Dob misc.

[norm]

Hi,

I'm new to all this and now doing my research on all things related to a 10" dob. I have a tonne of queries to start with:

1. How useful is the 9 x 50 finderscope found on dobs this size or should I go straight for the Telrad.

2. how does the telrad mount on the scope and do u leave the 9 x 50 on?

3. I've read everything about the 2: Crayford focuser, how bigger difference is there between that and the standard rack and pinion focuser in terms of smoothness etc.

4. what the hell is flocking paper and what is it used for.

5. I keep reading about terms like no slop or backlash - is that in reference to the focuser?

Apologies if these have been answered 50 zillion times. I'm new to this and just recently joined a club and keen on opinions etc.

Thanks again.:confuse2:

[ballaratdragons]

Hi Norm,

Welcome to a forum which is anything but the norm :rofl:

The 9 x 50 finder works fine for most people. I don't have any dramas with mine. Just wish it was a 90 degree angled finder.

I know nothing about Telrads.

Crayfords are spectacular!! The difference is amazing and very very noticable.

Flocking paper is used to reduce light reflection inside the tube. It is one way of doing it, there are many other ways.

Yes, slop and backlash can be a problem of Rack & Pinion focusers. Crayford do not suffer this and they are smoooooth!

[wavelandscott]

While not the owner of a 10 inch Dob I do have an 8 and 12.5...

The finder is fine...however, I prefer the Telrad...I find it easier to find things looking through the Telrad window at 1X...I don't get lost or disoriented and this makes things easier for me to find...I found that soon after I got the Telrad, I stopped using the finder scope at all and removed it from my scope...

R&P focuser works fine and they have been used successfully by lots of people for a long time...but, the crayford style is nicer (smoother) in the way it focuses...they both work fine...think of the difference between models of cars...both are transportation a Berlina works fine but a Statesman has a more luxious ride...it is not needed but nice to have if you can get it...

BD outlined "flocking paper"...

Where in Sydney are you?

Cheers!

[davidpretorius]

welcome i have a 10" dob from Andrews

i have found the finder scope to be very good, when i upgrade this area, i would actually go a laser pointer for around $120
??
everyone reckons the crayford is the best, i have the crayford and thoroughly recomend it. a must have!
for help in the tube i believe, someone will have t help here
yes sort of, but it can happen with motorized telescopes when the unit is driven to a spot and then stops suddenly.
i have just posted a video of my dob here: http://www.precons.com/iis/gallery/mydob-20050915_001.avi

about 300 k

it is a 10" premium with crayford.

keep asking questions

[ballaratdragons]

OK, thanks David, I will keep asking questions.

How Long is a Chinaman?
How far is 'up'?
What colour is red? :D

Oh, you mean Norm keep asking!

[RAJAH235]

Welcome, Norm.:welcome:
It appears that your 1st lot of Q's have been answered.
1. Done. Depends what you get used to.
2. The Telrad mounts either by self adhesive patches &/or screws. Both can be used/left on the t'scope.
3. The R&P, if necessary, can be modified/fixed if too sloppy. The 'Crayford' style focuser is smoother than the R&P.
4. See Ken's reply.
5. Multiple choice here. Focuser & goto t'scopes both included.
HTH. :D L.
ps. Next Q.

[iceman]

I'd recommend the crayford, for sure. It's worth the extra. It's so much smoother and easier to get to that critical point of focus without shifting the whole image and wobbling the scope when doing so.

Flocking paper is a non-reflective paper that people stick to the inside of their tube to reduce the light reflections from street lights etc entering the light path into the focuser. It helps to get a better contrast (darker background). You don't have to use "flocking paper" though, you can use any non-reflective dark material like felt/velvet. Others have painted their tubes with flat-black paint, others use baffles to ensure the stray light doesn't enter the light path.

PS: Welcome to the forum and how did you hear about us?

PPS: Where abouts in Sydney are you?

[rmcpb]

Norm,

All your questions have been answered. My bit is that a Telrad is brilliant, I have taken my finder scope off and use the Telrad exclusively, the Crayford is far better than the R&P (get the Premium version even if it means you have to wait a bit longer), don't worry about flocking in the beginning (better off getting used to moving the scope, collimation, etc).

BTW welcome to the forum :)

[norm]

Hi - thanks for all the feedback - greatly appreciated. I live in Ashfield. I recently won a pair of 15 x 70 Binoculars during an open night at SASI and they seem to do a great job. The difference between what u see with the naked eye and with the binos is quite amazing. I'm now sourcing a tripod as they do weigh a bit after a few minutes. Down the track though, mid 2006 I plan to get a dob. I'm just enjoying reading the comments/tips/advise.

Thanks again.

[Starkler]

On optical finders vs a telrad.

Optical finders are very useful for those who live in light poluted areas where the number of naked eye visible stars is much reduced. Star hopping using a telrad in such a location is much more difficult proposition.
If you have dark skies where you live , the optical finder can be done away with.

[ving]

like geoff said, the 8x50 is better for light polluted areas. I have a 8x50 and can see more stars than with naked eye/telrad and so star-hopping is made easier. I dont think the syies in ashfield are particularly rich in stars :). if you can get a right angle 8x50 finder you will save alot of strain on your neck too so ask about that when you go to get your scope.
if a crayford focuser is out of the question for whatever reason (by all means get one if you can tho) you can motorise a R&P at a low cost. :)

[mickoking]

Once I owned a 350mm truss tube Dob and it was fitted with a telrad, I didn't like it. The illuminated reticules even at their dimmest blotted out faint stars making finding obsure targets a bit hard. I am however, going to get a laser pointer to use as a finder in conjunction with my 8x50.

sorry to contradict the other advice you have recieved in this thread.:shrug:

[fringe_dweller]

hate finder scopes - to heavy - never really used anything but rigels 1x or just simply pointing scope in general direction - I find them very easy and simple to use. But then again i have memorised the positions of most of the touristy stuff and constellations/stars long ago. If neccessary i will use a pair of average binos to zone in, ie a comet. If you have the illuminated target on a blink shouldnt obscure anything?
Kearn

[mickoking]

I use a finderscope somewhat like telrad. I keep both eyes open, One looking thru da finder and the other at the sky. Takes a bit of practice but I have it sussed now. :thumbsup:

[rmcpb]

Norm,

Now living in the centre of Sydney is going to make the Telrad virtually useless so the finder scope that comes with your scope would be better.

One thing that would be essential on your scope when you get it is a tube extension to cut out the extranious light you will be putting up with. There are many ways of doing this, just cruize the forum as there are many threads on this subject, mine is simply made from cardboard that is velcroed to the tube.

Cheers