SingAstro

Hi,
Can someone help to comment whether a telescope with the following specs able to see something in the deep-space? Is it recommended to buy this scope?

114mm (4.5 inches) objective mirror
Focal Length : 500mm (20")
F Ratio: 4.4
Plossl 25mm Eyepiece
Plossl 10mm Eyepiece
2x Barlow lens


Thanks.

Can someone please also tell me roughly how much will this cost with Equatorial Telescope Mount? Thanks.

And how about this one?

OPTICAL DIAMETER 114mm=Reflector
FOCAL LENGTH = 900mm
RESOLVING POWER = 1.0
FINDER SCOPE 6x30mm
EYE PIECES H6 and H20
2x barlow lens, 1.5x Erecting prisms

Compare to the earlier one, which is better? Why?
Thanks?

Kaki Flyer wrote:And how about this one?

OPTICAL DIAMETER 114mm=Reflector
FOCAL LENGTH = 900mm
RESOLVING POWER = 1.0
FINDER SCOPE 6x30mm
EYE PIECES H6 and H20
2x barlow lens, 1.5x Erecting prisms

Compare to the earlier one, which is better? Why?
Thanks?

Hi,

There are actually too many variables. Different manufacturers can make the same scope with the same specs with different quality. If I were forced to choose, it would be the one offering Plossl eyepieces.

However, don't buy it yet. I have written a short article on the different scope types and this is available on the singastro website. Read it and try out the different types at the various observing sessions before committing to buying one. You should be aware that a reflector needs collimating. It is not difficult, but if you are queasy about fiddling with the optics, then it may not be the best option for you.

Kay Heem

mmm..
all scopes, good or bad can have the same physical specs but it is the quality of the optics, ota built, etc that determines the image performance.
If the scope is built properly, of course you will be able to see quite a few DSOs (eg M6 M7 M45 ). Whether they look great or not would depend on how good your optics are.

The "H" in the first scope's eyepeice seems to suggest they are huygen eye pieces, which are usually bundled with toys-r-us type scopes..Also, with 6mm and a x2 barlow, that scope would be trying to operate way beyond its capability at x300.

The second scope seems to be more reasonable with a maximum mag of only x100. However, without first looking at the scope and trying it out, we can never be sure.

Do read the FAQ in the FAQ section to have a better idea on what to choose.

rich

Hi Kaki Flyer,

To answer your first question, yes, a 4.5" scope is capable of seeing many deep sky objects, and is suitable for a firstscope in my opinion. It can be quite big though, so check first.

The F4.4 will give you a larger fov but will not be sharp at high definitions. You'll have to provide the brand as different makers vary in their quality.

Astro scientific for example is selling the 114eq celestron firstscope with eq mount at $650+ (on offer), but I think with that kind of money you might want to shop for better or cheaper options.

Hope this helps. Read kay heem's article and find out more!

Regards,
Chris

specs means nothing. brand is a more important considering factor. maybe if u can provide the links of the website where u got the specs from, we can provide more help.

~MooEy~

In your second option you talked about Huygen eps........ I think u are talking about the obsolete generation of celestron reflectors? Or worst, a Christmas trash scope :?

In the first option, the focal length is short thus it is more portable, but u might need to collimate it often as it is a reflector. What is the brand? I think you should join in an observation with Weixing's group this saturday night to get a better idea of the various scopes.

How come 2nd newt scope got erecting prism? i tot newts cant be used as spotting scopes?

Hi,
The shorter focal length version will be more portable, but it will also have more coma and also the quality normally is not as good as the longer focal length version if both from same company.

but u might need to collimate it often as it is a reflector

I also think this is true when I got my reflector, but after spending so much time with it, I found out that I don't need to re-collimate that often. I last collimate my reflector was around 1 month ago... few days before SingAstro Fest 2004. The collimation is slightly off a bit now, but it doesn't affect the image that much, so I didn't bother to re-collimate.

How come 2nd newt scope got erecting prism? i tot newts cant be used as spotting scopes?

I think it can be use as spotting scope... it generate a image same as a refractor without diagonal... only it is not that portable and look odd when use as spotting scope.

Have a nice day.