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Dalai

By Dalai
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Dalai

Dalai

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Hi all :)

Just a quick message to say hi and introduce myself.

im 28 and married with a 7 month old son an have only recently got into astronomy, Ive been watching too much Sky at night and really wanted to have a look for myself, i bought a cheap table top refractor scope and while its ok the mount is wobbly which makes finding anything but the moon a massive chore. So ive now ordered a Celestron PS1000 and cant wait till it gets here!

Bit nervous about setting up the EQ mount but ive read at least 3 or 4 guides so i reckon i've got a good idea.

Hope to chat to you soon!

Dalai

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Schorhr

Schorhr

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Hello Dalai,

welcome to the lounge! :-)

Be aware the telescope you have ordered is a catadioptre (a newtonian/reflector) with a build in barlow element) and it has multiple issues (adjusting/collimation is difficult, perhaps not parabolic mirror, the eq mount is a bit weak).

If it is an option see if you can change your order, but that's just my oppinion.

Still, I hope you will have fun with your new telescope!

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Dalai

Dalai

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Thanks for the replies :) Schorhr I wasn't aware about the built in Barlow element will that cause clarity problems? I was thinking of making (or trying at least) an alt-az Dobson mount for it.

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Schorhr

Schorhr

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Hello Dalai,

I did not mean to be a spoil sport and it may have sounded a bit harsh :-) I don't know the "Celestron PS1000" (I suppose it's this one: http://www.argos.co.uk/static/Product/partNumber/5800690.htm ?)

It would make a cute little dobsonian;

Due to it's short tube probably a bit difficult unless used on a table, perhaps a bit more cretical then the heritage's low dobsonian structure.

Building dobsonian mounts can be fun, and if I can do it, anyone can ;-) Great projects for cloudy evenings...

If it's possible to change it to another telescope, have you considered a 114/900 or 130/900 regarding your plans to build a dobsonian? You can pick those up for 40-70gbp new and even less used.

Otherwise the Heritage 130p is great and can still be mounted on a EQ or alt/a goto mount later, in case the dobsonian mount is too low for your taste.

About catadioptre designs:

This specific design has a ~5" mirror that has a real focal length of ~500mm, and if it is anything like the other cheap telescopes like this, the mirror will probably not be parabolic, but spherical. At this short focal ratio the light will not focus precicely in one point (spherical abberation) limiting contrast/magnification.

The second problem is that you can't collimate the optics as easy as other newtonians.

The barlow element is often build into the focuser, so you can take it off and adjust the thing like other newtonians, but it's a bit of a hassle - and then, still, the lens quality is another issue.

Barlows differ in quality, and as all lens-designs, they will decrease contrast (introduce at least some chromatic aberration, reflect some light, and who knows how well it's coated).

This beeing said, it does have some benefits. The short tube means reduced weight and allows a lighter, cheaper tripod&mount to be used. This is the main reason why those things are produced in the first place :-)

It's not like a Catadioptre is bad per-se, but it's not an ideal telescope design for getting into astronomy. Of course some other designs such as Maksutov Cassegrain variants are basically a Catadioptre design as well, but a different approach (for example a front lens or shaped secondary mirror) with it's own benefits and problems.

I have a mak, even a refractor with internal barlow, and a catadioptre newtonian here (127/1000), those are interesting designs, no doubt. It's great to show students different aproaches of building a telesce. But nothing beats the simplicity of a newtonian (well, a refractor if it's collimated), as it's less of a hassle when collimation is necessary.

I apologize if I upset you, I just dislike to see shops selling these type of telscopes to beginners. I almost did myself when I got started...

But perhaps I am just paranoid because of telescopes like the Seben big boss (which I hear is of questionable quality). If you can find out if the Celestron has a spherical mirror, I'd strongly recommend that you consider returning it. Overall it won't perform as well as cheaper telescopes with similar aperture when you need high magnifications, such as when looking at planets or small deep sky objects.

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Dalai

Dalai

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No I welcome your comments. Regarding building the Dobsonian I was going to make it slightly higher so I could view it using a chair, I'm 6ft 5 so don't fancy all that bending over lol

I looked at the seben

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Dalai

Dalai

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Sorry accidentally hit reply too early there and I can't figure out how to edit!!

I did look at the seben big boss and even thought of ordering it too! In the end it came down to the ps1000 and the astromaster 130eq. I only went for the ps1000 as I'd read somewhere to go for the biggest apature you can afford which is why I settled on that one, it'll be here tomorrow or Wednesday do I'll see what it's like, hopefully the sky clears up so I can see something!!

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