libraryman

Is it unfair or unrealistic to expect a dealer comment on these issues, because some feedback must be reaching them, i recognise that the dealers are very good and reviews show that to be the case but the silence is  deafening to me!

Ray 

Hi Olly, it was just an idea, i tried it and it seemed to change slightly, i just wanted someone else to prove or disprove my findings

I have to admit; i find it quite difficult to get a consistent assessment of the backlash. 

Thanks Ray

Just an idea!! find the tight spot on the dec axis then loosen the clutch and rotate the saddle into the polar position arrow up, relock the clutch and test for backlash, is it exists rotate the saddle back to the tight spot location and re-tighten the clutch, test for backlash..is backlash still zero?

Yes?

Undo clutch rotate saddle again to polar and  test again..if backlash is there it is either Ra or a clutch issue? possibly not an out of round worm wheel?

comments/ critique  welcome

Ray

Not sure that you can! However; i also wonder about the possibility of this; i'm making big assumptions here, but it's likely that they are produced on a CNC machine in one operation, that being the case, the  centre would be concentric though it would be possible for a dull tool to produce the effect on the gear cutting, i am also assuming that the worm wheel is Alloy.

i do not think it's the worm that's out, if there are any machining wizards out there they might have a skill view, though it's all irrelevant if the tightness at 180 degs is real.  

Ray

It might be prudent to do a number of checks to ensure that:

A: the dec backlash is completely dec backlash and not some RA creeping in..it can be difficult to separate to two

B: to ensure that the tight spot is there all the time?? i found inconclusive results that made me wonder!  

Ray

Hi all, it seems that there are two camps in the EQ8 backlash saga, those who swear that they have none and those like myself and Olly who appear to have backlash in both axis!

from my perspective i have reasoned that the Dec backlash (the only one that matters) can be dealt with by un balancing the scope, i have found that doing this does sort out the issue and my dec guiding is quite good.

Not an answer, i admit but i am waiting to get some driving under the belt, i am hoping that some bedding in will take place and the backlash can be adjusted correctly in due course.

I have spoken to one owner who did the adjustment and adjusted it just a little too much..the motors complained and the adjustment was backed off to suit.

It appears also that Skywatcher do not consider this an issue at all,   i have read one reply to a request for info that  "polar alignment, Balance etc" should be correct and no issues will then arise from small backlash differences.

This owner also had a tight spot @ 180degs, suggesting that the worm wheel was off centre or something worse.

I still feel that the EQ8 will live up to it's reputation (call me gullible) as a heavy duty mount with excellent tracking ability for half the cost of an AP 1200

I have forwarded at least 10 Backlash adjustment PDF's so it's not a rare occurrence at all. 

Ray

A very good illustration of the problem, i would assume that the matrix is removed up to but not including the Optical pad!! 

R

Can you purchase spare 450D sensors?

Ray

Thanks Gina, just off post for a sec...

hows the EQ8 going, have you managed to get some imaging in with it.

i found mine has a little Dec backlash but it's guiding well.

Back on post....yes that little border could well cover some vitals, i just wish that it was as easy as removing & changing the IR block filters. 

Ray

Yes i would agree with the diminishing returns point. i do not always cool my camera especially on frosty nights!

However; without your tenacity and the trials and tribulations of others attempting this mod, i would not be able to even contemplate it.

Is it fair then to ask!

Can the debayering mod with all it's risk and difficulty be termed "worth it" if one successfully completes without stuffing the sensor? 

And just one other query; the blue border..around the sensor..is that absolutely not to be broken into? 

Ray

Hi, since i retired, i don't have the income to grab different cameras, i just use my 450D and my550D, if i can get hold of another sensor, i will make one last attempt and confirm that i can remove the bayer without damaging the sensor then use my own camera!!!

It seems that  the main issues are 

1.Glass removal..though it can be achieved with care

2.sealing the sensor with an inert gas to prevent moisture once the cover glass is replaced...not sure about this yet!

Ray 

Did you still have to use heat on the 450D glass?  it is this aspect that worries me the most...i think that i can successfully remove the bayer without damaging either the sensor or the gold wires but that glass!!!!

Ray 

Not sure Gina, it was given to me by a friend who works with cameras, it did not matter too much to me since it was a test, the glass was a pain...need to work on that but the bayer must be very similar.

i will try it next without the glue because the tool i used really works very well.

and no matter how (reasonably) hard i press i cannot damage the gold coloured layer.

Are you going to try again?

Ray

Been following this thread and trying my own methods on duff sensors, this is my last attempt, i have found a material that i believe will remove the matrix without scratching the layer below!

there is a small scratch in the lower level but this was caused by the glass removal.

I used a small piece of Melamine with a flat end.

If someone else tries it please post results.

Ray 

i would recomend stainles steel fasteners, you can get very small quantities on line in any thread or size.

Regards Ray