MEII – IMT3b Observatory

Viewing Report 2nd June 2020 – IMT3

20:28 – 00:30

After a day of checking the mount and spending some 3 hours resetting the RA and DEC cam stop and spring plungers I have come out to see if I have resolved the image or made it worse. I can still hear the squeaking of the cables in the Through the mount position as the worm turns so I do need to remove 1 or 2 of them to free it up. However I no longer hear the knocking, tapping and grinding of the Dec axis. I am also going to capture some PEC data for Tom on the Software Bisque forum to look at. GingerGeek with his usual smoking jacket turned up to assist from a distance.

Whilst trying to find a star we came across a galaxy, NGC 5646 H126-1, which looked very interesting for the 12″, so we will come back and image that at a later date. We are in a rush for the clouds as it is to cloud over by 11:30pm. What we need to do is disable PEC, disable TPoint and Protrack and the guider relays then point at a star and guide without applying any corrections as per page 147 of the MEII manual for 15 minutes.

I went out to the dome and set with the help of GingerGeek the camera on the back of the 12″ to as close to 0 degrees as possible, in our case 0.81 degrees after plate solving.

We slewed to a start neat declination 0 and close to the Meridian on the East side of the mount called Tycho 326:747 and at 22:37 started to look at the auto-guider settings. The star was at DEC +01° 34′ 10.909″ and RA 14h 45m 20.1920. The auto-guider log in question for tonight was “Autoguider.018.log”. The star looked good in the main ZWO ASI1600mm camera which we would use to guide and collect the data. We did notice as per the image below over 15 minutes the star drifting East, so the polar alignment is out. More importantly we got the 15 minutes of data in the log as the clouds started to roll in, as can be seen in the star brightness below.

The resulting log file was read into the Sky’s PEC and the raw data shown below one we clicked ‘Fit’ on the data which scales it to this chart. The peak to peak was 0.7 arcsecs. We applied this to the mount –

Next whilst GingerGeek went off to get his beauty sleep…..he really needs it 🙂 I set about slewing to a bright star in the vicinity and calibrating the guider, since I had rotated the camera. The calibration was successful even though the RA looked slights odd as a fit. The different in the RA and Dec rate was potentially due to position on the sky and the error in the RA plotting data. I will go back and do another calibration next time it is clear.

I then slewed to M92, could not find a guide star very suitable so moved around a bit and then started to guide and see what the graph looked like. What surprised me was the the amplitude of the guiding was only 0.36 arcsecs which is really low and no guiding issues as I saw before. It looks like the adjustments to the spring plungers and cam stops may have been the cause and fix.

Guiding graph at +74 deg altitude and near M92

I performed a quick focus run whilst pausing the guiding and got 61836 and HFR 4.4 which is vert good for this scope.

Meanwhile the clouds from the North had started to drift in which was going to stop play 🙁

I managed to get a single frame and focus on M92 of 20s before the clouds stopped the guiding. So I shut up the dome, sent the logs to Software Bisque, or the chap on the forum who was kind enough to help and went off to bed.

Viewing Report 1st June 2020 – IMT3

20:25 – 00:15

Dome once again open to cool down

Solved FoV for Lodestar guider on 12″

Now guiding on star to West side of mount around 0 degrees Dec and near the Meridian to see if problem reoccurs, graph looks ok but there is a slight regular pattern of error.

Slewed to M92 which is a glob currently at Alt +74, Dec 43 and on the East side of the mount where I had issues last night. I plate solved the image.

The auto focus run looked good

Found guide star by moving M92 slightly off centre. Now guiding. All looked good for a short while. So each section of PHD2 graph is 25 points, so when you have 100 points selected there are 4 sections of the graph. This mean each section/column represents own my case 250 seconds as I expose for 10 seconds, so just over 4 minutes per section. So the errors I saw last night were about 12mins apart. This cannot be the work gear as it has a cycle of 2min 29sec. This is from the latest Paramount manual for the MEII.

Tracking at the sidereal rate, one revolution of the worm takes 149.6 seconds (2 minutes 29 seconds).
The right ascension gear has 576 teeth.
The declination gear has 475 teeth.

The error I am seeing is about 4mins. I cannot continue imaging as every few frames are trailed.

Viewing Report 3rd March 2020 – Travel Scope

Viewing time period – 19:37 – 22:35

Back out again tonight for a short period to look at guiding again. So with everything setup and a longer USB 2 cable in use I am now sitting in the warm Orangery. I will try again with the PHD2 software to guide and EzCap to acquire images from the QHY168C. I have set the Gain to 7 and Offset to 30 as previously used on my other QHY168C when used in Tenerife.

I polar aligned using PoleMaster. Then set about syncing the scope with Betelgeuse. It was only off slightly. The sync worked fine tonight. I then slewed to M35 and started the PHD2 guider software, selected a guide star and calibrated the guider. This worked well first time proving my new step size of 4 using a small ms time for the pulse worked.

Then I started guiding and very quickly realised the same problem as yesterday with DEC drift upwards. No amount of fiddling with the setting such as Hysteresis or Aggressiveness changes the constant upwards drift. I then remembered that I could calibrate the settings as the other night under Guider Assistant. I ran this made the changes but still the upward drift.

I then remembered that on the Paramount MEII in the dome I had to drift align with PHD2 to get it properly polar aligned and that PoleMaster was only good enough for short exposures or rough guiding. So I set about drift aligning.

The first thing to note is that the polar alignment was out by a fair bit to get the accuracy I require in both azimuth and altitude. I have now adjusted both and the graph seems a lot smoother.

So in all it took me around 1 hour to drift align and just as I was about to test the clouds rolled in!

DirectGuide and the Paramount ME II

So I used to be able to guide on the Paramount ME without the need for an ST-4 guider cable. This is achieved through information being shared about the position of the star to PHD2 and it then sending commands to the relays on the Paramount ME, however I had yet to be able to get this working with the Paramount ME II and using SGPro as the host program.

So for a short period on the evening of 5^th August 2019 I ventured out to complete the setup and get the guider working.

As information is key I had spent time re-reading pieces of the Paramount User Manual, The Sky X Manual and the PHD2 Manual, the later having partial information needed to setup, another piece of information was in The Sky X Manual.

So what did I do? Well DirectGuide is a bit like Pulse guiding that is supported on other mounts, however for the Paramount ME II pulse guiding is NOT supported. So you need to configure and setup for Direct Guide, but where?

Looking at the Connect Equipment window in PHD2 you are presented with 3 options, How to connect the camera, how to connect the mount and a 3rd option around how to connect an Aux mount. It is important to understand when to use that 3rd option around Aux mount as that is what can cause confusion when trying to get Direct Guiding to work.

Aux Mount should only be chosen if you are using an ST-4 cable, if you are not then this option should remain set to None. If you inadvertently select ASCOM Telescope Driver for The Sky within this box the mount will not behave correctly. So leave it set to None!

Camera needs to be set for the camera of choice, for me my trusty Starlight Xpress Lodestar is selected. For the Mount I selected ASCOM Telescope Driver for The Sky. Next you need to configure the Mount by clicking on the spanner and screwdriver icon next to the option.

Under here you can configure The Sky Controller Driver Setup, selecting The Sky version, X Pro for me and various options for the mount itself. The key checkbox is Use DirectGuide. This menu of options is from the ASCOM Chooser and you should select any settings you wish to enable. Mine can be seen below.

ASCOM Chooser for Mount and DirectGuide setting

I quickly configured the Camera also and below are the settings that work well.

On connecting to both the camera and mount, selecting a guide star and calibrating the guider it is apparent that I have configured the setup correctly. All is now well with the guiding and it produces a smooth chart with tonights seeing as can be seen after several dips produced by cloud at the begging of the guider graph.