saxon 8" fl 1000?

[Roobi]

Hi there everyone.
I was just wondering, I picked up a saxon 8" dob yesterday and i noticed on the sticker on the side of it it says d=200 f=1000.
I realised that all the 8" dobs have a focal length of 1200 and are 203mm in diameter, the f ratio is slightly different too being a f5, as opposed to the ones on the ozscopes site being f5.9. Is this a much older dob? It gave me beautiful views of the moon last night, crystal clear and sharp but i'm just a little confused as to hold old this little beast is. It's in great nik, not a mark on it. The guy who sold it to me said had never really used it, he had the ota on upside down so i didn't doubt him.
Should i be worried?

cheers

Roobi :question:

[Roobi]

ok so i've just rang astronomy alive and he's said its a much older scope and that the optics aren't quite as good as the new ones, and the focal length being 1000mm is quite a bit different to the 1200.
Comparable to my old astromaster 130eq am i right in believing its still quite an upgrade?
My fingers are crossed that it will still be a great scope nevertheless.
If anyone knows anything about these old saxons, i'd really appreciate the opinion.

Thanx again guys

[Suzy]

Bump. I see you've been sitting here a few days unanswered - I'm sure someone will respond soon Roobi. :)

[dannat]

i'm sure its fine..some reflectors at diff times have different focal lengths..some are f4/f5/f6 or even f8.
the 8" still gathers much more light than the 130eq, which is what is important -the optical imperfections show up a little more at f5 than f6 - but its ot a big difference. you will need to barlow or use shorter f/l ep's to zoom in anyway - but thats true of most dob mounted newtonians

[Steffen]

It may be a good catch, who knows. An f/5 8" Newtonian sounds well suited to EQ mounting and imaging if you're into that sort of thing.

Give it a good collimation and a star test, all shall be revealed.

Cheers
Steffen.

[Rob_K]

Funny, I've just been wrestling with a Saxon 8" f5 dob tonight, donated to our club recently. One of the members got all the moving parts moving again as it had been left outside for about 9 years, neglected! Am having problems with collimation, but I need to rethink what I am doing - will sleep on it...

Looks good, and fortunately the mirror looks undamaged. Maybe we could compare notes Roobi!

Cheers -

[Roobi]

Cheers guys and suzy for the bump, i was starting to think no one had seen one before lol.
Do you guys mean by the star test, checking weather when out of focus slightly on a bright star, it forms the symetrical rings?
I did this the other day and all looks pretty good so my fingers are crossed. As far as it being the shorter focal length, i think thats a bit of a bonus as i can carry it reasonably easily without having to remove the ota from the mount.
With the collimation, it was a bit tough. It took me hours to get it as close as i possibly could, and i followed several tutorials to get it as right as i possibly could Maybe its something about these particular scope Robk. I'l definatly get someone to check it out for me at the snake valley astro camp next weekend.
I had to dismantle the mount completely to wipe down everything. Its much smoother to move now, and the bolt on the lazy susan part needed ot be a tiny bit loosened for it to move easier.
I noticed that the finder scope (almost as good as my 130eq lol) seems a little out of focus, or blurry. Maybe it just needs a good clean too.

I'd love to hear how you go with your rob_k.


Cheers again guys