Basic drift align question

matt · #1 06-07-2006, 05:30 PM

OK. Really basic question but one I have to ask.

I'm about to try and learn the art of drift aligning but I'm afraid there's an embarrassing gap in my knowledge.

Every "How To" I've read talks about watching a star to see whether it moves north or south in the eyepiece.

I wouldn't have a clue which way is north, east, south or west when I'm looking through the ep!!!

Can anyone help?

RB (Andrew) · #2 06-07-2006, 05:45 PM

Matt I used Bert's advice in this post last week and it was the first time I had drift aligned and got this image.

Bert's explination is very easy to understand.

gbeal · #3 06-07-2006, 05:57 PM

Me too, but I don't tell anyone.
If you have K3 CCD Tools, there is a tutorial in there.
I use it all the time, and understand (but haven't tried it) that you can easily disply the lack of polar alignment with K3. (Robby told me this).

Lester · #4 06-07-2006, 07:05 PM

Thanks for asking the question Matt,

I printed it off, haven't checked the mount for 20 years, tracks okay but now I can tweek it with confidence.

matt · #5 06-07-2006, 07:10 PM

Thanks guys

RB - I had actually looked at Bert's post before. I was still unsure which crosshairs to use as the reference for drift "up" or "down" or whether or not there was a right or wrong way to orientate the crosshairs???

I also don't have much of a horizon in those directions. I'll persevere though.

By the way, how are your headaches? I hope you are feeling better

Gary - I'll definitely give that tutorial in "The Tools" a close look. I wasn't aware it even existed. Thanks mate

Lester - you can count on me to ask the basic questions

RB (Andrew) · #6 06-07-2006, 07:34 PM

Thanks Matt, I'm feeling fine so far.
Have to be careful of those all-nighters.

When I did "drift-align acording to Bert", I watched which crosshair corresponds to which adjustment control.
So when I'm pointing the scope straight up and am adjusting the azimuth I'll note which crosshair the star comes back to and ignore the other cross hair.

Same when I'm pointing the scope west, I'll watch which cross hair the star comes back to as I adjust the latitude adjuster, ignoring the other cross hair.

Soon you'll notice less and less movement as you adjust the star back to the centre on the corresponding cross hair.
By now it takes longer for the star to drift away.

When it doesn't drift any longer, you are aligned.

gbeal · #7 07-07-2006, 07:20 AM

OK, just to really confuse, try this one
http://www.petesastrophotography.com...alignment.html
I have just stumbled onto it, but it looks good. It "MAY" be for those northern hemisphere folk though.

billche · #8 13-07-2006, 09:26 AM

Hi gbeal,
Thanks for the link, its NOT just looking good, its fantastic!!!
I tried last night with my scope pointing more than 10degree to the west (by accident) and got the alignment done. I could track an object for the rest of last night with a 12.5mm ep on the C925 scope.
I only start using a telescope 3 months ago with no knowledge at all previously, so if I can do it then you all can do it.
Once again thanks gbeal.
Bill

Quote:

Originally Posted by gbeal

OK, just to really confuse, try this one
http://www.petesastrophotography.com...alignment.html
I have just stumbled onto it, but it looks good. It "MAY" be for those northern hemisphere folk though.

matt · #9 13-07-2006, 09:33 AM

Good stuff Bill

I haven't given it a try yet but your words are very encouraging.

Quick question: did you have to make any adjustments re: North-South/East West.... to compensate for Nth Hemisphere Vs Sth Hem... or did you follow the instructions to the letter?

Cheers

billche · #10 13-07-2006, 12:51 PM

Matt,
I tried not to just follow the instruction first but after I did some experiment by slewing the scope up/down & east/west, I end up found that the instruction is suitable for my situation. Please also keep in mind that I used a diagonal and if you couple the ep to the scope directly than things will change (I believed but may be wrong).
Bill

matt · #11 15-07-2006, 11:14 AM

Thanks Bill

Where is Stretton, by the way?

xelasnave · #12 15-07-2006, 12:09 PM

There is a note about the system I use here
http://www.iceinspace.com.au/forum/s...ad.php?t=11654
and an endorsement from another who finds it works well
alex

xelasnave · #13 15-07-2006, 12:13 PM

Mind you if you a going to do drift that site is the clearest I think I have come across but my method is so easy any one can do it first go.
alex

JohnG (John) · #14 15-07-2006, 12:13 PM

Hi Matt

Have a look at this site:

http://www.southern-astro.com.au/php...talignment.php

You have to get into your head that you don't adjust in RA (Left/right) the only adjustment you make is for DEC (Up/Down).

As I said in another post, I will be calling in at Spearo's place soon, I will run you through DA if you like. Just waiting on the birth of my second grandchild, any day now. On my way back from Sydney I will calling in at Spearo's so I will let you know by PM, should be in the next week or so.

Cheers

JohnG

matt · #15 15-07-2006, 01:01 PM

alex

what cam do you use to produce your star trail images?

john - definitely include me in your get together

cheers

xelasnave · #16 15-07-2006, 01:42 PM

Hi Matt I use a 300d and leave it run whilst getting other stuff ready (there is always other stuff) I dont worry even about a good focus first shot (it takes a few to get it spot on) just a ruff marker on the scope and use the time to fine tune focus. I had thought of a web cam set in the polar scope tube which seems like a good idea and when I get a lap top will try that approach. I have a eq5 mount which I now have some respect for because even a poor mount works well if spot on aligned. I am limited to shooting between the "bumps" however. On my wide fields such an alignment sees no adjustment of the tracking scope for up to 45 minutes exposures (only done that once )
alex
alex

matt · #17 15-07-2006, 02:19 PM

I'm having a look at Bert's drift align instructions.

I'm assuming he means point the scope (and mount) towards the south rather than north SCP?

This might also sound stupid, but when he says point the scope to a star close to zero declination (in the south) does that mean a star close to the South horizon or close to the SCP???

JohnG (John) · #18 15-07-2006, 02:31 PM

Neither, he means point it at the Celestial Equator, 0 degrees declination, the pole is + or - 90 degrees declination.

JohnG

matt · #19 15-07-2006, 02:38 PM

Hmmmmmmmmm...

methinks me needs to revisit celestial co-ordinate theory.

I'm clearly not getting the gist of this

JohnG (John) · #20 15-07-2006, 02:49 PM

Put simply, with the Polar Axis pointing roughly south, you use 1 star at 0 degrees declination, +/- 20 degrees or so overhead, then use a second star once again around 0 degrees declination either near the east or west horizon no more than about 20 degrees or so above that horizon.

JohnG