Out of sync by the same amount?

[asteele3]

The last 2 nights I have had some issues (I say some and it's hardly that bad but when I'm trying to image, it's a nightmare!!).

I put the tripod and mount out, face it north and to 51 degrees. I find polaris in the finderscope and then I move it to the centre of the crosshairs and when I look in the eyepiece of the scope it's always in there dead centre.

I start the star alignment, whether 1,2 or 3 and I normally do it for my first star on Alkaid in the big dipper as it's the only one I know lol.

When I go to look in the finderscope, it's always out by a cm in the same place (NE). I go to Saturn and the same thing happens, always out by the same margin but this time in the NW region. The same thing happened to Vega. However, when I went to M13, I could see a fuzzy patch through the finderscope and it was back to being a centre out in the NE region again. I mean, the object is always in the finderscope so I assume this isn't a big issue and it's just something small I'm doing wrong.

I went out on the 7th of July and I did the same proceedure as last night and it worked perfectly with only a 1 star alignment at Alkaid! Everything after that appeared right in the centre of the finderscope and the telescope!

I'm hoping you guys can help me what I'm doing wrong as it must be a simple solution as it's not that far out each time.

My solution is it might be that as Polaris moves around in a small circle each time, and it's not straight North? I must admit, I don't do the clock thing on the mount as someone said I don't need to do that.

Anyway, I'd appreciate a little help here and I know it may take a while to read through but tonight might by my last clear night here for a while so I would like to get it sorted tonight if possible!

Everyone else don't have this problem so I'm obviously just being thick minded! lol

The funny thing is, I managed to get a picture of M13 last night which saved the night from being a complete disaster, that was my first attempt at DSO imaging!

[daz]

I suspect your error is aligning polaris on the scope - polaris needs to be aligned with the MOUNT axis, not the scope.

What scope and mount is it?

[asteele3]

Oh yes, what an idiot lol.

HEQ5 Synscan go-to and Celestron C8 XLT OTA.

Of course because if I only align it through the scope, it's always going to be out by a margin because it's higher up than the mount!

[Capricorn]

Of course because if I only align it through the scope, it's always going to be out by a margin because it's higher up than the mount!

No, it is not aligned because Polaris is not on the axis of rotation, it is about a degree off.

You align through the polar scope and get polaris on the small circle of the reticule - not the centre dot of the reticule. The polar scope has therefore to be rotated to the correct position depending on the time, (GMT time).

Since Polaris is some 433 light years away an odd foot or a thousand will not make any angular difference at this end.

[Freddie]

There is a nice Astronomyshed tutorial about polar alignment on youtube which should help you get everything setup as it should be.

[asteele3]

Ok. I get the big dipper aligned so it matches what it is in the sky at the time and then I get polaris in the circle of the polarscope.

[Freddie]

To get a proper PA it's a bit more complicated than that. Have a look for that tutorial.

[asteele3]

I got a tutorial off a bloke from first light optics and he said to just get the big dipper in the correct position, get polaris in the circle and then do the star alignment! I did that a couple of weeks ago and it worked an absolute treat!

[Freddie]

That method will get you close but you need spot on PA for long exposure astrophotos