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Posted: Tue Jan 18, 2011 12:36 pm
by cloud_cover
Ken, see the above 2 pictures: The top picture is shirox's scope and mount: Its the Starblast Optical Tube Assembly (the telescope itself) sitting on a tripod and mount head. This particular mount head is known as an equatorial mount: If you point it at the celestial pole, that is, the point in the sky which all stars rotate around (in Singapore almost due north and for visual, non-photography purposes, can be a rough estimation), then the head will rotate to follow the stars movement in the sky, i.e. you only need to tweak 1 knob to keep the object in your view (it will move of coruse, due to Earth's rotation). Shirox's EQ does not (I think) come with any features like motors to automatically match the star's movements or a computer that will go to your desired object)
The bottom photo is the stock Orion Starblast, which as you can see comes with a base. This base can be moved in the left-right/up-down directions. It has no tripod legs and is meant to be used on a table or floor surface, but given a firm, flat surface will be very stable.
Naturally Shirox's cost more because his mount was bought seperately.
Ken, suggest you join some obs sessions and see the stuff before making any decisions
Its a lot of money to pay if its not to your liking...
Posted: Tue Jan 18, 2011 1:21 pm
by kensou
I planning to.. if I got a chance to xD As earlier on I expressed that I like to view finer details of stars than wider field.. so it would be better I go for higher mag right?
Posted: Tue Jan 18, 2011 1:30 pm
by cloud_cover
Well, stars will always remain pin-points of light no matter how you magnify them.
Higher mag has the downside of increased shakiness, increased difficulty in finding the object (cos' the field of view is less) and increased speed at which the target object moves out of view.
Don't worry too much about mag; a starblast 4.5 will give you enough mag for most things in Singapore.
*****Remember that a telescope's main function is to gather light, not to magnify objects*****
The magnification is determined by the eyepiece and over-magnification will simply result in blur images. In Singapore due to the atmospheric conditions you can't really get beyong 200x anyway except on good nights.
Generally high mag is useful only for planets (yep, the bino can't do those), moon craters and smaller nebula/galaxies.
Posted: Tue Jan 18, 2011 1:47 pm
by kensou
icic
I wont want that high of a mag that where by I see a star as a sun :x I know its impossible anyway haha
Posted: Tue Jan 18, 2011 2:12 pm
by shirox
The nearest star to the sun is the proxima centauri and will appear nothing more than a point of light in the eyepiece.
I have tried it on the moon, shows great details like craters.
On jupiter i can see the 4 moons as dots as i'm using fairly low magnification of 45x with a 2x barlow with 20mm ep.
As i switched to the 6mm, the objects appear dimmer but of course the power is at 75x.
At 150x i can't really focus my ep so it appears blur.
lol
Posted: Tue Jan 18, 2011 2:18 pm
by kensou
unable to focus??
Posted: Tue Jan 18, 2011 2:24 pm
by cloud_cover
Shirox: Pull out your barlow/eyepiece combination and see if it comes to focus. If so then all you need is more backfocus, which means the use of an extender tubing. Otherwise you can insert the barlow less deeply into the focuser but be aware this may result in it falling off!
Posted: Tue Jan 18, 2011 2:47 pm
by shirox
swee! i will try it! thanks cloud
Posted: Tue Jan 18, 2011 2:53 pm
by kensou
1day come sembawang let me view also!
den can teach me haha
Posted: Tue Jan 18, 2011 4:12 pm
by shirox
sadly i stay in the south and not driving anymore. Downgraded to a bike haha.
Unless i can modify my bike to be a mobile tracking bike mount haha