Hey guys - question

[SkysoBright]

Hey guys, i'm an old member that has rejoined. god know what my last username was. but anyway. i've rejoined as i'm thinking about getting back into astronomy.

One thing i'm looking at getting into is astrophotography. Now i've started doing a little research on the web as i'm wanting to photo DSO's. From the info i have seen i need a telescope around the f4 ratio.

I've been looking at the schmidt-cass types, but these seam to be f10. What it the best focal ratio needed for DSO's. And what is the best for planets.

Can i turn an f10 into an f4 by adding things on.. if you know what i mean.

Also, just another quick question. Why are telescopes from the US so much cheaper than from australia. An example of a telescope i've been looking at... Celestron Advanced Series C9.25-SGT Schmidt-Cassegrain Telescope is about US$2000, but in australia it's AU$3700. Can anyone shed some light on this.

Thanks in advaice.

[Octane]

Hi Jase,

You did mean astronomy and not astrology, right? :)

The Celestron scopes are expensive here because the distributor takes a cut of the profits. We are also a tiny market compared to the US and therefore lack buying power. This is something that is discussed every now and then here.

f/4 is great for deep space objects. But, as that is considered "fast", you need to collimate carefully, as aberrations can show up quite easily.

f/10 and beyond is ideal for planets. A lot of the guys that do hardcore planetary imaging, operate well in excess of f/22.

You can turn a slower scope into a faster scope, through the use of focal reducers. You might want to look at the Hyperstar and Fastar solutions.

Welcome back.

H

[SkysoBright]

lol. thanks on the astrology/astronomy typo. lol.

i use to own an 8 or 10" dob. can't remember which. but the viewing i had from that was amazing, especially as my first telescope.

i won't delve too much into the whole distributor thing, it's the same with all sorts of imported items, as it really doesn't suprise me.

thanks for the info.

[Paul Haese]

Jase, you have a number of options but if you are going to use one scope then go with a fast Newtonian. An f6 will be good for DSO work and with a 5x powermate or a 4x powermate you will be able to image the planets.

For me imaging the planets is done through my C14, but I don't use this scope for anything else. For DSO work I use a refractor or an RC. If you want to spend money then think along these lines. If however, your budget is limited then think the Newtonian path. Many fine images of the planets are taken with a Newtonian and DSO work can be done well with the same scope.

The next question you need to sort out is how much money do you want to spend on the scope? Remember if you spend the bucks on the scope to spend up big on the mount too. You can of course get great results with an EQ6 pro and a carbon fibre GSO Newtonian 10". A larger scope would require a larger and more expensive mount for DSO imaging.

Hope this has been of help.

[clive milne]

Jase,
If deep sky imaging is your thing, then the order of priorities goes something like this:

1) Mount
2) Skill
3) Camera (+ filters)
4) Dark sky
5) Optical tube assembly

ymmv.
~c

[clive milne]

Hey Jase,

I'm not sure if you are already aware of it, but this would be a phenomenally good start:

http://www.iceinspace.com.au/forum/showthread.php?t=86892

disclaimer: I have no personal affiliation with Chris, nor any financial interest in this item.