Re: Mach2 Unguided testing continues


Donald Rudny
 

I use Starlight Live.  I have PHD on my Mac also, so I could switch over to that for the calibration.  That would require going through the PHD calibration on a selected star for each object and maybe each calibration point.  It would be simpler to just use the keypad and the crosshairs by eye in the imaging program.  If the drift is significant in say, one or two minutes, I think it would be pretty accurate, especially at the longer focal lengths where I need it.  Like you wrote earlier, keep it simple and have more time for imaging fun.

Don

Don Rudny


On May 30, 2020, at 7:13 AM, uncarollo2 <chris1011@...> via groups.io <chris1011@...> wrote:


What program do you use to image? I use MaximDL which has both imaging and guide capability from the same chip. So for taking centering data I use the guide program, then for imaging I simply switch over to the imaging portion. I believe that PHD2 also has both capabilities. No separate guide camera needed, one camera does both data gathering during twilight and imaging after dusk.

Does that make sense or am I not explaining it well?

Rolando



-----Original Message-----
From: Donald Rudny <mkea13800@...>
To: main@ap-gto.groups.io
Sent: Sat, May 30, 2020 11:59 am
Subject: Re: [ap-gto] Mach2 Unguided testing continues

Hi Rolando,

Here is the link to the Pinpoint site.


There is a section on accuracy that suggests that it is very accurate.

I’m not trying to say that any system is better than any other.  I’m just trying to understand what is available and what options users may have.  Cost is important as well.  I believe Atrack is free, but Pinpoint runs about $150.  They have a 60 day trial period.  Some users out there with CP3’s might be interested in this, too.

I like your keypad method for what I do, which is usually a portable setup with my AP1100 and C11 Edge at  f/6 or f/2 with Hyperstar.  Sometimes I will do f/10.  It might not sound very portable, but I put everything in the back of my pickup and drive up to Maunakea to set up off the back of the truck.  It takes about 20 minutes.  It gets pretty cold, so we sit in the pickup and view the object images on an extended monitor.  I run the cables through the rear window.  When the VIS was open, we did something similar and put on shows for the visitors with the equipment there.  It was a big hit.  I use a Mac, so I was able to download our captured images to the visitors iPhones.  Some people stayed the whole night just to get all of them.  That’s when I first experienced your excellent mounts and keypad.  They had an AP1100 set up with an 11” RASA.  I didn’t purchase a keypad with my AP1100 because of the expense.  I decided to go with my iPad and SkySafari.  I have Luminos too.  Both work very well and are very inexpensive.  I did purchase APCC, but I find it lacking for the price.  No catalogue of objects.  No Mac version.  Not very intuitive.  About the only thing I use it for is to initialize the mount at my home observatory.  Then I switch to my iPad and SkySafari for control.

I really don’t like to set up the auto guiding stuff, so your keypad system interests me.  I think it would work best for what I need, but I would need to center the star by eye on my Mac computer screen with crosshairs.  How accurate will that be?  It will probably be more valuable for me running at f/6 or f/10 with the C11 than at f/2.  At f/2, I can already get a couple of minutes unguided just with using the RAPAS for PA.  It’s f/6 and especially f/10 that drift some.  

I do have the CP4, but I would need to invest another $900 for a keypad, so you see my dilemma.  I’m willing to invest, but I need to know that it will really work for me.

Thanks,

Don

Don Rudny


On May 29, 2020, at 7:38 PM, uncarollo2 <chris1011@...> via groups.io <chris1011@...> wrote:



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

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-----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


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