SynScan - Looking for a cross-reference of 1. to 3. level alignment stars

[casati]

Always a moment of despair when you try to do at least a two-star alignment from locations with limited sky view eg. from a balcony, out of a window etc.

It would certainly help if you know the content of the 2. alignment star list once you decide on the 1. alignment star - even more if you plan for a 3-star alignment.

Especially if you need at least a 2-star alignment to do a polar alignment with SynScan afterwards, because you have no sight to Polaris as well.

Why a cross-reference? The 2-star list depends on the first star choosen.

Has somebody already investigated this issue? Does a cross-reference exist?

TIA & Best,

Peter

[Gfamily]

If you download the SynScan App, you can go into emulation mode and see what is offered for first and second stars for the different alignment options. 

I don't know if it works in the same way on the handset, but I would hope its very similar. 

Certainly, using the app makes it much quicker to go through the options than using the handset. 

[Seelive]

I select the 2 (or 3) stars in advance of a night-time session. I power up the mount (polar alignment is irrelevant) and set the time and date to the time when I expect the mount will actually be aligned. Then I select the first alignment star from the provided list that I know will be visible at the expected set-up time, let the mount slew to where it thinks it is and just except it (as thought the star was perfectly centred in the eyepiece). Then I choose the 2nd star from new list provided that I also know will be visible. If I can't find a second visible star from those offered, I just restart the alignment process choosing a different visible 1st star until I get 2 (or 3) stars that I know will all be visible.

If the visible sky is extremely limited it can take several (hence time consuming) iterations but at least it is done during the day and when you set-up for your night-time session, you already know which stars to select.

[Zermelo]

I'm not aware of any analysis that says "if you chose this star first, then this is the list of second star choices". It would take some compiling (and if extended to three stars, impractically so).  In the app (which I have), and presumably also the handset, each subsequent star is given a "quality rating" out of 5, which I assume is just the result of the software applying Synscan's general rules for how to pick alignment stars (as detailed in the app manual) to the star(s) already selected.  Though I think the list is ordered by magnitude rather than quality, so sometimes you have to scroll down to find "better" stars.

As mentioned above, you can use the app (with a timeshift, by changing your phone's current time) to run an alignment in advance. Some people have also compiled guides to locate the Synscan stars.

[casati]

It is because of this time consuming process mentioned in the two post above (which by the way deletes the existent hibernation data!) that I've posted my question.

 

[Seelive]

43 minutes ago, casati said:

... which by the way deletes the existent hibrernation data ...

 

 

If you park the mount at the end of a session and it remains un-moved between sessions you shouldn't need to re-do the mount star alignment as any existing alignment 'parameters' will still be valid, but if you do move the mount between sessions then any 'saved' mount alignment data will become invalid so it will need to be 'recalibrated'.

[casati]

There seems to be a solution for an otherwise potentially uncompleted alignment, when a 2nd alignment star couldn't be located during 2-star alignment - using a second app eg. SkySafari for alignment.

According to an answer of Skywatcher Support to a question of another German user the "Align with Sync" could be used for this purpose:

Quote

The app can accept Sync command from 3rd Party Software. Depending on whether the Align with Sync page is open when Sync command received, the Sync data is used in one of two ways:
If the page is not open, Sync is used to improve accuracy in a small region around the sync target. If the page is open, Sync is used to perform the alignment.

http://www.astrotreff.de/topic.asp?TOPIC_ID=247020

Best,
Peter

Edited March 14, 2021 by casati