Problems viewing planets through my new reflective telescope

[ME!!]

Hi! I am Brooke and I am new to Astronomy. I recently got a new Celestron reflective telescope and I was really excited about it! Although, when I try to look at Jupiter, I "zoom" in and I big black dot appears in the center of the planet, but the planet looks like a big white blob like a star. 3 spokes come out of the black dot. I can see the moon perfectly. Help!

[bomberbaz]

You are simply not in focus, this is a common error. Put in the lower (probably 25mm) eyepiece first then train the scope around onto Jupiter. Using the focuser nob next to the eyepiece and starting from all the way in, start to wind it out slowly, you will get the view similar as you have described above and then as you slowly wind it out, the large blob will shrink to become a small white disc with bright white dots coming off off one or either side of it, these dots are the moon. Once you are at this point you can slowly try a little tweaking to get the tightest possible dot that is the main planet. Patience is the name of the game.

Once you master this try the higher powered (smaller numbered) eyepiece, usually 9 or 10. This is more tricky and again patience is needed.

[Dave In Vermont]

Hello Brooke. It sounds like a problem with your focusing. I'd suggest practicing focusing in the daylight out of doors. Find a distant object, such as a church-steeple, tall tree, phone-pole, etc. Then get this into your field of view through your eyepiece(s), and learn to carefully turn the focusing-knobs until the object become the clearest and sharpest you can make it. This is also a good time to align your finder with the main scope. This is best done in daylight, as objects in the night sky are moving, and your telescope magnifies the movement as much as it magnifies the object you're looking at.

Which Celestron reflector do you have? It should have a name and some numbers on it and the papers it came with.

Have fun -

Dave

EDIT: Hi Steve! Looks like we walked on each other! Great minds.....

[ronin]

The statement that you can see the moon perfectly is the puzzle. The moon and Jupiter are as far as the scope is concerned both at infinity so if one is sharp the other should be.

I notice that you say " I "zoom" in and I big black dot appears in the center of the planet".

On a scope you do not "zoom" in, are you getting a little confused, the description matches other reports. The bit you use to "zoom" in is I suspect the focuser and it does not zoom in. To get bigger or smaller you swap eyepieces. A bit of the problem is that although the UK and US use basically the same language we use it with just enough difference to cause confusion to each other.

The post reads that you have made this error, in that you have got the moon in focus, moved to Jupiter (which will be small - it always is) then adjusted the focus expecting the image to increase or decrease in size. It won't (might be a bit better if it did to be honest - could be an interesting bit of optics/mechanics). When I guess you have adjusted the focus the image will get bigger but it will be a blur, also after a bit it all turns into a "ring doughnut" shape. Which is what you appear to be describing.

If the moon is sharp, then get Jupiter in view then to get bigger you will have to go to a shorter focal length eyepiece. Chances are that when you swap eyepieces you will have to refocus again.

People do this likely owing to the terms used, I have heard people use the term "zoom" when they really meant "focus".

There is one other possible aspect, but not sure if it applies to Celestron's.

Synta make Skywatcher and Celestron. On the Skywatchers they provide an adaptor in the focuser to take a 2" eyepiece and a 1.25" eyepiece. For shipping they put the 1.25" inside the 2". It fits perfectly and all looks right. Minor problem is that it isn't. If they are both there you need to take the 1.25" adaptor out, take the 2" adaptor out, then put just the 1.25" adaptor back in.

The post does not say it but there is the chance that you have used the long focal length eyepiece for the moon and it has just focused, then swapped to the shorter on and that this one cannot achieve focus - because both (if present) adaptors are in the focuser. The object plane of the 2 eyepieces will be different so one might work the other might not. That is the other possibility. It is unfortunately a very common problem that people have initially caused by the way the adaptors are made and then shipped, it is however an easily fixed problem.

Hope one or other is relevent as then you can sort it. If not come back and people will have another go.

[ME!!]

Thank you for all of your replies. Bob, you are right I see 4 moons, aren't I supposed to be able to see Jupiter clearer? All I see is a white disk with the 4 moons. Yes sub giant I know I am not zooming in, I didn't know another way to put it. Green man I have a NexStar 130SLT. I have tried turning the focused all the way through both lens, but I still can't see anything

[R136a1]

Darkening at the center of the FOV means that you're probably out of focus. Did you let your telescope cool? This may be why you're not seeing any detail.

[Dave In Vermont]

Hi Brooke -

Can you get a star in your eyepiece? A bright one would be preffered. And bring the star to a sharp focus? By this I mean to the smallest, sharpest point-of-light you can focus it to. Your ability to do this will help to define what is going wrong for you.

Thank you for getting back to us. By the way - 'Little Green Man' isn't my name (or Sub Giant for that matter). These are our ranks, which are automatically changed as your number of posts on this site grow. In my case, I changed whatever my officially sanctioned rank would be with my post-count into 'Little Green Man' as I was tired of my auto-applied ranks were. You'll be able to do this with yours, too, as you continue to post. Right now your rank is 'Vacuum.'

Do also practice focusing in the daytime as I suggested in my previous post. As well as on a bright star. And let us know how this goes for you. The more information we have - the sooner we can fix any problems that are causing your difficulty.

No worries - we'll get you up & running,

Dave (which is my name! )