Polar Alignment with no view of Polaris (or much else for that matter!)

[johnrt]

3 hours ago, kirkster501 said:

I think you have to accept that whilst you might want the trees felled John, many people do indeed like tress (PITA that they are in your case) and many would be upset to see them go - I can understand Network Rail to some extent. I think you need to forget that line of approach to the problem and find a solution that you are in control of.

G'day Steve, thank you for your thoughts,

I can totally understand Network Rail, they are a business like any other and aren't just going to roll out 5 trained tree surgeons every time someone has a grumble, they'd be out of business!

I do like those trees, and don't want to see them go completely - we see some fantastic wildlife - owls, green woodpecker and loads more in them. The trains also pass level with the back bedroom window, so wouldn't want them to be any lower than the top of the house, as they are a nice barrier. Just a reduction in height to the top of the roof of the house would do me nicely

I'm still experimenting with the other polar align options, but I have to say, without much success. Other options could be take up solar or planetary imaging instead?

[johnrt]

So I finally managed to get someone responsible for this type of thing on the phone after almost 2 months of trying, Network Rail estimate their costs (not including the cost of the contractor to actually carry out the work, who I need to employ myself) to be between £2-5k depending on exact circumstances.

I'm still at a loss as to how to polar align when I lose my view of polaris due to the restricted views of the sky from my back garden, so this looks like my last winter of astro imaging as I imagine the new growth in spring will block out polaris once and for all.

[Thalestris24]

29 minutes ago, johnrt said:

So I finally managed to get someone responsible for this type of thing on the phone after almost 2 months of trying, Network Rail estimate their costs (not including the cost of the contractor to actually carry out the work, who I need to employ myself) to be between £2-5k depending on exact circumstances.

I'm still at a loss as to how to polar align when I lose my view of polaris due to the restricted views of the sky from my back garden, so this looks like my last winter of astro imaging as I imagine the new growth in spring will block out polaris once and for all.

Hi John

I can't see Polaris either since I image from my living room! Here's what I do:

1) I point the mount to true north using a compass app

2) I drift align to the east (or west) at about Alt 25 deg using the PHD2 drift align tool

3) I adjust azimuth to minimise drift in RA

4) repeat 2 and 3 if necessary.

In my case I only image to the east (or west) so that any Az PA errors are much less significant anyway

I'm not sure what mount you have? Some mounts with hand controllers allow you to do PA without using Polaris.

Louise

ps I've repeated myself by the looks of it! Still, there's more than one way to do PA

[Sevo]

Here is one very easy way for dough drift alignment 

https://starizona.com/acb/basics/using_polar.aspx

 

[Sevo]

How about StarSense? 

[ajk]

Hi John

Perhaps this may help?

Regards,

--Andy

http://www.alignmaster.de/Download.aspx

 

 

[StuartJPP]

On 13/10/2016 at 20:32, ajk said:

Hi John

Perhaps this may help?

Regards,

--Andy

http://www.alignmaster.de/Download.aspx

I found that AlignMaster depends on your mount having very little backlash (it was impossible to use when I temporarily had the ZEQ25GT) and the star pairs it sometimes chooses are not ideal. It is worth a try though.

Each iteration of AlignMaster seemed to get worse or the results were at best random. It was better when I tried it on the M-Zero but I always try to image with a clear view of Polaris.

[johnrt]

On 14/10/2016 at 23:09, StuartJPP said:

I found that AlignMaster depends on your mount having very little backlash (it was impossible to use when I temporarily had the ZEQ25GT) and the star pairs it sometimes chooses are not ideal. It is worth a try though.

Each iteration of AlignMaster seemed to get worse or the results were at best random. It was better when I tried it on the M-Zero but I always try to image with a clear view of Polaris.

Hmm, that's not good to hear Stuart, Alignmaster was going to be my next option, my AZEQ6 does have some backlash especially in DEC.

 

On 11/10/2016 at 18:14, Sevo said:

Here is one very easy way for dough drift alignment 

https://starizona.com/acb/basics/using_polar.aspx

 

Alas I have no visible southern view to drift align.

On 11/10/2016 at 18:35, Sevo said:

How about StarSense? 

I believe these are AZ mounts not EQ.

[Thalestris24]

Hi John

Just wondering what you can see in terms of east, west, south east, south west, altitude etc? In principle you can polar align on a single star. Astrotortilla can calculate PA error based on platesolving and there's a little utility called Polefocus that helps in making corrections.

Louise

[johnrt]

29 minutes ago, Thalestris24 said:

Hi John

Just wondering what you can see in terms of east, west, south east, south west, altitude etc? In principle you can polar align on a single star. Astrotortilla can calculate PA error based on platesolving and there's a little utility called Polefocus that helps in making corrections.

Louise

View due east

 

view due west

[Thalestris24]

Hi again

Looks like you'd be ok to drift align east or west (DEC) and compass align to the north. If you're not actually imaging to the south then azimuth adjustment is less important.

Hth

Louise

[johnrt]

1 hour ago, Thalestris24 said:

Hi again

Looks like you'd be ok to drift align east or west (DEC) and compass align to the north. If you're not actually imaging to the south then azimuth adjustment is less important.

Hth

Louise

I'm not sure that would be good enough Louise, I image at just under 1 meter focal length and under 1 arc"/pixel, in my experience my PA needs to be pretty good at that resolution & focal length.

[Davey-T]

I tried Alignmaster and it wasn't much help, used to need to be a contortionist to see some of the chosen stars.

Are you permanently setup John or do you need to PA every time ?

There must be a way to plate solve any where in the sky and compute the error and adjust the mount which is what my 10Micron does.

How have you been managing so far as you have posted some excellent images ?

Dave

 

[johnrt]

10 minutes ago, Davey-T said:

I tried Alignmaster and it wasn't much help, used to need to be a contortionist to see some of the chosen stars.

Are you permanently setup John or do you need to PA every time ?

There must be a way to plate solve any where in the sky and compute the error and adjust the mount which is what my 10Micron does.

How have you been managing so far as you have posted some excellent images ?

Dave

 

Thank you Dave! There is a list earlier on where it was suggested you can add your own pairs of stars to alignmaster for those of us with restricted views of the sky. 

At the moment my mount is just tripod mounted in the back garden, I can still see Polaris just through the trees and I align via the polar scope in my AZEQ6. I'm very close to losing my the view of Polaris due to the trees. 

[Davey-T]

1 minute ago, johnrt said:

Thank you Dave! There is a PST earlier on where it was suggested you can add your own pairs of stars to alignmaster for those of us with restricted views of the sky. 

At the moment my mount is just tripod mounted in the back garden, I can still see Polaris just through the trees and I align via the polar scope in my AZEQ6. I'm very close to loss my the view of Polaris due to the trees. 

Are they evergreens ? look like Sycamores or Oak maybe in you picture, if you get a winter view you could set up a permanent pier in the garden and leave the mount on it which is what I've done anyway to save time setting up.

Dave

[ajk]

On 10/16/2016 at 19:36, johnrt said:

Hmm, that's not good to hear Stuart, Alignmaster was going to be my next option, my AZEQ6 does have some backlash especially in DEC.

Hmm indeed, my AZEQ6 also has backlash in DEC.

I am lucky enough to use a Polemaster as the trees to my north are still low enough for the Polaris view (and should stay that way as they seem to have maxed out).

I saw the other two photos you posted, you really are hemmed in there @johnrt

The Alignmaster was just a suggestion, I haven't actually tried it but seem like the only computerised alternative to a Polemaster which could have helped. It's a shame others have noted it has issues.

[StuartJPP]

I'd still give AlignMaster a go. Don't believe everything you read on the internet (including from me).

I just didn't have much luck with it, maybe I did something wrong? For the cost of the trial period (free) it is worth checking out for yourself.

 

 

[iapa]

On 06/09/2016 at 16:03, johnrt said:

Indeed, but they are on Network Rail land, above a railway line, I really don't want to break the law, kill myself or a train full of people.

are there no laws in England covering loss of skylight/light by trees?

An email to the rail company may yield results.... probably not, but nothings worth not trying where imaging is concerned.

[johnrt]

1 hour ago, iapa said:

are there no laws in England covering loss of skylight/light by trees?

An email to the rail company may yield results.... probably not, but nothings worth not trying where imaging is concerned.

I'm afraid not. Under U.K. Law they are under no obligation to cut back the trees so long as they do not overhang my property boundary, which they do not. There is no right to light law in the U.K. 

I have asked them several times to reduce the height, and network rail have refused. 

[Davey-T]

Just come across this, don't know if it helps, looks very fiddly.

Dave

http://www.oarval.org/PolAlign.htm

[johnrt]

13 minutes ago, Davey-T said:

Just come across this, don't know if it helps, looks very fiddly.

Dave

http://www.oarval.org/PolAlign.htm

I read through that and found the whole thing a little befuddling.

[Davey-T]

2 hours ago, johnrt said:

I read through that and found the whole thing a little befuddling.

Me too 

Dave