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Celestron stargazer and lens set up help


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Hello everyone

My wife bought me a celestron stargazer and lenses. Always been interested in stargazing and starting out

I'm a bit lost on what lenses and Barlow lenses to use together. I have attached pictures of what I have 

 

Thanks in advance to anyone reading 🌠🌠🔭🖖

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Welcome!

The longer the focal length on the eyepiece, the lower the magnification and the wide the field of view (FOV).  The barlow just doubles the magnification.

Magnification only makes the image larger, the amount of light is limited by the aperture of the telescope - so don't assume that you'll get a better image at higher magnification.

For general observing, I would start with your 25mm eyepiece.  The 10mm is also reasonable.  The others are better eyepiece designs (probably) but are high magnifications and you might find them harder to use, as you'll need to have your eye closer to the eyepiece and your mount needs to be more stable.  The 6mm should be good on the Moon and planets (only Jupiter is realistically viewable right now).  The 4mms are probably pushing it.  I wouldn't use the Barlow with anything other than the 25mm, adding a Barlow to 10mm is analogous to 5mm (but dimmer) and a Barlow on 6mm and 4mm is unnecessary and the exit pupil will be tiny, plus your mount will be nowhere near stable enough.

I really wouldn't bother with the 5x Barlow.  That's excessive and I can't think of any situations where that is useful.  The 2x Omni Barlow is fairly decent (I have one).

Your setup should be Scope - Diagonal - Barlow (if using) - Eyepiece

Hope that's helpful.

Edited by GrumpiusMaximus
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That's a huge help !! Thank you so much , I'll give that a go. i really don't know what works with what or what I am able to view with my equipment 

 

I am assuming then you never put Barlow's together ? Id love to be able to see as much as I can with this equipment 

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3 minutes ago, galstar20241 said:

That's a huge help !! Thank you so much , I'll give that a go. i really don't know what works with what or what I am able to view with my equipment 

 

I am assuming then you never put Barlow's together ? Id love to be able to see as much as I can with this equipment 

I can't say I've tried it but I don't see a situation where that's helpful.

Bear in mind that the amount of light that's coming into your scope is the same regardless of the eyepiece you put in - so each eyepiece is dealing with the same image but just changing its size.  I have three eyepieces that I use regularly but looking at Jupiter this season but have often found that my image is actually sharper and I can get more detail in a less magnifying eyepiece and it's more comfortable for me to use due to the longer eye relief.

My advice for now is to go out on a decent night and look at M42 (the Orion Nebula) with your 25mm and the 10mm.  Don't worry about Barlows and the other eyepieces - just get a feel for what you can see with those two.  There are plenty of nights where I observe with only my 20mm eyepiece and get plenty of fun out of that.  Keep it simple until you get a better idea of what you're doing and looking at.  Ask me how I know...

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THE Omni Barlow is very likely the better of all the Barlows. If one unscrews the black bottom segment then one may end up with a  1.5x barlow to use on the 25mm lens, this would then give a 16.6mm focal length ep as well as a 12.5mm one in 2x form.

The 68 degs redline ep is  your high power moon ep  if the seeing and tripod can take the power.

 

Other options for EP's may be a zoom lens ep such as the 8 - 24mm Sv 171 or the 7.2 - 21.6mm Sv135 both from the SvBony stable , but certainly worth googling for reviews on them on this forum and the CN forum.

 

Edited by Naughty Neal
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The LT 70 scope is F10 so  practically any ep should show quite good correction in it .

25mm ep will give 28x mag and the 6mm 116x, so using the 6mm will tell you how much power one can use /push through the LT 70.

The Barlow at 2x will allow 56x mag with 25mm ep.

The limiting factor in any seeing will be the power that the tripod can handle and how long it takes for the view to settle down.

Edited by Naughty Neal
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Hi

I'm not sure which of the Celestron 'scopes this is, I think it could be either the 70mm or the 80mm ? It makes a difference

According to RVO the two models are Aperture: 80mm Focal Length: 900mm Focal Ratio: f/11, and aperture 70mm Focal Length 700mm Focal Ratio f/10

With either of those focal lengths, and a simple alt az mount , you are going to find the practical limit to the highest magnification means you will not need to use a barlow to reach high powers (worth keeping the Celestron though, it's nice and can be useful as I'll explain later )  the 4mm eyepieces similarly will be too much for this 'scope( but hang on the the TMB, it has a 58 degree FOV, if it's as sharp as the 6mm one I have it's well worth keeping for if you get a different 'scope in the future) .

The 6mm LER eyepiece might be useful , it's pretty high magnification for a 700mm (or 900mm) 'scope , (116x or 150x respectively) and the view may appear rather dim, and show up any eye floaters you may have, worth trying it on a bright target like the Moon. Expect the view to be rather jittery though, the high power will magnify the wobbles as well as the view.

The SVbony diagonal will be far better for astro use than the stock one that's in the 'scope in your photo, take that stock one out and leave it in a drawer with the 5x barlow and the 4mm plossl  :evil4:I guess the stock diagonal is a corrected view prism one, OK for daytime use birdwatching (but beware of accidentally pointing at the Sun, which will damage your eyesight without the proper full aperture filter) the SVBONY will be better made, metal not plastic, hold the eyepieces more securely and probably be sharper and brighter, but give you a reversed left/right view, which can be disconcerting to start with, but you soon get used to it.

I'd follow the Grumpy one's advice, start with the 25mm eyepiece, but then once I'd found a target I'd be taking the 25mm eyepiece out , unscrewing the lens cell of the Celestron Barlow, and putting just the lens cell on the threads there should be (I hope) on the underside of the 25mm, which will give you around 1.5x what the eyepiece alone does, so a nice 17mm ish eyepiece at 50x or 40x.

If the sky conditions, the mount and your eyes are fine with that, take the 25mm back out, unscrew the barlow cell, put it back on the barlow tube, pop the whole barlow in the diagonal, and the 25mm in the barlow. That makes the 25mm effectively  a 12.5mm , and gives you 72x or 56x magnification, and should give reasonable views of targets without too much wobble.

Only then go for the 10mm, if the wobbles from the mount allow.

Heather

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