Sent you an SMS reply Steve, unfortunately Saturn's rings will have to wait until it returns to our night sky, at the moment Saturn is keeping the Sun close company... it will become an early morning target around the 10th of January....
HI Steven like you I am new to astronomy i brought the exact same scope six months ago first do not try to clean your mirrors if you can see your refection in them they are fine if they ever get dirty use compressed air to clean them and with a collapsible dob scope you will need a light shroud will give you much better viewing as for the problem you are having i think it is to do with your focusing knob when you turn the nob does the eye piece move in and out if not there is a screw in-between the two focusing knob that need to loosened hope this works i will have a play with my scope tonight to give you more suggestions
The focus is moving and have not touched the mirrors. They look clean. Have had a mate (with 12 months experience with astrophotography) look at it to rule out any silly mistakes so something uncommon is going on.
Btw thank you to everyone who has replied. Think this is only the 3rd time I have ever posted on any forum and this is the only time I have had people wanting to help. Dispite my setback with my telescope, my early impression of the community adds to my interest in pursuing this as a hobby.
Hi, I have the 10" solid tube Skywatcher and my 2" to 1.25" adaptor looks much shorter than yours. It might be as simple as the wrong adaptor supplied?
His eyepiece holder is the same size as mine, so I'm guessing either the
solid tube version has a different adaptor, or the later 10" ones have changed to the shorter one that you have and he has the wrong one.
raymo
Last edited by raymo; 10-12-2016 at 11:37 PM.
Reason: correction
Hi Steve,
I have a shorter Takahashi/Baader adapter that we can use to test the scope to see where the problem lies. If you want to show things to the kids before the weekend I can call by sometime this week.
(I deleted your text by mistake and lost your number)
do not try to clean your mirrors if you can see your refection in them they are fine if they ever get dirty use compressed air to clean them
I wouldn't recommend cleaning your telescope mirrors in this manner. There is some good information in the projects and articles section on how to clean telescope mirrors.
Cheers
John B
Last edited by ausastronomer; 12-12-2016 at 09:42 AM.
I do recall reading of this kind of thing before with the skywatcher dob. It had to do with the eyepiece holder/adapter. I don't have one but if I recall there are two pieces or two adapters for the 1.25 and you don't use them together.
This is all from memory but that is what I recall. Seemed there was an extension tube included for some reason and this had to be removed for normal use.
Again, I don't have one but that is what I recall from reading of a similar.
Just checking that the focal length is measured from the primary mirror to the secondary. Just checked and it measures 970mm when focal length for this is 1200mm. Thinking maybe the rods for extending the telescope are from a small telescope.
You have to include the distance from the secondary to the end of the eyepiece for the total focal length. My 1200mm fl solid tube is 900mm from the mirror to centre of focuser tube and 300mm from centre of diagonal to eyepiece tip.
Just checking that the focal length is measured from the primary mirror to the secondary. Just checked and it measures 970mm when focal length for this is 1200mm. Thinking maybe the rods for extending the telescope are from a small telescope.
Thats why I quoted the specs for the extended length of the tube itself. (Not focal length, just tube length)
Straight forward and easy to see if something is adrift.
Quote:
Originally Posted by Allan_L
Hey Steven,
Got a tape measure?
When fully extended, what is the total length of the scope?
Specs say it should be 1120.
Just a thought!
When I have in focus issues with my Skywatcher collapsible dob I just lower the top OTA cage by an inch, tighten the screws then collimated. It used to be an issue for me with coma correctors and things like that. Not so much any more since I replaced the rubbish stock focuser with a lower profile gso 2 speed focuser. Which is surprisingly good. Can handle at least 1.6 kilo's of corrector and eyepiece without problems.
I don't know why anyone has to play around with the extension tubes; both
mine worked fine with or without a coma corrector, but the coma corrector
is made for the SW f/5 scopes, and doesn't require any mucking around
with spacers.
raymo
Btw thank you to everyone who has replied. Think this is only the 3rd time I have ever posted on any forum and this is the only time I have had people wanting to help. Dispite my setback with my telescope, my early impression of the community adds to my interest in pursuing this as a hobby.
Were here to help Ocellaris.
You could even ask for help by PM'S if need be.
Hi Steven. I hope you've sorted out everything. I was going to suggest trying a full optical alignment. This process precedes collimation. A carpenters square, tape measure, straight edge, bamboo skewer and a pencil is needed. Using the square and straight edge, check that the optical tube sections ends are squared against the tube.
Place the top tube section upside down on a flat surface. Place the square against the tube and check for any variances other than the thickness of the end ring. Do this at various points around the tube. This is to see if the tube ends are seated square with the tube.
(Do the same with the bottom section but primary mirror facing up.)
Turn the top section right side up. Place the straight edge across the top of the tube above the spider vanes. Measure the distance from the spider vane to the straight edge. Using the skewer, place this on the spider vane with one end against the inner wall of the tube and mark the skewer where it sits above the screw which holds the secondary mirror. Rotate the skewer and check that each spider vane is the same distance.
Check each strut against the straight edge.
With the scope assembled, measure from the top edge of the secondary section to the top of the primary section at various points around the tube.
Just a couple of other things to try. Without the 1.25 adapter in the focuser, try looking through a 1.25 EP starting from right inside the focuser itself then gradually moving further away.
Check and see if the focuser is squared with the tube.
See if you can swap the secondary mirror over with another.
Apologies if you'd tried all this already and hope it does work out.
Cheers!
Oh! I almost forgot. Check to see that the clips holding the Primary mirror in it's cell are just touching the mirror's surface. If they're too tight, pinched optics will result.
Cheers!
