Can I perform a drift alignment with polaris?

[skyquest1028]

Can I use Polaris to perform a drift alignment? If so, which way should I be looking to see Polaris drift. I'm using an Atlas EQ-G. I'm using my DSLR and APT live view with cross hairs to check drift.

I'm on a hill and the houses block my access to a southern star for an alignment check. Also, my DSLR is mounted with the scope, so my focuser is level with the DSLR. I know with an eyepiece the image is flipped but the DSLR uses a mirror so I think the image is flipped back to normal.

I'm thinking of purchasing alignmaster to help. Has anyone else used it with success. Every once and while I can get a decent 3 minute sub. The starts are not perfectly round but I think it has to do with my colimation and/or focus.

I use my RA setting circle to help determine the HA for polar alignment from a video I watch on youtube.

I have wasted many nights dealing with with this so hopefully some of these questions can be answered.

[Davey-T]

Don't think you can use Polaris to drift align as you need a star low in the east to see

the drift. Which star in the south are you using it can be quite high something like

Unukalhai at the moment.

If you are autogiuding and turn off the guiding then watch which way the star drifts then turn adjusters to bring it back to centre (vertically) and use the closest star to ideal that you can.

Just another thought. What scope are you using ? do you mean you are using the dslr to drift align? generally if drift aligning manually you'd use a high magnification eyepiece and illuminated reticule.

Davey-T

[Pete Presland]

i would say no, use one near the meridian and then one near the horizon

[skyquest1028]

I'm using an 8" dob. I don't have an eye piece with cross hairs so I zoom in X15 using the live view. The APT allows me to place cross hairs over the live view.

I don't have an autoguider setup yet. I'm trying to learn how to get a more accurate polar alignment first. I'll try those recommendations. I figured I could just reverse the steps for drifting since I can see polaris right there. I figured if my alignment was perfect and I powered off my mount, I would see some type of drifting that would indicate my polar alignment was off.

I was thinking about using the alignmaster software. I registered for the software but they haven't sent me a key yet. I heard good things about it.

[stargazing_chris]

You need a starr that drifts a lot for drift aligment, and polaris is the with the least drift, you nedd a star over your head for the declination adjustment and one that just rose in the east for RA.

It should work with the dslr.

Chris.

[badgerchap]

I haven't learnt the intricacies of drift alignment yet, so forgive me if this is nonsense:

Can't you just sort of 'invert' the method and use a star in the northern sky instead?

[Psychobilly]

I guess in the Northen Hemisphere the more Southerly the star you use the more apparent drift you willl see...?

Apart from the initial Polar alignment I try to avoid using Polaris as an alignment star.

Peter...

[skyquest1028]

Thanks for the help. I figured I would update with results. I found a youtube video

that helped me understand what I was doing. Awesome video to watch. With my setup, I'm using an orion 8inch dob and a canon 1000d. I purchased APT in order to take advantage of the mirror lock delay.

With APT it allows me to put a crosshair over the live view. It also has a built in drift tool but I wanted to learn manually first. I have the canon aligned with the scope. If you were looking at the back of the camera in the focuser with the telescope on it's side, it would be perfectly aligned as if you were looking down the focuser with your eye. Hopefully that makes sense. This is important because of the direction of the drift.

First I pointed to a star south and verified that the star traveled from left to right when I pressed left or right on the Ascension controls. If it doesn't then you need to rotate the camera or eyepiece so that it does. Now I watched for drifting north or south. If south, move the left knob which pushes your mount westward. If north then move the right knob which pushes your mount eastward. A good tip is that I was able to see Polaris through my polar finder the whole time. You should be somewhere near the circle that Polaris travels on.

Once I had no drifting after 10 minutes I moved to a star on the east side. Same thing as above, I made sure the star traveled left to right when I pressed left or right on the controls. If star drifts north, I had to adjust the front knob to bring the mount lower. If star drifts south then I had to raise the mount by adjusting the rear knob (Altitude).

I repeated these steps for a couple hours until I got it right. After all of this I checked Polaris and found that it was slightly under the circle in my Polaris scope. The circle that Polaris travels around. So I guess next time I will try to position it close to that area and then perform the drift alignment.

Anyways I hope this helps anyone else. The you tube video is worth the watch.

[Brinders]

I'm confused, how on earth do you Poloar align a dobsonian in the first place which is an alt az mount - or do you mean you have de-mounted an newtonian and mounted it on an equatorial mount?

Brinders

[Brinders]

Do apologise, I see from your first post you are using an EQ mount, it was your second post Skyquest 1028 that had me confused. Must read more carefully in future!

Brinders

[Gina]

I found a youtube video

that helped me understand what I was doing. Awesome video to watch.

.

.

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Anyways I hope this helps anyone else. The you tube video is worth the watch.

Thank you for the link That video is a great idea - shows exactly what happens. The concept of how the scope/mount tracks is very difficult to grasp and that video shows it perfectly

[themos]

I'm glad you liked my youtube video! They say the only way to understand something is to explain it to someone else and that's what I tried to do.