SingAstro

orly_andico wrote:IMHO the best beginner scope is a fast Newtonian (dobsonian). Something like a 6" f5 or 8" f5 would be ideal.

why? the usual recommendation in this list is a Mak. But Maks have a rather narrow FOV and a long focal length, making them beginner-unfriendly. plus, with the dobsonian you don't need to pay extra for the mount.

I wouldn't say f/5 is good. You need a much better eyepiece set to accommodate the fast focal ratio. I found Meade Plossl performs just fine on f/8 dobsonian but the view is intolerable in f/6 dob.

Mak is very easy to use unless you don't attach any finderscope to it. If you observe under heavy light pollution, the advantage of aperture becomes even more obvious, especially when you use light pollution filter. Dobsonian (simply a newtonian with a Dobsonian mount named after John Dobson) is the biggest aperture telescope you can get within a budget. The next is hard to say, anyone?

Having said that, the most used scope is the best scope, not the scope collecting dust in your living room.

jimmyleong wrote:Ok thanks will get some reading done first. Another thing, what's so not good about the telescope sold at national geographic?

Don't start with Star Parties.

Actually starting with a Binocular (< $100) is great for sweeping view of the night sky. To jumpstart further, the NG Refractor can compliment with good view of the Moon and maybe better view of Jupiter and its moon. Also it will be fun picking up the Ring of Staturn. Please do however have a stable tripod ! All these at a low start up cost.

Because once you look thru those scopes at the Star Parties any other view thru an average or inferior ones may put you off unless you are prepare to start the hobby with a fair amount.

Lee wrote:

jimmyleong wrote:Ok thanks will get some reading done first. Another thing, what's so not good about the telescope sold at national geographic?

Don't start with Star Parties.

Actually starting with a Binocular (< $100) is great for sweeping view of the night sky. To jumpstart further, the NG Refractor can compliment with good view of the Moon and maybe better view of Jupiter and its moon. Also it will be fun picking up the Ring of Staturn. Please do however have a stable tripod ! All these at a low start up cost.

Because once you look thru those scopes at the Star Parties any other view thru an average or inferior ones may put you off unless you are prepare to start the hobby with a fair amount.

That is one unique way of putting it! I must say there is some degree of truth to it too! lolx

I agree. Am glad I didn't start that way. Haha.

I think I know of someone who was nicely "poisoned" thru a starparty. ;P

andeelym wrote:I agree. Am glad I didn't start that way. Haha.

I think I know of someone who was nicely "poisoned" thru a starparty. ;P

Oh yes... poison is good. XD

Lee, a truly unique one.

Kim Miau wrote:I wouldn't say f/5 is good. You need a much better eyepiece set to accommodate the fast focal ratio. I found Meade Plossl performs just fine on f/8 dobsonian but the view is intolerable in f/6 dob.

Interesting. I used a 10" f4.9 for years, and didn't notice any objectionable coma or anything at low magnifications. "Intolerable" certainly seems exaggerated. I was in fact using a home-made eyepiece (an Erfle kit from Surplus Shed). A co-club member also had a 10" f5 with a 24 Pan. Stars were tighter in the Pan, but not mind-blowingly so. Although: fast scopes with cheap wide-fields indeed would have poor edges. I don't consider Plossls wide fields though. BUT: if you have bad astigmatism, faster scopes will look a lot worse than slow scopes.

I base my opinion of the unfriendliness of Maks on my C9.25. I already miss that 10" dob. It was way easier to use than the cat which is like looking through a straw (but I already have too many scopes so I'm in no mood to get another newtonian anytime soon). And I do have a finderscope. It's darn hard to find stuff if the GoTo doesn't land them in the field, unlike the fast dob where a bit of nudging usually gets you want you want.

orly_andico wrote:

Kim Miau wrote:I wouldn't say f/5 is good. You need a much better eyepiece set to accommodate the fast focal ratio. I found Meade Plossl performs just fine on f/8 dobsonian but the view is intolerable in f/6 dob.

Interesting. I used a 10" f4.9 for years, and didn't notice any objectionable coma or anything at low magnifications. "Intolerable" certainly seems exaggerated. I was in fact using a home-made eyepiece (an Erfle kit from Surplus Shed). A co-club member also had a 10" f5 with a 24 Pan. Stars were tighter in the Pan, but not mind-blowingly so. Although: fast scopes with cheap wide-fields indeed would have poor edges. I don't consider Plossls wide fields though. BUT: if you have bad astigmatism, faster scopes will look a lot worse than slow scopes.

I base my opinion of the unfriendliness of Maks on my C9.25. I already miss that 10" dob. It was way easier to use than the cat which is like looking through a straw (but I already have too many scopes so I'm in no mood to get another newtonian anytime soon). And I do have a finderscope. It's darn hard to find stuff if the GoTo doesn't land them in the field, unlike the fast dob where a bit of nudging usually gets you want you want.

Oh yes, I should have mentioned that I have a bit of astigmatism. That's probably what makes the difference so easily discernible. To be more specific, the difference between the fast (f/4) and slow (f/8) is obvious if observed with mediocre wide field of view eyepiece. I tried the Orion 8" f/6 with an Orion 80 degree AFOV eyepiece. The coma is very significant for stars in the 15% outer range. Though, the center area is superb and the contrast is even higher than my SCT.

I don't have much experience in using Newtonian so just take my words with a pinch of salt.

thanks for all the inputs... more is definitely welcome...

there is a Celestron C4.5 newtonian with Vixen Polaris mount for $200 USD on astromart right now. That's an f/8 scope I believe. Fantastic deal if i may say so myself.

Robin, f/4 definitely there will be problems even with Plossls. but there's a big difference between f/4 and f/5.. f/6 with an 80 degree eyepiece yes there would be issues. But your original assertion was even with Plossls (50-degree) it is intolerable. That i would believe for an f/4... but not an f/5 or f/6.

Unless you have a car, its good to start small. get something you can carry easily around first but not anything smaller than 5" for Singapore. Its sad if you get discouraged having to lug large equipment around the island.
You can drop by Astroscientific at the Science Centre or Joo Beng's house at Astrobargains to check out the types of scope available. Once you are more comfortable and able to determine what suits you, then choose your desirablel configuration.