Help - how to use platesolving to control CG5

[Robrj]

On 12/10/2017 at 01:06, RobertI said:

Thanks Rob, I think I was being confused the way NexRemote works - once you use the hand controller to align, you should't use the NexRemote software, and vice versa. But it sounds like with CdC/astrotortilla/Ascom setup you can align with the handcontroller and then use CdC & AT. I will give this another go next time, thanks. ?

I think with Nexremote, if you do the alignment, it's the same as doing it with the hand controller.  I've not used it as it's not compatible with Starsense.

[Robrj]

On 12/10/2017 at 03:59, Thalestris24 said:

Hi Rob

Using Astrotortilla there's no real need to star align. However, having good balance and good PA is important regardless. Then you should naturally be quite close to star alignment and AT will centre your target. I know you have a small fov and that might make things a bit more challenging...

Louise

Don't you need to do an alignment to get CdC or Stellarium to work with the mount?

[Thalestris24]

12 minutes ago, Robrj said:

Don't you need to do an alignment to get CdC or Stellarium to work with the mount?

With my AVX I just do a 'quick align' when I power up. I think it computes an alignment simply based on the time. My AVX is semi-permanently set up but not star aligned in the mechanical sense but isn't a *million miles out. Astrotortilla gets me centred on target quickly.

Louise

*in absolute terms it's probably a few light years out hee hee.

[RobertI]

Thanks for the responses again everyone. Ok so I think I would need to do a quick align (scope set up at index marks and pointing to celestial north pole) as doing a full align is the very thing I am trying to avoid ( ) partly because it has not always been reliable, probably due to user error, partly because it is just such a pain, and partly because the ideal spot for observing in my garden means I only see half the sky which does not help alignment. Having said that, last time out I did a five star alignment (I was in place where I could see the whole sky, but was not my preferred spot) and the gotos got the image near the centre of the chip each time. 

Anyways, next time out I shall try the quick align, CdC slew to object, Astrotortilla platesolve route and see how it goes. Watch this space . 

[Thalestris24]

37 minutes ago, RobertI said:

Thanks for the responses again everyone. Ok so I think I would need to do a quick align (scope set up at index marks and pointing to celestial north pole) as doing a full align is the very thing I am trying to avoid ( ) partly because it has not always been reliable, probably due to user error, partly because it is just such a pain, and partly because the ideal spot for observing in my garden means I only see half the sky which does not help alignment. Having said that, last time out I did a five star alignment (I was in place where I could see the whole sky, but was not my preferred spot) and the gotos got the image near the centre of the chip each time. 

Anyways, next time out I shall try the quick align, CdC slew to object, Astrotortilla platesolve route and see how it goes. Watch this space . 

Hi good luck! Remember that platesolving depends on having a decent number of stars for the software to detect a unique pattern. With a small fov you probably need to check the number of stars detected and maybe vary your exposure and sigma value to suit. You might possibly have to slew the scope to somewhere nearby where there are more stars (I'm just guessing that you might have to!). That shouldn't be a problem. If you can solve and sync in a nearby part of the sky, you should be ok to then just slew to your target without having to platesolve your actual target. Hope that doesn't sound complicated!

Louise

[spillage]

On 12/11/2017 at 23:41, RobertI said:

Thanks for the responses again everyone. Ok so I think I would need to do a quick align (scope set up at index marks and pointing to celestial north pole) as doing a full align is the very thing I am trying to avoid ( ) partly because it has not always been reliable, probably due to user error, partly because it is just such a pain, and partly because the ideal spot for observing in my garden means I only see half the sky which does not help alignment. Having said that, last time out I did a five star alignment (I was in place where I could see the whole sky, but was not my preferred spot) and the gotos got the image near the centre of the chip each time. 

Anyways, next time out I shall try the quick align, CdC slew to object, Astrotortilla platesolve route and see how it goes. Watch this space . 

I would not bother with alignment as this is done in the platesolve. 

I would suggest checking PA though.

With my gear I use APT, I choose my target and the mount is moved near to it and then APT takes a series of single shots to check position and makes adjustments as needed. I can then update my mount with this position.

You should be able to make a platesolve from the home position and then update these co-ordinates.

If you can save a single image you can reuse this for platesolving.

Not sure if any of this is of any help.

[Robrj]

On 12/1/2017 at 11:33, Robrj said:

So I assume your scope is f/9.  With a .63 reducer, I get the following:

Scale Minimum is 0.3

Scale Maximum is 0.5

Indexes should include 4200 - 4206

My Custom Options line would look like this:

--sigma 70 --noplots -N none -H 0.5 -L 0.3 -r -objs 100

 

At 0.33x, I get:

Scale Minimum is 0.6

Scale Maximum is 0.8

Indexes would include 4202 to 4208

Custom Options:

--sigma 70 --noplots -N none -H 0.8 -L 0.6 -r --objs 100

 

To calculate what focal ratio you're at, you can get the arcsec/pixel from Astrometry.net and plug your info into the 5th calculator down:

http://www.wilmslowastro.com/software/formulae.htm

I noticed an error with my Custom Options line:  the noplots flag should be no-plots.  

--sigma 70 --no-plots -N none -H 0.8 -L 0.6 -r --objs 100