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Walking on the Moon

Of course, I have another question.....collimating

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So I'm a few days in to using my new telescope. I've used it every night this week so I'm feeling more and more comfortable with it. When I look at very bright objects such as Venus I understand that their brightness causes the flares I see them around. But I also get this with a lot of fairly bright stars.   And finally this morning, I got to see Jupiter for the first time. Only I couldn't see any surface details, not because of its distance,  but rather because there was a flare coming off of Jupiter as well.    I saw three of its moons, but they didn't have a flare, just the planet itself.

I'm using an 80mm refractor , ioptron 8502.   I've read that refractors be design have some "flaring" but I feel like it's happening to the extent that I can't even enjoy plants like Jupiter.   Also, I'm only viewing it on a 25 mm eyepiece, and a 10mm eyepiece.  

I  Research images of Jupiter online for 80 mm telescope they don't seem to have this glare to them.   Understand a lot of them may have used software to edit the photos, but I'm not even seen the color of the planet itself.  Just mainly red & blue light coming from the surafce.  

This is normal for money for my type of telescope?? Do I need to do this "Collimating" that I've read about?

 Sorry to have so many questions on here, but you guys of been great in all of your help, and  it's gotten me a long way from where I began!!



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the earths atmosphere can make viewing the large planets an unpleasant experience.

at the moment it is low in the sky meaning there is more atmosphere for you to look through increasing chances of a poor view.

the location of the "jet stream" also affects planet viewing , if you are looking through it then Jupiter can look like someone has a hairdryer on full speed across it.

finally, the large planets have their own atmospheres and weather, it is quite possible that this will also make the view poorer.

give it a few attempts and you will have better conditions at some point, astronomy is very much a waiting game :)


as for you collimation question, to do a quick check you need to get a star central in your view with your high power 10 eyepiece, then turn the focus knob to defocus  the star slightly. You want to see a set of rings appear around the central point, the rings should be evenly spaced around the star.

Refractor scopes rarely need collimation in my experience:)



Edited by alanjgreen
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A refractor does not require collimation. This is just for reflectors. I am guessing the two eyepieces that you have are the ones that came with the telescope? It's possible that these will be fairly low quality (but can be upgraded) compared to the telescope optics. The lower the magnification (using the 25mm) the brighter the image. It might just be that your eyepiece just isn't performing very well. It also sounds like there is an amount of chromatic aberration, this is seen as blue and red egdes to the discs of objects due to the different speeds of the light spectrum travelling through the scope optics. I remember getting my 90mm refractor and the disc of Jupiter was very bright with the 25mm. very little planetary detail visible apart from the two main equatorial belts. Things improved when I bought a couple of second hand plossl eyepieces. Then it got better still when I bought a nice ortho.

Try looking for a used plossl eyepiece. You could replace the 10mm that came with the scope (if this is what you are using) or look at something like a 15mm to sit in the middle. I believe the scope comes with Kellners which aren't great.

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Collimation is most necessary for reflector telescopes where the primary and secondary mirrors need periodic adjustment. Refractor telescopes generally are well collimated when they leave the factory - and unless they are dropped etc, will usually retain their collimation throughout their life.

Your telescope is what is known as an achromatic refractor. The main, objective lens is in fact a sandwich of two types of glass with complimentary qualities called a doublet. Although this will produce very sharp views, it also has an undesirable effect known as Chromatic Aberration (C.A.) or fringing. Different coloured light comes into focus at very slightly different lengths often causing a purple-ish fringe around brighter objects. I think this may be the glare you are experiencing.

You really have two options - adapt and live with it :icon_biggrin: (the good news is that the older you get, the less the human eye notices C.A.) or try a filter. Baader Planetarium make a Fringe Killer filter which can be useful http://agenaastro.com/baader-1-25-fringe-killer-filter.html

I think I've heard a pale yellow filter can also help to reduce C.A.

Have patience, atmospheric conditions may also be the cause of your problem. Similarly the eyepieces supplied with your scope may not be the best quality.



Edited by Putaendo Patrick
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Once again, you all have helped tremeandoulsy.   It sounds like I'm on the right path. I'm going to definitely invest in some better eyepieces because I routinely hear how much of a difference that makes

 And I'll give the planets and million attempts because like you said it could just be atmospheric conditions

Thank you, thank you, thank you! 

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I am pretty certain that better eyepieces will make a difference over your Kellners. Just don't expect to go from what you are currently seeing to Hubble like images in front of your eyes! Improvements are often subtle at first but as you will learn with this hobby, even the most subtle improvements can start to feel like giant leaps. Meade make some decent plossl's as do companies like celestron and Skywatcher to name just a couple. Ebay usally has a few up for sale at any one time and you can get a bargain. If you can get one for £20 or so and treat it nicely you should be able to sell it for pretty much what you paid.

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I'm shopping eBay this morning to upgrade the eyepieces..  thanks for that tip.


and as for the moon filet, I did pick one up, and it was quite an amazing difference.  It's funny how we want more light in our pieces, but then use a filter to cut down on overly bright objects.  I love this hobby..





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