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Old 13-02-2017, 01:51 PM
acotiga (Andrei)
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Polar alignment SH in under 2 minutes

I have't visited the forum in a while, but I would like to tell you about my newest development, if forum rules allow.

Being driven almost mad by SH polar alignment, I have developed a new device which now allows for quick polar alignment in a matter of minutes. It consists of three green lasers set at different angles corresponding to Acrux, Rigel kent and SCP. By aligning the lasers on the two reference stars, the third will automaticaly point at the SCP. The device sits next to the telescope on an ordinary photo tripod.

PA is possible within minutes with a degree of accuracy of about 10 arcmin. Better accuracy can then be achieved by using the azimuth and altitude bolts while looking through the telescope until the famous "right angle triangle" is in the right spot.

For more quick information please see www.iprintu.co.nz.

What the device allows is to go portable, anywhere in the S hemisphere, polar align within minutes and start your photo session.

Please ask as many questions as you can think off. The product will go into production in about a month and I'm happy to say that for the upcoming South Island Stardate (in NZ) I will have one with me to be tested by the larger community.
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Old 13-02-2017, 01:58 PM
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Because it uses lasers, I don't think it will be widely accepted.... I wouldn't like some Johnnie_comes_Lately is aligning their mount while I am already taking images..
Also, it assumes southern part of the sky is visible, which is not the general case.
I prefer the classic, passive polar scope with accurate reticle.
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Old 13-02-2017, 02:46 PM
glend (Glen)
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What Bojan said, and...

The use of lasers anywhere near a city is sure to attract the attention of the authorities in Australia.

Sharpcaps PA tool gives precision alignment in the same time, and the download is free. The recent release of Sharpcap contains a plate solve map for the southern hemisphere. As long as you have access to some kind of usb camera, even a webcam, you can polar align quickly. You can use you imaging camera, no problem. No mount power or internet access required, just a laptop with Sharpcap and said camera.
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Old 13-02-2017, 06:34 PM
acotiga (Andrei)
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Thank you both. Valid points. Though:

- Using only the polar scope has been a no go for me and others I know. We are observing from a 21arcsec/mag but still have problems with seeing Octans with the naked eye. Finding it in the EQ6 polarscope is an exercise in futility.
- part of the southern sky is obscured. Because it's 3d printed, the device can be very easily customised for any other star pairs. For obvious reasons it's a good idea to keep to circumpolar stars.
-Johnie-comes-lately: there is no substitute for etiquette.
- lasers near the city: I went for 10mW lasers for a reason. I know that I personally love my 50mW which is visible in full moon nights, but it's overkill. A 10mW laser beam in the sky is not going to be visible at more than 1km away. It is quite faint 100m away, yet alone 1km. As for airplanes...we are almost under the flight path. A 10mW laser will go for almost 2km in the sky and would not be considered a critical distraction. Again, etiquette, judgement and caution are required.
- Sharpcap sounds good. I will actually give it a try. However, realistically speaking I think I will have a ball getting 15 stars in the field of view of 1deg.

Don't worry, I don't mind. Keep them coming, thank you. There is a tool for everybody. If you found you PA method and are happy with it, I'm glad for you. This is mainly for people still trying methods out and not finding one.

However, let me be skeptical and doubt that if you give my device a try, you wouldn't love it. Not going to replace your method necessarily, but love it none the less. Mainly think of all the "newbies" picking up the hobby and meeting endless nights of frustration.

Remember how long it took us (I will assume you were like myself) trying to get the first drift alignment. Remember the hours lost and so on. I know that there are other methods now (Sharpcap, Pempro, EQalign, etc) but it's still a fiddly task.

Anyway, thanks again for the comments and please let me know of any other comments.
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  #5  
Old 14-02-2017, 11:36 AM
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jenchris (Jennifer)
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Use the Force young Skywalker.
I like your idea but it seems overkill
I've done a drift align with a dslr and APT in live view. Took about 5 mins.
I now use PHD2 and it's down to about 3 mins.
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Old 14-02-2017, 12:25 PM
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A 10mW laser will go for almost 2km in the sky and would not be considered a critical distraction.
Maybe OK in NZ but we live in a nanny state.
Down here, anything above 1mw is an illegal weapon :-)
Several people have been arrested in the last few weeks alone for using them.

Andrew
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Old 14-02-2017, 01:00 PM
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Quote:
Originally Posted by acotiga View Post

PA is possible within minutes with a degree of accuracy of about 10 arcmin. Better accuracy can then be achieved by using the azimuth and altitude bolts while looking through the telescope until the famous "right angle triangle" is in the right spot.
Well, when the telescope has a polar scope, just center the +6.9 star BQ Octantis which is only 10' off the pole.

I did this often, allowing 4 minutes exposure with 600mm FL with pinpoint stars without guiding. No lasers required.

Quote:
Originally Posted by AndrewJ View Post
Maybe OK in NZ but we live in a nanny state.
Down here, anything above 1mw is an illegal weapon :-)
Several people have been arrested in the last few weeks alone for using them.

Andrew
Presumably, powerful lasers are allowed in New Zealand ? In the EU there is a 5mW maximum limit.

Last edited by skysurfer; 14-02-2017 at 01:12 PM.
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Old 14-02-2017, 01:31 PM
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Quote:
Originally Posted by skysurfer View Post
Well, when the telescope has a polar scope, just center the +6.9 star BQ Octantis which is only 10' off the pole.

I did this often, allowing 4 minutes exposure with 600mm FL with pinpoint stars without guiding. No lasers required.
Actually if you also use the double star right near BQ and centre your polar scope crosshairs on a point that makes a slightly flattened isosolies triangle with them and on the Sigma Oct side... you will be within at least 2' of the pole . This is how I have always polar aligned my Tak NJP mount (which is renowned for having an accurate polar scope). On a dark moonless and steady night this can be done in literally seconds (on unsteady moonlit nights it is harder to see these faint stars). I have done a 10min unguided exposure at 1140mm FL after doing this

The flattened isosolies triangle is getting flatter each year due to precession too, so in a couple of decades or so you will just have to point the cross hair at the midpoint between BQ and the double star and you will essentially have perfect PA in 10 sec - heaven!



Mike

Last edited by strongmanmike; 14-02-2017 at 01:45 PM.
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  #9  
Old 14-02-2017, 02:02 PM
acotiga (Andrei)
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Let's settle first the assumed laser problem. In Au, like in NZ, laser pointers are restricted import items. Special dispensation is required. However, this PA device is not a laser pointer, much less a handheld laser pointer. Can it be used recklessly? Yes, anything can at the end of the day. Stupidy doesn't know any bounds. But it's unlikely that a fellow astronomer would start hunting planes and the device is not suject to the ban. Please have a look at HERE. The closest equivalent would be laser firearm sight. I would also recommend the Wiki page of lasers and aviation safety. they have a pretty good explanation of the effects of a 5mW laser at 1.1km away. As responsible users, it is important to understand what effect our lasers might have and while not trying to minimise the problem, I'm trying to tackle it from a common sense point of view.

Secondly, alignment with BQ octans is indeed a very good and reliable method. If you are able to find it at night in the vast emptiness which is around the S pole without problems, then you obviously don't need the lasers. The lasers point you in the vicinity of BQ Octans and then feel free to tweak while looking through the telescope. For this I hope your telescope has a better DEC setting circle than the EQ6.

Tiny variations in your DEC setting will impact your ability to PA while looking at the BQ Octans asterism through the scope. And we are talking minutes, when 1mm on the EQ6 setting circle is 2 degrees.

I think this has turned into a "how do you polar align" type of thread. The device is aimed at beginners and people who haven't yet settled on a method. While I find some of the methods intriguing, I've had problems with some of them in the past and gave some up in frustration.
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Old 14-02-2017, 02:09 PM
acotiga (Andrei)
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Quote:
Originally Posted by strongmanmike View Post
on unsteady moonlit nights it is harder to see these faint stars
You said it. Lasers would however be visible.
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Old 14-02-2017, 02:18 PM
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Almost $350 for this gadget is way too much, compared with $50 Polar finder.
Laser cost is <$10 from China...

Last edited by bojan; 14-02-2017 at 03:37 PM.
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  #12  
Old 14-02-2017, 02:49 PM
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Quote:
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Down here, anything above 1mw is an illegal weapon
In NSW you just need a permit, unless an exemption applies. From the relevant NSW Police site:

Quote:
Note that you will not need to obtain a permit to possess/use a laser pointer with a power level greater than one milliwatt if you are a member of an approved astronomical organisation.
Join your nearest astronomy club, and you're safe.
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Old 14-02-2017, 06:07 PM
AndrewJ
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I will see if i can dig out the old thread on this, but each state is different.
In Victoria, being a member of an Astro society wasnt given an exemption like some other states. You needed to get the equivalent of a gun license and keep it valid.
Just found this
http://www.police.vic.gov.au/content...ument_ID=25574
and as far as i can see, its still a prohibited weapon with no leniency by the plods. You need to get ( and pay for ) a dispensation on a case by case basis. $190 if you can get it.

Andrew

Last edited by AndrewJ; 14-02-2017 at 06:17 PM.
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Old 14-02-2017, 06:46 PM
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Atmos (Colin)
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Victoria is very strict on anything mower powerful than a 1mw laser irrespective of distance.
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Old 14-02-2017, 07:41 PM
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Another disadvantage is that the two stars (Alpha Centauri and Acrux) are rather close to each other, compromizing the accuracy.
This also requires that both stars should be in the sky at all times which is not always the case in all SH.
Another method, apart from the polar scope method, using setting circles and a single star, max 30 deg altitude + zenith (or two stars at least 60 degrees apart) alignment has the same accuracy, which works worldwide, incl NH.
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Old 15-02-2017, 05:25 AM
acotiga (Andrei)
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Quote:
Originally Posted by skysurfer View Post
Another disadvantage is that the two stars (Alpha Centauri and Acrux) are rather close to each other, compromizing the accuracy.
This also requires that both stars should be in the sky at all times which is not always the case in all SH.
Another method, apart from the polar scope method, using setting circles and a single star, max 30 deg altitude + zenith (or two stars at least 60 degrees apart) alignment has the same accuracy, which works worldwide, incl NH.
Acrux and Rigel kent are about 15 degrees apart. That's not close. Secondly, accuracy has nothing to do with how close they are but to how carfully you place the lasers ON the stars. As the two stars form a triangle with SCP, if you determine two corners of the triangle, the third will be automatically determined.

Also, it is true that the two stars dip below 15 degrees from the horizon at certain times of the year, but because of the vible lasers, you may set up the device up to 40m away where line of sight is no longer a problem. The device can be easily customised for any other pair of stars.

From my experience, the setting circles method works only if you have very accurate gradations or encoders.
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Old 15-02-2017, 05:49 AM
acotiga (Andrei)
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Quote:
Originally Posted by AndrewJ View Post
I will see if i can dig out the old thread on this, but each state is different.
In Victoria, being a member of an Astro society wasnt given an exemption like some other states. You needed to get the equivalent of a gun license and keep it valid.
Just found this
http://www.police.vic.gov.au/content...ument_ID=25574
and as far as i can see, its still a prohibited weapon with no leniency by the plods. You need to get ( and pay for ) a dispensation on a case by case basis. $190 if you can get it.

Andrew
As far as I can see, the full weapons list refers to handheld laser POINTERS. I repeat, this device is not a laser pointer. Here is a rendition of the device. It's about 150x150mm. Not quite a laser pointer.
Attached Thumbnails
Click for full-size image (Laser ansamble v4 - IMG 1.jpg)
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Old 15-02-2017, 07:09 AM
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I can only imagine showing up to a star party with all the Newbs arriving with their new Laser SCP devices all throughout the night - setting up, turning on and moving their mounts around with lasers flashing around the place !

If their lack of ability is any indication they will spend an extra hour or two trying to calibrate the device to their optical alignment as well !
Talk about light pollution

I see anything with lasers being banned at all events if not already.
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Old 15-02-2017, 07:14 AM
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A ball 15cm in diameter... in a box ~20cm cube. Another bulky thingy to carry around.

If I were designing something for that purpose, I would have used specially designed holographic reticle (or transmissive mirrors), to project the mesh/beams on the sky, powered by single laser, and all that fitting into the polar axle.
(now, please don't use this idea, because I have a patent for it).

But as Rally said, it would probably be banned very soon at all astro-gatherings.

Or why not use a design similar to RDF or Telrad (also patented..)?

Last edited by bojan; 15-02-2017 at 09:03 AM.
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Old 15-02-2017, 08:22 AM
AndrewJ
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I repeat, this device is not a laser pointer. Here is a rendition of the device. It's about 150x150mm. Not quite a laser pointer.
People asked re the "definition" when the legislation came in and were told that even if a laser was "affixed" to a telescope, it was a defined weapon in Victoria. The fact you could pick up your ball and point the lasers "anywhere" ( ie what you actually need to do to use it ) would probably classify it as "hand held" immediately.
But anyway, if you know better, get a formal statement from the Victoria Police to tell us its OK here ( Lots of luck )

Andrew
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