Alignment choice

[Dreamsphere]

What criteria do others use to decide when to use polar or alt/az alignment?

Thanks in advance.

[E621Keith]

I guess it would be the mount. If you have a GEM, you would use polar alignment. If your mount is an Alt-az goto, then you would align it which ever way your mount use, 2 stars, 3 stars, sky align ... If your mount is a manual alt-az, you won't need any alignment at all.

... or have I completely misunderstood the question?

[Dreamsphere]

Hi Keith.

Thanks for the prompt reply. I have a Meade ETX125 GOTO and the tripod offers an opportunity to align in alt/az or polar mode so my question relates to when to use which?

Regards

[Si W]

Hi Martin

I have the ETX90, i usually always aligned in alt/az if I was doing visual work only, so much easier, if i had the LPI on, or DSI i would have it in polar alignment.

Hope that helps.

Simon

[Dreamsphere]

Hi Simon.

Thanks for the advice but do you mind me asking why, especially as I have recently acquired a DSI?

Kind wishes

[Si W]

Hi Martin

First of all you can do astro imaging in Alt/Az, or Polar mode, in Alt/Az you are restricted in the time or length of that exposer as the object is rotating slightly clockwise as seen as it moves from east to west, when the scope tracks, it basically steps in its motion horizontally and vertically across the sky as it tracks an object. Meade do provide software to compensate for de-rotation called Drizzle, this already comes with autostar suit and envisage, and you should of got the disc with your telescope. In Polar however you don't have a problem with rotation as your telescope is aligned with the north pole, so when the object your imaging rises in the east the scope will follow it as it rises and rotates and follows the true motion of the object. What i will say is when you change from Alt/az to Polar, you will need to train your drive every time and the same is true from Polar back to Alt/az.

Simon

[Dreamsphere]

Hi Simon

Thank you for a most illuminating and informative response. So far much of my effort wi the DSI has been spent in getting it to communicate properly under Windows 7 64 bit. It would appear that Meade aren't too hot on their updates! Frustrating but thankfully I enjoy a challenge (at least when it's as cloudy as it has been of late!).

Thanks again for your help.

Kind wishes

[Si W]

Hi Martin

You got that right, Meade are really slow with updating there software when Windows releases a new op system, i was using Vista a few month ago with autostar suit and envisage, what a nightmare. However one cold night in December while out with my telescope and laptop, i dropped the laptop and it completely killed the hard drive, now i have a new laptop, and as far as Window is concerned, im back with good old XP and no issues with bugs etc, What i would advice is join the ETX group, someone on there might have some info on Window 7 and Meade software.

EDIT have you tried the new version on envisage 7.0.9, it has the DSI drivers

http://www.meade.com/support/downloads.html

OS Compatibility:

Windows 7 (64-bit)

Simon

[kk4df]

aligned in alt/az if I was doing visual work only

I always us the wedge on my LX90 and polar align. Firstly, I'm usually putting the DSLR on sometime during the observing session. Secondly, I probably still need the practice of doing good polar alignments.

[Dreamsphere]

Hi Simon

I'm already a member of the ETX group and the Meade 3M community. The latter revealed others in a similar predicament but did get tipped off to the update you kindly pointed me to. To date I still haven't got everything working even with this latest relase.

I'm rapidly coming to the conclusion that I'll make my laptop a dual boot machine and just run all my astronomy software under Windows XP but it's a crying shame not to use the PC's capabilities because Meade can't get their act together.

Good job it's been so cloudy lately...

Thanks again.

Hi Martin

You got that right, Meade are really slow with updating there software when Windows releases a new op system, i was using Vista a few month ago with autostar suit and envisage, what a nightmare. However one cold night in December while out with my telescope and laptop, i dropped the laptop and it completely killed the hard drive, now i have a new laptop, and as far as Window is concerned, im back with good old XP and no issues with bugs etc, What i would advice is join the ETX group, someone on there might have some info on Window 7 and Meade software.

EDIT have you tried the new version on envisage 7.0.9, it has the DSI drivers

Meade Instruments Corporation - Software Downloads

OS Compatibility:

Windows 7 (64-bit)

Simon

[Dreamsphere]

Hi kk4df

Thanks for the reply ~ great advice! I certainly need all the practice I can get with setting up!

Best wishes

I always us the wedge on my LX90 and polar align. Firstly, I'm usually putting the DSLR on sometime during the observing session. Secondly, I probably still need the practice of doing good polar alignments.

[Ender Of Days]

Ive been noting done the numbers when aligning my 125,

by using the bubble/compass to point North (selecting "Compass") the first aligning star had an immediate error of around 40 Min's,but once centred the mount ran pretty much perfectly,I ended the session on Polaris and leveled the scope,

Next time (without moving the scope) I started by selecting "Polar",this time the first aligning star was actually in the F.O.V of the 26mm,so required minimal centering,

However it appeared to be just as accurate using the GOTO as aligning using the "compass" setting, so Im a bit surprised at the mo as I thought using "Polar" would be better,The mount obviously removes the error during the aligning process

JJ..

[Dreamsphere]

Hi JJ

Just to clarify, aAre you leaving the scope in the alt/az arrangment and selecting 'Polar' in the handset? I find my ETX125 isn't particlulary accurate finding the aligning stars although it's helped by leveling the tripod and setting the 'north' leg with a compass rather than guessing. I was having huge problems (as in 90 degrees out!) until I changed the battery in the LNT module.

Thanks for the input.

Best wishes

Ive been noting done the numbers when aligning my 125,

by using the bubble/compass to point North (selecting "Compass") the first aligning star had an immediate error of around 40 Min's,but once centred the mount ran pretty much perfectly,I ended the session on Polaris and leveled the scope,

Next time (without moving the scope) I started by selecting "Polar",this time the first aligning star was actually in the F.O.V of the 26mm,so required minimal centering,

However it appeared to be just as accurate using the GOTO as aligning using the "compass" setting, so Im a bit surprised at the mo as I thought using "Polar" would be better,The mount obviously removes the error during the aligning process

JJ..

[Ender Of Days]

"Are you leaving the scope in the alt/az arrangment and selecting 'Polar' in the handset?"

Yes,but as I say it doesn't seem to matter as once the align star is centered,it performs as well as selecting Compass

Ive also been playing with the "High Precision" setting using either way to align and its just as good ,

JJ..

[Dreamsphere]

Thanks JJ et al. All I need now is an opportunity to actually observe something. 10/10 cloud for night after night here :-(

[kk4df]

I've been playing with a new method of polar alignment, and can now say it's been successful four times in a row. This should work for any Meade Autostar or similar scope that tells you where the celestial pole is at the completion of the alignment process. This method typically requires an alignment followed by one wedge adjustment followed by a final alignment.

First, I level the tripod and use a compass to aim north. Then I do the "Easy" alignment, letting it select two alignment stars for me. I use a 9mm reticle eyepiece to make certain I'm dead centered in the eyepiece on each star. Once aligned, the controller briefly indicates where the true celestial pole is located, both in direction and magnitude. Now, the goal is to move in that direction by the amount of the error and align again.

I took some measurements and did a little math to find that for my wedge, the altitude adjustment moves about 55 minutes per rotation and the azimuth screws move about 33 minutes per full rotation.

Except for one time when had a large initial error, I get the desired "less than 5' from the pole" message after one adjustment. Make the adjustments indicated after the first alignment, turn the screws the desired amount, and align again.

Maybe someone else wants to try this and let me know how this works for you.