Re: Mach2 Unguided testing continues


Roland Christen
 


How accurate is centering a star by eye.
I actually do it automatically in MaximDL. I switch the main camera over to guide mode, let the guider program pick whatever star it wants in the image and let it autoguide. At the end of 3  - 5 minutes I press the Enter button on the keypad and let the program advance to the next calibration point. I don't do the centering manually, i let MaximDL do that. When I have gathered enough points I switch the camera back over to imaging and take my exposures.

I can see where Atrack can adjust the guide rates after each image, however that means that there is drift in the image that is being measured. I'm not 100% convinced that plate solve can determine the position to an accuracy level of sub-arc seconds, so i did not pursue this method. Besides, if you're going to use fancy software for this, then I would simply use APCC Pro and make an all-sky model, and be done with it. My program is for portable setups where the user has a mount, scope and keypad, maybe a laptop and maybe just a digital camera. No fancy software, just the basics to have some imaging fun.

Rolando


-----Original Message-----
From: Donald Rudny <mkea13800@...>
To: main@ap-gto.groups.io
Sent: Sat, May 30, 2020 12:12 am
Subject: Re: [ap-gto] Mach2 Unguided testing continues

Rolando,

I haven’t used Atrack, but have been reviewing the manual and I believe the program continuously adjusts the drift rate as you capture images.  They are saved in a file that is watched by the program and plate solved through Pinpoint.  I believe there is also a modeling routine that I assume can be saved as long as the setup remains the same.  As I say, I’m not 100% sure of this, but it looks like it’s worth taking a look at.  

One question I have on the AP keypad system is accuracy.  How accurate is centering a star by eye.  I would think that a longer time between inputs would be necessary to improve accuracy.  If I have a fairly decent PA, I would think I might need a 10-15 minute drift measurement.  A longer focal length would also help.

Don

Don Rudny


On May 29, 2020, at 6:15 PM, uncarollo2 <chris1011@...> via groups.io <chris1011@...> wrote:


Basically you get one data point in about 200 seconds (3 - 4 minutes) which sets the drift rate at that point int he sky. So that will work for a while, maybe 1/2 hour to an hour, after which the drift will have changed. So then you take another 3-4 minute run to establish a new drift rate. You do that every hour or so along the path that the object takes.

That's exactly what I'm doing also. 3 - 5 minute drift measurement which is good for an hour. However, if I take just 3 drift measurements along the path, spread out over a 5 - 6 hour period, the CP5 will then compute a continuously variable tracking rate for all points in between for the entire 6 hour period. I can do this measurement all at once before the sun goes down using 3 widely spaced stars of Mag4 or brighter and an H-a filter.  Takes about 15 minutes total. This path is then computed and ready to go when twilight ends. I can even do another object path at a different Dec, download it and be ready to image two objects. In fact, if the two Dec lines are widely spaced, I can image all objects in between also unguided because the model computes the variable tracking rates for the entire sky area as well as +- 10 degrees outside those two Dec lines.

Below see the tracking graphs for the imaging that I am doing tonight. They show how the tracking rates vary over approx 45 minutes.

Rolando

<dummyfile.0.part>



-----Original Message-----
From: Steven Steven <steven447@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Fri, May 29, 2020 9:52 pm
Subject: Re: [ap-gto] Mach2 Unguided testing continues

That comment has to do with a long-time on-line chess game, not for you/forum. Sorry, it's wrong context, I've a busy day on email today.

In reply to your own query, you set up each object separately. I use the Autosave feature on Maxim and when finished with one object, move to it, train ATrack, an make the second one. It's that simple. The User Guide is a good start and will answer your queries without reference to chess moves. 😉 

S


Join main@ap-gto.groups.io to automatically receive all group messages.