SGP

[Matzi]

Alright, I figured since I had a few questions about SGP, I might as well, collect them all in one topic about this only.

So I was out last night, and used SGP with my stock Nikon D5300, I only took one sub on different targets, under different exposure lenghts and ISO. But all pictures had two things in common. They were all Monocrome! And when I tried processing the frames just for the fun of see what I could stretch out from them, well the histrograms were all in the opposite direction that they should normally be, they were all to the right?

Also when navigating around I did the following: I used Sharpcap for Polar alignment, and reached Excellent alignment. Then I used CDC, and my PS4 Controller. I manually found Capella, and centered it, and synced it with CDC. Then the slewing worked great, and all targets I found was pretty much centered, more or less. But from what I read in SGP, you can Platesolve, does this mean that SGP can slew around and find the different targets on it's own? So I won't need to use CDC anymore?

[AngryDonkey]

6 minutes ago, Matzi said:

They were all Monocrome!

They look monochrome but have all the colour data. The bayer matrix on top of the camera sensor puts colour filters over individual pixels, usually in a square of four pixels e.g. Red, Green, Green and Blue. When you look at your captured image data closely you will see this pattern. The idea is that now you use other software to calculate each individual pixels colour value (RGB) from the surrounding pixels, that is called de-bayering. There are many program which can do this but unfortunately SGP is not one of them (on purpose apparently , it's an acquisition program and strictly speaking, although it might be nice to get a quick sneak preview, de-bayering I guess falls under post processing).

[Matzi]

1 minute ago, AngryDonkey said:

They look monochrome but have all the colour data. The bayer matrix on top of the camera sensor puts colour filters over individual pixels, usually in a square of four pixels e.g. Red, Green, Green and Blue. When you look at your captured image data closely you will see this pattern. The idea is that now you use other software to calculate each individual pixels colour value (RGB) from the surrounding pixels, that is called de-bayering. There are many program which can do this but unfortunately SGP is not one of them (on purpose apparently , it's an acquisition program and strictly speaking, although it might be nice to get a quick sneak preview, de-bayering I guess falls under post processing).

Can Photosop do this, or?

[AngryDonkey]

And yes you can use SGP for all telescope slewing as long as you have plate-solving setup and working. My normal workflow goes like this:

• Sync the telescope 'Home Position' so that the telescope roughly knows where it is
• Now you could already ask SGP to 'precision center' your target by clicking 'Center Now' but generally it's best not to plate solve around the pole region (where your scope will be pointing in the home position) so it's better to slew to a different region before continuing
• So you could slew directly to the target (accepting the fact that it won't be precise) by using the 'Slew Now' button and then continue with a 'Center Now' click which will plate solve and center the target (and also update your mount so that it knows where it is).
• I usually do an intermediate step by slewing to a region near declination 0 to carry out the PHD calibration (which should be carried out +-20 degrees from the equator). There is an additional docking module called 'Scope Centering' where you can also carry out a plate solve and mount update independent of the target. I use that before moving onto the real target. 

[AngryDonkey]

25 minutes ago, Matzi said:

Can Photosop do this, or?

Unfortunately I don't know, I would imaging it can (I'm sure someone can confirm). I think all dedicated astro processing software packages (PixInsight, AstroArt, MaximDL, APP etc.) will have it but none of them are free. I am not 100% sure but I believe IRIS is free and can do it for DSLR's otherwise if you manage to convert the files to the FITS format FitsWorks is also free.

[Matzi]

Thanks Mike!

But I got a few more in-depths question about your workflow. How do you sync it in SGP when your polar aligned? How do you slew it? Manually? If so, with a controller, using the ASCOM/EQMOD? When to slew to a target, how/where do you find your target in SGP?

Sorry for being a complete newbie, but these are questions that I feel I need to ask, to get a better understanding when out doing it.

[AngryDonkey]

11 minutes ago, Matzi said:

How do you sync it in SGP when your polar aligned?

In general it doesn't really matter where you slew from i.e. the handset, your mount software or SGP (there are slew controls in 'Control Panel -> Telescope' but they are a bit fiddly) because the telescope talks to SGP which should keep everything updated.

Firstly you need to make sure that you carry out an initial 'Sync Home Position' command whilst the mount is in the 'home' position i.e. pointing at the pole with counter weights down (on a conventional mount). This will give the mount a rough position to work with. It might be the case that EQ mod automatically does this when the mount starts so make sure that the scope is in the CWD on start but I'm sure you are doing that anyway ?

I personally do the first slew from my mount software or the handset for the reasons mentioned above (to calibrate PHD2), then I use the 'Scope Centering' docking module in that position and click 'Solve and Sync'. This will carry out one platesolve and update the mount on it's exact location (if you mount is able to build a model of multiple points then every subsequent plate solve in SGP will add another point to the model). Then (once I've finished everything I need to do here) I use the 'Center Now' button in the 'Target Settings' window (the one that pops up when you click the cog next to the target). This will then kick off the exact centering process and get me to my target.

As mentioned above if you want to go to the target straight away you could also:

• Polar Align
• Make sure the mount knows it is in the home position i.e. 'Sync Home Position' 
• Open the Target Settings in SGP and use the 'Slew Now' button to slew to the target (this will be off as the mount hasn't got an exact position yet)
• Open the Target Settings again and click 'Center Now'. This will now exactly center your target

I think this is the quickest way to get to the target. A word of caution though, if the target is near the meridian (and your camera close to the tripod or pier) I would build in an extra step to confirm that the mount definitely knows where it is to avoid any possibility of pier or tripod crashes. 

[Matzi]

Thank you

I found the center now, sync and blind sync. But I couldn't find anywhere to find a target

[Matzi]

Also I used to use Live View to focus my Nikon D5300, and align it with the guidescope/vice versa. But yesterday, I couldn't get the Live View screen up, I was doing Frame and Focus, clicked the Live View button, and yes the camera was connected. And pressed start. It started,  but no Live View appeared in SGP.

[AngryDonkey]

21 hours ago, Matzi said:

I found the center now, sync and blind sync. But I couldn't find anywhere to find a target

In SGP you need to create targets in the sequence window (Target List). It doesn't have a database so you need to enter RA and DEC (there is also and option to import from an online source). You can also use the framing and mosaic Wizard which is great to frame your shots. This will also automatically create the target for you.

By the way you should read through this tutorial, it's a great way to get up to speed with SGP and understand the general workflow:

http://alexastro.com/Alex Home Page/Articles/SGPFirstWeekv31.pdf

It's a fairly long pdf but well worth the time and really recommended!

[Matzi]

Thank you again Mike. I'll read it once I get home from work

[Matzi]

Hi Mike

I actually read and followed that. But I still remain with 3 questions.

1. I don't know what to type in arcseconds/minutes under camera setting. My scope is a SW80ED, tried googling it, but couldn't find anything

2. I can't seem to find the Live View screen, after my camera is connected, and I check the Live View in the Frame and Focus.

3. I downloaded the astrometry platesolve for SGP. But not sure how it works. Does it need to run somehow, or does it just work once installed?

[AngryDonkey]

Sorry for coming back to this late. Did you manage to sort out the above issues?

[Skipper Billy]

Have a read at this - it takes you from 'zero to hero' with SGP.

http://mainsequencesoftware.com/content/SGP-The First Week.pdf

It's not far from witchcraft once you get it set up properly !!