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Help me see more detail on Jupiter

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#26 wrvond

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Posted 22 July 2021 - 12:15 PM

+1 on the polarizing filter. I have an old single Polarizing Filter and it's like putting on those Tactical sunglasses as seen on TV. Variable polarizers are actually 2 filters that twist to control light transmission. Most users say they put one part on the diagonal and the other on the eyepiece. That way you can control the light transmission by twisting the eyepiece.

That's what I do. waytogo.gif



#27 SteveG

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Posted 22 July 2021 - 12:44 PM

In my experience, polarizing filters reduce resolution more that a standard ND filter. I have a single polarizing lens that I quit using years ago because of this. Instead I use a quality 25% ND filter, or more magnification.

 

On a good night of steady seeing, I've never seen an improvement with any filter at all, including the Neodymium.



#28 peta62

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Posted 22 July 2021 - 01:04 PM

I am not sure he means the eccentricity of Jupiter, but you are right. You can tell it's slightly out of round. However, in the video there does appear to be a little "eccentric" blurring of the image toward the upper right. It may be collimation or cooling, not sure...but my guess is the scope needs to be collimated. Especially if it was dropped.  

Exactly what I meant.


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#29 Redbetter

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Posted 22 July 2021 - 04:10 PM

I think there are serious problems with the instrument, so maybe it's is reasonable to trash it and buy a new instead of trying to fix. looks like there's not only huge collimation problems but also smth with focusing mechanics.

 

No, no, no.   I don't know why you would even start to come to such a conclusion.  You can't make any judgement based on an uncollimated instrument, and particularly on one target very low in the sky.  


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#30 Redbetter

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Posted 22 July 2021 - 04:29 PM

Hi All,

 

thank you for your help so far it has been good, I think I have made a slight improvement with everyone's advise. I took the telescope and shot a few small videos and managed to get this. Did I manage to get some details on Jupiter? I think i can see bands?

 

After reading your advise about collimation, i looked at a star and the circle wasn't quite in the middle but not very far off nevertheless it wasn't in the centre. Will this make my observing less efficient, I couldn't really collimate it whilst trying to turn the screws in the dark of night aswell as trying to look through my eyepiece it's pretty hard, so i just left it for now. Will it make a massive difference? should I be able to get better than what i got above with the size of my scope?

 

Thanks for the help so far.

Sounds like it is way out of collimation from your descriptions so far.  Yes, collimating it should make a massive difference.  As for aperture, a 40mm will do better than that.  (This is complicated somewhat by the low position, in your sky.)

 

Collimation is pretty simple, you don't have to be staring into the eyepiece when you make the adjustment (that is actually quite hard.)  Instead with the star centered in the eyepiece at high power and slightly defocused, you evaluate which screw/knob to adjust (the one closest to the axis that the collimation is off.) Then adjust a very small amount, logging how much and in what direction (e.g. 1/16 turn clockwise, noting which screw was turned.).  Then go back to the eyepiece, recenter the star and re-evaluate.  Did it get better or worse? 

 

If it got worse and in the same direction, you turned the screw the wrong way, turn the screw in the other direction.  If it is now out in the other direction, you overshot and will have to estimated how much to back off.  If if now seems corrected on the original axis, it might still be a little out in the direction of one of the other screws.  Repeating with smaller adjustments on the appropriate screw should allow you to dial it in.

 

After collimating you should see that diffraction rings are uniform around moderately bright stars in the center of the field at high power.  Planetary/lunar detail should be greatly improved.



#31 VNA

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Posted 22 July 2021 - 04:48 PM

Hello: More than likely a question of collimation. So easy to knock out collimation a tube of that size.

(Most likely already mentioned?)



#32 TheUser

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Posted 23 July 2021 - 03:24 AM

No, no, no.   I don't know why you would even start to come to such a conclusion.  You can't make any judgement based on an uncollimated instrument, and particularly on one target very low in the sky.  

 

not with 125 aperture and 152 magnification. his image gives no single normal band on the planet disk. it's not OK.

 

for me there's not only aberrations but also some kind of pathological unfocuse.
 

c'mon. altitude can't affect so extremely the image, and if it were atmosphere we sometimes could see details and the image were shaking

 

such image can be also the result of extreme impurity of optical surfaces, that's why important to see the photos of instrument


Edited by TheUser, 23 July 2021 - 03:27 AM.


#33 peta62

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Posted 23 July 2021 - 05:39 AM

not with 125 aperture and 152 magnification. his image gives no single normal band on the planet disk. it's not OK.

 

for me there's not only aberrations but also some kind of pathological unfocuse.
 

c'mon. altitude can't affect so extremely the image, and if it were atmosphere we sometimes could see details and the image were shaking

 

such image can be also the result of extreme impurity of optical surfaces, that's why important to see the photos of instrument

1. I see two bands on the picture in post #18.

2. I would never trash equipment without doing tests that cost me only some time - collimation.

3. It can be collimation, seeing, low altitude combined. I have pretty poor views with good scopes too time to time.

4. I agree with impurity, it should be checked too, see above 1.



#34 Redbetter

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Posted 23 July 2021 - 06:13 AM

not with 125 aperture and 152 magnification. his image gives no single normal band on the planet disk. it's not OK.

 

for me there's not only aberrations but also some kind of pathological unfocuse.
 

c'mon. altitude can't affect so extremely the image, and if it were atmosphere we sometimes could see details and the image were shaking

 

such image can be also the result of extreme impurity of optical surfaces, that's why important to see the photos of instrument

I am not sure what you are talking about but some of the particulars are wrong.  It is a 127mm scope, not a 125.  I see no mention of 152x, since it has ~1250mm focal length and a 10mm eyepiece and 2x Barlow, the magnification would likely be ~125x or the 250x originally stated.

 

Low altitude with accompanying terrible seeing can indeed wreck the image badly, especially as experienced by a novice observer.  You seem to be referring only to the video taken through the eyepiece at 250x (which is preposterously high for the conditions and aperture.)  The other image later (magnification unstated) shows several belts and is likely closer to actual focus.  This sort of unprocessed video is usually a very poor representation of the visual image, presenting much less detail than what the eye can see.

 

At any rate, the scope is not collimated based on the description and what I can see in the images so far.  Like I said, I have seen a 127 Mak image wrecked by poor collimation, as received by from the factory.  Until the collimation is addressed, we have no idea what sort of image the scope can put up.  Best to start with the things that can be addressed, and work from there.

 

Declaring such a scope unsalvageable and suggesting  "trash it and buy a new instead of trying to fix" as you did is unhelpful bad advice.  It is downright irresponsible to tell a novice something like that, before they have even done any troubleshooting.  Jumping to wild and unsupported conclusions is not troubleshooting.

 

Photos of the instrument, might help, but only if there is something glaringly wrong with the OTA that the OP has not told us about.


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#35 rhetfield

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Posted 23 July 2021 - 01:26 PM

Hi All,

 

thank you for your help so far it has been good, I think I have made a slight improvement with everyone's advise. I took the telescope and shot a few small videos and managed to get this. Did I manage to get some details on Jupiter? I think i can see bands?

 

After reading your advise about collimation, i looked at a star and the circle wasn't quite in the middle but not very far off nevertheless it wasn't in the centre. Will this make my observing less efficient, I couldn't really collimate it whilst trying to turn the screws in the dark of night aswell as trying to look through my eyepiece it's pretty hard, so i just left it for now. Will it make a massive difference? should I be able to get better than what i got above with the size of my scope?

 

Thanks for the help so far.

If the color on this picture is accurate, it looks like the OP might be looking through the smoke that has been plaguing many of us.  I do see at least one - maybe two bands.



#36 Oort Cloud

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Posted 23 July 2021 - 04:04 PM

Probably best if you provide more info. What was the local time of the observation? What is your approximate latitude? If it was early when Jupiter was still low in the sky, then this would not be unusual. If you are far north and Jupiter remains low all night, you could have a similar problem.

But the first recommendation is to look at the planet without the Barlow. 250x is a lot to ask of a 5" SCT, even if the planet is well placed and the seeing is perfect. 125x will give you an idea of conditions and should show reasonable levels of detail for the aperture as a starting point.

It is hard to tell from the video, since Jupiter might never be centered in the eyepiece, but I am seeing that the image has sharp lower left disk edge and a blurred (or dimmed) upper right. This could be an indication of miscollimation. You should check collimation (your Barlow will work well for this with the 10mm) with a reasonably bright star centered in the field. If you are far enough north, Polaris will work for this, having the advantage that it moves slowly in the eyepiece.

The fading on one side could also be an indication of atmospheric chromatic dispersion, but I can't tell because I don't see clear reddish hue on one side and bluish on the other. Atmospheric chromatic dispersion occurs when objects are low in the sky (prismatic type refraction dispersion by the atmosphere.)

Poor seeing can produce a featureless blob, lower magnification can help somewhat to produce a somewhat resolved image for the eye. Larger features should be resolved on the Moon at low power, even if the smaller features on planets are mere blurs.

If your scope is warm and the night sky is cool, the you might be having some thermals.


All good advice, I'd just like to add one fact that is not always known to beginners...when you collimate, the star must be dead center. Once you adjust, it will move. You must recenter after each adjustment. I am lucky to use a camera now, which helps immensely, as the software is able to place a reticle at the center of the field, and is also able to zoom in on the star. But they do make reticle eyepieces as well. Short of either of those options, you can greatly defocus the star, and if it's bright enough, you'll still be able to see the donut even when it fills the eyepiece. This is more useful when collimating on Polaris, as it won't move while you're moving the focus back and forth. This helped me a lot when I was starting out with my SCT.
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#37 TheUser

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Posted 24 July 2021 - 05:06 AM

I am not sure what you are talking about but some of the particulars are wrong.  It is a 127mm scope, not a 125.  I see no mention of 152x, since it has ~1250mm focal length and a 10mm eyepiece and 2x Barlow, the magnification would likely be ~125x or the 250x originally stated.

 

Low altitude with accompanying terrible seeing can indeed wreck the image badly, especially as experienced by a novice observer.  You seem to be referring only to the video taken through the eyepiece at 250x (which is preposterously high for the conditions and aperture.)  The other image later (magnification unstated) shows several belts and is likely closer to actual focus.  This sort of unprocessed video is usually a very poor representation of the visual image, presenting much less detail than what the eye can see.

 

At any rate, the scope is not collimated based on the description and what I can see in the images so far.  Like I said, I have seen a 127 Mak image wrecked by poor collimation, as received by from the factory.  Until the collimation is addressed, we have no idea what sort of image the scope can put up.  Best to start with the things that can be addressed, and work from there.

 

Declaring such a scope unsalvageable and suggesting  "trash it and buy a new instead of trying to fix" as you did is unhelpful bad advice.  It is downright irresponsible to tell a novice something like that, before they have even done any troubleshooting.  Jumping to wild and unsupported conclusions is not troubleshooting.

 

Photos of the instrument, might help, but only if there is something glaringly wrong with the OTA that the OP has not told us about.

 

the truth is OP will not be using this particular scope any longer.

just imagine: before to come here he already tried anything he was able to. even after some advises he put some addition effort. but all this brought not much help.

 

his instrument since now gonna collect dust somewhere in the closet /corner. isn't it not the same as be trashed?

 

125 mm aperture is big enough to compensate (to some extend) atmosphere and collimation problems. yes the image will not be perfect but details should be there, much details (but not one-two mirage band).

 

P.S.: isn't it impossible also that primary mirror can be defective, culled from the very begining?


Edited by TheUser, 24 July 2021 - 05:10 AM.


#38 Redbetter

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Posted 24 July 2021 - 06:04 AM

the truth is OP will not be using this particular scope any longer.

just imagine: before to come here he already tried anything he was able to. even after some advises he put some addition effort. but all this brought not much help.

 

his instrument since now gonna collect dust somewhere in the closet /corner. isn't it not the same as be trashed?

 

125 mm aperture is big enough to compensate (to some extend) atmosphere and collimation problems. yes the image will not be perfect but details should be there, much details (but not one-two mirage band).

 

P.S.: isn't it impossible also that primary mirror can be defective, culled from the very begining?

Hopefully the OP has the sense to disregard some premature advice given, and take the time to collimate the scope instead to find out what he/she is working with.  The only reason to give up at this point is if the OP listens to you.  

 

To put this in perspective, this the equivalent scenario you are suggesting:

  • Person goes out to start his new car, turns the key, nothing happens. 
  • The new owner declares the car "trash", calls the salvage yard to pick up the auto, then goes car shopping again. 

Lessons learned by the owner in the scenario?  None.  Chances they were correct to jump to such a conclusion...very slim.  Result, taking a complete loss while learning nothing

 

There is nothing to lose by adjusting collimation, there is plenty to gain by dialing it in.  Furthermore, one could get a replacement scope and have the same sort of problem.  Catadioptrics arriving out of collimation is not exactly unusual.

 

As for what is possible...there is quite a bit possible, but we haven't eliminated much of anything so far.  [It is called troubleshooting, rather than brashly drawing to a final verdict with little information.]  I wouldn't even put the primary on the list of most likely possibilities at this point (could be, but there is no way to tell until the system is evaluated.)   This could be collimation, it could be a bad diagonal (sometimes they take the impact from a fall for example), could be several things.  I will wait to hear what the OP finds before declaring the scope dead.

 

I don't see any rush, gear isn't cheap or widely available now, so this is the time to figure out what one has.


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#39 TheUser

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Posted 24 July 2021 - 08:17 AM

there's no any signs of OP



#40 peta62

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Posted 24 July 2021 - 07:48 PM

there's no any signs of OP

Maybe because he takes only the reasonable advice and tests the scope,



#41 Paul Sweeney

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Posted Today, 11:49 AM

To the OP: your viewing from England, I am viewing from Heidelberg, Germany. For us in Northern Europe, the skies are often turbulent, and both Jupiter and Saturn are too low in the sky to get a good steady image. Nights where the sky is steady that low in the sky are quite rare. The moon is also quite low at the moment, so you will have the same issue.

Do not touch the collimation of your scope based on what you have been seeing. There are several things that may look like a collimation problem, and adjusting the collimation will only make things worse. If there is a club in your area, contact them. There you can get help from experienced people first hand, and also learn the collimation process.

As mentioned above, sketching is an excellent way to hone your observing skills. Because the sky is unsteady, you will only have fleeting glimpses of the surface features. Sketching makes you look harder and register what you see. Once you have found a detail, it is added to the mosaic being assembled in your brain. Next time you look, your brain knows that the detail is there, and you will look for it and find it again. That is how you learn to really observe.
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#42 Starman1

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Posted Today, 03:11 PM

Hi,

I have been taking out my celestron astro fi 5 telescope to try to look at Jupiter and I just seem to get a ball of white, does anyone know what i could be doing wrong/not doing properly? I have taken a video on my phone of what i am seeing, but I can't seem to see any detail at all. I am using a celestron astro fi 5 telescope with a 2x barlow lens and a 10mm eyepeice and that's really all. I did try to look at with with a moon filter but it didn't make much difference. Nay tips much appreciated

 

Video below

 

https://youtu.be/yT-N6StdtXk

Some facets of optimizing planetary observations:

https://www.cloudyni...ail/?p=11254658




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