#41  
Old 05-08-2019, 09:17 AM
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Merlin66 (Ken)
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Guys,
I find the SunCalc App to be excellent for meridian alignment.
https://www.suncalc.org/#/-38.1667,1...1.15/13:31/1/0
Just enter your location (You'll get that from GPS or Google maps) and the date.
Recommended.
(I set up my portable HEQ5 for solar observing by using the aligned finder (fitted with a solar filter). The top of the EQ head is set horizontal using a spirit level, counterweights down. Set the Dec using the circles to the solar Dec (as given) and check the solar image is visible in the finder...tweak as necessary. Use the alt/az adjusting bolts to bring the solar image exactly in the middle of the cross wires at the specified time. Perfect meridian alignment. Sound complex but like many things in life - the first time is the most difficult - after that it's a piece of cake! I've now marked the tripod feet position on the deck and find that works now 99% of the time.)
Hope that helps.
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  #42  
Old 05-08-2019, 09:17 AM
raymo
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No probs John, as the youngsters would say these days.
raymo
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  #43  
Old 22-03-2021, 07:14 PM
poider (Peter)
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update

Quick update I used the stick and the sun, marked out my line and placed my pavers, I only need put my legs in the paver holes and i am near spot on each time, but now my tripod has broken and I am using my camera tripod, a bit shorter but I can still get pretty close, i can find the sigma octans most night in my alignment view finder, but now I am going up to Uluru for a week and need to have a quick way to find the SCP from there. I will let you all know how I go.
From home I can get some decent shots at up to 5 minutes with the camera, no telescope on a good day with the star adventurer.
Thank you all for your help, It has been a while since posting as I don't get out as much as I should, I have bad lungs and cannot go out when it is too cold or when the neighbors are burning bad stuff in their combustion heaters, but I do get out occasionally.
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  #44  
Old 24-03-2021, 09:53 AM
Startrek (Martin)
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Quote:
Originally Posted by poider View Post
Quick update I used the stick and the sun, marked out my line and placed my pavers, I only need put my legs in the paver holes and i am near spot on each time, but now my tripod has broken and I am using my camera tripod, a bit shorter but I can still get pretty close, i can find the sigma octans most night in my alignment view finder, but now I am going up to Uluru for a week and need to have a quick way to find the SCP from there. I will let you all know how I go.
From home I can get some decent shots at up to 5 minutes with the camera, no telescope on a good day with the star adventurer.
Thank you all for your help, It has been a while since posting as I don't get out as much as I should, I have bad lungs and cannot go out when it is too cold or when the neighbors are burning bad stuff in their combustion heaters, but I do get out occasionally.
Peter,
The solar noon shadow stick method is bullet proof , the human race has been using the suns shadow for thousands of years for time measurement, constructing monuments and buildings , cultural and spiritual reasons and even Indiana Jones used it in Raiders of the lost Ark ( pardon the joke )
The Compass has its use but not ideal for aligning tripods to true south
Glad it has worked out for you
The more accurate you are with your shadow stick set up and true south line , the more accurate and closer you will be to true south and resultant polar alignment
Cheers
Martin
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  #45  
Old 24-03-2021, 11:12 AM
AdamJL
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Out in the field, which is where I do all of my shooting (not possible at home), I just use a rough alignment with a good compass, then dial it in with the digital.
Since I only shoot in 3 locations, I know exactly where to point my mount. Everytime I fire up the PoleMaster, Sigma Octantis says hello to me at first attempt in the image.
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  #46  
Old 24-03-2021, 09:17 PM
Hemi
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I think the solar noon method is fine, but for me it’s not that useful as you can only use it at noon. I normally get to a dark site late afternoon. I also find it a bit of a hassle with the sticks and string and all.
There are a number of these threads and I’m flummoxed why people struggle with compasses (iPhone or regular). It just has to get you in the ball park, after which you have to use another method anyway (drift, aspa, sharpcap etc).

I use my iPhone compass and a small orienteering compass. Then ASPA or PemPro, session dependent.

Best
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  #47  
Old 24-03-2021, 09:25 PM
Hemi
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Quote:
Originally Posted by Merlin66 View Post
Guys,
I find the SunCalc App to be excellent for meridian alignment.
https://www.suncalc.org/#/-38.1667,1...1.15/13:31/1/0
Just enter your location (You'll get that from GPS or Google maps) and the date.
Recommended.
(I set up my portable HEQ5 for solar observing by using the aligned finder (fitted with a solar filter). The top of the EQ head is set horizontal using a spirit level, counterweights down. Set the Dec using the circles to the solar Dec (as given) and check the solar image is visible in the finder...tweak as necessary. Use the alt/az adjusting bolts to bring the solar image exactly in the middle of the cross wires at the specified time. Perfect meridian alignment. Sound complex but like many things in life - the first time is the most difficult - after that it's a piece of cake! I've now marked the tripod feet position on the deck and find that works now 99% of the time.)
Hope that helps.

Thanks Merlin,

Missed your post...very neat method, will try this.
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  #48  
Old 25-03-2021, 04:24 AM
astro744
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Quote:
Originally Posted by Startrek View Post
Peter,
The solar noon shadow stick method is bullet proof , the human race has been using the suns shadow for thousands of years for time measurement, constructing monuments and buildings , cultural and spiritual reasons and even Indiana Jones used it in Raiders of the lost Ark ( pardon the joke )
The Compass has its use but not ideal for aligning tripods to true south
Glad it has worked out for you
The more accurate you are with your shadow stick set up and true south line , the more accurate and closer you will be to true south and resultant polar alignment
Cheers
Martin
Thousands of years ago there were no apps to help you find solar noon, (as your method attached to the other thread suggests). You need to determine solar noon another way first and you can do this simultaneously as solar noon will be when the sun is at its highest point and therefore any vertical stick shadow will be the shortest length. The shadow length will vary depending on where you are located in latitude and the current season.

Place the stick as described over a concrete slab and mark the end of the shadow with a dot from morning to evening every hour to every few minutes as you approach solar noon and afterward. When you connect to dots you will get a curved line. Solar noon occurred when the radial (shadow length) is at its shortest. You can confirm this by placing a dot at precise solar noon that you obtained the time using your app but note this was not an option thousands of years ago.

As for the various shadow methods used in the movies all I can say is you must be very lucky to be at the right place at the right time of day and the right time of year and for it to be sunny and not overcast. The best flawed example I remember is in National Treasure when the sun cast a shadow on at a particular spot to reveal a clue. What a fluke to be there at the precise moment the clue was hidden even when they thought they were smart enough to take daylight savings into account. (Still enjoyable movie though!).
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  #49  
Old 29-01-2022, 10:00 AM
poider (Peter)
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Quote:
Originally Posted by Ukastronomer View Post
Personally I think the multi billion $ GPS system may be more accurate than a $10 compass

Which Multi million dollar GPS?
I have used 5 apps on my phone
and 5 different resources on the net
Pro compass, Commander compass, I phone compass, Astro locator and polar alignment pro for the I phone apps
and on the net magnetic declination .com, google earth, google maps, gps coordinates and find my gps
The results varied five were one coordinate and five were another
these are relatively close but are 35km apart
So maybe the multi billion dollar Gps System need to be re callibrated
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  #50  
Old 29-01-2022, 10:59 AM
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mura_gadi (Steve)
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Not for finding celestial south but...

On my SW goto, I used the pavers and made a mark on the pavers for an inverted "L" pole. I return the scope to the same leg position and check level on the stand.

Then use the pole on the paver mark, move the scope till the edge of the scope hits the pole, I know I'm pointing north, move the scope up till it hits the "L" bar and I know I am level.

Saves a bit of time in the backyard over compass and a spirit level, well, once you've setup up the pole anyway.



Steve
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  #51  
Old 29-01-2022, 06:25 PM
poider (Peter)
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I have three pavers in my back yard now with holes... the leading paver is south I was doing well but have now bought a new stronger 'surveyors' tripod, tonight I will check my alignments and make sure I can repeat it in the field.
I went to Uluru to get some really dark skies and try for some really good shots, Uluru recorded its highest rainfall in many years whilst were were there, so now I am booked for the Flinders Ranges to bring some rain to the dry parts of the state.
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