Dobsonians for first users.

[creeksky (Pete)]

Skies have cleared, rain has gone.
The stars are near ready to fairly blaze upon the valley!
T.A.R.S has been positioned on the launch trolley....

http://i57.tinypic.com/30hrh5k.jpg

look out U.F.Os and D.S.Os

[creeksky (Pete)]

Had some great views of the cresent moon using 25mm +2x barlow and the 10mm
Brilliant! crystal clear.
Clouds started coming from the west and had a look a Sirius wow! It was like a supanova!
Then Jupiter rose and it was brillant too, could make out 2 brownish bands and 3 moons.
Questions:
What is the silver screw for in the centre of the crayford focuser?

Sometimes changing EPs I would push the focuser out of focus, and was hard to re-adjust?

How can I adjust the finder scope, there doesn't seem to be enough free play to move it?

Also I still cannot seem to find a way to focus the finder scope?

I think I need a beekeepers suit for the mossies

[inertia8 (Australia)]

If it's like the gso one there should be a screw to lock the focuser and another adjusts the tension of the mechanism. Ie if that is very loose and you put a heavy eyepiece in the focuser will drop all the way in with the weight.

[raymo]

I assume that your Saxon has the same finder as all other Skywatcher Newts. This being so, you will see that the rear end of the objective lens holder is knurled. Hold the lens holder and slacken off the knurled section, which is a separate ring. Turn the lens holder to focus the finder, and tighten the knurled ring while holding the lens holder.
The silver screw on the bottom of the focuser is a lock screw to keep
the focuser locked in focus whilst imaging, or sometimes if you have a very heavy eyepiece in the focuser. The screw should therefore be slack when adjusting focus.
You must have a different finder, because most have two adjusting
screws and a spring loaded third one located equally spaced around the rear end of the part of the mount that the finder slides into.
Hope this helped.
raymo

[Suzy]

Originally Posted by creeksky

Also I still cannot seem to find a way to focus the finder scope?

I think I need a beekeepers suit for the mossies

Hi Pete,

For the mozzies, I found the best results were by taking my box fan outside and blowing them away. I have a really really long extension lead. I find even when I use RID, they still buzz around my head trying to bite my ears and nose and bits and the sound of bzzzz bzzzzz around my head all night is really annoying and distracting to observing .

As for the finder. I have a Saxon dob. I no longer use the finder that came with it as I have a Stellaview finder now, but wow, I didn't know it could be focussed. All the time I had it, I was doing the glasses on/glasses off dance for the finder. Thanks for that info Raymo.

[raymo]

No problems Suzy. I don't know about when the scopes are sold as Saxons, but when sold as SW the manual that comes with it tells you pretty much all you need to know.
raymo

[inertia8 (Australia)]

Raymo/Pete,

Having just taken responsibility for an ASV loan scope, a Bintel 8" Dob, it has a RACI finder scope and the mechanism for focusing the finder is exactly the same as you described. Hold the objective, slacken off the knurled ring, then rotate the objective to focus and tighten the knurled ring to secure focus.

Mozzies, thanks for the tips Suzy, I was out using the dob for the past 3hrs and the coil I lit, plus the Bug off wasn't working 100%, I'll try a box fan.

Reasonably good viewing in Melb tonight, managed to wait long enough for Eta carina neb and its nearby cluster and NGC open cluster to be visible from my deck... breathtaking some of these objects!

[Suzy]

Pete, I got scared off with using repellents.
Apparently, a lot of people don't like using coils because it's not good to get that stuff on the mirror ? I don't know how true this is or how many people still do it. Perhaps someone who knows would like to comment. I read a thread a few years back.
And as for the RID or Aeroguard it's an instant killer to eyepiece glass if that stuff gets on them. So I'm extremely careful on where I put it on and only do rarely and with caution. So I ended resorting to the fan, which really did work the best.

[creeksky (Pete)]

Thanks raymo, inertia and Suzy.
Yes, I had heard insect repellent is bad, I did not rub it on with fingers, nor spray near scope. (20 metres away)just sprayed my legs-so they went for my face so did that too and put on a long sleeved shirt.
The fan idea is a great, but a bit wary of running it across the road and wet grass and electricity.
I will have a play with the finder scope, glad you have an 8 inch to try Inertia, have fun!

[gaa_ian (Ian)]

Those are some great tips there on controlling the Mozzies as well as protecting your EP's and Mirrors !
Thanks Suzy, I have a little battery power fan I use for camping, so I will try that next Obs night :-)

[BeanerSA (Paul)]

Originally Posted by creeksky

Sometimes changing EPs I would push the focuser out of focus, and was hard to re-adjust?

Unless you use "parafocal" eyepieces, where the focus point is always at the same place, you are always going to have to re-focus after changing eyepieces. Different physical length eyepieces = different focal points.

[Suzy]

Thanks Ian, so glad to be of help. I actually got that beaut tip about the fan from Jeanette Lamb .

Pete, to protect it from wet grass caused by dew, I wrap up in a plastic bag & tie a knot where the socket connects to the lead.

[creeksky (Pete)]

Originally Posted by BeanerSA

Unless you use "parafocal" eyepieces, where the focus point is always at the same place, you are always going to have to re-focus after changing eyepieces. Different physical length eyepieces = different focal points.

For some reason I keep "playing with" the center screw on the crayford focuser?
Either thinking it is the eyepiece screw or making a difference to the focus ,maybe even a fine tune to make faint fuzzies appear?
I get a fright when the EP and all drops down further than I expect ,when changing EPs.
Sometimes it all goes to faded star donuts, and I have to reassess and play with that screw.

Should I just leave it set tight or firm and not touch it?

Thanks Suzy I could try the plastic bag trick or Ians idea maybe even a USB fan.
If I start having elec handy next it will be a cd player, celophane red desk lamp laptop and tablets.
I could make a hijab head cover out of mossie netting, with eye holes cut out.

[raymo]

I have to assume that you are referring to the silver screw either on the bottom or the top of the focuser. It is a lock screw, and must be left
loose when focusing. It only needs nipping up when you want to prevent the weight of a large heavy eyepiece, or a camera, from causing the focuser to move thus losing focus. Just pop any eyepiece all the way in and focus as necessary. If the focuser starts to slip, there are four screws on the bottom of the focuser that can be nipped up a little. When you change eyepieces you have to refocus, unless as Paul said, you have what are known as parfocal ones.
Takes seconds to refocus, just turn the focuser in the direction that makes the doughnut smaller, and keep going until the object is sharp.
Did you sort out the finder focusing?
It just occurred to me that you might be referring to the smaller silver wheel on the end of the focuser shaft. If so, you have a dual speed focuser, and
the small wheel is geared down by a factor of 10, which makes fine focusing easier.
raymo

[creeksky (Pete)]

Thank you raymo, it is to hold the focuser, if I tighten it the focuser will no move, must be for heavier EP or 2 inch EP.I will leave it alone.

Haven't tried the sight scope yet it's been 40C and don't want to cook the mirror or with thunderstorms around be struck by lightening- it is 2015.

Just taken with tablet to the east, sun shining on storm.
[IMG]http://i60.tinypic.com/13z790i.jpg[/IMG]
Have been trying to construct a denver chair, as jupiter gave me a back ache, but worth it!
[IMG]http://i58.tinypic.com/2u7yick.jpg[/IMG]
Taken now tiny moon in the west.

[Suzy]

Nice pics Pete .
If you spanned left a bit more you would've caught gorgeous Venus low on the horizon with the crescent Moon (setting in the west), has been a beautiful sight these last couple of days. But never mind that, it's still a really lovely pic I love the crescent stage of the Moon, it's so picturesque. Thank you for sharing your pics .

[raymo]

I understand the lightning, but you won't cook the mirror; you can look at the sun with the appropriate filters.
raymo

[NTgazer (Chris)]

Definitely don't use high deet content repellants like bushmans it ruins some plastics and rubbers. A Thermacell is my best defence and a battery operated fan - 18V makita especially when it's hot and humid

[creeksky (Pete)]

[QUOTE=raymo;1150412
Did you sort out the finder focusing?

raymo[/QUOTE]

Yes, have sorted the finder scope the black rubber O ring had been pushed further inside the holder than needed,(it came that way) Now the finder is not on an angle but aligned with scope and enough free play to adjust,also it's focuser I now know how to use.
As a friend once said to me many times "read the manual"

[creeksky (Pete)]

I have almost finished my version of a Denver chair.
Has taken 8 hours to build, cost zero, all from wood I had laying around, and screws.
Still have to make more notches for height adjustments (as I don't have a bevel)
Nor sure how to use one, so had to adlib.
It takes my weight, (65kilos) but it creaks a bit -creeky-sky- chair.
Going to make a moveable foot rest too somehow.....and a metal cross brace+ a cushion.

http://i60.tinypic.com/6tpnj6.jpg

http://i61.tinypic.com/2zrqnn7.jpg

Looks like a clear night coming up yippie, but I am tired from building the chair....