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Miketmbt
2006-Oct-24, 03:22 PM
You all have wonderfull photographs! I have been strugling with polar alignment. How long did it take some of you to get a good alignment? I have been trying some piggyback photography and when I get it close, I try to make a small adjustment and it always seems to be in the wrong direction. Any tips?

andyschlei
2006-Oct-24, 05:57 PM
You all have wonderfull photographs! I have been strugling with polar alignment. How long did it take some of you to get a good alignment? I have been trying some piggyback photography and when I get it close, I try to make a small adjustment and it always seems to be in the wrong direction. Any tips?

My Celestron CGE mount has a built-in alignment routine. Your exact alignment procedure may depend on your mount.

A quick Google of Polar Alignment led to this link (http://www.darkskyimages.com/gpolar.html) that looked pretty good.

HTH,

--Andy

Miketmbt
2006-Oct-24, 09:01 PM
Great. Thank you. I cant wait to give it a try. Its raining today =(

paul f. campbell
2006-Oct-24, 11:20 PM
Hi Miketmbt first welcome to this forum. There is a freeware program out there called POLARFINDER BY Jason Dale. This program gives you up to 6 screens in real time of where polars should be in a 8x50 viewfinder. It has been a great help for me. It will also work for those who do not have a 8x50 finder scope. Try it.

dmill120
2006-Oct-25, 05:16 AM
Hi Mike,
what are you using to do your guiding with?
even a perfect Polar alignment will still have to be corrected during long exposures, the problem is called Periodic Error, this is caused by imperfections in the Right Ascension drive worm gears, some mounts can compensate for this to some degree, with a built in periodic error control or PEC.
But the mount must be trained to do so.

If you master the drift alignment method, (this took me over an hour the first time I tried it) you should be guiding on a star using a high to medium power reticule etched eyepiece, either on your guide scope, or in your image train, if you are employing a radial offset guider.

Some scopes invert left to right and some invert the image upside down. or even both.
I use a Refractor without a diagonal, so my image is upside down.
If you employ a diagonal on a refractor with your guiding eyepiece then your image in your eyepiece is inverted left to right, Flip you hand box over so that the buttons are facing away from you when making adjustments.

This will help with the left to right problem. if your not sure which way your scope image is orientated, use it during the day to determine its orientation, and move your control buttons to verify which ones do left and right, and up and down, by positioning your hand box either buttons down or upside down and facing in the right direction, you can avoid hitting the wrong button

Be patient this isn't easy at first an can be quite frustrating, but once you master the drift align method you will find it will go faster each time you do it.

The Program Paul has mentioned is a very good program, I use it and, I highly recommend it as a rough guide only, but for some reason or another, mine is for the view thru a POLAR AXIS finder scope and not a regular finder scope,

If you do have a POLAR AXIS Finder scope, it will also need to be installed correctly, and mechanically aligned with your mount, this means your finder is at the center of the rotation of the RA axis, so when you point the cross hairs at a given object and move the scope in RA, the cross hairs should stay on target!

My version of Polar finder is not for a regular finder, but Paul is right it should still get you close enough to start a Drift Align. but you need to know if you have a correct image finder or the usual inverted left to right.
The program can show you both with a mouse click.
I hope this helps!
Dennis:)

Miketmbt
2006-Oct-25, 03:30 PM
Hi Mike,
what are you using to do your guiding with?
even a perfect Polar alignment will still have to be corrected during long exposures, the problem is called Periodic Error, this is caused by imperfections in the Right Ascension drive worm gears, some mounts can compensate for this to some degree, with a built in periodic error control or PEC.


I dont have anything for a guidescope if that is what your asking. All I have is an RA motor on my mount. I am still shopping around for a illuminated eyepiece like what was shown on andyschlei's post. I am a bit of a noobee still. :boohoo:

dmill120
2006-Oct-25, 07:27 PM
Hi Mike.
From What you have told me, then I am assuming that you are not guiding thru your'e main scope, or not guiding at all. and just Piggybacking your Camera on top of your telescope is this right? is this a Refractor or, a Reflector?
If your RA motor drive does not have a hand controller to adjust your clock drive, then you are very limited in how long you can go without star trailing. this will depend on how accurate you drive is, your polar alignment and, periodic error inherent in your RA drive gears. another thing to consider is what type of lens you are using on your camera, if its like a 50mm lens it will be more forgiving that a telephoto or Zoom lens.

You will also more than likely need a declination drive that is also adjustable.
For piggy back astrophotography without guiding, and with just an accurate polar alignment and, a short focal length lens on your camera you may still be able to do some limited exposure shots. this will depend on all the factors I listed
here is what you should have to get those really faint, long exposure shots.
1) a German EQ mount or, a forktype mount on a EQ wedge.

2) adjustable motor drives both in RA and, in DEC with a hand controller

3) a medium to high power illuminated recticule eyepiece, the longer the focal length on your camera's lens, the higher the power on your eyepiece.

Astrophotography can be quite expensive to get into, the most important part of a good system is the mount and, its ability to correct for guiding in both Axis.
but you can still get some decent shots if you are using a Digital or DSLR and take short exposures piggybacked and, then stack your exposures with alignment and stacking software.

If there is a astronomy club nearby, you should join and get a better Idea of what you want to do before you spend any money what you currently have may not give you the results you want, do some research online before you go out and spend on anything!
here are some links for you to check out
http://www.starastronomy.org/Library/Spectrogram/03-00.html#photo
http://www.galaxyphoto.com/thizy.html
http://www.weasner.com/etx/ref_guides/astrophotography.html
Do research before you spend your hard earned Money!
Dennis:)

Miketmbt
2006-Oct-25, 08:23 PM
Hi Mike.
From What you have told me, then I am assuming that you are not guiding thru your'e main scope, or not guiding at all. and just Piggybacking your Camera on top of your telescope is this right? is this a Refractor or, a Reflector?

Yes. I have cannon digital SLR with a 200mm lense piggybacked. I was trying to get an exposer of about 5 min but I am not aligned well enough. My EQ mount has an RA motor with hand controls but no DEC motor.

dmill120
2006-Oct-25, 09:16 PM
you should be able to do pretty good with that set up.
the key is to find out how long your mount will let you go before you get stars that are out of round or they appear egg shaped. with a DSLR a stack of 30 sec to 1 min should be no problem ,but you will need a lot of subs to cancel out the noise or amp glow from your camera you may not even need that eyepiece!
once you figure out which way is up and down in your camera view you can just use that to drift align with short subs on a bright star as long as you follow the Drift alignment steps.
If your mount is pretty good you may go 5 mins with no problem, do you have a shorter lens for your camera? I would try this with a 50 mm lens you will be able to expose a hell of at lot longer and get excellent results. dec should not b a problem as long as you have your mount level before you drift align, use a bubble level or a torpedo level.
Dennis)