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Another Newbie Question re Star Adventurer and Polar Alignment

Polar Alignment EQ Mount Eclipse
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#1 mdredmond

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Posted 27 February 2024 - 09:30 PM

Okay folks, you've been very helpful and I appreciate it as I frantically try to catch some decent pictures of what will certainly be the last North American eclipse I ever see...  2017 was amazing in Casper and I want to do better this time.

 

My goal is for a laptop to control the camera while my Star Adventurer (at least mostly) takes care of alignment.  To that end I've requisitioned a MacBook from work to run Eclipse Maestro and rented a 500mm Nikon prime lens with a Nikon 1.4x teleconverter.   That puts me at 700mm on a full-frame camera. 

 

Side note re earlier post: I did talk to Nikon today and they told me since the equipment is all theirs and matched up, I WILL be able to specify a desired aperture, even in manual mode, and the camera will not offer one that the attached lens and converter can't deliver.   

 

There is a non-zero chance that I won't be able to polar align the night before.  This is mostly owing the the fact that I need to sleep and don't necessarily want my mount and tripod sitting out in the parking lot of a state park overnight.  I might be able to get up early but let's assume I can't or that I need to move because of clouds.

 

Anyway on to my actual question regarding polar alignment:

 

 If align my Star Adventurer w/ Equitorial Wedge in the morning using an app like PSAlign to get *roughly* on the NCP and then start tracking the sun, then use the Declination and Azimuth adjustments (not RA) to re-center the sun periodically (say, every 15 minutes), am I correct in thinking that this will bring my mount into better polar alignment?  Seems like Declination will only need to be adjusted once and it might take a few tweaks on azimuth. 

 

I was just going to try it but it's been cloudy. 
 

Maybe I just need to spend a few nights practicing on the moon to see if my assumption is true.

 

Or am I totally off base?

 

 

 

 


Edited by mdredmond, 27 February 2024 - 10:20 PM.


#2 Dustyhills

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Posted 28 February 2024 - 12:21 AM

Not sure why you would want to use a 500mm lens and 1.4x teleconverter? The coronal display is much larger than that lens can cover. I would go with a wider field of view and take exposures ranging from very fast all the way down to several seconds and then stack the images to get the entire corona during totality. I used Nikon backyard in 2017 and programed the entire exposure range so I could watch the eclipse and the pictures came out great. I created two exposure routines in Backyard, one for the partial phases and one for totality that I could stake later and get the entire coronal display which can easily be 2 degrees or more if done right



#3 Celerondon

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Posted 28 February 2024 - 02:14 AM

Okay folks, you've been very helpful and I appreciate it as I frantically try to catch some decent pictures of what will certainly be the last North American eclipse I ever see...  2017 was amazing in Casper and I want to do better this time.

 

My goal is for a laptop to control the camera while my Star Adventurer (at least mostly) takes care of alignment.  To that end I've requisitioned a MacBook from work to run Eclipse Maestro and rented a 500mm Nikon prime lens with a Nikon 1.4x teleconverter.   That puts me at 700mm on a full-frame camera. 

 

Side note re earlier post: I did talk to Nikon today and they told me since the equipment is all theirs and matched up, I WILL be able to specify a desired aperture, even in manual mode, and the camera will not offer one that the attached lens and converter can't deliver.   

 

There is a non-zero chance that I won't be able to polar align the night before.  This is mostly owing the the fact that I need to sleep and don't necessarily want my mount and tripod sitting out in the parking lot of a state park overnight.  I might be able to get up early but let's assume I can't or that I need to move because of clouds.

 

Anyway on to my actual question regarding polar alignment:

 

 If align my Star Adventurer w/ Equitorial Wedge in the morning using an app like PSAlign to get *roughly* on the NCP and then start tracking the sun, then use the Declination and Azimuth adjustments (not RA) to re-center the sun periodically (say, every 15 minutes), am I correct in thinking that this will bring my mount into better polar alignment?  Seems like Declination will only need to be adjusted once and it might take a few tweaks on azimuth. 

 

I was just going to try it but it's been cloudy. 
 

Maybe I just need to spend a few nights practicing on the moon to see if my assumption is true.

 

Or am I totally off base?

I think that your PS Align Pro idea is a good one.  But I can’t prove it because, like you. I haven’t tested the hypothesis yet.  So let’s do it!

 

We don’t even need to wait for nightfall because any clear sky will do.  I plan to intentionally randomize my altitude and azimuth adjustments so that the mount doesn’t have any idea where it is.  Then I will start the process by leveling my tripod because of the repeatability factor and slight advantages during the actual polar alignment process.  Next I will use the daytime alignment tool to center the crosshairs.  Finally I will execute a GoTo, center, and test my tracking.  I will repeat this cycle several times from start to finish.  If this process consistently yields good tracking results then I will stick with it. If not, I will add steps to enhance the routine. 

 

Don

 

Daytime Alignment Tool - Day Mode

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#4 michael8554

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Posted 28 February 2024 - 05:21 AM

In 2006 I imaged a 4 minute eclipse in Libya.

 

Using a Nikon Coolpix 4500, which has a fixed zoom lens.

 

Attached to the eyepiece of a 500mm refractor.

 

Back then I'd never heard of drift due to PA error.

 

I roughly pointed the EQ mount towards north and imaged away, tweaking RA and Dec every so often.

 

No problem.

 

As Dustyhills said, check the FOV of your images before going, to be sure the FL/camera combination will allow you to capture the full corona on slow exposures.

 

Don't forget to take the filter off at Totality, I missed 30 secs or so before I remembered !

 

28Feb_0002.jpg

 

(Scan of a print).


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#5 mdredmond

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Posted 28 February 2024 - 09:49 AM

Not sure why you would want to use a 500mm lens and 1.4x teleconverter? The coronal display is much larger than that lens can cover. I would go with a wider field of view and take exposures ranging from very fast all the way down to several seconds and then stack the images to get the entire corona during totality.

Not a bad idea.  In 2017 I got really nice pictures of the inner corona and I guess that's been my focus (no pun).   I shot with a 200mm on a cropped lens and it was quite small in the pictures This year I'll have full-frame so I thought 700mm would look good.  I'm using the examples at mreclipse.com as a reference.



#6 Applal

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Posted 28 February 2024 - 09:56 AM

I imaged the 2017 eclipse with my Canon D850 on a manual but nice tripod with a 300mm Nikon lens, just bumping it slightly to keep up with the movement of the Sun. I was easy and rendered the results I wanted.

Using your equipment and good solar filter on the front of your lens, start practicing on the full sun. You can bracket exposures during the actual eclipse if you want.. 

 

Attached Thumbnails

  • Solar Eclipse-13 (1).jpeg

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#7 michael8554

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Posted 28 February 2024 - 01:10 PM

I forgot to say, preset the correct Latitude on your mount for the location.




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