Thanks Chris you got the questions before I did. Besides I am still using sky6 which is a bit different from Skyx when it comes to Tpoint modelling.
Bert using Tpoint is a necessity anyway because you will want accurate pointing for the imaging you want to undertake. Using Tpoint now will get you down below 10" and is repeatable everytime. When I do an image now I can rely on landing at the same spot every time. That makes mosaics easy too.
If you use the description that Chris just told you your mount will be setup and ready within a couple of hours and that includes a 150 or so tpoint model.
Sorry if I got my/your wires crossed. I did not want to rely on setting up the mount with a pure imaging system.
My aim was to have the mount aligned before I put on the optic and camera etc for imaging. I am well aware that images solved by tpoint and plate solve etc will give a very good model for the sky.
I am of the old school that knows where every major object is and to get to it we do it manually.
My aim was always to approach this very carefully. I still find it disconcerting when the mount decides to do a meridional flip when the new object is very close but over an imaginary line.
I also wanted to have a full understanding of what was really happening and not just make do because it works or it is easy.
This will save me many frustrating errors down the track.
Once you have the polar alignment greatly satisfied, does your mount atl reading agree with your location site? eg.. 33.6 for Sydney. And sometime the SkyX will not slew to particular region with slew limits error. Is there a way to overcome the limit restriction? and if so will it cause any damage to the mount/scope?
regards
DAvid
The altitude of my mount is very close to the site latitude.
The slew limits are there for a reason so your OTA doesn't hit the pier or tripod.
If you look on page 109 of the user guide it shows you how to adjust the slew limits.
It might be a good idea to start another thread with all of your questions?
Even a Sticky, PMX Q&A
Don't make it harder than it has to be. There's really not much to it and it's not difficult either. The learning curve is short and sweet and then you'll either be an expert or think you are.
I am new in every aspect of astronomy. After spent many nights and tens of hours of drift alignment following often contracted instruction from webpages, I managed to have fairly still star on illuminated reticule over more than 10 mins at both North/equator star (for Azi) and West (for alt), from then I tried TPoints run, quite accurate on almost every slew....then the trouble, I followed the Tpoint recommendation to adjust the mount azi/alt (off over 100arcmins), back to SkyX...every star slew is far far off...My drift alignment and TPoint seemed fighting each other. Please help... I want to get this alignment business over and go on to do other more interesting things..
David
Hi David,
If you adjust the mount's Alt Az using the polar alignment directions from T-point then that model is no good anymore because things have changed.
You have to delete the model and do a new T-point model.
I'd have to read the manual on this point again as you may also be able to do a synch on a star to realign the model after adjustments with the Sky X.
After a bit of encouragement from Mike S. I had a go at assembling the image train.
The total distance from the back plate of the RH200 to the focal plane of the camera is 109.1mm. The Atlas focuser is fully retracted. The focal plane of the RH200 is 115mm from the back plate. So focus is within the range of the Atlas focuser which is 9mm.
Once the Altlas focuser is extended the three screws that hold the zero tilt adapter can be loosened and the orientation of the camera and filter wheel can then be reset.
Paul I will have the finder and 100ED as a guide scope either side of the RH200 so the whole lot can be easily balanced.
I opted for the ten position filter wheel since I have 3nm NB filters I will need a [NII] NB filter as well. The red continuum filter is another reason.
I certainly see why you wanted to include those filters. Large scale projects with multi banded images are very interesting and add flavour to any image. With any luck the finder will offset the weight, but I think you might have to put something on the front in the opposite position. Often getting balance can be difficult and the one thing that the SB mounts require is very good balance. You should not have the counter weights on the RA offset at all. Perfect balance is the goal. I don't think it will be a problem, just something to bear in mind if you cannot get DEC tio balance out perfectly.
Had a play with the mount last night for the first time without any cloud. It is stunningly stable. I thought my belt driven EQ6 was stable and had very little backlash the PMX is far better.
I did a quick drift align as it is something I am very familiar with. I then went to the home position and then slewed to a star and synchronised, the PMX went repeatedly to any position in the eastern sky. It was off in DEC in the western sky no doubt due to the geometry of the scope(s) not being exactly orthogonal to the EQ axis.
Paul the filter wheel can be easily oriented with the bulk vertical to the DEC axis. I do not see any problems.
Bert
My thinking is that at some point you will want to rotate the camera. Do you have a rotator between the filter wheel and camera. If so this will not present the problem I have suggested. However, if there is no rotator involved then when rotating to get the framing you want will result in the filter wheel being moved to another position and creating balance issues. This is because the camera and filter wheel tend to move as one and you rotate this assembly around the axis of the telescope.
Most often the rotator goes between the telescope and the filter wheel.
I hope that makes sense and you can see what I am talking about.
In any event you need that size filter wheel and you will either find it problematic or not. Just thinking ahead a little for you.
Paul I want to do mosaics so having the camera oriented in the DEC and thus RA is essential. The field of this setup is 3.5x3.5 degrees. Rotating to fit in an object of interest is not even on the plan.
The side by side I have is fully adjustable (all possible degrees of freedom) to get perfect static balance. It is also very rigid and orthogonal.
Just ordered the 50x50mm 3nm NII and 5nm red continuum filters. This is not an exercise for the faint hearted as just the filters have cost $7k Aus. Looks like it is baked beans for another few months.
My mind was becoming numb to ,the point of paralysis with the thought of everything I was trying to understand with both the hardware and software.
I have managed to polar align the PMX with T-point. Just like everything it is easy when you finally know how to do it. As usual clouds were trying to spoil things.
This morning I fired up the Atlas focuser and IT's ALIVE! I can now remove the Zero Tilt Adapter to finally assemble the image train in it's final orentation.
The adapter Luke Belleni made for me is now matte black inside to minimise scatter.
The NII and Continuum filters arrive on Tuesday as I just paid customs and GST on them.
Should see first light on about Thursday if the weather report is correct.
Excellent Bert, Tpoint did seem daunting the first time I used it too, but looking back now it seems relatively simple compaired to other automated sequencing. How did you go with your pointing in the end? I recall some of the other PMX owners got theirs down below 10" of arc for their pointing.
Paul I set up my finder and the 100ED (both fitted with GstarEX cameras) to point at exactly the same place in the sky. This way when a star is in the center of the field of the 100ED 24' X 18' it is also in the marked field center of the finder of field 22 X 17 degrees. This way I am sure what I star I am using to add to the calibration run.
I roughly aligned the polar axis by drift aligning. Then did a calibration run only on the Eastern sky.
Result is image one below.
I then adjusted the mount according to the numbers that Tpoint gave me for azimuth and elevation adjustment. Then I did another calibration run.
The result is image two below
The improvement is remarkable.
If only the clouds would go away I think I can do even better. It is difficult learning new methods when weather interrupts.
