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Any body have any personal opinions on BRESSER MESSIER AR-102XS ED

accessories beginner Celestron double star observing optics astrophotography
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#1 eddykhan993

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Posted 13 July 2020 - 11:40 AM

on my last post I was told to sign up to astrobin to check pictures that can be taken from the telescope you're searching. I was particularly interested in BRESSER MESSIER AR-102XS ED. does anybody have any personal experience with this OT? it says the focul length is 460mm and the f/r is 4.5 doublet. again any experience with this for AP or knowledge would be great as I'm still in the search for my next AP setup. currently I have a not so great at all for AP LCM114 which I did not know would not be good for AP until I bought it (bare in my mind it is the telescope that has kicked started my journey in AP and for that I'm thankful for it)

#2 sg6

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Posted 13 July 2020 - 12:06 PM

Appears it does have an ED element - really surprised at that. Notice they say almost nothing about it either.

However even with an ED element at f/4.5 I suggest it is too fast and would display CA. An ED element reduces CA it doesn't remove it, and f/4.5 is in my opinion too fast for a doublet and even for a good triplet.



#3 eddykhan993

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Posted 13 July 2020 - 01:22 PM

Appears it does have an ED element - really surprised at that. Notice they say almost nothing about it either.
However even with an ED element at f/4.5 I suggest it is too fast and would display CA. An ED element reduces CA it doesn't remove it, and f/4.5 is in my opinion too fast for a doublet and even for a good triplet.

my i ask what is CA and could you explain what doublet and triplet means. im trying to gather as much information as possible.

Edited by eddykhan993, 13 July 2020 - 01:23 PM.


#4 Huangdi

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Posted 13 July 2020 - 01:42 PM

my i ask what is CA and could you explain what doublet and triplet means. im trying to gather as much information as possible.


It's quite simple. Let's just say there are two main types of telescopes. (there's more, but this is just for understanding)

1. A reflector with mirrors that reflects light, this results in no chromatic aberration (but has other disadvantages)

2. A refractor, with lenses, that refracts light.

Now we're talking about refractors.

The issue with them is that light retracts differently. And that is what chromatic aberration is. The most dominant form of CA is blue fringes around bright objects, such as stars or the moon. The cause of this is that the blue wavelength is being focused az a different point compared to red and green.

Aberrations show many colors though.

So, how do we combat this? Quite simple, We use multiple lenses to try and get all of the major wavelengths to refract at the same point. It's difficult to do that with one lens, and even with two lenses it's not easy.

That's why you usually have a triplet(=3 lenses) with specialized extra low dispersion glass (fpl53/fcd100 for example) elements to get an image free of CA.

I hope this helps :)
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#5 Stelios

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Posted 13 July 2020 - 02:01 PM

on my last post I was told to sign up to astrobin to check pictures that can be taken from the telescope you're searching. I was particularly interested in BRESSER MESSIER AR-102XS ED. does anybody have any personal experience with this OT? it says the focul length is 460mm and the f/r is 4.5 doublet. again any experience with this for AP or knowledge would be great as I'm still in the search for my next AP setup. currently I have a not so great at all for AP LCM114 which I did not know would not be good for AP until I bought it (bare in my mind it is the telescope that has kicked started my journey in AP and for that I'm thankful for it)

Bottom line--don't buy it for astrophotography. It's a visual scope with less CA than one without the ED lens, but it will still be pretty poor for astrophotography. 


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