How to Polar align when you can't see Polaris

[stargazerlily]

Before you all say "No you can't" .... please let me explain.

My house faces due south. I have a large patio at the back which I use for setting up the scope. Unfortunately, I can't see Polaris as the house is in the way. The lawn beyond the patio slopes to the south ... not much but enough for it to be a challenge setting up the mount. If I move onto the lawn far enough so that I can see Polaris, I can't see much of the night sky (southern sky) as my view is obstructed by trees.

I do a very simple alignment on the patio by aligning the North arrow on the tripod to face due north (my latitude is 51 degrees).

I was wondering if there is any other technique that I could use? Perhaps align the scope more accurately (some how) if I knew the position of Polaris on a given day and at a given time. I'm hoping to upgrade my mount to a HEQ5 syntrek or equivalent when I save up all my pennies, so maybe I could use EQMOD or something ... or am I talking gibberish???

Am I the only one to have this problem???

Cheers

Pete

[yuklop]

Absolutely not alone. I also have exactly this problem as I observe from a small balcony off the south end of my flat. I also, like you did a rough align, which turned out OK, enough for minimal trailing on 30s exposures. I then "played" with it a bit by making small adjustments and seeing if the trails got better or worse. Not sure I improved it too much though.

I was told I should take my scope off my balcony, go down to the street, do the alignment and return and it should still be OK as long as the north position is correct both times. I'm pretty sure this will result still in some inaccuracy however and I didn't do it yet.

And finally I am working on the shoestring astronomy autoguiding techniqe using a modified MS studio webcam (done and working well). I have to modify my non-goto hand controller and do the usb electronics etc, then when all is working well with the main scope, buy a guide scope and those expensive mounting rings. This should improve but not completely fix tracking accuracy as there will still be some error due to misalignment right?

But anyway, if anyone has a nice method for aligning the scope whilst its pointing south (pointing directly east and west is also a problem) then I'd love to hear it.

Dan

[barkis]

Hi Pete. Polar alignment is not dependent upon being able to see Polaris. I can post up three images with Instructions on how to do it, but if you do not intend to do any Imaging, I would make do with a rough alignment, such as you do now. It's good enough for observational work. Also, If your setup is not a permanent, one, then you need to ensure everything is put exactly in the same place each time you want to do some Imaging.

Just say so if you would like the Instructions posted up in this thread.

Ron.

[yuklop]

Er yeah, images or links to images with instructions would be fantastic!

cheers

[barkis]

Here are the Images anyway, they may be useful to others too.

As I said, they are Very Old, from 1982, but still very valid.

I hope they can help you.

Click on the images a couple of times to enlarge them.

Ron.

[stargazerlily]

Hi Ron,

Yes ... please could you post the images and the instructions.

The thing is ... I'm interested in imaging .... only of the moon and planets at the moment (the rough polar alignment works ok for this type of imaging) but would to branch out at some time in the future an try some DSO.

Pete

PS: Opps ... just beaten me to it. Thanks

[Viv]

I have exactly the same problem - Polaris through the houe, as I view from the patio.

Drift alignment - the only way

Here is my thread, with a couple of brilliant links posted

http://stargazerslounge.com/beginners-help-advice/135269-polar-alignment.html

[melsky]

Alternatively get a Celestron mount and use the all-star polar align routine after you’ve done a rough alignment, you can use any star in the database to get the final precision.

Mel

[Viv]

Alternatively get a Celestron mount and use the all-star polar align routine after you’ve done a rough alignment, you can use any star in the database to get the final precision.

Mel - would be lovely to do that - but ouch !!

£1195 !!

http://www.rothervalleyoptics.co.uk/celestron-cgem-computerised-mount_d4576.html

Then you can add a further £170 for a GPS Unit !

[stargazerlily]

Thanks everyone for your help. I'll have a look at the Drift Alignment method.

Cheers

Pete

PS: Nice to know that I'm not alone ...