I have mentioned this before but I just wanted to provide an example of why this might be a method for those of you with polar scopes to try.
Back in 2005 I carefully drift aligned my NJP mount with Starfire and then made a drawing and memorised the position of the cross hairs in relation to the other field stars in teh polar scope. I have since adjusted for precession (approx)
On Thursday night I positioned the cross hairs to the SCP position I know in the star field, as usual. I hadn't tested the accuracy of this polar alignment method for a while.. so I put a guide star on the cross hairs at 600mm FL and went inside for dinner (45min?), when I returned I was delighted to see the guide star had only drifted about 2 pixels and in RA only...not bad for just eyeballing through a polar scope.
Who needs Polar Align max etc?? If you have a polar scope (all it needs is cross hairs, other circles and Polaris positions etc can be ignored) I recommend you take the time to get familiar with your polar scope field, then in the future and provided you can see the SCP, you can be very accurately aligned in minutes - very useful for those who are portable
i am impressed - not for the fact that the polar scope has proved to be almost spot on but the fact you can see the SCP in Newcastle or were you elsewhere?
The south celestial pole through an eyepiece FOV 30Arc minutes. Roughly a 10" SCT with a 26mm Plossl eyepiece. Taken from stellarium
but quite close to what I actually see.
The first is the J2000 view which I used originally. The second is the J2011 view showing the precession of 11 years
Sounds real good Mike if you know where to look. I can't see anything south from where I am because of LP which makes using my polar scope very very hard.
Darn Mike, you have me worried now. I've been at this game longer than most and my best polar alignment routine has so far been roll it out and line it up roughly with a tree that is about a kilometer away across the paddocks. When I got real flash I tried drift aligning, but not with the steely determination it deserved.
So, I am ashamed to say, I couldn't tell you where the stars should be in the polar scope, even though I do have one (I think?) in the NEQ6.
Maybe I should take a look. I have had the mount head off the pier a while back so it could be anywhere.
Gary
The south celestial pole through an eyepiece FOV 30Arc minutes. Roughly a 10" SCT with a 26mm Plossl eyepiece. Taken from stellarium
but quite close to what I actually see.
The first is the J2000 view which I used originally. The second is the J2011 view showing the precession of 11 years
Barry
Those charts are good Bazza. When I first did the accurate drift align in 05 the location of the SCP was closer to the position in the first map ie I used to point the cross hair to a pioint that made an equilateral triangle with the two doubles (both appear singular through my polar scope though), I now point to a position that forms a slightly flattened equilateral triangle with the two doubles...hence, looking at your charts, why I get so close ..I think by about 2030 the SCP will sit perfectly between the two double stars, this should make for very accurate polar aligning using this method and very easy too.
i am impressed - not for the fact that the polar scope has proved to be almost spot on but the fact you can see the SCP in Newcastle or were you elsewhere?
The two double stars in Barry's maps ( I see them as two singular stars though) are indeed hard to see form mums place in New Lambton (especially with a moon up!), but I guess I am so familiar with them now it is still a good method, as evidenced by the original post
Sounds real good Mike if you know where to look. I can't see anything south from where I am because of LP which makes using my polar scope very very hard.
If you drfit align you must know here to look ie look through the polar scope after the drifting shows you have good alignment..? ..if you can't actually see the area of the SCP (trees, house etc) then yes you are unable to use this method. Would be very quick when at Wiruna for example, the reference stars are very easy to see from a dark sky, took me litterally a minute or two to get within 2' of the SCP when I last visted Wiruna with my gear
Darn Mike, you have me worried now. I've been at this game longer than most and my best polar alignment routine has so far been roll it out and line it up roughly with a tree that is about a kilometer away across the paddocks. When I got real flash I tried drift aligning, but not with the steely determination it deserved.
So, I am ashamed to say, I couldn't tell you where the stars should be in the polar scope, even though I do have one (I think?) in the NEQ6.
Maybe I should take a look. I have had the mount head off the pier a while back so it could be anywhere.
Gary
Well, if you need accurate PA and want it quick each time here's a method to try next time you are out ..and have the mount back together
The south celestial pole through an eyepiece FOV 30Arc minutes. Roughly a 10" SCT with a 26mm Plossl eyepiece. Taken from stellarium
but quite close to what I actually see.
The first is the J2000 view which I used originally. The second is the J2011 view showing the precession of 11 years
Barry
What's the grid ring spacing on these charts in arc min..?
If you drfit align you must know here to look ie look through the polar scope after the drifting shows you have good alignment..? ..if you can't actually see the area of the SCP (trees, house etc) then yes you are unable to use this method.
You're right. I have a clear line of sight to the SCP and I'm currently relatively well aligned so I'll have a peek in the Polar scope see if I can see anything. It's just the LP that is shocking. Sodium lights and what not from the industrial zone and the M7/M5 interchange... and people wonder why I do so much Ha.
You're right. I have a clear line of sight to the SCP and I'm currently relatively well aligned so I'll have a peek in the Polar scope see if I can see anything. It's just the LP that is shocking. Sodium lights and what not from the industrial zone and the M7/M5 interchange... and people wonder why I do so much Ha.
Do it next time you have drifted well at Wiruna, look in the polar scope and memorise (draw) the cross hair location in relation to the stars you can see, hopefully you will see it pointing close to where the charts Barry posted show it. When you get back home you may find it harder to see the right stars but at least you will be more familiar and have a better chance of recognising what you need.
Those charts are good Bazza. When I first did the accurate drift align in 05 the location of the SCP was closer to the position in the first map ie I used to point the cross hair to a pioint that made an equilateral triangle with the two doubles (both appear singular through my polar scope though), I now point to a position that forms a slightly flattened equilateral triangle with the two doubles...hence, looking at your charts, why I get so close ..I think by about 2030 the SCP will sit perfectly between the two double stars, this should make for very accurate polar aligning using this method and very easy too.
Mike
According to stellarium The south celestial pole will be almost exactly between the two numbered stars on my 100th birthday
Yes that triangle apex was within an arc minute or so in 2000. I used it with my permanent mount. It got so easy to find in the end that I lined up the etx125 on my homemade wedge in the back yard.
If someone can paint the equatorial grid on the sky it will be even easier
Nice writeup Mike and thanks to Barry for the position post that makes it
easier to follow.
I'll try that next time I am at my dark site. I guess you have to let your eyes adjust to the dark for a while. I find the polar scope very very dim even at a dark site. Perhaps I am too impatient.
If you want to get familiar with the view you can do it how I did it initially using the LX200 in alt/azm mode aligned accurately on two stars.
Just slew directly down to the south till you get to -90 (the GPS model will hit a software stop). Use your widest angle eyepiece to see the view. It is very recognizable.
Nice writeup Mike and thanks to Barry for the position post that makes it
easier to follow.
I'll try that next time I am at my dark site. I guess you have to let your eyes adjust to the dark for a while. I find the polar scope very very dim even at a dark site. Perhaps I am too impatient.
Greg.
Is your NJP permanetly set up at your dark site? If so I guess it must be at least reasonably well aligned already so just look through the polar finder and you will see the two doubles in Barry's map easily and they should be near the centre of view. They may look singular though unless the seeing is excellent? You will be able to see Sigma in the FOV too somehwre near the outer 1/3 of the field, you need to place the cross hair on the Sigma Octans side of the two (double) stars, point the cross hair at the point indicated on Barry's 2011 map and you will deffinitely be within at least 2' of the pole but probably closer to 1' I'd say
If I was out in the wilds I would use this for a quick setup. You can attach it to a small monitor from Jcar that people use for reverse view in their car.
Not cheap but a lot easier for us old blokes than waiting for dark adaption and cricking your neck.
