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Help - want to see the moon’s craters in detail

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Hi all


i have a skywatcher az gti 130mm. I’m a very new newbie.

i have a 10mm, and a wideview and 2x Barlow lenses. I can see the moon but when I zoom in I can’t see the detail enough . Attached is my best close up that’s clear enough 

Hoping to fix this, i bought a 5x Barlow hoping to see the moons craters but it was just blurry. I can’t even return this anymore 

any help with what lens I should buy, I was thinking of buying a 6mm? I’m trying to see the craters of the moon in more detail and then make a start on the planets.


Edited by J123
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  • J123 changed the title to Help - want to see the moon’s craters in detail

Don’t worry, sure there is a way around this. 130mm reflectors can produce very sharp views of the moon and it’s craters. The theoretical upper limit of magnification in your ‘scope by the usual 2x aperture in mm convention would be 260x. I think your ‘scope has a focal length of 650 mm, so this upper limit would be achieved using a 2.5 mm eyepiece. However that’s quite an extreme focal length, particular for you ‘scope design so you’d probably be better off  with lower mag. 130x would be more than reasonable and could be achieved using your 25mm (is that your “wide field” focal length?)  and the 5 x Barlow. I wonder though if you are referring to zooming in with your phone/camera - do you see good crater detail visually at the eyepiece? Maybe it’s the photography side of things that is adding to the lack of clarity. Have you come across collimation at all? This is the term that refers to alignment of the mirrors/ optical path to  ensure sharp views - it could be that it is that that needs paying attention to also. A few variables here - would be helpful to have some more information before recommending eyepieces - although it is certainly the case that a reasonable fairly low cost upgrade to the standard supplied eyepieces would make a significant difference to you. 

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@Orange Smartie makes a good point - detail along the terminator was striking last week but Is vastly different this. Having said that you’d still expect sharp views and images now, just without the contrast and shadow detail. Have a look at some of the images of even the full moon in this forum to see what is possible. 


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There are a number of issues  that can have an impact on the quality of the image at the eyepiece.

Some may be environmental, such as; in the summer, the moon can be relatively low in the sky,  so turbulence in the thicker depth of atmosphere can affect the view. 

Similarly, depending on the position of the jetstream,  high altitude winds can cause poor viewing. ( see here https://www.netweather.tv/charts-and-data/jetstream ).

Also, if your scope hasn't been collimated since it was unpacked,  then the mirrors may well be slightly out of alignment,  and you're not going to get the best views.  

And,  as had been mentioned,  the best views will be along the terminator,  so best to observe in the week to ten days after new moon (or before the new moon if you are an early riser). 

Edited by Gfamily
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Another small point to consider is that a lot of the cheaper 5x barlows are like milk bottles. Also using it with your 10mm is going to be 325x. This is too much for a 130ml reflector. You would need fantastic seeing with a well collimated telescope to even get close. Take a step back and grasp the basics. Check the collimation of your reflector first. There’s many great guides on the forum. Good luck 

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On 13/06/2022 at 22:08, J123 said:

any help with what lens I should buy, I was thinking of buying a 6mm? I’m trying to see the craters of the moon in more detail and then make a start on the planets.

My suggestion is DONT buy any more eyepieces until you have mastered how to get best focus with your current setup. Slowly go up from 10mm to higher magnifications. This way you will realise if scope needs collimation etc. As others have mentioned its not just the eyepiece that gives you a clear picture, there are other factors like stability of mount, alt of planet/moon etc.

Edited by AstroMuni
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