
Attempting to Observe Jupiter/Venus
- conor-figgy
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Attempting to Observe Jupiter/Venus was created by conor-figgy

Apologies for the crude ms paint drawing. The grey is the planet and the black is the structure of the mirror holder (as far as I can see). So, my questions are:
1) Why can I see the struts of the holder? I've observed the moon many times and it's never been in the way.
2) I couldn't get either planet into any recognisable focus, and ideas to why?
Thanks!
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- astroado
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Replied by astroado on topic Re: Attempting to Observe Jupiter/Venus
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- PaulWalsh
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- Coldfieldboundary
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- conor-figgy
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Replied by conor-figgy on topic Re: Attempting to Observe Jupiter/Venus
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- dave_lillis
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- Super Giant
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Replied by dave_lillis on topic Re: Attempting to Observe Jupiter/Venus
On bigger dobs, you do get the vains holding up th secondary as spikes on the brightest stars.
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Carrying around my 20" obsession is going to kill me,
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- conor-figgy
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- Nerro
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- conor-figgy
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Replied by conor-figgy on topic Re: Attempting to Observe Jupiter/Venus
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- Nerro
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Replied by Nerro on topic Re: Attempting to Observe Jupiter/Venus
If it doesn't go all the way up it means it's too loose and you will need to tighten it.
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- conor-figgy
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Replied by conor-figgy on topic Re: Attempting to Observe Jupiter/Venus
- Celestron 10mm eyepiece
- Celestron 20mm erecting eyepiece
- Celestron 6mm eyepiece
- Celestron Omni 2x Barlow Lens
Just checked my focuser, seems to be working just fine.
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- Nerro
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Replied by Nerro on topic Re: Attempting to Observe Jupiter/Venus
Now if you will see the spider vanes then your scope is way out of collimation and i mean way off as I don't know what else could be wrong...
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- conor-figgy
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- conor-figgy
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- dave_lillis
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- Super Giant
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Replied by dave_lillis on topic Re: Attempting to Observe Jupiter/Venus
If the bright illumination/planet image in the center perfectly center or is it oblong/lobsided.
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.

+ 12"LX200, MK67, Meade2045, 4"refractor
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- conor-figgy
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- mykc
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Replied by mykc on topic Re: Attempting to Observe Jupiter/Venus
Mike
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- dave_lillis
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- Super Giant
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Replied by dave_lillis on topic Re: Attempting to Observe Jupiter/Venus
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.

+ 12"LX200, MK67, Meade2045, 4"refractor
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- Graham
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Replied by Graham on topic Re: Attempting to Observe Jupiter/Venus
SourceIn a misaligned scope, the star is out of focus and will appear as a doughnut shape with a dark center. If your telescope is misaligned, this dark patch will be perfectly centralised within the bright ring. This is actually the shadow cast by the secondary mirror, and you may also see the spider veins (as in the figure below). When the optics are in need of alignment the dark patch will be off center.
If it is collimated then perhaps it is collimated with mirror travelling too far up the tube?
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- conor-figgy
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Replied by conor-figgy on topic Re: Attempting to Observe Jupiter/Venus
So, collimation it is then.
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- Calibos
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Replied by Calibos on topic Re: Attempting to Observe Jupiter/Venus
Are you using the eyepieces that came with the scope?
I read that the scope has some kind of correct image prism thingie for Terrestrial viewing. Can this be removed? It might be preventing you reaching focus for celestial objects.
You do realise that even with a barlowed 7mm giving you about 150x that Jupiter in the eyepiece wont look much bigger than the full moon looks to your naked eye when you look up at it. ie. Are you sure you aren't bypassing perfect focus when the image of Jupiter is at its smallest and sharpest because you are saying to yourself, "Nah, shouldn't be that small!" 'Fraid it is mate

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- conor-figgy
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Replied by conor-figgy on topic Re: Attempting to Observe Jupiter/Venus
I'll try look into this correct image prism.
Actually, you might have something there... I don't think I actually used the 6mm and the barlow together as I thought it would be too much, whoops. Hmm, perhaps I was trying to view it with an underpowered eyepiece and therefore went way way past the focus point. Well, tonight shall hopefully tell! Cheers!
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- dave_lillis
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- Super Giant
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Replied by dave_lillis on topic Re: Attempting to Observe Jupiter/Venus
If you are seeing exactly the image from 4 posts ago, then your eyepiece is not focused, maybe your primary mirror is too far down the tube ?.
if it is what you're seeing then your moon images must be out of focus aswell and look mushy/blurry/soft.
In that image from 4 posts ago, it is slightly out of collimation, but you still be able to see some sort of image when focused. What do they brightest stars look like through the lowest power eyepiece when focused , are they dougnnuts?, flaired with a fan like comet tail, or like boiling dots/points ?
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.

+ 12"LX200, MK67, Meade2045, 4"refractor
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- conor-figgy
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Replied by conor-figgy on topic Re: Attempting to Observe Jupiter/Venus
I don't have a laser collimator, neither do I know any other amateur astronomers around where I live. Should I just wait until I get a chance to bring it to someone knowledgeable or invest in a laser collimator and learn how to do it myself?
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- dave_lillis
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- Super Giant
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Replied by dave_lillis on topic Re: Attempting to Observe Jupiter/Venus
hmm, interesting, so when you get the boiling point for the star, thats the focus position and that'll be the focus position for every object in the sky with that eyepiece obviously. i'm kinda wondering are you thinking that the scope is focused when the focuser tube is fully racked in, by what youre saying.tried to observe a star it looked like the image posted earlier and the boiling dots/points as I focused "out" if you know what I mean.
The boiling is normal unfortunately, the atmosphere and thermals in the scope causes it.
IF you are seeing stars like that, then there is nothing wrong. Spider vains are normal on the brighter stars when focused, nothing you can do about it. If you view of Jupiter is very small, you could get spider vains there aswell.
If you move the scope to Jupiter and all you see is a fuzzy disk without changing focus or eyepeice, then I'm left wondering is this a "unrealistic expectation" thing going on here,
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.

+ 12"LX200, MK67, Meade2045, 4"refractor
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