Date   

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




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

Jeffc
 

OAG or Guidescope?

I assume thats a Celestron 9.25 with a focal length of 2350mm. 

Does it have mirror locks?

My guess is you are using an OAG at 2350 FL and the guide star is jumping around due to seeing.   Iirc this is known as “chasing the seeing”.

-jeff 

On Jun 1, 2021, at 11:26 AM, Kenneth Tan <ktanhs@...> wrote:

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: Back Focus Troubles #Absolute_Encoders

Jeffc
 




On Jun 1, 2021, at 12:35 PM, Andrew Jones <andjones132@...> wrote:




My second question is, why does Back Focus spacing matter? When using a refractor with a Crayford style focuser, it is not clear why getting precise Back Focus spacing is so important when the camera sensor will be moving in or out to achieve focus anyway.


My understanding is the flattner goes on the focuser drawtube and the camera attaches to the flattner.  At least that is the how the AP and just about every other flattner I’ve seen works… it threads on to the draw tube.  

Ie.  path of the photons is:
Front lens -> OTA -> focuser body -> focuser draw tube -> flattner -> filter wheel -> camera -> sensor. 

The focuser focuses incoming light on the flattner , similar to an eyepiece.  The space between the flattner and the sensor is critical and should be fixed .. and likely/hopefully  not affected by temperature changes. 

The FSQ 106n (which I’ve used) has elements fixed inside the OTA which did not move with the focuser but this was a different optical design than the typical doublet or triplet refractor. 

Flattners and reducers afaik will not deliver consistent FOV over focus changes which would be required as temperature changes. 

-jeff 


Re: APPC emergency Stop Window keeps disappearing

Tom Blahovici
 

Hi Ray,
The window doesn't appear to open at all when the mount slews.  There is no other window hiding it, and I do not have multiple monitors. As to off screen I didn't see this in the task bar, one of the first things I looked at. I'll try the turning off of the position saving and see if it returns.  It's going to be a while though, I just took down my observatory for a while.
Thanks, Tom


Re: Back Focus Troubles #Absolute_Encoders

ap@CaptivePhotons.com
 

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

 


Back Focus Troubles #Absolute_Encoders

Andrew J
 

I could use some help and guidance to better understand Back Focus.

 

The first question relates to the impact Filters have on Back Focus. For several years I have been trying to get a definitive answer on the how adding filters to an imaging chain affects the Back Focus calculation and in turn how this impacts the length of the spacers required to achieve the recommended Back Focus for a particular scope configuration. For example, I have TEC140ED with Field Flattener that requires 85mm of Back Focus. I also have Chroma filters, that requires an additional 1mm of Back Focus per the manufacture. To keep the math easy, let’s assume my Camera and Filter Wheel (without filters) consume 35mm of the Back Focus. When I add the Chroma Filters to the equation, do I need a 49mm (85 – 35 – 1) or 51mm (85 – 35 + 1) spacer to achieve optimal Back Focus? This would seem like an easy thing to answer, but I just got off the phone with telescope and eyepiece manufacturer, and depending on who I talked to I got completely opposite answers.

 

My understanding is that when they say the filter adds 1mm, it means just that, it ADDS 1mm to the Total Back Focus between the OTA and the camera sensor. Sticking with the example above and the 85mm of native Back Focus, adding Chroma filters to the optical path would changes the Total Back Focus from 85mm to 86mm. If correct, then the answer to the question above would mean I need a 51mm spacer (85mm native BF + 1mm for filter = 86mm Total BF; 86mm Total BF – 35mm Cam/FW = 51mm spacer). Hoping the knowledgeable experts here can confirm if my understanding is correct.

 

 

My second question is, why does Back Focus spacing matter? When using a refractor with a Crayford style focuser, it is not clear why getting precise Back Focus spacing is so important when the camera sensor will be moving in or out to achieve focus anyway. Referring back to the example above, assume instead of the 51mm spacer I went completely nuts and added a 41mm spacer instead so that my Back Focus spacing was 10mm short. Assuming I had 10mm of travel available on my focuser, what would be the difference between having the 51mm spacer and the focuser racked to say 49mm to achieve focus vs. having a 41mm spacer and the focuser racked to 59mm to achieve focus? It is the same 100mm distance from the back of the OTA to the camera sensor either way. So why does it matter which spacer is use? I have spent a fair amount of money over the years with Precise Parts in an attempt to precisely achieve the Back Focus recommendations for various scope configurations. I never really stopped and asked why this is necessary. Hopefully someone here who understands optics can reassure me that the money spent on getting the “optimal” back focus was a worthwhile cause.

 

Thanks in advance for the education.

 

Andrew J


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

Karen Christen
 

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

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

 

That’s a fun album, Mike! There are quite a few hats shipping recently, so I hope to see some in the album over the summer.

 

Clear Skies,

Marj Christen

Astro-Physics

11250 Forest Hills Road

Machesney Park, IL 61115

Phone: 815-282-1513

www.astro-physics.com

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of M Hambrick
Sent: Tuesday, June 1, 2021 8:49 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Added album Photos of Forum Members in their A-P Logo Hats #photo-notice

 

It would help to have the link to the album>

https://ap-gto.groups.io/g/main/album?id=264707


Re: CP5 update?

 

Yes, that email is from me! Thanks for checking with us though. You can never be too careful.

 

Liam

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Marj Christen
Sent: Tuesday, June 1, 2021 9:49 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] CP5 update?

 

Yes, it is legitimate but only affects a few people. Please follow the instructions in the letter thank you. 


On May 31, 2021, at 9:49 PM, weihaowang <whwang@...> wrote:

Hi,

A few days ago, I got an email from AP regarding a special firmware update for CP5, saying that it
will require a special firmware load.

I don't see any discussion about this here, so I wonder if this is legitimate and if I should proceed.  

Cheers,
Wei-Hao

--

Homepage:

http://www.asiaa.sinica.edu.tw/~whwang/

Astrobin gallery:
http://www.astrobin.com/users/whwang/

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