Celestron Astro Master 114

[Andyv]

Hi Folks, just joined. I've never done astronomy before but I've been given a Celestron Astro Master 114. It originally was bought as a present for a teenager but he never took to it and it languished in a shed for a few years. I've tried setting it up but I don't get very sharp images and it seems very prone to vibrations when turning the knobs. It's also really tricky to line it up to things - even the moon, though I thought I'd got the star pointer set up correctly.

I suspect I need to take the mirrors out and clean and collimate them then ensure the mount is moving freely. 

Sorry to sound so dumb. I suspect if it was new I'd have been up and running by now, but I think the original owner messed things up when originally assembling it, so it would be good to know where to start to get it right, without making it worse.

[Mick H]

Found this on youtube might help!

https://youtu.be/K4elIbVuAXk

[joe aguiar]

Dont take out mirror yet take a couple pics of it first post it. If u take it out u must re collimate then, if u dont know how then thats an issue. 

Many people over clean the mirror minor dust or dust in general wont do much and is norm for an open reflector. 

 

[joe aguiar]

Had to end that 1st part as my train went in subway and didn't want to lose info.

Anyway let us see the mirror first

And if u post few pics of the scope so we can see how your setup. 

If u have a 5x24 finder I think u need to upgrade that right away.

We just answered that last week to another guy who got a similar scope . After he made a new thread called you guys were right. Look at it it could also help u too.

If u have 0.965 focuser and ep u also need to change that but hopefully u got the better 1.25 inch focuser. If your ep are hygens h20 h12.5 or sr4 then those are also no good need to chang asap.

So that bascally it till we see your scope and mirror. 

Joejaguar 

Edited December 4, 2019 by joe aguiar

[Alan64]

The kit you have there is quite similar to my Celestron "PowerSeeker" 127EQ...

https://stargazerslounge.com/topic/340294-celestron-powerseeker-127eq/

It is not a classical Newtonian per se, but rather a catadioptric, or compound, design; also known colloquially as a "Bird Jones" reflector.  In a nutshell, what the designers did in the case of our telescopes was to take a fast(f/4 or so) spherical primary-mirror and combine it with a correcting/barlowing, cemented-doublet lens.  That lens extends the focal-length and focal-ratio to 1000mm and at f/9 in the case of your own; 1000mm and at f/8 in the case my own.

It does behave in some ways like a fast Newtonian.  For example, at the low-powers the views are plagued by coma.  It is, rather, at the medium to high powers where the telescope will excel, and for which it was designed, configured and intended.  

Our telescopes are economical alternatives to the much-costlier Schmidt-Cassegrain design, like the Celestron C5; a long focal-length crammed into a short, compact optical-tube.

To collimate the telescope properly, the cell containing the doublet-lens should be removed/unscrewed from the end of the focusser's drawtube, and then to collimate it in the manner of a classical Newtonian.  Do not remove the doublet from its cell, as that is unnecessary.  I then used a sight-tube, and a collimation-cap to tweak, and I couldn't be happier with its perfomance.

[bingevader]

Do you have an astro club near by that you could take it to for help in setting it up?

I'd make sure it was properly set up before replacing or upgrading any parts.

The same goes for collimation, it may well need doing, but make sure everything else is in order first.

Have you tried aligning the finderscope in the day time first?

Edited December 4, 2019 by bingevader

[Andyv]

Some great responses here which I'll take the time to digest. So far I've not touched the mirrors, though the primary I can see is a little dusty and with the eyepiece out I can see some crud in there. It might be the secondary mirror or the lens under the eyepiece. I'm hoping it's not the silvering on the mirror.