synscan align: can I choose my own star?

[alacant]

synscan 3.37

Is it possible to align on a star of my choice? Often I can't do a 3 star align since my view west is blocked.

TIA

[Tinker1947]

Just do  2 Star align and you can choose stars from a scolling list, helps you identify them as well...

[groberts]

Hmm I'll be interested to hear what the answer is - I have had the same problem in the past.  I believe you might be able to expand your choices by downloading an additional file of stars?     

[wimvb]

See p 26 of the synscan manual: Setup | Alignment Stars | Adv. Filter

If you have limited visibility, you can turn the star filter off.

If you go for 2 star alignment, you have to make sure that cone error can be neglected, i.e. the scope is pointing in the same direction as the mount. Usually this is not much of a problem, and it is a simple adjustment you can do anytime.

This may be of help (alignment nr 5)

https://stargazerslounge.com/topic/252404-eq-setup-some-pointers/#comment-2751296

 

[Cornelius Varley]

The chosen alignment stars need to be on the list.  Or just do a two star alignment on stars that are visible to you.

[hobsey]

I maybe wrong here but I think it's only the Celestron Nexstar system you can choose your own stars to align to.

[Cornelius Varley]

1 hour ago, hobsey said:

I maybe wrong here but I think it's only the Celestron Nexstar system you can choose your own stars to align to.

 

You are not wrong.

[alacant]

Is it correct to say that if I'm correctly polar aligned and home positioned, I shouldn't need to align?

[Tinker1947]

If you park it in the home position every time and power off, provided the mount is not moved you could on start up choose a Star and let it slew to it once its stopped slewing undo the clutches and manually align (if it needs it) this will put the mount where it thinks its pointing, this would save doing a 2 or 3 star alignment, this will work only if the mount is not moved (packed away).

[Owmuchonomy]

There is always a good selection of stars to choose from on Synscan 3.37.  If you scroll down the list and none are appropriate keep going. My list changes to incorporate less well known stars but increases the choice.  I would be surprised if at least 2 of them are not visible from your vantage point.

[bruno]

I only do a one star align most times, I get my polar alignment using polar finder & my polar scope then i align with one of the stars on the syn scan, then i send the mount back to home position to see if the lines i have marked on my mount line up if they do i select & slew to my object.

hope this helps

[Cornelius Varley]

12 hours ago, alacant said:

Is it correct to say that if I'm correctly polar aligned and home positioned, I shouldn't need to align?

Unless the mount has been parked from a previous session and has not been moved it will still need to be star aligned. The "home" position is the starting point for the star alignment routine. The handset needs to know a base point from where it can calculate the location of the the first star, after the first star the subsequent stars are located from the first point. If the mount is not aligned first any goto commands will be inaccurate. The star alignment routine can be skipped and the mount used as an ordinary driven mount but will not function as a goto mount in this configuration.

[alacant]

Thanks for the replies everyone.

Even after checking polar alignment with the polarscpe and hour angle and bubble level home position, I often find that the first star is off target -not in the fov of a st80- I have to slew say a full-moon's maybe two worth to get there. After that, the second star is much nearer the crosshairs than the first. I know the polar alignment is pretty good as I'm getting 30s unguided snaps on a 760mm f5. Time, daylight saving and logitude are all good. Dunno. 

[Owmuchonomy]

18 hours ago, alacant said:

Thanks for the replies everyone.

Even after checking polar alignment with the polarscpe and hour angle and bubble level home position, I often find that the first star is off target -not in the fov of a st80- I have to slew say a full-moon's maybe two worth to get there. After that, the second star is much nearer the crosshairs than the first. I know the polar alignment is pretty good as I'm getting 30s unguided snaps on a 760mm f5. Time, daylight saving and logitude are all good. Dunno. 

Polar alignment is the process for aligning your mount with the Earth's axis. The scope GoTo alignment is for aligning your scope with the the night sky based on your local position. They are not the same thing.

[alacant]

Hi, thanks. Let's say I have good polar alignment and the mount placed in the home position with time, longitude, latitude, altitude, daylight saving (from today) and time zone set correctly. I don't suppose it matters but why is the first star often not in the fov whilst the second always is?

Cheers and TIA.

 

 

[kendg]

I think you have found another great question.  Mine does the same thing all the time. First star way off next star (s) bang on.

Doesn't matter much. I use eqmod and Astrotorilla now. Got that tip here. But then again you need to be doing imaging.