Date   

Re: Problems using ASI air pro and AP mounts

Worsel
 

Kenneth

One advantage to using PHD2 proper versus the PHD version built into the ASIAIR is that you can post your Guide and Debug logs on the PHD2 forum

https://groups.google.com/g/open-phd-guiding

See How to ask for help with PHD2

The PHD2 forum cannot possibly provide insight on modifications that others make to the open source code.

Bryan


Re: Will the Mach 2 support .....

Greg McCall
 

Hi, would that setup still be OK if you built and loaded a tracking model from APPM in place of guiding?


Re: Question: How do I safety replace the CW shaft adapter (got it off, grease?)

Roland Christen
 

WoW, you have a generous neighbor to give you a mount for free. Stuck out tongue winking eye

Rolando

-----Original Message-----
From: Roger Howard <cargostick@...>
To: main@ap-gto.groups.io
Sent: Tue, Jun 1, 2021 8:39 pm
Subject: Re: [ap-gto] Question: How do I safety replace the CW shaft adapter (got it off, grease?)

1100GTO.  I got it free with the help of my neighbor, but just wanted to post that I used some lube on the insert to hopefully keep it from happening again.  Yes, I do have the insert.

--
Roland Christen
Astro-Physics


Re: Question: How do I safety replace the CW shaft adapter (got it off, grease?)

Roger Howard
 

1100GTO.  I got it free with the help of my neighbor, but just wanted to post that I used some lube on the insert to hopefully keep it from happening again.  Yes, I do have the insert.


Re: Will the Mach 2 support .....

Marcelo Figueroa
 

What!!!, you don't have an infinite number of telescopes, what kind of world is this where you can't have an infinite number of telescopes ??? :D
 
Great setup, we will be watching for the results. Here we are betting on the ASI 6200. These new cameras are ridiculously sensitive.


Re: VIDEO - Mach2 Right Ascension Belt Adjustment

Joseph Beyer
 

Interestingly the belt seems to be the astronomical mount equivalent as the drive belt on…Harley Davidsons.  Probably no relation.  The drive belts on the motorcycles have a service life of 60-100K miles.  My guess is the belt on the Mach2 lives in a much kinder environment and the life span will reflect it. 

On Jun 1, 2021, at 6:06 PM, M Hambrick <mhambrick563@...> wrote:

I am going off topic a little bit here, but many of us who started driving in the 1970's will remember the introduction of these toothed rubber timing belts in automobile engines. Prior to this the timing was always maintained with chain sprockets.

Belt driven engine timing got a really bad rap in the US, and deservedly so because the US carmakers chose to introduce this concept on the really cheap cars like the Chevy Vega, Ford pinto, etc. The life expectancy of these timing belts was supposed to be about 30,000 miles. I was working as an auto mechanic in those days, and our shop saw a lot of cars come in with engines that had to be almost completely rebuilt because the timing belts broke while the cars were going down the road at 55 mph.

In the late 1980's a new type of hydrogenated nitrile rubber was introduced onto the market that was designed for use in hot, oily environments, and most of the timing belts were converted over to this new polymer. I think that Kevlar also showed up at about the same time. Now, most timing belts will last at least 100,000 miles.

Mike


Re: VIDEO - Mach2 Right Ascension Belt Adjustment

M Hambrick
 

I am going off topic a little bit here, but many of us who started driving in the 1970's will remember the introduction of these toothed rubber timing belts in automobile engines. Prior to this the timing was always maintained with chain sprockets.

Belt driven engine timing got a really bad rap in the US, and deservedly so because the US carmakers chose to introduce this concept on the really cheap cars like the Chevy Vega, Ford pinto, etc. The life expectancy of these timing belts was supposed to be about 30,000 miles. I was working as an auto mechanic in those days, and our shop saw a lot of cars come in with engines that had to be almost completely rebuilt because the timing belts broke while the cars were going down the road at 55 mph.

In the late 1980's a new type of hydrogenated nitrile rubber was introduced onto the market that was designed for use in hot, oily environments, and most of the timing belts were converted over to this new polymer. I think that Kevlar also showed up at about the same time. Now, most timing belts will last at least 100,000 miles.

Mike


Re: Will the Mach 2 support .....

M Hambrick
 

Thanks for showing us this imaging setup Roland, and yes, please share your results including your guiding graphs.

Mike


Re: Back Focus Troubles #Absolute_Encoders

M Hambrick
 

Hi Andrew

I will try to throw my two cents worth into this discussion, and hopefully will not confuse you even more.

First, If the filters are said to add 1mm of backfocus, I would interpret this to mean that they will add to the total backfocus length so that instead of 85 mm your backfocus will be 86 mm.

Second: To your question about why the backfocus specification matters I would say that unless you are using a telecompressor or field flattener in your imaging train then the backfocus probably doesn't matter (as much) because as you stated, you will adjust the focuser until the image is in focus, and that is as good as you will get.

Take a look at the drawing below. You will see that there are actually two backfocus dimensions; dimensions X and Y. If you are using a telecompressor or field flattener, dimension X from the back of the compressor or flattener is critical and will determine whether you get pinpoint stars across the whole image, or if they are points in the middle and elongated at the corners. Just about every field corrector or compressor on the market will have a specification for the total backfocus, and if you have filters you will have to account for them in determining what the actual backfocus is. As Dale has said, it is better to be a little bit undersize and to make up any difference using shims. Once you have assembled your imaging train, the distance from the rear of the corrector to the sensor is fixed, but it will still be necessary to adjust the focuser to reach focus.

If you are not using a field flattener, then dimension Y is really what you are interested in because it will give you an idea of how far out the focuser has to be racked to achieve focus. You may decide that if you have to rack your focuser a long way that it is better to add an extension to your imaging train. In the sketch below you can see that I have to rack out the focuser on my Stowaway about 2-1/2". I am considering adding 2" thread-on extension in front of the flattener so that I do not have to rack the focuser out so far.

The worst case scenario is if you can not rack your focuser in far enough to reach focus.

I hope this helps.

Mike


Re: Question: How do I safety replace the CW shaft adapter (got it off, grease?)

Roland Christen
 

What mount, and do you have the steel insert?
Putting some ice on the cwt shaft will cause it to shrink slightly and it might come free that way.

Rolando

-----Original Message-----
From: Roger Howard <cargostick@...>
To: main@ap-gto.groups.io
Sent: Tue, Jun 1, 2021 6:12 pm
Subject: Re: [ap-gto] Question: How do I safety replace the CW shaft adapter (got it off, grease?)

I have to chime in here for posterity.  I just got my mount a few months ago with the new CW shaft and the Delrin spacer installed and just had my manhood called into question trying to remove the counterweight shaft.  After about 20 minutes I had to call my neighbor to help me get the thing removed.  I have now placed a few drops of Hoppes #9 firearm lubricant on the threads and I will report back here at a later time if this doesn't help.  Next I'm going to try one of those ninja claw training devices from the back of a comic book to improve my grip strength :)

--
Roland Christen
Astro-Physics


Re: VIDEO - Mach2 Right Ascension Belt Adjustment

Roland Christen
 


That seems to be more than strong enough for the application.
It's overkill for sure. It is designed for significant power transmission, so should never stretch or wear out.

Rolando


-----Original Message-----
From: M Hambrick <mhambrick563@...>
To: main@ap-gto.groups.io
Sent: Tue, Jun 1, 2021 6:34 pm
Subject: Re: [ap-gto] VIDEO - Mach2 Right Ascension Belt Adjustment

Another great video Tony.

Like you, I have always been impressed to see how A-P machines so many of their parts from solid aluminum bar stock. 

That cogged belt is also impressive. The part number indicates that it is a 3 mm pitch belt. What is the width ? I am guessing that it is at least 3/8" wide. That seems to be more than strong enough for the application.

Mike

--
Roland Christen
Astro-Physics


Will the Mach 2 support .....

Roland Christen
 

Hello AstroNuts,

We get this question many times, "will the Mach2 support my scope, camera etc." I can't really answer specific setups since I don't have infinite variety of scopes at my disposal. However, to give you some idea I am presently testing two scopes piggybacked on the Mach2.

Here is my present setup. I am using it to test various optics, cameras and field flatteners. It consists of a 160EDF refractor with QTCC and a full frame ZWO 6200 color camera, which provides a very wide field. On top rides an oldie but excellent 130 EDF refractor with 2.7" focuser, 67PF562 Flattener and my QSI 683WSG camera, Lodestar off-axis guider and an 8x50 Baader finder for good measure. Both scopes sit in rings that are attached to dovetail plates. When you add up all the parts, the whole shebang weighs close to 70 lb with the weight centered about 9 inches from the top of the Dec axis. I have approximately 75lb worth of counterweight which includes the weight of the standard Mach2 cwt bar and the shorter extension.

Is it stable and does it slew, track and guide effortlessly? Yes on all counts. It does need to be closely balanced, but not ridiculously so. Using MaximDL6, in poor seeing i get on the order of 0.4 arc sec rms guiding. In good to excellent seeing I get 0.1 to 0.15 arc sec rms guiding. My guide exposure is between 2 and 5 seconds with 1.5 seconds between exposures. Best guiding seems to be when the exposures are 4 to 5 seconds, and I get very few excursions that are larger than 0.5 arc sec pk.

By the way, I don't usually guide with one scope and image with another. In this case I am guiding with the lighter weight 130EDF and I am getting perfect round stars with the 160 below. The 160 is shooting at 960mm focal length with a 3.75 micron/pixel camera, 0.8 arc sec per pixel. ZWO 6200 camera. resolution with this camera in medium seeing has yielded 1.4 arc sec FWHM stars in a 5 minute exposure.

I will be shooting tonight if the weather holds, and I can record some guide graphs for anyone interested. Seeing is supposed to be good (4 out of 5) but transparency will be poor. I'm doing a shootout between the CMOS camera with 3.75 micron pixels and my older QSI683 CCD camera with 5.4 micron pixels. Which camera records images faster? Which has better contrast? Any bets on the winner?

Rolando


--
Roland Christen
Astro-Physics


Re: VIDEO - Mach2 Right Ascension Belt Adjustment

M Hambrick
 

Another great video Tony.

Like you, I have always been impressed to see how A-P machines so many of their parts from solid aluminum bar stock. 

That cogged belt is also impressive. The part number indicates that it is a 3 mm pitch belt. What is the width ? I am guessing that it is at least 3/8" wide. That seems to be more than strong enough for the application.

Mike


Re: Question: How do I safety replace the CW shaft adapter (got it off, grease?)

Roger Howard
 

I have to chime in here for posterity.  I just got my mount a few months ago with the new CW shaft and the Delrin spacer installed and just had my manhood called into question trying to remove the counterweight shaft.  After about 20 minutes I had to call my neighbor to help me get the thing removed.  I have now placed a few drops of Hoppes #9 firearm lubricant on the threads and I will report back here at a later time if this doesn't help.  Next I'm going to try one of those ninja claw training devices from the back of a comic book to improve my grip strength :)


Re: Problems using ASI air pro and AP mounts

Kevin Cook
 

Ken - One thing I discovered about the ASIAIR version of PhD guiding is that you have to set the guiding rate to 1X in TWO places - on the AP hand controller keypad (or on AP mount software if using that) and on the ASIAIR pull-out tab (it pulls out to the left from the right-side vertical control panel).  This ASIAIR pull-out tab is the same one you use to select your target and direct a GOTO.  The guiding rate needs to be set at 1X in both places or the guiding is all over the place.   Kevin


On Tue, Jun 1, 2021 at 2:32 PM Kenneth Tan <ktanhs@...> wrote:
Hmm I wonder if there is something wrong with my setup. I use a 250 mm fl guide scope with an ASI 1290 cam as guidecam

On Wed, 2 Jun 2021 at 05:29, marsh.family <marsh.family@...> wrote:
Hi Kenneth

I've had very unpredictable guiding performance with AsiAir Pro until the latest version with multi star guiding. 

I haven't had too many chances to test it out but the guiding was very good when I did. Better then the best with the previous version. And seemingly more stable. I just started it up and it worked. No tweaking. 

Chris



Sent from my Galaxy


-------- Original message --------
From: Kenneth Tan <ktanhs@...>
Date: 2021-06-01 5:21 p.m. (GMT-05:00)
Subject: [ap-gto] Problems using ASI air pro and AP mounts

I have a strange problem. I am using a c925 on a AP 1600 . I can run it without guiding for about 30 s with fairly round stars.  The moment i try to guide with the phd on the asiair pro, it is all over the place. Unpredictable spikes in both axes.  Has anyone encountered this problem? I will try with phd proper the next time.

 
Kenneth


Re: Problems using ASI air pro and AP mounts

Kenneth Tan
 

Hmm I wonder if there is something wrong with my setup. I use a 250 mm fl guide scope with an ASI 1290 cam as guidecam

On Wed, 2 Jun 2021 at 05:29, marsh.family <marsh.family@...> wrote:
Hi Kenneth

I've had very unpredictable guiding performance with AsiAir Pro until the latest version with multi star guiding. 

I haven't had too many chances to test it out but the guiding was very good when I did. Better then the best with the previous version. And seemingly more stable. I just started it up and it worked. No tweaking. 

Chris



Sent from my Galaxy


-------- Original message --------
From: Kenneth Tan <ktanhs@...>
Date: 2021-06-01 5:21 p.m. (GMT-05:00)
Subject: [ap-gto] Problems using ASI air pro and AP mounts

I have a strange problem. I am using a c925 on a AP 1600 . I can run it without guiding for about 30 s with fairly round stars.  The moment i try to guide with the phd on the asiair pro, it is all over the place. Unpredictable spikes in both axes.  Has anyone encountered this problem? I will try with phd proper the next time.

 
Kenneth


Re: Problems using ASI air pro and AP mounts

marsh.family
 

Hi Kenneth

I've had very unpredictable guiding performance with AsiAir Pro until the latest version with multi star guiding. 

I haven't had too many chances to test it out but the guiding was very good when I did. Better then the best with the previous version. And seemingly more stable. I just started it up and it worked. No tweaking. 

Chris



Sent from my Galaxy


-------- Original message --------
From: Kenneth Tan <ktanhs@...>
Date: 2021-06-01 5:21 p.m. (GMT-05:00)
To: main@ap-gto.groups.io
Subject: [ap-gto] Problems using ASI air pro and AP mounts

I have a strange problem. I am using a c925 on a AP 1600 . I can run it without guiding for about 30 s with fairly round stars.  The moment i try to guide with the phd on the asiair pro, it is all over the place. Unpredictable spikes in both axes.  Has anyone encountered this problem? I will try with phd proper the next time.

 
Kenneth


Problems using ASI air pro and AP mounts

Kenneth Tan
 

I have a strange problem. I am using a c925 on a AP 1600 . I can run it without guiding for about 30 s with fairly round stars.  The moment i try to guide with the phd on the asiair pro, it is all over the place. Unpredictable spikes in both axes.  Has anyone encountered this problem? I will try with phd proper the next time.

 
Kenneth


Re: Added album Photos of Forum Members in their A-P Logo Hats #photo-notice

Kenneth Tan
 

Thx

On Wed, 2 Jun 2021 at 03:26, Karen Christen <karen@...> wrote:

Hi Kenneth,

 

I suggest you start a new thread with your concern.  I’m not sure you’ll get the help you’re looking for in the thread about AP hats and their travels.

Karen

AP

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Kenneth Tan
Sent: Tuesday, June 1, 2021 1:26 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Added album Photos of Forum Members in their A-P Logo Hats #photo-notice

 

I have a strange problem. I am using a c925 on a AP 1600 . I can run it without guiding for about 30 s with fairly round stars.  The moment i try to guide with the phd on the asiair pro, it is all over the place. Unpredictable spikes in both axes.  Has anyone encountered this problem? I will try with phd proper the next time.

 

Kenneth


--
Karen Christen
Astro-Physics


Re: Back Focus Troubles #Absolute_Encoders

Dale Ghent
 

What Linwood said. I'll add that it's a good idea to not fixate on a single exact number when it comes to back focus distance. There are manufacturing variations in the objective or mirror of the scope as well as the corrector that will combine to slightly alter what the back focus distance turns out to be. In other words, the distance on paper will land you pretty close and on slow scopes it might be just fine, but faster focal ratios will require some more tuning. In it end, it might be that the BFD wasn't 80.8mm, it might be 80.2 or 81.1 or something close, but not exactly what the documentation says.

With that in mind, I always slightly undersize my ensemble of adapters and extensions by 1 or 2mm. I then use shims, available in an assortment of diameters and sub-1mm thicknesses, to bump the sensor out some more until it its inside the corrected field. When fine-tuning this distance, the on-paper value isn't what you follow, it's what you see in the corners of your frames.

On Jun 1, 2021, at 16:00, ap@captivephotons.com <ap@CaptivePhotons.com> wrote:

The best example I have seen is the spacing guide in this web site about half-way down. It shows what happens to an in-focus image when spacing is too short or too long.



https://optcorp.com/blogs/astronomy/how-to-set-the-correct-back-focus



The center will always look good, since you can reach focus in the center. But without proper backfocus the corners are then distorted (well, they are always somewhat distorted but the right backfocus gives them the minimum distortion, which is sort of its definition).



My understanding of a filter is it adds, meaning if the backfocus from OTA to camera was specified as 146.5mm (e.g. my C11) then when I add a 3mm Chroma filter, I add 1/3rd that thickness, and now use 147.5mm in total.



I find that the most confusing things about backfocus are all the (legacy I think) descriptions of 55mm and DSLR spacing, where the ASSUMPTION is you are starting with a specific set of camera and T-Adapter lengths, and so they only talk about the rest of the equation.


The second most confusing is the point of measurement. My Refractor is measured from the shoulder of the male threads of the last component, i.e. the point closer to the OTA at the base of the threads. My SCT is measured from exactly the opposite, on its male threads you measure from the end of the threads, the further point from the OTA. This is a detail often hard to find, but can vary by 10mm or more. Indeed in that opt article it shows the backfocus measurement point matching my refractor, but WRONG for my SCT.



And yes, backfocus helps keeps Precise Parts gainfully employed. 😊



Linwood



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