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Reticule nightmare!


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Hi

I am trying to align my reticule to the mount on my HEQ5 Pro but having a nightmare.

when I checked it for the first time it was off but very slightly. But each change I now make is making it worse....my target is now nearing the edge of the polar circle when I rotate 180 degrees.

i have followed astro baby's instructions by losening the screw opposite where I want to make the change and en by tightening the screw nearest when I want to change made....but each change makes it worse.

Any help or advice is welcomed as I'm losing hair rapidly :-)

Cheers.

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Hi Nephalem,

I used to have a similar problem with my HEQ5. The screws for the polar scope reticule were simply too small and would fall through. First thing is to replace them. They are standard M3 screws so, 3 x M3 thumbscrews ordered from any model shop should do you good. Have them about an inch in length. Then, take a small LED torch or even a skywatcher power tank (with the LED lit up facing you). Place the LED light on your TV. Now, adjust the altitude of your mount such that you can see the LED through the polar scope. Then onwards, follow the standard procedure of loosening and tightening the M3 screws to adjust the reticule. Longer screws give more room for movement and hence make the adjustment easier.

Regards,

Sathya

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Thanks for the m3 screw tip. I have miraculously managed to get it more or less back to its original position. I used the 'tv ariel' aligning method....it's ever so slightly marginally off......is this likely to cause an issue when I do astrophotography?

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is this likely to cause an issue when I do astrophotography?

Probably not... Just make sure you know where Polaris needs to be at the time you are doing your polar alignment (I use PolarFinder). If you are autoguiding then programs like PHD do a good job of guiding out relatively poor polar alignment. If you are not guiding then you are probably going to have to learn how to drift align anyway...

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Hi Nephalem,

While looking through the trticule of my HEQ5 Polar scope, I realised that even if polaris were to be in the offset little circle there is still a lot of room for error. I'd probably give it a quicky drift align and then use PHD for guiding. This way you will have a longer guiding period. Now the error is even more in your mount because you say that the reticule isn't fully aligned. The tolerance you have given to the reticule will compound with the already present tolerance of the circle and will only compound. We need to remember that the NCP is only 3/4th degree away from the pole star and any compound error may even make it only half as accurate as it is designed to be.

Regards,

Sathya

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By the way, a good place to find M3 thumbscrews is the rear end of CG5 mounts. They have this weird cap that is replaced when you put in their optional polarscope. This cap has 3 x M3 screws sticking out of it. I used those on my HEQ5-PRO.

You may also find one of these caps on Astrobuysell UK.

Regards,

Sathya

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Thanks x6gas, I have an autoguider and I think I might use Alignmaster if needed. As I said its now just a fraction out so I'm hoping it wont affect the tracking too much.

The Celestron GoTo mounts have a polar align function: you do the usual GoTo set-up with calibration stars, centre a suitable star then the polar align routine points the mount at where that star should be and you move the Alt / Az knobs to get the star in the centre of the filed of view and bingo! I'm sure not as accurate as drift aligning but fairly close... Not sure if the SW mounts have the same feature?

However, I've found that a reasonably rough polar align is adequate when autoguiding, to be honest. Before you get in to the realms of searching for the perfect polar alignment, give it a try and see what your set-up will guide out. My experience is that ensuring that both axis of the mount are smooth has more impact on good guiding than polar alignment that is bang on, but other's experience may be different.

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Take your Polar scope out of the mount, clamp or hold it steady on a work top / table top, with one of the three grub screws facing up, very, very carefully loosen and take it out, replace with a thumb screw till it touches the reticule, repeat the process with the other two screws, if you knock the scope when doing this you may find the reticule will fall out of its position, in which case you will have to unscrew the eye piece end and reassemble it all, should not be a problem :)

John.

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