Date   

Re: guiding calibration woes

CurtisC
 

What is Voyager?


Re: RAPAS on Mach2

Terri Zittritsch
 

Hi Wade, peace..  just trying to understand.    Like I said in my original post, it may be that I'm just seeking something that isn't really practical or possible.   I have a full guiding setup, but when I get these posts using encoder mounts or my mount, showing incredibly flat controlled tracking, I'm trying to see if I can achieve this as well.     

I see the same things in forums, on claims of incredibly precise polar alignment, and as I said in the previous post, I don't know how they can make such claims.  I spent an hour one night polar drift alignment and had better alignment than usual, but it took an hour, and it still wasn't good enough for very long subs.   Long subs for me, with a CMOS camera, are still under 10 minutes or less.  I've done 20 minutes, but it's unusual.   Most of my subs are 1 minute (luminosity).    Although, having purchased some chroma 3nm filters, those seem to take some really long exposures to get a good amount of signal!

I measure drift in PHD2, using their drift alignment tool.. which takes forever to settle.. so it's a long process (for me).   Usually when I'm doing  polar alignment, I'm set up with camera, filter wheel, etc.. and want to do something that doesn't require me to take it apart and put in an eyepiece.    And PHD2 also gives me an estimate of my polar alignment error, which is based on drift, not instantaneous bouncing around the mean which I understand is all atmosphere.

I've only done one model, a 35 point small model, and I think it took around 25 minutes (it's been a while since clear skies).    And most of the plate solves were pretty fast.    I noticed the meridian points, solved twice, and most others once, so it does more than 35 solves for 35 points.    I use SGPro, which seems a bit slow to download files from my camera, which may make it slower than others.    The results of the 35 point model did not allow 1 minute subs, and I had unacceptably elongated stars.      But that's one data point,  and there is a lot to learn.  


Terri



Re: Case Foam CUTTING PATTERNS for AP Mounts

Joe Zeglinski
 

Hi Fred,
 
    Therein again, lies the problem – “ACCURATE & PRECISE Mount Outline Measurements”. 
 
    We don’t have any, of reasonably good accuracy, to throw money at someone making case foam to order from gun-case experts. I suppose the same goes for any other kind of delicate instrument case foam enclosure, such as Theodolites, etc.
 
    Even worse, if we had AP-provided accurate outlines with dimensions of our “specific” AP mount model, their case layout job would still not prove entirely satisfactory. Making a foam fit a regular rifle, pistol, or small canon, even a refractor, is fairly straight forward. But, we have the additional Rotational Dimension of the RA Fork/Base angle,  “rotated” from its upper saddle and angled in the Forks, differently for every individual’s local Latitude unless one unbolts the saddle, every time. The RA section will still be “oddly-placed”.
 
*******
    To solve that extra problem, I think it would make things easier, to purchase  such “foam-shaping services”, as you mention, if we could send them  an “official” outline with annotated dimensions  for our mount, especially the individually RA adjusted base configuration. That would result in a satisfactory foam insert, the first time, instead of multiple refits, lost scope time, costs, etc. for something so simple.
 
    Something I thought of subsequently, was to make an RA “rotatable foam disk BASE section”, inserted into a circular cut-out in the case foam, with its fixed DEC (and upper  RA Head and Saddle) section, which never changes shape. The small remaining piece, which does depend on Latitude, is the Forks with its Base and RA axle.
 
    If THAT pattern could be cut into a separate, circular foam disk, then the owner, or fabricator, could insert/rotate the foam disk so the Fork/Base fits the angle of the permanent, fixed cut-out of the rest of the RA & Saddle section. It would likely be a one-time fitting, but easily readjusted if a person moves to a new home, or other regular long term observatory site. Then, you wouldn’t need a new case foam insert – simply,  rotate the foam disk. Manufacturing the special fit foam,  would be easy, quick, and done in just one fitting.
 
    Then again, wouldn’t this be a great Service that could be done via Astro-Physics?
No need to inventory, “case products”, depend on telescope case makers to survive in business, or have long delay times, for every user request, and AP could hook-up with one or more such CASE “Gun-Foam” shapers, to pass our orders through, instead of everyone hunting (pun),for their own supplier, or hacking out their own case foam blocks – possibly repeated if the user eventually wears out or damages the foam, or gets tired of their particular scope “Luggage” (double-entendre pun).
 
    Or, as I originally suggested, at least AP could provide the GROUP,  a set of printable stitching diagrams to hack out, sculpt,  ( or case “foam-pluck”) our own foam inserts.
 
**** Did we get the Mount CASES all wrong, these many years ? *****
 
    Another approach, cases WITHOUT much foam, none of these actually sculpted,  inside them at all – Consider ... “AIR CUSHIONED CASES”.
 
    Foam line any Cube Case with flat foam squares,  then insert an air bag - possibly made of rugged beach mattress canvass material - and inflate it with a bicycle pump,  or car tire battery-operated “inflator”,  with the RA section sitting (approximately) in the middle of the air bag. If its shape is loose enough, its INSIDES will mostly CONFORM to the RA assembly (minus the Saddle’s D-Plate), The base and lid/top would be thicker normal foam squares, for vertical protection. For extra vertical confinement, the lid case foam could have a simple cut-out layer, loosely the shape of the saddle, to restrain the mount inside the semi-flexing (depending on inflation pressure)  air bag. Then the RA section can bounce around even in rough travel, but can never actually hit the sides of the (possibly additional),  foam lined hard case walls.
 
   Or, just Make your own Case Inner Tube – using a kid’s toy   Visit TOYS R’ US (see below)
 
    Fill it up (sufficiently) to conform to the RA section. sitting on the base foam cushion. Buy and stack two of these, if needed, and at least as a “partial spare tire backup” inside,  if one gets accidentally punctured. Make inflating & deflating easy and quicker – by attaching a regular bicycle pump hose to the air inlet(s), and lead it/them to  outside of the case wall, for easier access.
For example:

48" Gold Hologrpahic Glitter Pool Tube  - and/or -   Big Boss 4"X58" Pool Noodles

    and .....
 
 
    I suppose, an alternative Air Cushioned Travel vehicle, rather than a special-sized cubic air bag, would be to buy, “vey baggy” inflatable air seat cushions, to insert or prop up, against the case walls. Once they are “hard-inflated”, as above, they would provide the similar side protection, as a conformal inflatable bag with less cost and better availability. Any extra corner space can additionally be stuffed with vertically positioned  regular small foam “waist support” (e.g. porch swing) cushions,  or those cut from lengths of swimming pool toy “flexible but stiffer, Styrofoam - Pool Noodles”, as above,  (with its cushioning center air channel hole)”.
 
    A nice BONUS - when you are tired, packing up the mount case in the cold (winter) dark night  for the long trip home, trying (otherwise) to not damage a case’s foam outline as you might otherwise with a regular foam case: - 
... You still have your handy bicycle pump, or even far better - the cigarette lighter plug (from the car,  or telescope power pack),  DC-operated air pump, to quickly, “hard re-inflate” the case air cushion(s).
 
    Just a thought ... too much ?
Joe Z.
 
 
 

From: fl.lusen via groups.io
Sent: Thursday, April 16, 2020 12:32 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Case Foam CUTTING PATTERNS for AP Mounts
 
Joe,

I came across this guy at a local gun show.  https://agvii.com/custom-cases/ I am sure there are many more like him around the country.  He can use your case or provide one.  He can use your measurements or you can send him the item and he will custom fit it.  This could be another alternative.

Fred
 
 


Re: RAPAS on Mach2

Dean Jacobsen
 

On Thu, Apr 16, 2020 at 01:15 PM, W Hilmo wrote:
and I’ve seen more than one person polar align to Kochab in that scenario).
I didn’t know anyone was watching me...  🙂

I used just the RAPAS for aligning my portable imaging rig for years.  I have no idea how close it was or how repeatable it was from session to session.  It is a great time saver.
 
--
Dean Jacobsen
http://astrophoto.net/wp/ 
Image Gallery - http://astrophoto.net/wp/image-gallery/
Astrobin - https://www.astrobin.com/users/deanjacobsen/ 


Re: RAPAS on Mach2

W Hilmo
 

Honestly, I’ve never measured my polar alignment error.

 

Beyond that, I don’t even know how to measure it in a way that would be useful in conversation.  I don’t know if you follow Cloudy Nights or not, but there is a near obsession over there with polar alignment.  I’ve seen people making polar alignment error claims that border on the ridiculous (like people claiming to be within 5” of the pole, etc.)  The drift from a 5” polar alignment error would be so small that I don’t know how you could detect it with a single exposure.  I would think that looking at the total field rotation for an entire night would be a better way to try and see a very small error.  I am pretty sure that people are just running some tool like a PoleMaster or SharpCap and just repeating what the software claims.  The thing is, that the software claims are not repeatable, even in the same session.  It’s made even more confusing because I am pretty sure that different software packages calculate the polar alignment error differently.

 

Even with PEMPro, which is the gold standard for software aided drift alignments, I can watch the calculated error bounce around by some number of arc seconds with each exposure, just due to seeing effects.

 

I take a more pragmatic view.  If I don’t get any noticeable drift in a single sub, and if I don’t get any field rotation over a night of imaging the same object, then I’ll call the polar alignment “good enough”.  If your goal is to do longish exposures unguided, especially at a longer focal length, then I would probably do it one of two ways:  If you take the time to run APCC, an APPM model will compensate for any polar misalignment, as well as drift from other factors (as long as they are repeatable).  That would be my preferred method.  If I didn’t want to do an APPM run for some reason, then I would do the RA Drift Alignment that’s described on the Astro-Physics site at the below link.  To do it, I would run PHD2 with my main imaging camera and guide corrections disabled.  This would give me a graph of the guide star during tracking that I could use to know which corrections to make:

 

https://astro-physics.info/tech_support/mounts/drift-alignment-ra-correction-method.pdf

 

The other option, that is new to the keypad firmware that will be available for the Mach2, will be that you can get tracking compensation right from the keypad (and it will also be available for the CP4).  I don’t believe that any of us have that keypad firmware yet, so I don’t know of anyone outside of the Astro-Physics folks that have first hand experience with it.  If I understand what I’ve heard correctly, it will work by calibrating on a couple of stars in the path of your object and building custom tracking rates for your specific target.  I’m guessing that it will be pretty effective.

 

At the end of the day, I believe that it’s important to understand a few methods to do an  effective polar alignment and also to not obsess over it.

 

In the meantime, how do you know that your polar alignment is causing problematic drift?  If the Mach2 ships with PEMPro, I would suggest that you start its polar alignment wizard and let it track for a while.  It will clearly show you any drift (and offer the change to make an adjustment to correct it).  If you don’t have PEMPro, then you can do a similar thing with PHD2 (as I described above, using it to facilitate a drift alignment).

 

And finally, I want to close the loop on a comment that I made earlier about my personal workflow at field sites.  I mentioned that I do both a daytime polar alignment and also use the RAPAS to tweak it.  The purpose of the daytime polar alignment is to get the mount reasonably close to polar aligned before it starts to get dark.  That way, when it gets to be dusk, you are pretty much guaranteed that Polaris will be both inside the view of the RAPAS and also obvious.  If you wait until after dark and start with the RAPAS, it can be tricky to find Polaris correct, especially if it lands outside of the RAPAS field of view.  In that case, it takes longer than 30 seconds (and I’ve seen more than one person polar align to Kochab in that scenario).

 

Hope that you find this information useful,

-Wade

 

 

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Terri Zittritsch
Sent: Thursday, April 16, 2020 12:30 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] RAPAS on Mach2

 

Thanks W Hilmo,

Not sure I ever see field rotation with any of my gross polar alignment methods.  I think you'd have to be pretty far off to see field rotation (but honestly don't know what that would be).  I'm trying to understand what kind of measured repeatable polar alignment people get.    Is 2 minutes, 3 minutes?   30 seconds?   With Polemaster, it's advertised at 30", and I see all kinds of claims on-line (hard to believe claims.. and claims that would be hard to even measure), but who knows.  Maybe I am just the worst polar aligner ever.    If I can do an accurate polar alignment (30") in 30 seconds, I will be exceptionally happy!!   I've never tried the daytime polar alignment.


Terri


Re: RAPAS on Mach2

Terri Zittritsch
 

On Thu, Apr 16, 2020 at 01:47 PM, W Hilmo wrote:

 

When I set up in the field, my general workflow is to set up the mount during the day and go through the daytime polar alignment routine.  Then, at dusk I use the RAPAS to do a final tweak to the polar alignment.  If I do this, and then blink a stack of a whole night’s imaging, there is no noticeable field rotation between the first and last images of the session.  The daytime alignment takes me two to three minutes while the sun is up, and the tweak with the RAPAS takes about 30 seconds.

 

Thanks W Hilmo,

Not sure I ever see field rotation with any of my gross polar alignment methods.  I think you'd have to be pretty far off to see field rotation (but honestly don't know what that would be).  I'm trying to understand what kind of measured repeatable polar alignment people get.    Is 2 minutes, 3 minutes?   30 seconds?   With Polemaster, it's advertised at 30", and I see all kinds of claims on-line (hard to believe claims.. and claims that would be hard to even measure), but who knows.  Maybe I am just the worst polar aligner ever.    If I can do an accurate polar alignment (30") in 30 seconds, I will be exceptionally happy!!   I've never tried the daytime polar alignment.


Terri



Re: RAPAS on Mach2

Roland Christen
 


The instructions note that you can loosen the 'do not loosen' screws to readjust the reticle if it's moved during shipping,
You can never adjust the reticle, it is permanently affixed inside the eyepiece. However the eyepiece is simply held in the back of the polar scope via a small setscrew, and this entire assembly can be rotated. We made this so you can do fine adjustment of the vertical reticle line in the field. Even if you are off several degrees it has very little if any effect on the actual polar alignment.

Rolando


-----Original Message-----
From: Terri Zittritsch <theresamarie11@...>
To: main <main@ap-gto.groups.io>
Sent: Thu, Apr 16, 2020 12:27 pm
Subject: Re: [ap-gto] RAPAS on Mach2

On Thu, Apr 16, 2020 at 11:17 AM, uncarollo2 <chris1011@...> wrote:
No need to level the mount super accurately. The polar scope will still work well even if you are off by many degrees.
 
If your mount is not vertical, you can align the polar scope reticle to be vertical:
1) Aim the mount so that the scope points directly at Polaris (put Polaris on the center crosshair).
2) using the mount's altitude adjuster, run Polaris up and down the vertical crosshair. Loosen and turn the eyepiece until the crosshair is aligned with the up-down motion of Polaris.
3) tighten the eyepiece in place and then use the alt and az adjusters to put Polaris at the proper place on the reticle according to the polar app.
 
Rolando
Roland, I didn't expect you to respond.    The RAPAS feels like the rest of the kit I have from AP, solid and built like a tank!  Being an engineer, I can appreciate it all.

Throughout the instructions I received, in numerous places, are notes to make sure the mount is level which is why I asked.  It didn't take long to think about the implications of the mount not being level, or more accurately, the RAPAS not being precisely vertical, on the accuracy on polar alignment.   The instructions note that you can loosen the 'do not loosen' screws to readjust the reticle if it's moved during shipping, but doesn't seem to be part of the normal (do every time) alignment process.   At least not in the instructions I have, so thanks for sharing this.
I'm just trying to understand whether there is any way to do really accurate polar alignment, 30" or less,  in order to do short unguided exposures, without going to the traditional drift alignment.. I've found drift alignment to be a miserable process to go through.  Life is too short, and clear skies much shorter!   I'm not setting up on a level surface, or on a pier, every night is different.   Since I have all of the equipment, guiding is not a terrible thing to have to do.   I'm just thinking I have this really really nice mount, and is there any way to take advantage of it's full capability in a portable situation.   


Terri




Re: RAPAS on Mach2

W Hilmo
 

I have found the RAPAS to be quite accurate.

 

It is suggested to have the mount level because if it’s not level in the east/west direction, it means that the reticule would be rotated clockwise or counter-clockwise, depending on which direction the mount is unlevel.  If you stop and think about it, you would need to have a significant unlevel situation for it to be a problem.  Certainly if the mount “looks” level, then it should be fine.

 

When I set up in the field, my general workflow is to set up the mount during the day and go through the daytime polar alignment routine.  Then, at dusk I use the RAPAS to do a final tweak to the polar alignment.  If I do this, and then blink a stack of a whole night’s imaging, there is no noticeable field rotation between the first and last images of the session.  The daytime alignment takes me two to three minutes while the sun is up, and the tweak with the RAPAS takes about 30 seconds.

 

If you are going to image unguided, my suggestion is to do an APPM run before it gets dark enough that you are wasting productive imaging time, so that you can use a tracking model.  You should be easily able to get a 100 point, or so, run before it gets really dark.  The tracking model will compensate for any residual polar alignment error (which, from my experience with the RAPAS, will be really small, if noticeable at all).

 

I did do one really good PEMPro polar alignment to check the RAPAS calibration.  This is a one time exercise per mount (I have two mounts, so I’ve done it once for each).  To be honest, though, I found that just as shipped (without the one-time calibration), the accuracy of the RAPAS is pretty good.

 

 

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of Terri Zittritsch
Sent: Thursday, April 16, 2020 10:28 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] RAPAS on Mach2

 

On Thu, Apr 16, 2020 at 11:17 AM, uncarollo2 <chris1011@...> wrote:

No need to level the mount super accurately. The polar scope will still work well even if you are off by many degrees.

 

If your mount is not vertical, you can align the polar scope reticle to be vertical:

1) Aim the mount so that the scope points directly at Polaris (put Polaris on the center crosshair).

2) using the mount's altitude adjuster, run Polaris up and down the vertical crosshair. Loosen and turn the eyepiece until the crosshair is aligned with the up-down motion of Polaris.

3) tighten the eyepiece in place and then use the alt and az adjusters to put Polaris at the proper place on the reticle according to the polar app.

 

Rolando

Roland, I didn't expect you to respond.    The RAPAS feels like the rest of the kit I have from AP, solid and built like a tank!  Being an engineer, I can appreciate it all.

Throughout the instructions I received, in numerous places, are notes to make sure the mount is level which is why I asked.  It didn't take long to think about the implications of the mount not being level, or more accurately, the RAPAS not being precisely vertical, on the accuracy on polar alignment.   The instructions note that you can loosen the 'do not loosen' screws to readjust the reticle if it's moved during shipping, but doesn't seem to be part of the normal (do every time) alignment process.   At least not in the instructions I have, so thanks for sharing this.
I'm just trying to understand whether there is any way to do really accurate polar alignment, 30" or less,  in order to do short unguided exposures, without going to the traditional drift alignment.. I've found drift alignment to be a miserable process to go through.  Life is too short, and clear skies much shorter!   I'm not setting up on a level surface, or on a pier, every night is different.   Since I have all of the equipment, guiding is not a terrible thing to have to do.   I'm just thinking I have this really really nice mount, and is there any way to take advantage of it's full capability in a portable situation.   


Terri



Re: RAPAS on Mach2

Terri Zittritsch
 

On Thu, Apr 16, 2020 at 11:17 AM, uncarollo2 <chris1011@...> wrote:
No need to level the mount super accurately. The polar scope will still work well even if you are off by many degrees.
 
If your mount is not vertical, you can align the polar scope reticle to be vertical:
1) Aim the mount so that the scope points directly at Polaris (put Polaris on the center crosshair).
2) using the mount's altitude adjuster, run Polaris up and down the vertical crosshair. Loosen and turn the eyepiece until the crosshair is aligned with the up-down motion of Polaris.
3) tighten the eyepiece in place and then use the alt and az adjusters to put Polaris at the proper place on the reticle according to the polar app.
 
Rolando
Roland, I didn't expect you to respond.    The RAPAS feels like the rest of the kit I have from AP, solid and built like a tank!  Being an engineer, I can appreciate it all.

Throughout the instructions I received, in numerous places, are notes to make sure the mount is level which is why I asked.  It didn't take long to think about the implications of the mount not being level, or more accurately, the RAPAS not being precisely vertical, on the accuracy on polar alignment.   The instructions note that you can loosen the 'do not loosen' screws to readjust the reticle if it's moved during shipping, but doesn't seem to be part of the normal (do every time) alignment process.   At least not in the instructions I have, so thanks for sharing this.
I'm just trying to understand whether there is any way to do really accurate polar alignment, 30" or less,  in order to do short unguided exposures, without going to the traditional drift alignment.. I've found drift alignment to be a miserable process to go through.  Life is too short, and clear skies much shorter!   I'm not setting up on a level surface, or on a pier, every night is different.   Since I have all of the equipment, guiding is not a terrible thing to have to do.   I'm just thinking I have this really really nice mount, and is there any way to take advantage of it's full capability in a portable situation.   


Terri




Re: Case Foam CUTTING PATTERNS for AP Mounts

fl.lusen
 

Joe,

I came across this guy at a local gun show.  https://agvii.com/custom-cases/ I am sure there are many more like him around the country.  He can use your case or provide one.  He can use your measurements or you can send him the item and he will custom fit it.  This could be another alternative.

Fred

-----Original Message-----
From: Joe Zeglinski <J.Zeglinski@...>
To: ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Tue, Apr 14, 2020 1:33 pm
Subject: [ap-gto] Case Foam CUTTING PATTERNS for AP Mounts

Hi,
 
    Since this topic of cutting foam inserts for all kinds cases,  to house any of AP’s mounts (past and present models), comes up so often, I wonder if George or Howard could take on a customer project, to make accurate “cutting forms” for us.
   
    Howard did such an excellent job on his mount dimensions page, for many years now, I would assume it wouldn’t be difficult to provide a Silhouette cut-out pattern, from their CAD drawings, which we could then print for cutting our own foam blocks, to any size case – even if printed on two, or more, profile sheets, then  taped for production. Or, a single smaller sheet pattern, and each user would then enter a “scale factor” into their Print Option box, for a several sheet printout. We don’t need a large commercial printer for that – although that could also be done at a Print Shop with such CAD large, single sheet printers, if desired.
 
    It might be a bit tricky to account for the position of the rotated base angle, which depends on a user’s Latitude, but even that could be printed in two parts, swivelled and taped/stapled to the RA axle head paper section accordingly, prior to the case foam block’s surgery.
 
    The print pattern document should be scaled,  dimensioned, and a 12-inch and 30 cm. metric ruler printed beside it, just to be sure our printer’s output remains true to the same mount scale. That would save many of us hacking out terribly shaped foam blocks.
 
    I think this would be a very helpful, and useful project. Yet another example of Astro-Physics renowned attention to its loyal customers.
 
Joe Z.


Re: RAPAS on Mach2

Roland Christen
 

No need to level the mount super accurately. The polar scope will still work well even if you are off by many degrees.

If your mount is not vertical, you can align the polar scope reticle to be vertical:
1) Aim the mount so that the scope points directly at Polaris (put Polaris on the center crosshair).
2) using the mount's altitude adjuster, run Polaris up and down the vertical crosshair. Loosen and turn the eyepiece until the crosshair is aligned with the up-down motion of Polaris.
3) tighten the eyepiece in place and then use the alt and az adjusters to put Polaris at the proper place on the reticle according to the polar app.

Rolando



-----Original Message-----
From: Terri Zittritsch <theresamarie11@...>
To: main <main@ap-gto.groups.io>
Sent: Thu, Apr 16, 2020 9:59 am
Subject: [ap-gto] RAPAS on Mach2

Hi all,
I've received a RAPAS to use with my Mach2 when I'm doing outreach or in other instances when I don't use a computer.   But I've not been very satisfied with the results from the polemaster I have, once I get down to actually measuring drift.. The actual drift implies much less accuracy than advertised, or that many claim to achieve.  I have not been able to get close to 30 arc seconds, but you wouldn't think this from the screen indication.   Given others experiences I've read about, I am also hopeful the RAPAS will do better, but I'm a bit unclear on this point.

So now I have the RAPAS, for a Mach2.  It is attached on the side of the mount, rather than through the central axis as we know the Mach2 doesn't have this capability.    I've also read that the mount needs to be leveled east-west accurately because the RAPAS needs to be vertical (it is fixed, not rotating in any installation).    But there is only so much accuracy in leveling the mount, or more importantly, getting repeatability.   A bubble level or electronic level is only so accurate.   I've read that .5mm of tripod settling on one foot with 1M separation between the feet will result in adding 2 arc minutes of alignment error.     I don't know how Chris Woodhouse calculated this, and maybe I'll draw this up as a geometry exercise, but you get my drift (pun totally intended).   Leveling by-leg is likely millimeters of inaccuracy or non-repeatability use to use.   0.5mm is totally unrealistic.  

I think the scope load moving side to side may introduce at least a .5mm if not more, or settling.    I'm reading in the RAPAS instructions I received, which implies that accuracy is effected by loading (so may not be repeatable scope-scope unless they have the same weight profile).

So I'm wondering if I'm chasing something that isn't achievable.. like chasing the seeing.   Am I chasing after good polar alignment that just isn't achievable on a portable setup without doing drift alignment?     For instance, for unguided imaging.   

What is the practical accuracy, and repeatability of the RAPAS?  Has anyone here actually checked it on a portable installation.   I've asked Roland and he said he doesn't know, but that I should ask those on the forum.


Terri



  









RAPAS on Mach2

Terri Zittritsch
 

Hi all,
I've received a RAPAS to use with my Mach2 when I'm doing outreach or in other instances when I don't use a computer.   But I've not been very satisfied with the results from the polemaster I have, once I get down to actually measuring drift.. The actual drift implies much less accuracy than advertised, or that many claim to achieve.  I have not been able to get close to 30 arc seconds, but you wouldn't think this from the screen indication.   Given others experiences I've read about, I am also hopeful the RAPAS will do better, but I'm a bit unclear on this point.

So now I have the RAPAS, for a Mach2.  It is attached on the side of the mount, rather than through the central axis as we know the Mach2 doesn't have this capability.    I've also read that the mount needs to be leveled east-west accurately because the RAPAS needs to be vertical (it is fixed, not rotating in any installation).    But there is only so much accuracy in leveling the mount, or more importantly, getting repeatability.   A bubble level or electronic level is only so accurate.   I've read that .5mm of tripod settling on one foot with 1M separation between the feet will result in adding 2 arc minutes of alignment error.     I don't know how Chris Woodhouse calculated this, and maybe I'll draw this up as a geometry exercise, but you get my drift (pun totally intended).   Leveling by-leg is likely millimeters of inaccuracy or non-repeatability use to use.   0.5mm is totally unrealistic.  

I think the scope load moving side to side may introduce at least a .5mm if not more, or settling.    I'm reading in the RAPAS instructions I received, which implies that accuracy is effected by loading (so may not be repeatable scope-scope unless they have the same weight profile).

So I'm wondering if I'm chasing something that isn't achievable.. like chasing the seeing.   Am I chasing after good polar alignment that just isn't achievable on a portable setup without doing drift alignment?     For instance, for unguided imaging.   

What is the practical accuracy, and repeatability of the RAPAS?  Has anyone here actually checked it on a portable installation.   I've asked Roland and he said he doesn't know, but that I should ask those on the forum.


Terri



  









Re: No Light on CP4

George
 

Aw…shucks!!!    <G>  

 

Let me unfurl my cape and fly around a bit…   <G>

 

Seriously, I’m pleased that everything worked out well.

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-282-1513

Email:  george@...

 

From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of uncarollo2 <chris1011@...> via groups.io
Sent: Wednesday, April 15, 2020 9:28 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] No Light on CP4

 

Great! beats a trip back to AP. Thanks to George, my hero.

 

Rolando

 

 

 

-----Original Message-----
From: stinerjohn <stinerjohn@...>
To: main <main@ap-gto.groups.io>
Sent: Wed, Apr 15, 2020 6:30 pm
Subject: Re: [ap-gto] No Light on CP4

George came to the rescue.  Apparently, several years of putting the CP4 on the pier, removing it, and repeating the process night after night, bounced it around enough to loosen one of the boards. With his instructions, I opened the magic box, pressed the board back into place and fired it back up.  It now works like a charm. Thank you so much for the great assistance. 


Re: No Light on CP4

George
 

John,

 

You’re always most welcome.   I’m pleased that it worked out well.   Stay safe and enjoy!

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-282-1513

Email:  george@...

 

From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of stinerjohn@...
Sent: Wednesday, April 15, 2020 6:31 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] No Light on CP4

 

George came to the rescue.  Apparently, several years of putting the CP4 on the pier, removing it, and repeating the process night after night, bounced it around enough to loosen one of the boards. With his instructions, I opened the magic box, pressed the board back into place and fired it back up.  It now works like a charm. Thank you so much for the great assistance. 


Re: guiding calibration woes

Wayne Hixson
 

Excellent! The only trouble I had with Telescope was the telescope not moving. That was caused by two things - one, I hadn’t connected the telescope. 😄 and two, I hadn’t enabled pulse guide in the AP driver. I’m using Maxim very happily this very minute with Voyager. 


On Apr 15, 2020, at 9:35 PM, CurtisC via groups.io <calypte@...> wrote:

I got it working!  I had to change the guiding settings to use "Telescope" instead of "Guider Relays."  Makes sense.  Else why tell MaxIm to connect the "Telescope" using the V2 driver? 

I can calibrate and guide.  I wonder how I had it set in the past, when it worked.  Hmm.  

Wayne, what problem did "Telescope" give you?  If you don't use "Telescope," what do you use?

Anyway, I'm off and running.  Thank you, gentlemen.


Re: guiding calibration woes

CurtisC
 

I got it working!  I had to change the guiding settings to use "Telescope" instead of "Guider Relays."  Makes sense.  Else why tell MaxIm to connect the "Telescope" using the V2 driver? 

I can calibrate and guide.  I wonder how I had it set in the past, when it worked.  Hmm.  

Wayne, what problem did "Telescope" give you?  If you don't use "Telescope," what do you use?

Anyway, I'm off and running.  Thank you, gentlemen.


Re: Switching Power Supply

Phillip H Coker <pcoker36@...>
 

My other pastime is amateur radio and I have three switching power supply units for my radio equipment but one of them has now become surplus. I was concerned that a switching supply might not be up to the surge demands when the 1100 is slewing. But since you and Roland have good results with switching power supplies, it appears that this will not be a problem. Thanks for the response.

Phil

Phillip Coker
Florence, Colorado

On Apr 15, 2020, at 15:59, Mike Dodd <mike@mdodd.com> wrote:

On 4/15/2020 5:18 PM, Phillip H Coker wrote:
Would a 13.8v 23a switching power supply be suitable for my
AP1100/CP4? I operate only portable on a 100 a/h LIFePo battery but
would like to have an AC backup power supply.
Why not buy a Mean Well 15V 7A switching power supply from eBay. I use one for my AP1200, and Roland said he's used them with good results.

Mine is shown in this photo <http://astronomy.mdodd.com/observatory.html#EquipmentHolder> with the plastic cover I made for it.

--
Mike

Mike Dodd
Louisa County, Virginia USA
http://astronomy.mdodd.com


Re: No Light on CP4

Michael Hambrick <mike.hambrick@...>
 

Dittos on that. I set mine up and take it down every time too.


Best Regards

Michael Hambrick
ARLANXEO
TSR Global Manufacturing Support
PO Box 2000
Orange, TX 77631-2000
Phone: +1 (409) 882-2799
email: mike.hambrick@...


Re: No Light on CP4

Roland Christen
 

Great! beats a trip back to AP. Thanks to George, my hero.

Rolando



-----Original Message-----
From: stinerjohn <stinerjohn@...>
To: main <main@ap-gto.groups.io>
Sent: Wed, Apr 15, 2020 6:30 pm
Subject: Re: [ap-gto] No Light on CP4

George came to the rescue.  Apparently, several years of putting the CP4 on the pier, removing it, and repeating the process night after night, bounced it around enough to loosen one of the boards. With his instructions, I opened the magic box, pressed the board back into place and fired it back up.  It now works like a charm. Thank you so much for the great assistance. 


Re: No Light on CP4

Donald Rudny
 

Good to know, John.  I do the same with mine every night.  Thanks for letting everyone know.

Don Rudny

On Apr 15, 2020, at 1:30 PM, stinerjohn@... wrote:

George came to the rescue.  Apparently, several years of putting the CP4 on the pier, removing it, and repeating the process night after night, bounced it around enough to loosen one of the boards. With his instructions, I opened the magic box, pressed the board back into place and fired it back up.  It now works like a charm. Thank you so much for the great assistance. 

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