Drift aligning for dummies

[sejanus]

hey guys

I'm going to give drift aligning a crack tonight if it's clear now that i have an f/4 scope I'm ready to give photography a bit more of a hit than 30sec exposures :)

Is this the right idea below ;

1 - Get Octans in the polar finder to get me as close as I can to start with (haven't bothered doing that before - suspect it'll be a challenge in itself).

2 - turn mount on - skip the alignment process. turn tracking on.

3 - slew to a star on the east and watch for drift. correct the drift with the latitude knob.

4 - slew to a star directly overhead. watch for drift. If it drifts, physically move the whole setup a small bit to the left or right - this seems pretty awkward - I think I've got this bit wrong!

5 - once I have the star reasonably fixed motion wise, run a 3 star alignment to get the goto working. strap camera in :)

I was looking for octans last night - i think I had it - at about midnight I kinda drew a line heading even right from rigil kentaurus and I could see a small triangle if I averted my eyes slightly - this was about where starry nights was telling me it was so i am hoping thats it!

Can someone please move polaris to the southern hemisphere ;)

[[1ponders]]

Your about right. You will only have to move the mount if you are a considerable way out. Normally you would use the azimuth adjustment.

Try this link for a drift alignment simulator

http://www.petesastrophotography.com/index.html?mainframe=/tutorial.html&tutormain=/tutorial/polaralignment.html

It's very good.

[RB]

Yep what Paul said about azimuth adjustment.
Also you do have a double cross hair illuminated reticle?

Another great site for drift alignment is here:
http://www.andysshotglass.com/DriftAlignment.html

[sejanus]

thanks guys, yeah andrew I have a 12mm one - I should probably get a more powerful one but it should do for now.

cheers

[RB]

I suppose you can use a barlow with it.

[sejanus]

yeah thats a point, I have a 2.5x barlow - reckon that would be ok?

[[1ponders]]

Which scope are you using to do your alignment with?

[RB]

I'll let you know when I see your photos.....:P :lol:

Yeah it should be ok, it might be a little high but give it a go.

[sejanus]

Probably the 8" newt

[74tuc]

Re: Point #4: " - slew to a star directly overhead"

This is not strictly true. Choose a star close to the celestial equator. For at the latitude of Sydney a star that is overhead will have a dec. of about -34 degrees which is "a bit" far off the celestial equator.

Jerry.:)

[74tuc]

For best results:

1. Use your ED80 in the straight through mode (no star diagonal) at X100 mag. Make sure that the reticle cross hairs run N-S / E-W

2. Guiding(reticle) eyepiece should be an orthoscopic (for un distorted field).

3. For stars (20 degs. above the horizon) adjust the altitude on the mount.

4. For stars close to transit adjust the mount azimuth.

5. I have attached a list (C_stars.txt) of stars I use for drift alignment.

6. I usually start with transittting stars these are the easiest to use.

7. You do not need to use the SCP stars for initial alignment, many transit stars on the celestial equator are brighter and much more accurately placed and you do not need a polar alignment 'scope you use the main scope. Besides the main 'scope all you need is a spirit level and a plumb line.

Regards,

Jerry.:)

[rogerg]

http://www.rogergroom.com/rogergroom/esh_rog_item.jsp?Item=27

[xelasnave]

I find when all else fails, I get confused more as I try harder... point the scope (in home pos) at the pole and do a time exposure.. you will see circles scribbed by the star trails.. centre them using the mount az and alt.. I found that method very good one night when the illiminated reticle had flat batteries:lol: :lol: :lol:
alex

[sejanus]

lol alex, thats a novel (yet obvious) way to do it :)

thanks jerry i appreciate the info