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Newbie struggling over first telescope!

Posted: Wed Jul 19, 2017 12:25 am
by DCWZ
Hi! Newbie here!

Currently deciding between for a first telescope, between SkyWatcher Traditional Dobsonian 6-Inch vs Orion Skyquest XT6 vs Meade Lightbridge Mini 130mm telescope.
Both are dobsonian, the former 2 with an aperture of 6 inches and f/8, the latter with aperture 5 inches and is f/5.
My main issue is the difference between the bigger aperture and higher f/ number (slower) vs smaller aperture and larger f/ number (faster), as well as the quality between the SkyWatcher and the Orion.
My main purpose is for viewing with perhaps some light astrophotography with webcam. As much as SG is heavily light-polluted, I still hope to pick out some deep-sky objects if possible.
Any recommendations and advice for such a light polluted place in SG?

Thanks a lot!!!

P.S. Are dobs capable of pointing at zenith?
P.P.S. I am only selecting dobs because they appear to offer greater apertures for the same price. Any other recommendations are welcome! :)

Re: Newbie struggling over first telescope!

Posted: Thu Jul 20, 2017 2:51 am
by ivan
Hello,

For visual purposes, aperture is generally king; at 6" is likely to yield brighter and sharper views. Longer f-ratios are also generally associated with better planetary capability, which will most certainly be useful if you are viewing or imaging planets with a webcam. Having a faster f-ratio is generally more important in imaging diffuse objects (which encompasses primarily deep sky objects). However, a tracking mount would be more useful in this case. It would be difficult to get an exposure longer than one second (or thereabout) without tracking at such a magnification. However, shooting planets is still very much possible since the exposures required are much shorter.

Unfortunately, light pollution is present everywhere in Singapore, albeit to a slightly lesser extent in certain areas. Light pollution doesn't affect planetary views much, if at all, so these tend to be more feasible targets from Singapore. Brighter deep sky objects are visible, while diminished. Observing when the moon is not in the sky does help somewhat. If possible, going to a dark sky in neighbouring countries is highly recommended at least once.

Dobsonians are capable of reaching Zenith, although it gets a little more difficult to point and track (manually, that is). Waiting for objects to clear the zenith for a short moment might make things easier.

Hope this helps!

Re: Newbie struggling over first telescope!

Posted: Fri Jul 21, 2017 1:35 am
by DCWZ
Thank you for your recommendation @Ivan! Greatly appreciated!
After reviewing your comments and doing more research, it has come to me that perhaps the SkyWatcher is a little too heavy for my ambition of flying them out with me to escape the light pollution of Singapore. Meanwhile, it is an extremely unfortunate realisation that Orion does not ship to Singapore! I have tried to research on some ways to forward the packages to Singapore such as VPost and ComGateway, but it appears that they are generally unreliable. Does anyone else recommend any other way that I can make it work reliably and not break too much of a bank?
On the other hand, I have also recently discovered a 6" reflector OTA by Celestron selling at a reasonable price on Woodland Hills.
https://telescopes.net/store/celestron- ... rce=criteo
I got moved by it, but the original Go-To mount that comes with it far exceeds my budget considerations. Hence I would also like to enquire anyone who knows about this, whether I can pair a cheaper, non-GoTo mount with this OTA? Would something as simple as a sufficiently strong camera tripod (with any modification possible, please teach me) hold this, since it is only a little more than 4kg?
Thanks a lot!!!

Re: Newbie struggling over first telescope!

Posted: Fri Jul 21, 2017 11:43 am
by Hardwarezone
Skywatcher and Orion scopes if they look the same, are produced by the same factory , but Orion reflector at this size and equivalent price tend to cheap out on the focuser with rack&pinion while SW use single speed crayford.

Orion price tend to be higher than Celestron & Skywatcher but they are better at customer support in the USA.
For us foreigners , we can't access their "better" customer support while we have to shoulder the higher pricing than C or SW brand ... so it doesn't make sense unless the product is unique/exclusive under their O brand.


SW 6" newt (singlespeed crayford) is more like 6kg after eyepiece and finder mounted. You should plan your mount to be around 10kg capable with the extra margin to reduce vibration.
It cost synta only about $100 US dollars to produce each of that scope.
After dealer profit margin and shipping cost to singapore only $200+ sing dollars
Not sure whether still taobao-able in 2017.

Re: Newbie struggling over first telescope!

Posted: Wed Aug 09, 2017 12:41 am
by Tatters
I'm new to SingAstro too but let me share my experience.

I live in an HDB in the West near WCP (bad LP there) and my most used scopes are a 127mm Mak an 80mm F/11 refractor.

I can go up to 150x usable magnification on planets and the moon using a 6mm with my refractor. I have it on a wooden tripod that I can grab the whole thing and lug it downstairs.

My 127mm Mak is a planet killer and on my Skyview Pro mount, i can easily go up to 200x when viewing the moon or planets near zenith.

I find that portability is key as one is very limited by lack of dark skies. Higher magnificatons will give you better contrast and portablity allows you to easily transport it to a place with better viewing.

I don't do AP so for visual observing a good altaz mount will suffice. The Skyview Pro EQ is rock solid and includes a drive but it's not really a grab and go setup. I will be getting a Twilight I to mount my Mak and refractor on to make it easier to grab.

I also use 15x70 binos to scan the heavily light polluted skies.

But I think a 127mm is very well suited for visual observing as it's compact, light, and has really good optics with no discernable false colors on bright objects and offer very contrasty view. It can also fit in overhead baggage on a plane.

Re: Newbie struggling over first telescope!

Posted: Wed Aug 09, 2017 3:56 pm
by Airconvent
If compactness is key and you have access to dark skies, compact truss dobs would be good.

https://youtu.be/-muZ9KRMY40

Ref threads :
viewtopic.php?f=3&t=13932&p=93344
viewtopic.php?f=3&t=11589&start=40

Re: Newbie struggling over first telescope!

Posted: Wed Aug 09, 2017 4:27 pm
by Hardwarezone
Tatters wrote: I will be getting a Twilight I to mount my Mak and refractor on to make it easier to grab.

.
The mount arm of T1 can be reinforced to be much more rigid or stable at 5kg capacity.

http://i.imgur.com/YaGcZ9R.png