Celestial north alignment shortcut?

[zillah]

A question to the wise from us newbies. I've recently bought an astro master 130EQ and know that I'm supposed to polar align it each session.

Because my home observing is done from my concrete driveway, after aligning the scope with the front leg pointing north, if I mark the driveway between the 2 rear legs and extend the line the length of the drive (8m), the next time I'm out, providing the rear legs are back on the line, am I still aligned?

[TiTanecd]

My viewing spot is behind my house, in my outside bon fire area, and the pavering blocks line up exactly to the compass, N/S and E/W, and gives me a rough guide of the SSP (southern hemisphere).

I have same mount, and I find the top of the mount where the 3 legs and the base of the GEM meet that is not always level. So I normally have to fine tune that. And it is more difficult adjusting legs and balance every time I add my DSLR / adjusting weights / adding 70mm on the back.

Having a rough guide to where your legs are helps.

I have found that having your legs in the correct orientation helps with the balance. I have the single leg pointing towards the SSP (in your case North), as it holds the weight of the scope a lot better.

Side Note:

I'm actually going to make a metal base for my scope. Flat plate on the ground, 4 rods up with a flat top which my GEM mount will rest on. Uncle owns a metal shop.

[ronin]

Although close you will not exactly repeat the alighment, there will be a small difference.

Aspects like are the legs extended to exactly the same length - accurate to less then 1mm, has the head moved at all,

Another little point is unless you were 100% accurate at the first set up then you would be repeating the errors from that setup.

You would/could be close and for visual that may be OK, however I would say that at each go things would get worse.

If it were that easy that is what everyone would recommend doing.

[zillah]

Thanks guys, I thought that my plan was a little bit too simple to have been overlooked by everyone. Not that it'd make a great deal of difference at the moment, getting lovely clear blue sky's during the day but as the sun goes down on one side ofthe sky, the clouds are rolling in from the other!

[TiTanecd]

Simple answers have helped me many times before. The idea of knowing where roughly it is is good. It really helps me because in the south we don't have a South Star and LP is so bad, over the SCP that I can only just barely make out the stars over the city (20km to the south)  at around 10pm with my 32mm EP. 

I feel the pain too

[LukeSkywatcher]

Simple solution is once you have aligned the scope once, make 3 marks on the concrete where the tripod lets sit and then just use those 3 marks every time. No need for geometry.

Unless you are doing imaging, there is no need for the polar alignment to be 100%. Maybe even buy a small compass. That will get you close.

[RichM63]

Others may very well disagree, but for Visual Observing as an Amateur, your method is what I use pretty much all the time.

I have the 3 feet marked on the ground.

Good enough for a tweaked input type session when using the computer, even better when using manual control.

Ya' don't need to be Polar aligned to get from Tesco to Waitrose, you just need to be able to follow the route.

[LukeSkywatcher]

"lets" = legs. Sorry for the typo. 

I'd like to just add another bit of info here, which i found useful when i was using an EQ mount;

Once the polar axis leg of the tripod is roughly pointing north, its pretty easy to get it 100% spot on by simply moving the back two legs of the tripod to the left or the right (shift the back end of your setup to the left or right). Use the Moon as a guide. The longer an object stays within your view through the scope, the more accurate the alignment. It takes a bit of time to do but once done............you are good to go. You need a watch,clock of some sort to do this.

1/ Roughly point the polar axis of tripod to the North.

2/ Move the scope tube around til you have the Moon in the centre of your field of view

3/ Move the scope using the RA control until the Moon is out of view just to the left and then time how long it takes to come into view and then go out of view to the right. 

4/ Repeat step 3 over and over again while slightly shifting the back two tripod legs either to the left or the right each time (and time it).

When you have the moon entering your field of view from the left and it takes the longest time to go out of your view to the right................you have aligned your scope perfectly.

Now with the scope tripod in this position, you can go ahead and make the 3 marks on the concrete and each time you use the scope,simply place the tripod on those marks and you are perfectly aligned.

I used this method (not sure if its a tried and tested method or if i invented it, but it worked for me) when i used an EQ mount and i got the time it takes a full moon to cross my field of view in a 90mm scope from about 4 mins to 12 mins  (or something as good).

If this is all gobbledygook to you, feel free to contact me and i'll explain it a bit better.

I'm not sure but to me it sounds a bit like the "drift alignment" method.

[LukeSkywatcher]

Others may very well disagree, but for Visual Observing as an Amateur, your method is what I use pretty much all the time.

I have the 3 feet marked on the ground.

Good enough for a tweaked input type session when using the computer, even better when using manual control.

Ya' don't need to be Polar aligned to get from Tesco to Waitrose, you just need to be able to follow the route.

Even for imagers, i think once aligned, using 3 markers on the ground is the best solution. It makes sense to know where exactly the legs of your gear go every time. Most serious imagers though have their scope on a pillar in an obsy in their garden.

*Imagers fear the cold...............observers thrive on it*.

*tongue in cheek comment*

You guys do a fantastic job. Without imagers, us observers would never see the real beauty of the universe.

[DaveS]

Pretty much what I've had. Three paving slabs on my shingled area with small dimples made with a cold chisel type drill. Don't make them too big or your legs will float around in them.

The house I'm moving to has a patio so I'll be doing the same there. Also debating whether to put in a pillar for imaging.

[OscarTheGrouch]

I have my tripod set up with a "south" leg instead of "north", but that's just because it's easier to fit on the patio area I use.  I make sure that the "south" leg is the same each time, because the site isn't level - I've marked the correct height for each tripod leg with a CD marker pen and made marks for the mount and tripod top so that when I put everything together it goes back exactly as it was before.  It means that I can go from "packed away" to "out and observing" with the minimum of fuss and fumbling.

I did toy with the idea of using luminous paint to mark everything up, but decided that was probably a step too far....

[ollypenrice]

Small drillings in the patio are often used as 'locators.' Keep the legs to the same extension and don't change the angle of the head. This will be remarkably accurate.

Olly