupiter and should be good for Saturn.

In the 8mm line there are the Astro-Tech Paradigms, in the 6mm there is the William Optics 6mm Planetary. I will say I think that the WO's are the same as the Astro-Professional range and they be a bit less. Worth searching round.

Has Canada drifted South :D ? You say Canada and 33 latitude? :help2:

Edited by ronin
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My first thought was eyepieces too, but most eyepieces that come with a scope are not that bad (I'm including H and SR type eyepieces here, which despite their narrow field and problems at the edges should be adequate for viewing banding on Jupiter, but the Celestrons will almost certrainly be Kelner types). Is it possible the image was slightly out of focus? That would lose you the detail on Jupiter very quickly, as it is quite a low contrast object. Seeing conditions could also contribute, though I've never known seeing to be that bad. Collimation could be another factor. Ithink the most likely might be Robin's suggestion though. My first view of Jupiter (I suspect most people's firt view) was of a small white ball with almost no perceptible detail, and the bands started to emerge after a couple of minutes.

A couple of questions might tease this out. When you look at a star what do you see? A bright, sharp pinpoint of light or something else (blurry, fuzzy, with a little tail etc)? Also, when you say Jupiter looks like a shiny dot, do you mean a small round dot or an actual pinpoint. Jupiter will be small with a Barlowed 10mm eyepiece, but it should not look like a dot. Imagine something more like a pea, held at arms length. If it wasn't about that size then something else is wrong (though I'd be stuck as to what).

Not saying a nice shiny new eyepiece would not be nice, but might be best to try other routes first before spending the money.

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Sounds like you are seeing things the way most of us see them. Should be able to see 2-4 bands on Jupiter, depending on local seeing conditions. Its moons simply look like stars. The more you observe the more you will see. Saturn is a WOW in most scopes. The 130mm is no exception. No surface detail to speak of but the rings are visible alright. Mars is a fickle planet. Its such a small sphere in a scope that detail on its surface is difficult to pick out. The polar caps should be visible as white areas to the top and bottom.

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22 hours ago, billyharris72 said:

 

A couple of questions might tease this out. When you look at a star what do you see? A bright, sharp pinpoint of light or something else (blurry, fuzzy, with a little tail etc)? Also, when you say Jupiter looks like a shiny dot, do you mean a small round dot or an actual pinpoint. Jupiter will be small with a Barlowed 10mm eyepiece, but it should not look like a dot. Imagine something more like a pea, held at arms length. If it wasn't about that size then something else is wrong (though I'd be stuck as to what).

 

Hi Billyharris,

Stars are a bit blurry/fuzzy on the edges of the eyepiece but look like dots in the centre. Jupiter is a small yellowish round that glares annoyingly with Barlow + 10 mm.

I forgot to mention that I was on a rooftop in a average light polluted area...

 

23 hours ago, ronin said:

 

Has Canada drifted South :D ? You say Canada and 33 latitude? :help2:

hahahah not it hasn't , I am currently on vacation in the mediterranean area... 

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Interesting. It sounds like your collimation is fine, and that you have the hang of the focuser. I wonder if the cooling air and a rooftop location isn't a big part of it. Seems like that would cause rising air currents that could cause seeing problems. Are you able to move to somewhere grassy, and preferably not looking over an area not too heavily built up? That often results in a better view.

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Are you on vacation? I ask because there is nowhere in Canada that is anywhere near 33 degrees. I am also in Canada but at around 43 degrees, I am quite close to as far south as Canada gets unless you consider Florida as part of Canada

Edited by VSOP

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