need some help from perth

[bmitchell82 (Brendan)]

hey all,

over the last few months i have been having some very dire problems with skywatchers budgo focuser design (same focuser for 3 different tube diameters).

Now before anybody tells me that my collimation is out. with the wide variety of tools i have used from 200 dollar plus hotec lasers, to astrosystems barlow lasers to cheshire eye pieces to star testing has been used to collminate.

I know the axis of the focuser is not matching that of the primarys axis.

I used multiwebs ideas from when i first posted about this issue, but this only slightly improved the situation but not enough for me to go thats good enough.

with the fast F# of 4.7 these things become far more noticable and affect things more and more. From reading a extremely good thread on cloudy nights

http://www.cloudynights.com/ubbthrea...Number/3532772

it has become apparent that i need some different tools to do the job

there for if there is somebody in the perth area who has a autocollimator and experienced and is willing to let me either meet you somewhere, come to your house or something to see if i can get this thing worked out i would be eternally greatful

brendan

[Blue Skies (Jacquie)]

I have one, part of a Tectron collimation kit (Sight tube, cheshire and autocollimator, 3 different tubes for the collimating process). I don't use it often, so I could lend it for a short period, but I think you'll need to track down your own eventually, seeing how collimation is a ongoing issue.

[bmitchell82 (Brendan)]

i do have tools its just they arnt the right ones for aligning the optical axis with the focuser axis. generally my laser and cheshire are ample sufficient to get the beast tamed. but the insessive tinkerer in me took the focuser apart without knowing how bad syntas design was.

though it would be greatly appriciated to have a lend to see if i can sort this thing out.

today though i had another go at getting everything aligned to the best of my equipments and my own ability attached is a pic of the outside defocucused image with a 2x barlow, Meade DSI ccd, SW 254mm dobsonian, i belive that its pretty close.

If there is anybody who knows what star patterns should look like could you have a look at this picture taken

http://s700.photobucket.com/albums/w...closesmall.png

[marki]

It's not quite centered and is not round, kind of eliptical? I cannot see the diffraction rings either, how far did you back the focuser out? I have an auto collimator but you can pick these up for $30 from the US. Could be an interesting exercise putting a ronchi on that primary as well.


Mark

[Blue Skies (Jacquie)]

I meant that you might best tracking down and buying your own autocollimator, Brendan, I did see that you had all the regulation gear already.

Sorry, I've distracted by real life this week and not replied sooner. Drop me a pm if you still want to organise a loan. I don't think I can help you much with the actual work required, its been a long time since I used it, I'm usually happy with what the cheshire does, but I can lend you some literature as well.