SingAstro

Excellent analysis, Weixing!

I have the Celestron C6 f/10 SCT OTA. It has good sharp optics and I consider it to be just about the largest airline portable scope in terms of aperture. I brought it to a dark sky site in Western Australia last April, hand carrying it into the cabin, with a Vixen Porta mount and a Manfrotto tripod going into the checked-in luggage.

IMHO, for refractors, I think a 5-inch class (120-130mm) ED or APO is the most optimum (the sweet spot), provided the model is light weight, in terms of resolving power, objects viewable and demands on a mount / portability. Having much better colour correction than a 6" (150mm) f/5 achro, I would rate it as 'Good' or 'Very Good' for planets, 'Good' for portability, and then adopt your other ratings above on the other attributes on the 6" achro. I would therefore rate it, overall, above a 6" achro, a 6" reflector, and a 6" SCT; the 6" scopes would likely edge it out marginally on DSOs and planets (SCT and reflector only).

In summary, and to repeat, I would recommend consideration of the Skywatcher 120mm ED, as it is among the cheaper and lighter (5 kg) 120mm EDs out there. I have the older champagne colour model; the current model is black.

My above comments apply to visual use only, as astrophotography has a very different set of considerations.

Nice analysis Weixing! Will be even better if a general price is included for each of them.

Taking 6-inch diameter aperture as a standard basis to compare performance of different telescope designs is one of a few valid ways due to portability considerations in general. Using a fixed price/budget is another.

Inch for inch, refractors gives the best view and also the most expensive view. So comparison using same aperture methodology alone will almost always favour refractors in terms of visual performance, especially if ED/APO optics are involved.

Joshelerry wrote: ↑Tue Aug 20, 2013 9:57 am Hi all, thanks for the information.. Some clarification here

1) Brand is Celestron omni series, saw these 2 similar specs scopes but of course price is much different! So comparing refractor and reflector to know more about them. Read that at least refractor can be use as terrestrial viewing

2) I am into photography and so matching them will be good. Hence astro photography will be in the plan definitely! Do own a tripod and hence can be used for alt-az functions. While CG-4 for astronomy. Do own a car.

3) Found out Orion Astrograph 8" f3.9 which is good for photo taking. Knowing that the bigger objective will allows deeper space viewing. How do u compare Orion to Celestron?

4) B&H do sell Celestron telescopes and Orion from its own website. Is it alright to buy online from overseas? I use B&H often but for telescope not sure if shipment can damage parts.

5) Practically in Singapore how much deeper can we view? I mean on clear skies of course but knowing there is severe light pollution, can those remote spots which you people often go be good enough to view deep space objects beside solar planets and moon? ( of course with the right equipment)

Will join one of the viewing session someday

Hi Joshelerry,

Is Celestron Omni XLT 150 Telescope a good beginner telescope?

Hi Joshelerry

Did you managed to get the Omni XLT 150mm telescope?