Permanent Polar scope Reticle Centring

[sbooder]

Hi All,

Like others with the EQ6 I had replaced the hex screw adjusters for my polar scope reticle with thumbscrews to make adjustment easier, but I found they were forever coming loose which made me bin the idea and think of another way to do this.

I decided to work on the premise that the polar scope its self both inside and out must be turned to an acceptable degree of accuracy, and as the polar scope is threaded all must be fairly well centred?

Working on this hypothesis I took the reticle out to have a look and to my delight I noticed it is made with a concaved edge much like the end of a 2” EP adaptor for a focuser (the bit that goes in the barrel).

So I rummaged through my box of O-rings to find the perfect fit (both for the reticle and the inside of the polar scope) the fit is important. One must find a ring that is perfect, not too tight around the reticle, so as not to deform because it is too stretched and not too tight in the polar scope, so it will not be compressed unevenly.

Once I found the perfect fit (sorry, I have no idea what the O-ring came from or what size it is, I may get around to taking it out and measuring it at some point) I placed the reticle back in perfect position in the polar scope so the Polaris bubble was correct position when scope is parked.

Then using Dion’s O-ring insert idea to keep the polar scope EP from wobbling in conjunction with my new reticle O-ring and screwing the EP back in place firmly I set about testing the reticle for centring.

Testing on fixed terrestrial point, this puppy is spot on for a full rotation. I took the mount off and gave it a little shake and replaced and tested again…Still good, and the best thing is no thumbscrews or hex screws, there is just no need for them.

I have used the mount twice since doing this and have had top alignment both times.

[MG1]

Excellent...that's now on my to-do list!

I had been trying to source some nylon tipped thumb screws for that job with little success. Best I could find we're nylon tipped grub screws which could have thumb turns attached to the end.

But now you've saved me the bother...cheers!

[sbooder]

My pleasure.

[beamish]

well done Simon- I too tried and dropped the thumbscrew idea for the same reasons, so I'm pleased that a relatively simple fix has been found- tho I went down the centring route fiddly , very bl**dy fiddly)

[sbooder]

The only real problem I had was having to take out the reticle a couple of times to clean it of my greasy mitt prints...D'oh!...gloves!!

[Rob L]

Aligning the reticle in the polar scope has got to be one of the most difficult and maddening things I've had to do. I swopped out the grub screws on mine for thumb screws (makes it so much easier).

Since doing it I haven't checked it again. I'm too scared, because it's probably found it's way out of alignment again, the thumbscrws are both a blessing and a curse

I'll definitely be giving this a go.

Thanks, Rob.

[Gina]

I'm puzzled... Why do you need to touch the polar scope reticle on an NEQ6?

[beamish]

I'm puzzled... Why do you need to touch the polar scope reticle on an NEQ6?

Gina, you ideally ought to centre the reticule in any polarscope-that way you can accurately align the the mount to the polar axis and hence get a more accurate polar alignment.

[Gina]

Gina, you ideally ought to centre the reticule in any polarscope-that way you can accurately align the the mount to the polar axis and hence get a more accurate polar alignment.

Ah I see. I thought the reticle would be set right why you buy the mount (costs enough) but perhaps I'm too naive

[beamish]

that would be nice tho but alas

[MG1]

Never mind the fact that the reticule is no longer accurate due to procession..! Ho hum!

[Reggie]

or that you have to futz with things twice a year for the clocks going forwards/backwards.

[chrisshillito]

Never mind the fact that the reticule is no longer accurate due to procession..! Ho hum!

I've now released the EQMOD version that shows the error. Its not too bad - its still in the bubble!

Chris.

[MG1]

[atharh]

Hi sbooder, im thinking of doing the thumbscrew mod, what size thumbscrews do I need?

Thanks

Sent from my iPad using Tapatalk

[beamish]

Hi sbooder, im thinking of doing the thumbscrew mod, what size thumbscrews do I need?

Thanks

Sent from my iPad using Tapatalk

seriously, you'd be better off trying this first- the T-screws come loose very easily.

[sbooder]

Hi sbooder, im thinking of doing the thumbscrew mod, what size thumbscrews do I need?

Thanks

As said above, the thumbscrews come loose very easily. I even tried little springs on the TSs before I did this little mod, to keep pressure on the TS to stop it coming loose but it did not work very well.

But to answer your question. I used the thumbscrews from old scope stuff like old 1.25 2x barlows and diagonals, they are the correct size.

[sublime_mick]

Hi All,

Once I found the perfect fit (sorry, I have no idea what the O-ring came from or what size it is, I may get around to taking it out and measuring it at some point) I placed the reticle back in perfect position in the polar scope so the Polaris bubble was correct position when scope is parked.

Then using Dion’s O-ring insert idea to keep the polar scope EP from wobbling in conjunction with my new reticle O-ring and screwing the EP back in place firmly I set about testing the reticle for centring.

Testing on fixed terrestrial point, this puppy is spot on for a full rotation. I took the mount off and gave it a little shake and replaced and tested again…Still good, and the best thing is no thumbscrews or hex screws, there is just no need for them.

------------

any picture instructions on how you did this?

[Pitsmoor Col]

This sounds like my next job (when I get the time) I have noticed the T screws coming lose, but all I have been doing is tighten so they just touch the polar scope, and hope for the best.

[deafasabat]

Has anyone ever said what size the magic O ring is?    I can measure the diameter of the reticule groove, and presumably the internal bore of the scope (not taken it apart yet and assume that there is not an internal step or anything). Would this be enough for me to specify an O ring to a dealer in these things?

[EMFLOCATER]

How the heck are your new thumb screws loosening!!? When you align the reticle ten give the thumb screw a good snug. Its a metal ring that the screws tighten against. Are 4 wheeling to your site with the mount in the back of the vehicle? I can not see once tightened how they can come loose.

Don

[StevieDvd]

How the heck are your new thumb screws loosening!!? When you align the reticle ten give the thumb screw a good snug. Its a metal ring that the screws tighten against. Are 4 wheeling to your site with the mount in the back of the vehicle? I can not see once tightened how they can come loose.

Don

That last snug turn would mis-align the polarscope though

Never use the polarscope now, the Handset polar alignment was good enough for an accurate setting until I used a permanent pier setup and the Polar Align software from Themos (a forum member) provided an even better one.

[kendg]

Ah I see. I thought the reticle would be set right why you buy the mount (costs enough) but perhaps I'm too naive

Actually, since I found the PA option in the alignment menu (AX EQ6) I almost forgot I have a polar scope.  

I assume that the option exists on the EQ6 too.

[stevenlouth]

On 12/9/2011 at 16:02, Rob L said:

Aligning the reticle in the polar scope has got to be one of the most difficult and maddening things I've had to do. I swopped out the grub screws on mine for thumb screws (makes it so much easier).

Since doing it I haven't checked it again. I'm too scared, because it's probably found it's way out of alignment again, the thumbscrws are both a blessing and a curse

I'll definitely be giving this a go.

Thanks, Rob.

Hello

I hope you are still frequent visitor to the SGL website, because I am trying to align the reticule in my polarscope. The reticule came out when I unscrewed the eyepiece lens, the whole thing was out of focus and couldn't be adjusted with the grub screws. It had stuck itself to the eyepiece-lens with the nasty oil they install at the factory). 

Anyway, how did you do get it back in the right orientation? Is it all about the transit of Polaris and certain dates/times?

Regards, Steve

[Stub Mandrel]

The orientation doesn't matter, you just need to centre it when setting up.

When aligning you turn the mount until the reticles is correctly orientated.