20 replies to this topic

[Alay]

My newbie hat is on for this question, so pardon if there's an obvious solution I haven't found on my own; I promise I searched first

 

The situation:

I have an equatorial mount (on a tripod) that is semi-permanently located on my apartment roof.  Once it's set up and aligned, I will not be adjusting it's location very often if ever.  I don't have a permanent pier for it and can't necessarily install it.  Also lugging something cement up 4 flights of stairs sounds like an unfun task

 

During the summer (now), my city gets to around a Bortle 7.6+.  Depending on the Moon and other lights, seeing Polaris can be a bit of a struggle with the naked eye.

My only telescope (see below) is a 1000mm refractor with a 9.8f.

 

I'm having difficulty getting a polar alignment, which is kind of cascading problems...

• In order to be able to polar align via three-point plate solves (NINA), I need a minimum number of stars visible and roundish stars.
• In order to have a minimum number of stars visible I need longer exposures (due to high F ratio and light pollution), which requires a good polar alignment to not blur.

 

I tried it by hand with a polar scope but I wasn't able to manage it very well due to the difficulty in visually seeing Polaris.

I also tried with the guide camera instead (SV905c) through a 60mm guide scope but it really wasn't up to the challenge. Too much noise.  Works fine for guiding but can't get a plate solve in ASTAP off it.

 

My next idea is to slap my DSLR and 200mm/f5.6 lens on top of the mount and try to align with that.  The lower FL should make it less prone to alignment blur for initial setup, and I can pump the gain pretty high on it while wide open.  I haven't tried this yet, waiting for a clear night.

 

Am I on the right path?  Any alternative methods I'm missing?

Edited by Alay, 18 June 2025 - 10:24 AM.

[Arcueid]

My balcony is facing south so Polaris is not visible, and it's bortle 8+.

What I did is, First roughly adjust the alt and az using my phone's compass, then use drift align in PHD2 to refine my PA, then switch to my main scope and TPPA in NINA. 

I can do TPPA using a 350mm FL and IMX585 sensor, so you should be OK with your setup, assuming you have a sensor larger than  4/3.

 

My next idea is to slap my DSLR and 200mm/f5.6 lens on top of the mount and try to align with that.

This should work as long as NINA could correctly decode your camera's raw file. I have done similar using Samyang 135mm f/2 and my astro camera.

[Tapio]

It's too late now but I would do polar alignment when it gets dark. And then when you are set put marks for your tripod in roof (I assume you can do that when you say it's semi-permanent).

 

Another solution now could be using SharpCap Pro's polar alignment routine.

It's less demaning on stars and you can use finder scope for it.

[Phil Perry]

Once it's set up and aligned, I will not be adjusting it's location very often if ever.

Are you saying that once aligned, you may never polar align it again? Not a good idea -- even a permanent pier needs to be checked at least a couple of times a year (in case something loosened up and slipped). A tripod that you place in the same spot each time can still be a bit off, and needs polar alignment to at least be confirmed each time it's set up. If you're careful not to bump the mount, and have the foot placement marked, it should be close each time (as a starting point), but still needs to be checked.
 

[Alay]

Are you saying that once aligned, you may never polar align it again? Not a good idea -- even a permanent pier needs to be checked at least a couple of times a year (in case something loosened up and slipped). A tripod that you place in the same spot each time can still be a bit off, and needs polar alignment to at least be confirmed each time it's set up. If you're careful not to bump the mount, and have the foot placement marked, it should be close each time (as a starting point), but still needs to be checked.
 

Nah I'll probably still run the check routine once a month or so; maybe before each session since metal will adjust a bit from the heat/cooling.  But it shouldn't be massively off compared to how it is before the first run through

 

Thanks for the suggestions.  I'm not familiar with Sharp-Caps method.  How does it differ from NINAs?

[freeme62410]

There's an adapter you can buy, I believe from Move Shoot Move, but others exist, that will allow you to use your phones gyro to get a rough PA. Shooting wider will help with the trailing. It only needs to be somewhat close. using a color cam isn't doing you any favors either. if your guidescope is mono, it can likely handle shorter exposures better. Maybe increase the gain a bit too. GL
 

My newbie hat is on for this question, so pardon if there's an obvious solution I haven't found on my own; I promise I searched first

 

The situation:

I have an equatorial mount (on a tripod) that is semi-permanently located on my apartment roof.  Once it's set up and aligned, I will not be adjusting it's location very often if ever.  I don't have a permanent pier for it and can't necessarily install it.  Also lugging something cement up 4 flights of stairs sounds like an unfun task

 

During the summer (now), my city gets to around a Bortle 7.6+.  Depending on the Moon and other lights, seeing Polaris can be a bit of a struggle with the naked eye.

My only telescope (see below) is a 1000mm refractor with a 9.8f.

 

I'm having difficulty getting a polar alignment, which is kind of cascading problems...

• In order to be able to polar align via three-point plate solves (NINA), I need a minimum number of stars visible and roundish stars.
• In order to have a minimum number of stars visible I need longer exposures (due to high F ratio and light pollution), which requires a good polar alignment to not blur.

 

I tried it by hand with a polar scope but I wasn't able to manage it very well due to the difficulty in visually seeing Polaris.

I also tried with the guide camera instead (SV905c) through a 60mm guide scope but it really wasn't up to the challenge. Too much noise.  Works fine for guiding but can't get a plate solve in ASTAP off it.

 

My next idea is to slap my DSLR and 200mm/f5.6 lens on top of the mount and try to align with that.  The lower FL should make it less prone to alignment blur for initial setup, and I can pump the gain pretty high on it while wide open.  I haven't tried this yet, waiting for a clear night.

 

Am I on the right path?  Any alternative methods I'm missing?

[Tapio]

Nah I'll probably still run the check routine once a month or so; maybe before each session since metal will adjust a bit from the heat/cooling. But it shouldn't be massively off compared to how it is before the first run through

Thanks for the suggestions. I'm not familiar with Sharp-Caps method. How does it differ from NINAs?

Here's a short video:
https://youtube.com/...h?v=x7uLQi4x8Uo

[Alay]

Here's a short video:
https://youtube.com/...h?v=x7uLQi4x8Uo

Oh that's massively simpler than NINA's method.  I'm switching and trying that next clear night!

Luckily my main imaging camera is mono.  The guide camera (SV905c) is color and so is the DSLR, but either is fine.  I could always stick the mono onto the guide scope for the purpose of initial polar aligning it too I suppose.

[fewayne]

Oh that's massively simpler than NINA's method.  I'm switching and trying that next clear night!

IDGI. In NINA with the 3-pt polar alignment plugin, you click "go" and wind up with an adjustment display. If you're OK with all the defaults, it's one button click, it moves the mount for you, and you go straight to the alt/az adjustments.

 

No disrespect to SharpCap, which I love (and will continue paying for). But help a geezer out, here: How is it massively simpler?

[Domdron]

Does NINA support binning for PA? I use it for PA in Kstars. It brightens stars and reduces noise.

[Alex McConahay]

The best polar alignment you can get is an old-fashioned drift alignment.  It does take time, but it is reliable and as close as you can get to perfect. 

 

YOu align as well as you can (using polar scope, Polaris, plate solving, whatever). Then you point your scope to the celestial equator, right about at the meridian at a nice convenient styar. drifts up or down. Ignore any movement of the star east or west. If it drifts up you adjust the azimuth to the east. If that increases the rate of drift, change around, and adjust to the west. If the original east slows the drift, move it to the east again until the movement stops. (If the movement slows to the west instead, keep adjusting west until it stops.)   At some point, you may go too far east or west, and start drift in the other direction. At that point, just reverse your adjustment until you get the drift to stop. Now, point to the east or west, and focus on a star about 20 degrees above the horizon, and on the celestial equator. And you start adjusting altitude until the star does not drift. Now go back to equator/meridian, and adjust the azimuth again (the altitude adjustment affects the azimuth). Do it again in the east or west, and the meridian/equator until there is no movement. 

 

PHD2 has a built in process for this. 

 

There are better descriptions of the process (with or without PHD2) in various places.

 

Note that setting up on a roof has its own problems with hot rooftops in summer, building and wind vibrations, and so forth.  

 

Alex

[rj144]

Raise the gain for alignment and then lower it.

[Spaceman 56]

you need to list the mount your using.  

 

if you are using a Skywatcher Mount with a hand controller the solution is in your hands.

 

1. 3 star align.

2. Polar alignment routine from within the handset.

 

this will get you close enough once you master it.  

 

beyond this I suggest EKOS which is a free download and works wonderfully.  

[Alay]

you need to list the mount your using.  

Vixen GP with the EQStarPro upgrade kit.

 

Sharp Cap worked like a charm.  I get a great polar alignment in under a minute.  Well worth it.

[Phil Sherman]

The best polar alignment you can get is an old-fashioned drift alignment.  It does take time, but it is reliable and as close as you can get to perfect. 

 

YOu align as well as you can (using polar scope, Polaris, plate solving, whatever). Then you point your scope to the celestial equator, right about at the meridian at a nice convenient styar. drifts up or down. Ignore any movement of the star east or west. If it drifts up you adjust the azimuth to the east. If that increases the rate of drift, change around, and adjust to the west. If the original east slows the drift, move it to the east again until the movement stops. (If the movement slows to the west instead, keep adjusting west until it stops.)   At some point, you may go too far east or west, and start drift in the other direction. At that point, just reverse your adjustment until you get the drift to stop. Now, point to the east or west, and focus on a star about 20 degrees above the horizon, and on the celestial equator. And you start adjusting altitude until the star does not drift. Now go back to equator/meridian, and adjust the azimuth again (the altitude adjustment affects the azimuth). Do it again in the east or west, and the meridian/equator until there is no movement. 

 

PHD2 has a built in process for this. 

 

There are better descriptions of the process (with or without PHD2) in various places.

 

Note that setting up on a roof has its own problems with hot rooftops in summer, building and wind vibrations, and so forth.  

 

Alex

I do my drift alignment using my imaging camera. Individual measurements take just over a minute and easily show drift that's under half a pixel. When I did this regularly and remembered which way to move the mount when reading the images, it took me less than 10 minutes to get an almost perfect polar alignment. (My imaging is now done from a pier mounted rig at a very dark site.) These are my notes for doing this:

 

https://www.cloudyni...age/210432-darv

[dhaval]

If you have a guidescope, and are using PHD for guiding, there is a fantastic drift alignment tool in there. You will still need to be image a star with the scope pointed to the South and looking towards the meridian, but that should make it really easy to polar align. Takes some time, but once you master it, it is usually quick.

[dx_ron]

It's hard to imagine a justification for trying to steer beginners toward drift alignment, given how many other easy and perfectly adequate tools there are.

[Alex McConahay]

It's hard to imagine a justification for trying to steer beginners toward drift alignment, given how many other easy and perfectly adequate tools there are.

Yeah, drift alignment is not where I start, but I don't find a drift polar alignment all that difficult. IT takes more time, yes, and there are better solutions with software that can solve a plate and give you the information the polar alignment technique uses. I'll grant you that. 

 

However.

 

The special case we are talking about is------what if those other things do not work?

 

Then there is drift alignment----which will work without the plate solve. And that is what the original post was looking for.

 

Alex

[dhaval]

It's hard to imagine a justification for trying to steer beginners toward drift alignment, given how many other easy and perfectly adequate tools there are.

PHD2 drift alignment does not equal to manual drift alignment in terms of complexity. It is actually very easy and quick. PHD2 tells you exactly how much to move the RA or DEC, just like NINA's 3-point alignment.

[Spaceman 56]

It's hard to imagine a justification for trying to steer beginners toward drift alignment, given how many other easy and perfectly adequate tools there are.

I spent a couple of months learning Drift using the D.A.R.V method before I came across more modern solutions.

 

before Drift I used the Skywatcher Polar Alignment routine, thats available in the handset, which also worked to a point.

 

I think these two experiences gave me a better understand of what I was trying to achieve, because I was forced to think about it carefully for a few months.

 

I don't think Astrophotography is a race to achieve world class images, more that it is a journey towards world class images.

 

I therefore feel spending time learning things (along the journey) is just fine, and perhaps even beneficial in the long run.  

 

Spaceman 

[psienide]

Imaging from bortle 9 with setups at the same focal length as well as longer and slower. Never really had a problem and i'm having to re align often because i break down my setup. One key thing is if you're not seeing enough stars pointed at polaris, you can always slew to where there are more stars and do NINA TPPA from there. I actually always slew my telescope to point to the northeast quadrant of the sky and do TPPA from there. If the issue is not enough stars because you're using filters - raise the gain and/or exp time. I sometimes use exp times up to 15s for this - it's usually not a problem if you get the reticle close enough.