Using the Polemaster

[Moonshed]

I purchased the Polemaster last year and find it just brilliant. One thing that does bother me is that Polaris is always very close to the bottom of the screen, making it difficult to line up the template stars using the slider as I can only see two of them. In order to bring Polaris more into the centre of the screen I lengthened the north facing tripod leg. This helped, but it now means  the tripod is no longer level as can be seen by the bubble level built into the mount. Does this matter? Or is the level just as a guide for field work?

[geordie85]

There was a discussion on here a short while ago about of the mount needs to be perfectly level or not. 

I'm unsure of the outcome but there are plenty people who think your mount doesn't have to be perfectly level so I wouldn't worry about it too much. 

[RayD]

Once you run the software the altitude adjustment on your mount (not the tripod) should bring it up to around the centre. 

Don't forget also that you can maximise the screen.

Technically it doesn't matter on a GEM whether the mount is exactly level, but it won't hurt to get it somewhere near, even if by sight only, and from there all your adjustments should be on the mount, not the tripod.

[Moonshed]

Okay, thanks for the advice. I didn't think it had to be perfectly level and it isn't far off anyway, just that I'm used to having it dead level.

[newbie alert]

There are for's and against having a level mount....im definately pro for having it level..if you can only see 2 stars in their circles then the others will be also..

Have you tried sharpcap with the polemaster camera?

[spillage]

Having the mount level only assists with adjustment and there is no need to worry about it. I think the final say was something along the lines of the ground (earth) is curved so it technically not level.

[geordie85]

5 minutes ago, spillage said:

Having the mount level only assists with adjustment and there is no need to worry about it. I think the final say was something along the lines of the ground (earth) is curved so it technically not level.

I beg to differ. Theres more than too many videos on YouTube saying the earth isn't curved haha.

[Waldemar]

Though levelling is not a must, it does make things easier. Level is in relation to the center of the earth, so is latitude, in other words there is a distinct relationship between level and latitude. Have your tripod levelled makes it easier to polar align the next time. Just level it again and most of the time you only need to adjust azimuth. For AP it is a bit more demanding of course.

So next time do not adjust your tripod legs. Just level first, set your altitude and fine tune with polemaster.

Next time you setup, you will need little altitude adjustment, cause bubble levels are not really accurate, but it won't be much. Azimuth will now be the most demanding adjustment.

[Moonshed]

Thanks for all the help, much appreciated. I just want to clarify that I do NOT adjust my PA by adjusting the tripod legs, that would be a pointless exercise. I have long ago marked out three small holes in my concrete platform that is where I place my tripod legs and know that it will be plenty good enough for visual observing, but for astrophotography I always have to use the PoleMaster and adjust the MOUNT for precise alignment. It just seems odd to me that even after carrying out PA using the PoleMaster Polaris is still right at the bottom of the screen, even in full screen mode, and I would have thought it would be more or less in the centre of the screen. That is why I raised the question about the bubble level, but anyway it works regardless. It just puzzles me and I can't stand unresolved puzzles. There must be a reason that causes this. Anyway, with the weather being what it is currently this is all rather academic.

[carastro]

Don't rely on the spirit level bubble on the mount, they are notorious for being inaccurate.  This is probably the cause of your whole dilemma.  Try it with a separate longer spirit level before putting the mount head on.  Get it level then put the mount head on and look at the spirit level on the mount and see if it agrees with what the separate spirit level says.  I can't see any other reason for Polaris being at the bottom of the screen.  

On a separate issue, I am now using Polemaster (which I agree is wonderful), and I found difficulty following the same star when you rotate the mount twice as it would often go off the screen.  I have solved this now thanks to RayD telling me to expand to full screen (duh), and also I have spotted a set of 3 stars in a triangle one of which I now use as my chosen star and if I take my eyes off the screen to see how far the mount has rotated, it is easy to re-find the star in question.  It would have been useful if once a star had been chosen if the software had put a marker on the chosen star.  

Carole 

[kens]

If you have the Polemaster mounted on the RA axis (some people mount them on their OTA or elsewhere on their mount) and after alignment the NCP is not centred that means the camera is not exactly aligned with he polar axis. In effect it has "cone error". Maybe the Polemaster mount is not squarely fitted or the hole where it goes it not made square. Changing the tripod legs wont change it. The alignment should still be ok

[Moonshed]

I have the PoleMaster fitted in the mount, the opposite end to which we look through to align, when we have knees and backs that allow us to do that. I feel that the fitting must be correct because when I have finished the procedure the alignment is as good as can be expected. My Celestron has a focal length of 2000 mm and rated at F10, not ideal for astrophotography. With the Easyguider fitted the speed improves to around F5. I can go for 2.5 to 3.0 minutes without star trails appearing and that is plenty good enough for me. Without the PoleMaster I would have had to give up any idea of AP last year, but know I have a new lease of life. Thank science for the technology!

[Moonshed]

24 minutes ago, carastro said:

Don't rely on the spirit level bubble on the mount, they are notorious for being inaccurate.  This is probably the cause of your whole dilemma.  Try it with a separate longer spirit level before putting the mount head on.  Get it level then put the mount head on and look at the spirit level on the mount and see if it agrees with what the separate spirit level says.  I can't see any other reason for Polaris being at the bottom of the screen.  

On a separate issue, I am now using Polemaster (which I agree is wonderful), and I found difficulty following the same star when you rotate the mount twice as it would often go off the screen.  I have solved this now thanks to RayD telling me to expand to full screen (duh), and also I have spotted a set of 3 stars in a triangle one of which I now use as my chosen star and if I take my eyes off the screen to see how far the mount has rotated, it is easy to re-find the star in question.  It would have been useful if once a star had been chosen if the software had put a marker on the chosen star.  

Carole 

I agree that if the system marked your chosen star it would make things a lot easier. That is a good point about the accuracy of the spirit level, and I will take your advice and check it with a yard long level that I have and is very accurate. Thanks for that.