Polar aligning without North star?

Hi folks,

I have recently bought a Celestron C11 SCT with GoTo. I have it about a month and have only had it out once due to the weather My question is: Is there a way to polar align without being able to see the North star? I'm moving into an apartment this week with a South facing balcony and I don't think I'll be able to see Polaris, plus it doesn't get dark enough to see it until about 11:30pm these days anyway.

I tried using a compass (taking into account magnetic variation of course!) but it seems a bit crude. I just stand back, hold the compass in my hand and look to see if the scope is roughly facing celestial North. The compass doesn't help with the altitude either which I assume I just set to 53 degrees. I would like to have this more accurate too though.

Even with this crude alignment, the GoTo function works reasonably well especially when I do a 2-star align and add at least 2 calibration stars, but when I start taking photos, I will need the Polar alignment to be better.

Anybody have any handy tricks or tips for polar aligning?

Thanks,
Brian

Brian,

Be thankful that you have clear horizons due south and instead of due north. The best way to polar alignment (vis a vis accuracy) is by using a technique called "drift alignment" where we use a star due south and near the ecliptic for finetuning adjustments in azimuth and a star low and due east (or west) for finetuning altitude.

If you do a quick check using Google for "drift alignment", you should find lots of material including videos describing the process as viewed through an eyepiece with crosshairs.

Drift alignment is probably your best bet if you can't see the north star. I've read that this is more accurate approach for astrophotography.

www.darkskyimages.com/gpolar.html explains a bit about it.

As for getting your latitude, you should be able to get this off a map or google earth.

good luck!

Thanks for that Anthony and Albert. I'll give it a try on the next clear night. Looks kind of complicated though. I'll let ye know how I get on.

I don't think I have an eyepiece with cross hairs. Could I use the finderscope instead? It is perfectly aligned with the scope.

Brian,

Stay far away from the finderscope since it is too wide field and you will not catch the fine drift movements which will require finetuning in your polar alignment. For example, the eyepiece with cross-hairs I was referring to is around 12.5mm focal length which translates to mid-power for many telescope configurations.

As for the process itself, it may sound complicated but it is really quite easy and quick.

Hi Brian,

You can also Drift align by using your webcam you don't have to buy a cross-hair eyepiece. Just do the same procedure but just using your webcam.

hope this helps