Hari,
I am assuming you are using a ball head along with the MSM in which case don't go too crazy trying to get your tripod level, it doesn't matter what the tripod is doing (even if it's leaning sideways) as long as your axis of rotation is polar aligned. The ball head should pointing 40° above the horizon and be lined up exactly to the North.
The good news is you will be able to apply the same skills to polar align a GEM if you decide to go in that direction and it will be easier.
My best advice to you is to try this from a dark location on a night with good transparency with absolutely no Moon in the sky. In other words you will need to wait 2 or 3 weeks until the Moon goes away. When it's dark again I want you to try taking 25 subs each of the same subject at ISO 800, 1600, 3200 and 6400. This should only take a couple of hours and you should be able to easily complete this task on a DARK (that means no Moon) clear night. Then calibrate and stack your data to compare .
Remember, all of the noise lives on the left side of your histogram, if you want to reduce it then you need to either increase your exposure time or your ISO. The key to collecting good data is to histogram off of the left edge. If you are unable to extend your exposure time because of polar alignment error then (aside by being limited by your aperture) the only other thing left to do is to amplify the signal before it’s converted to a digital value, yes you do this by increasing the ISO. Otherwise the ADC will not be able to distinguish the signal (your image data) from the noise its burried in from the left edge of the histogram.
CS,
-Lou
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Posted by: Hari Doraisamy on 1/21/2021 at 4:54 PM
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Thanks Lou! This was taken with:
ISO 1600 F 5.6 10 sec subs
Increasing to 15 sec+ gave me severe star trails
From: mailer@mail2.clubexpress.com <mailer@mail2.clubexpress.com> on behalf of Astrophotography <astrophotography@dvaa.org>
Sent: Thursday, January 21, 2021 5:46:27 PM
To: Doraisamy, Hari <hari.doraisamy@sap.com>
Subject: re: [Astrophotography] January Image Challenge <<-------------------------------------------------------------------------------------->>
Posted by: Elias Varvarezis on 1/21/2021 at 4:45 PM
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Hari,
I am in a constant battle with the trees, I feel your pain.
Your polar alignment looks pretty good but it looks like the data was pushed a little too far in post-processing.
Can you post your exposure information? (shutter speed, aperture and ISO).
CS,
-Lou
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