Hello from Dublin - Ireland - Forums

Topic starter

Nov 11, 2020

Have been an amateur photographer for 20 plus years. Now want to give AP a real crak - especially with lockdown. I'm in a Bortle 8 area. I Have a Canon 5Dmk 4 full frame with 700-200 2.8 and 100-400 2.8, a recently modified Canon 600D and also an MFT Lumix G9 with a few different focal lengths. Got a good tripod and have the Star Adventurer mount.

So all good to go to give this a go. But… having given andromeda an initial lash, its obvious focus and tracking were off. What I really struggle with is the Polar alignment initially - when I look through the scope I see a few stars, have used a few apps to help locate Polaris , but am still not sure if its the right one. Then when I think I'm PA and move the camera to shoot the PA all gets lmis-aligned again.

With my current kit - without any autoguiding and just a tracker any advice on how to polar align without finishing looking like quasimodo after I contort to look through the polar scope on the Star Adventurer. Thanks in advance.

Engaging

Jérémie

Nov 16, 2020

Hi ! I have an iOptron Skyguider Pro and that’s really similar to the SA you have, for polar alignment.

I used to do just like you to polar align, through the finderscope of the mount, bent with a knee in the mud, until I decided to abandon my DSLR for a cooled camera.

Nevertheless I can advise you :
- in a Bortle 8 sky you can spot polaris by eye without doubt, so you can roughly align the SA without looking through the finderscope, that will make more stars be visible.
- then try to adjust better through the finderscope and the reticle (with the apps). Chances are polaris will be the most visible and you won’t have many star around to mistake it with…

Now, what you can do (never tried with the DSLR) :
- now, I still roughly polar align by eye or sometimes with the integraded finderscope
- but then, I use Sharpcap to make the polar alignement through the camera
The process is simple : you roughly aim polaris, then Sharpcap takes a first picture and platesolve it very quickly. Then it asks you to rotate your scope (and camera) 90 degrees in right ascension. It plate solve again. Then it compares both pictures and determine where the center of rotation is, and compare it to where it should be (celestial north). It tells you to adjust altitude and azimuth of the mount left or right, up or down. It does so in real time.
But you need a camera…

That being said, I have read there are ASCOM drivers for DSLR and that you can use them to be able to work with Sharpcap. Google « Sharpcap Canon » and you should get some links to Cloudynights forum where they explain how to use a DSLR with Sharpcap.

If you can use your dlsr that way, then you can reach really good polar aligment without bending too much :-)

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Jérémie

Nov 16, 2020

- in a Bortle 8 sky you can spot polaris by eye without doubt, so you can roughly align the SA without looking through the finderscope, that will make more stars be visible.

Just to be more precise : you can align in azimuth by eye, and pre-adjust in altitude by knowing your GPS coordinates (53degrees for Dublin). With that, you should already have polaris in the finderscope when bending the knee, and limit your time for suffering 😬

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Astrodub

Topic starter

Nov 16, 2020

Much appreciated many thanks for taking the time.

lucian_nicu

Nov 16, 2020

Hello.
I am a user of Ioptron Skyguider Pro but I think most or all of the steps are identical to SW Adventure.
To bring Polaris into the reticle is not difficult, but the exact positioning of Polaris is done using the Simple Astro Tools ("Polar Finder" section ) application. You have to fill in the GPS location (I use the phone application for that), the date and time. At the end I check "See graphical solution" and it shows me the correct position of Polaris.
I only do this with the tracker on the tripod. After I place Polaris exactly where it should, I start tracking and then start mounting the counterweight bar, the counterweights and finally the telescope / photo lens with the camera already mounted. I check the balance and at the end I check the polar alignment again. I usually have to adjust a little. At the end I make a test frame of 1-2 min. If everything looks good, it means that I am polar aligned and can get to "work".
This routine guarantees me about 60% keepers at 3 min exposure, about 75% keepers at 2 min exposure and over 80% keepers at exposures of max 90 sec.
I hope it helps.
Good luck and clear sky!

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Astrodub

Topic starter

Nov 16, 2020

Cheers for the advice much appreciated

Astrodub

Topic starter

Dec 1, 2020

Thanks will give it a go appreciated

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