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Sky-Watcher AZ-GTi Equatorial Mount Polar Alignment Deep Sky
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Nikolaos Bafitis avatar
Nikolaos Bafitis avatar
Hello,
I recently bought and equatorial mount to add to my azgti so that I could take deep sky images with exposures of over 1 minute, but found that even after I downloaded the correct firmware and polar aligned it ( I don’t really know how to polar align it so a detailed explanation would help) it wouldn’t track the deep sky objects and there was significant star trailing in my images, how do I fix this?
Beat Wirthmueller avatar
Beat Wirthmueller avatar
Hi Nikolaos

As you experienced a good polar alignment is the key for astrophotography

Living in the northern hemisphere we can use Polaris - the North Star - to align our mounts. But keep in mind that Polaris is circling around earth's rotation axis. There are different apps and software to show you where you can target Polaris in your finderscope. To communicate with my Sky Watcher Star Adventurer Gti I use their software SynScan Pro. There you find the option Utility, then got to Advanced and then you find the Polar Scope. It shows you the sight as if you are looking through the polarscope of your mount with the actual position of Polaris.

Now you have to get Polaris at the exact position in the polarscope of the Gti using the different screws on your mount. It may be helpful to position the mount to North using a compass and to start with the alignment before complete darkness so it get's easier to identify Polaris among all the stars.

Depending of the focal length of your optics star trails may appear on long exposures. With my WO RedCat 51 I was able to get good results with exposures up to 90 Seconds without star tracking.

Hope this helps - good luck - Beat
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Nikolaos Bafitis avatar
Nikolaos Bafitis avatar
hello, are there any online tutorials on how to polar align with my mount, and also I don't understand what screws you are talking about as my Sky-Watcher Star Adventurer Equatorial Wedge doesn't seem to have any screws that move it around.
Davgar82 avatar
Davgar82 avatar
Hello. This is my handmade solution for polar align with AZ gti, i kwon that there are some comercial solutions. Laser pointer must point to celestial north pole. After of this, you can do better align by software, PHD2 for example.Sorry about my english level...
Nikolaos Bafitis avatar
Nikolaos Bafitis avatar
What if I can’t make that?
CaptnCook avatar
CaptnCook avatar
Hi Nikolaos,
If you've EQ modified your AZGTi you have two options:

1) you can PA using the synscan software directly from your imaging camera (Not the polar scope routine). This other routine asks you to use one of the alignment stars and offsets it first in Az and then Alt. It calculates PA based on your adjustments. I have used this and it works fine. Bear in mind that the AZGTi has a lot of periodic errors so you might find you are limited to 30s without guiding.

2) You can fit an additional guide scope and use that to polar align eg using sharp cap. Then you will end up using that camera to guide (Phd2) so you can have exposures much longer of many minutes. PA doesn't have to be very accurate if your are guiding.

Cheers
Gary
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SkyHoinar avatar
SkyHoinar avatar
Hi Nikolaos,
What is exactly the mount that you have?
Usually the equatorial mounts are equipped with a polar scope and come with a user guide where the polar alignment routine is also explained.
Nikolaos Bafitis avatar
Nikolaos Bafitis avatar
i have a skywatcher equatorial mount for the staradventurer, but attached it to the azgti mount
CaptnCook avatar
CaptnCook avatar
That's more than good enough for FL up to say 400 mm.

I have the same and either PA option 1 or 2 work well. In fact option 1 can be used without needing to see the celestial pole which is an advantage. Just chose an alignment star fairly near by.
SkyHoinar avatar
SkyHoinar avatar
Nikolaos Bafitis:
i have a skywatcher equatorial mount for the staradventurer, but attached it to the azgti mount

I suppose it is something like this (an equatorial wedge)?
https://www.astroshop.eu/equatorial-wedges/skywatcher-polar-wedge-star-adventurer/p,45120
There is video clip there showing how to polar align it.
Nikolaos Bafitis avatar
Nikolaos Bafitis avatar
I don't have a polar scope and i'm using a telescope so I dont think that video would apply to me, thanks for sending it though.
Davgar82 avatar
Davgar82 avatar
https://starlighthunter.com/articulos/buscador-polar-az-gti/ 
I found this article by Oliver Gutiérrez where he explains quite well how to make a homemade polar finder support. It seems simple. If you are not very handy, you can search the web for "az gti polar scope adapter". The Kepler brand has a commercial system at least.