Moon slowly drifts out of view ??? MESU

[kirkster501]

Hi all, on DSO imaging my mount can keep thje subject bang in middle of the FOV for hours on end.

Why is it that when I am doing lunar imaging (and visual), The Moon steadily drifts out of the FoV view????  I use Sharpcap and set it to Lunar mode (the little cresent symbol).  It still drifts out though.  My mount is polar aligned perfectly.  The only thing I can think off is that I am not guiding whereas I would be in DSO work.

Any thoughts please??  I see no option in Sitech to set the mount to Lunar mode...

Thankyou in advance.

Edited January 24, 2021 by kirkster501

[Swoop1]

Do you have a separate controller for the mount or is all control via you software?

If a separate controller, try selecting lunar rate on that as well?

[Nik271]

I would guess that because the Moon orbit is not perfectly circular its angular speed varies a little over the month, so over longer exposures there may be some error with the Lunar tracking speed set in the mount.

[kirkster501]

9 minutes ago, Swoop1 said:

Do you have a separate controller for the mount or is all control via you software?

If a separate controller, try selecting lunar rate on that as well?

Thanks.  I do it all via software.  Yes that's a thought to try and use the handset too.

Reason this is important is that I am doing LRGB lunar imaging in high resolution (relatively).  It is a pain to keep re-entering after the object slowly drifts away.

[Swoop1]

May not work but, technology being the wonder that it is, the left hand (software) may not be telling the right hand <controller) what it is doing!

[The Lazy Astronomer]

I had a similar problem when I tried some high resolution moon imaging a few months ago (15 panel mosaic). Gave up trying to figure it out and just used st4 guiding in the end - problem solved!

[tooth_dr]

29 minutes ago, kirkster501 said:

Thanks.  I do it all via software.  Yes that's a thought to try and use the handset too.

Reason this is important is that I am doing LRGB lunar imaging in high resolution (relatively).  It is a pain to keep re-entering after the object slowly drifts away.

Open up Skyview in Sitech control box and click on the moon on the sky map, there it gives you the option to ‘track object’ and thus will do it at lunar rate rather than sidereal 

[PhotoGav]

Exactly how are you setting the mount to Lunar Rate Tracking?

I have a Mesu 200 and to change the rate setting I have to run a vbs script. You don’t describe doing that anywhere. It very much sounds like you have not really set the mount to Lunar Rate...

[Laurin Dave]

I've wondered about this too... just Googled it and Don W says both @PhotoGav and @tooth_dr suggestions work but that the 'track object' in Skyview only works for Moon Sun and a couple of planets (doesn't say which ones)

Dave

[kirkster501]

Thanks for the suggestions, I will look into that Skyview option, I've not thought of looking there.

I am getting more and more into lunar imaging in LRGB or HaRGB, the skies being what they are lately in the UK.  Almost every time the sky is clear The Moon is beating down so I might as well embrace that fact and work with it.  

[PhotoGav]

The vbs route is very simple. You will find a folder of standard vbs scripts in a folder here: C:ProgramData/SiTech/SiTechExe/VBSScripts (see screenshot). You just double click the script you want to run, e.g. LunarRate.vbs and it will change the parameter. A dialog box appears telling you what the current setting is and you just click OK. Don’t forget to run SiderealRate.vbs to put it back to sidereal rate when required!

Hope that sorts the issue out for you.

 

[kirkster501]

Thanks Dave. So you return to sidereal rate when you've done by just clicking on that script then?

[PhotoGav]

1 hour ago, kirkster501 said:

Thanks Dave. So you return to sidereal rate when you've done by just clicking on that script then?

Exactly, double click the vbs file for the rate that you want to set. Give it a go!

[steppenwolf]

6 hours ago, PhotoGav said:

I have a Mesu 200 and to change the rate setting I have to run a vbs script. You don’t describe doing that anywhere. It very much sounds like you have not really set the mount to Lunar Rate...

This is how I do lunar tracking on my Mesu 200 too.

[kirkster501]

Thankyou guys!  Will try that next time I am doing my moon stuff.

[kirkster501]

Problem sorted!  Thanks guys!