Date   

Drift Alignment To Help With Unguided Images

Tony Benjamin <tonybenjamin@...>
 

I have an AP 1100GTO AE. I have done a 280 pt pointing model. Even with that I can't get even a 2 min sub without star elongation.

So, I'm going to recheck my polar alignment to make sure thats dialed in. But what about drift alignment? How do you go about it? Is there any good sources on this for AP mounts and PEMPro - or other software?

Aside from the above - is there something else I need to do to get at least a 5 min unguided sub?


Re: Pillars of M16

Terri Zittritsch
 

Thanks Roland, Again, your shots are great.    The Rasa is a special scope.  One of our club members purchased an 11" rasa, and he gets a lot of signal pretty quick at f2.2.    He just purchased one of those 60M pixel CMOS sensors to use with it.    

Another of our club members said he's being sent a Stowaway soon, I guess his number came up, and he's incredibly excited.      


Terri


Re: Serial to bluetooth for CPC3

drgert1
 

@Steve: You have a good point there. It just so happens that all other cabling goes from the laptop to the end of the OTA. Focuser, camera, guide cam. And the connection to the mount serial port was the only one going the other way. Replacing it with BT cleans up the cabling for me considerably.
Clear Skies,
Gert


Re: GTO

Steven Panish
 

There is a rough daytime procedure in the handbox or CP manual, as I recall.  After that, PHD has a semi-automated drift alignment procedure that is very easy to use and is very accurate.  It has some other rougher methods as well but I haven't used them and can't remember if they require a view of the pole.  I found PHD's drift procedure easier to use than the PemPro drift align (sorry Ray!) but that will work too.  The drift align methods assume good orthogonality, which is a weakness if your scope is long FL.

Steve

On Fri, Aug 28, 2020 at 4:43 PM drgert1 via groups.io <drgert1=yahoo.com@groups.io> wrote:
Roland Christen has published a polar alignment routine in the manual. It uses park positions and slews to reference stars to line up the mount. It is good for a first shot. Refinement can be done with more precision using 3rd party tools.
Clear Skies,
Gert


Re: Serial to bluetooth for CPC3

Steven Panish
 

I'm not sure what bluetooth buys you, since your other devices are likely also connected to the PC via USB.  I use an 8 port USB3 hub, which has everything plugged into it, and a single USB3 output goes to a laptop.  The CP3 uses a typical serial to USB converter.  Everything works fine, but I'm not doing high framerate lucky imaging, which might push the bandwidth.  This appears to be a pretty intelligent USB hub, it works flawlessly.  I can then connect remotely to the observatory laptop via a remote console program and control the cameras, mount, focus, planetarium program, etc.  

Steve

On Fri, Aug 28, 2020 at 5:55 PM drgert1 via groups.io <drgert1=yahoo.com@groups.io> wrote:
Hi Woody,

Thanks! I went ahead and ordered the BT adapter (Amazon's brand). They're generic. The (almost illegible) piece of documentation that they copied on the website says that the 'Batt' input is OK up to 24V (Interesting). I'll try the AP 6V socket. I haven't used that connector since I have the mount >10years ago. :-) Will see what happens on the PC side. Using a Dell E7470 laptop with BT built in.

Clear Skies,
Gert


Re: Serial to bluetooth for CPC3

drgert1
 

Hi Woody,

Thanks! I went ahead and ordered the BT adapter (Amazon's brand). They're generic. The (almost illegible) piece of documentation that they copied on the website says that the 'Batt' input is OK up to 24V (Interesting). I'll try the AP 6V socket. I haven't used that connector since I have the mount >10years ago. :-) Will see what happens on the PC side. Using a Dell E7470 laptop with BT built in.

Clear Skies,
Gert


Re: Serial to bluetooth for CPC3

Woody Schlom
 

Gert,

 

I don’t think I ever used the CP3’s 6v outlet to power my RN-270.  But I did use it to power an old StarGPS.  The newer StarGPS units are now self-powered.

 

I’d have to look at the RN-270’s detailed specs to see if the mount’s 6v power supply would work, but I’m almost certain it would work.  Heck, if two AAA batteries will work, a good solid 6v power source sure should.

 

I can check, but I’m about 99% sure the RN-270 is also center-positive.  I can also check if necessary, but I think the RN-270’s external power socket is also 3.5mm.  It’s smaller than 5.5mm.

 

P.S.  There is a Win-10 version of COM2TCP, so they’re still selling it.  I also have one of the SkyFi-III serial to WiFi devices – and it does indeed work with everything I’ve got.  But I usually only use WiFi in the field for outreach events.  And WiFi is becoming a problem at the large events because so many mounts are now using it – and so we’re beginning to run into interference and not enough available channels problems.  Just ask anybody who’s tried to use WiFi at the Grand Canyon Star-Party.  And for those reasons, I prefer Bluetooth.

 

Woody

 

 

: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of drgert1 via groups.io
Sent: Friday, August 28, 2020 2:23 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Serial to bluetooth for CPC3

 

Thank you, Woody for the detailed info.

Do you remember the GTOCP3 has this 6V 'auxiliary' plug?  AP documentation says:
"This 6-volt output accepts 3.5 mm mono phone plugs. It’s original purpose was to power the Pentax 6x7 camera directly
from the mount. Its most common usage today is to power the StarGPS. It has also been used to power BlueTooth units
for wireless connection to the mount’s COM ports. Center is positive. It will supply up to 200mA of current."

Has anybody used this to actually power Bluetooth ?

Clear Skies,
Gert


Re: Serial to bluetooth for CPC3

drgert1
 

Thank you, Woody for the detailed info.

Do you remember the GTOCP3 has this 6V 'auxiliary' plug?  AP documentation says:
"This 6-volt output accepts 3.5 mm mono phone plugs. It’s original purpose was to power the Pentax 6x7 camera directly
from the mount. Its most common usage today is to power the StarGPS. It has also been used to power BlueTooth units
for wireless connection to the mount’s COM ports. Center is positive. It will supply up to 200mA of current."

Has anybody used this to actually power Bluetooth ?

Clear Skies,
Gert


Re: Serial to bluetooth for CPC3

Robert Berta
 

Woody has a good write up above. I had the Sky Saferi version....the Sky BT adapter was the one I used. You do need that utility he mentioned...COM2TCP for windows. I am not sure that is even available any more...if you go this route look for that first.

That being said it is a PITA to do it this way.  My SkyBT adaptor finally died so went with latest SkyFi adaptor which works extremely well. I use with both my Android phone and tablet running Sky Safari Pro as well as my PC and The Sky. I have both 900 CP 3 and 1100 CP 4 mounts. I tried to get the AP wireless on the CP4 to work with my Android tablet and my PC but despite many tries and firmware updates from AP, the wireless still won't hold a connection reliably....it keeps dropping the connection. AP knows about this and working on it for three years at least but still no solution. I suspect the wireless receiver in the CP4 is the issue. On the other hand the SkyFi works flawlessly over very long distances so I have been using that with both the two AP mounts, a Celestron GPS Pro fork mount, and a Ioptron Mini Tower Pro for outreach. I was hoping that the wireless issue would be solved on the APs since that was one of main features I wanted to use on the CP4 and reason for getting it with the 1100.


Re: Serial to bluetooth for CPC3

Woody Schlom
 

Gert,

 

It’s been many years now, but yes, I did that with my Mach1-GTO.  I used a RN-270 serial to Bluetooth adapter (RN is Roving Networks). 

 

The SkySafari guys used to sell the identical adapter but they called it their “SkyBT” adapter.  I’m pretty sure they’ve used up their inventory and aren’t selling it any more.  But the RN-270 is still available. 

 

The RN-270 can be self-powered with two AAA internal batteries (disposable or rechargeable), or through the RS-232 connector, or externally.  There’s an external jack that I think wants 4v – 9v DC (NOT 12v!).  I now power mine almost exclusively from one of those external rechargeable USB Lithium battery packs.  And when you power externally, you MUST insert two AAA rechargeable batteries inside the RN-270 as the external power goes through those internal batteries.  If you use disposable batteries inside – they’ll explode.  And if you don’t put any batteries inside, it just won’t work.

 

The internal AAA batteries are susceptible to ambient temperature.  And when the ambient temp. drops below around 55°, battery life drops too.  The solution is more expensive AAA Ultimate Lithium disposables (which work great in sub-freezing temperatures), or external power.

 

I used mine with my Mach1-GTO two ways.  1) controlling the mount with SkySafari-Pro running on an Android phone or tablet, and 2) controlling the mount with TheSkyX running on a Win-7 Pro laptop.  I haven’t tried it with Win-10 Pro yet, but I’m sure it still works.

 

The “trick” to using Bluetooth on a Win laptop (at least it used to be) is a little utility program called COM2TCP.  At least when I did this, you had to have that little utility to connect using Bluetooth.  And I see that there’s now a Win-10 version of COM2TCP.  So that tells me, it’s still needed.  The utility isn’t free, but it’s inexpensive and works.

 

After that, I don’t recall the settings for TSX, but I’m pretty sure I have them written down - somewhere.

 

P.S.  Wireless range with the RN-270 is amazing.  They claim up to 300m (330 ft.).  I don’t know about that, but I’ve successfully used mine at 75 ft.  Of course the further away it is from the Bluetooth device at the other end, the harder the transceiver has to work – and therefore, it uses the batteries faster.

 

Hope that helps.

 

Woody

 

From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of drgert1 via groups.io
Sent: Friday, August 28, 2020 12:01 PM
To: main@ap-gto.groups.io
Subject: [ap-gto] Serial to bluetooth for CPC3

 

Hello All,

Is someone using the CPC3 (older generation AP mounts controller) with serial ports with a Bluetooth adapter to connect to Windows10 laptop (with Bluetooth built-in capability) ?
Expectation is to have this transparent to AP driver on the laptop  and connected software.

I.e. this device mounted at CPC3 serial connector :
https://www.amazon.com/Gozens-Bluetooth-Adapter-External-Antenna/dp/B00R2N6BQ0/ref=pd_lpo_147_t_1/147-7007716-6003520?_encoding=UTF8&pd_rd_i=B00R2N6BQ0&pd_rd_r=cd5bfeee-f53e-488e-89af-6321f8fb34af&pd_rd_w=IYjNl&pd_rd_wg=ix6zt&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=N48JZ78EFVQ4NR05SZ5N&psc=1&refRID=N48JZ78EFVQ4NR05SZ5N

Clear Skies,
Gert


Re: GTO

drgert1
 

Roland Christen has published a polar alignment routine in the manual. It uses park positions and slews to reference stars to line up the mount. It is good for a first shot. Refinement can be done with more precision using 3rd party tools.
Clear Skies,
Gert


Serial to bluetooth for CPC3

drgert1
 

Hello All,

Is someone using the CPC3 (older generation AP mounts controller) with serial ports with a Bluetooth adapter to connect to Windows10 laptop (with Bluetooth built-in capability) ?
Expectation is to have this transparent to AP driver on the laptop  and connected software.

I.e. this device mounted at CPC3 serial connector :
https://www.amazon.com/Gozens-Bluetooth-Adapter-External-Antenna/dp/B00R2N6BQ0/ref=pd_lpo_147_t_1/147-7007716-6003520?_encoding=UTF8&pd_rd_i=B00R2N6BQ0&pd_rd_r=cd5bfeee-f53e-488e-89af-6321f8fb34af&pd_rd_w=IYjNl&pd_rd_wg=ix6zt&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=N48JZ78EFVQ4NR05SZ5N&psc=1&refRID=N48JZ78EFVQ4NR05SZ5N

Clear Skies,
Gert


Re: APPM and color cameras #APCC

W Hilmo
 

If the gain is about 1.14 electrons per ADU, it would work out just about right.

 

From: main@ap-gto.groups.io <main@ap-gto.groups.io> On Behalf Of inoddy@...
Sent: Thursday, August 27, 2020 4:08 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM and color cameras #APCC

 

Regarding the IMX571 it has a "75ke full welll" and 16 bit output. But 75k doesn't fit into 16 bits. How do you think they handle the extra 10k?


Re: GTO

Mike Dodd
 

On 8/28/2020 12:55 PM, CurtisC via groups.io wrote:
Use PEMPro.
PEMPro works great. So does drift alignment if you don't have PEMPro.

--- Mike


Re: GTO

CurtisC <calypte@...>
 

Use PEMPro.  Aside from that, be sure to check your documentation.  There are probably several methods of visual polar alignment, none of which involve Polaris, and there's probably a method of daytime alignment.


GTO

Shailesh Trivedi
 

I am a new owner of an AP1100 GTO. Though I have a RAPAS, due to my neighbor's tree growth, I am no longer able to see Polaris. Is there a method I can use to polar align without a clear view of polaris?

Any pointers to this newbie will help.

Seperately, any pointers for daytime polar (rough) alignment will also help.

Thanks in advance,

Shailesh Trivedi


Re: [ap-ug] Pillars of M16

Roland Christen
 

Focus drift is a problem of course. I focus at the beginning and in between each exposure. I have a thermometer nearby and have calibrated my focus knob and know pretty much where the knob needs to be as the temperature drops. In winter it drops fast by a large amount, as much as 10 - 15 degrees F at first when the sun sets, and then probably 5 deg per hour.

My 160 needs refocusing if the temperature drops 3 deg F. Right now, the temperature of the scope may start out close to 95F and drop to around 80 in the hour before sunset. After that it drops more slowly if the air is heavy with moisture. On a really clear fall night the temperature will change from high 80s to mid 50s after dusk. Then I won't be able to do 1 hour images.

Rolando


-----Original Message-----
From: Cheng-Yang Tan via groups.io <cytan299@...>
To: kmachhi@... <kmachhi@...>; main@ap-ug.groups.io <main@ap-ug.groups.io>; main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Fri, Aug 28, 2020 10:21 am
Subject: Re: [ap-gto] [ap-ug] Pillars of M16

HI Rolando,
   One thing that occurred to me this morning is the issue of focus drift due to temperature changes. Did you change focusing because of temperature or left it as is for the 1 hour shot and then refocused before the next shot? Or is the temperature in your observatory pretty steady throughout the night. For my FSQ106, I have to refocus every 1 degC change which means it can be as frequent as every 20 minutes. For my AP130, it is a lot more tolerant of temperature changes. 

cytan

On Thursday, August 27, 2020, 02:43:24 PM CDT, uncarollo2 <chris1011@...> via groups.io <chris1011@...> wrote:


Not unguided but modeled and nudge guided. By that I mean that the mount runs on a sky model which produces a custom rate that adjusts the RA and Dec tracking to what is needed to counter the atmospheric refraction, plus a minimal guiding. I use a Lodestar off-axis guider set for 10 second exposures and let the guider nudge the mount every once in a while to keep it on track.

Drift is complex when imaging close to the horizon and the tracking rate changes from minute to minute as the mount moves Westward and the object begins sinking into the southern horizon. You can get a simple model to work well for 5, 10 or even 15 minutes, but long 1 hour exposures are not going to work when imaging at or near 1 arc sec per pixel image scale.

In my second image, which was taken from several hours past the meridian, the guide star drifted 15 arc seconds in both axes due to atmospheric refraction in that 1 hour time frame.

Rolando


-----Original Message-----
From: Khushrow Machhi via groups.io <kmachhi@...>
To: main@ap-ug.groups.io
Cc: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Thu, Aug 27, 2020 2:18 pm
Subject: Re: [ap-gto] [ap-ug] Pillars of M16

Is the 1hr sub unguided with the Mach2? 

Khushrow

On Aug 27, 2020, at 11:17 AM, Roland Christen via groups.io <chris1011@...> wrote:


Hi Astronuts,

The recent M16 image that Ignacio posted presented me with a challenge to see what could be achieved here in Northern Illinois, using a 160EDF refractor. Challenge indeed it was. The object is only about 30 degrees above the horizon, directly over a huge mall and auto dealer complex, the Moon was quite nearby. Seeing down near the horizon is quite iffy in the best of nights. Plus, we still have smoke in the skies from out west. temperature was in the mid-80's so my camera would not cool down to below about -15C.

Even though i was shooting thru a narrowband H-a filter, I didn't know what to expect. On top of that I decided to go for broke and do 1 hour subs, two of them were combined in the images I just posted:

https://www.astrobin.com/full/7bqswe/0/
Full Res:
https://www.astrobin.com/full/7bqswe/0/?real=&mod=

While you may think this was insane, before you open the links, take a look at my sky conditions in the photo below:

<dummyfile.0.part>



Re: Pillars of M16

Roland Christen
 

Liam purchased the Cmos camera to use with his RASA 8" scope. I have not had a chance to use it myself on my scopes. From what I've seen, it is quite sensitive and has higher resolution due to the smaller pixels. From the limited amount of imaging we did one night with the RASA 8 scope, it seems that this combination should produce some great images, but it does not do well here under hazy and heavily light polluted skies. When stray light from the sky impinges on the scope aperture, it illuminates the insides of the scope, including the mirror, back and side walls. The light reflects off those surfaces and bathes the Cmos camera with extraneous light which greatly increases the background noise level. A scope like that with this sensitive Cmos camera really needs a pristine dark sky to work properly.

Rolando


-----Original Message-----
From: Terri Zittritsch <theresamarie11@...>
To: main@ap-gto.groups.io
Sent: Fri, Aug 28, 2020 7:09 am
Subject: Re: [ap-gto] Pillars of M16

I always check out your images Roland, which are always fabulous.    I hear from Liam that you've purchased a CMOS camera as well, an ASI1600 (I think mono).   I've only used CMOS and am interested in what your opinion is compared to your CCD.    The camera you use is one of the premium CCD cameras out there, and from your shots, either you're amazingly talented in processing or your data is pretty clean.    Probably a lot of both I suspect given your experience.    I'd love to have you compare and contrast CCD and CMOS.    There was a recent article in sky and telescope on this topic (i forget what month) when testing out a large mono CMOS..  I didn't think it was very informed when talking about things such as resolution, since most of us who started with DSLRs have had small pixels for quite a long time (it's not new by a long shot).    Although they did mention the noise differences.

Terri


Re: [ap-ug] Pillars of M16

Cheng-Yang Tan
 

HI Rolando,
   One thing that occurred to me this morning is the issue of focus drift due to temperature changes. Did you change focusing because of temperature or left it as is for the 1 hour shot and then refocused before the next shot? Or is the temperature in your observatory pretty steady throughout the night. For my FSQ106, I have to refocus every 1 degC change which means it can be as frequent as every 20 minutes. For my AP130, it is a lot more tolerant of temperature changes. 

cytan

On Thursday, August 27, 2020, 02:43:24 PM CDT, uncarollo2 <chris1011@...> via groups.io <chris1011@...> wrote:


Not unguided but modeled and nudge guided. By that I mean that the mount runs on a sky model which produces a custom rate that adjusts the RA and Dec tracking to what is needed to counter the atmospheric refraction, plus a minimal guiding. I use a Lodestar off-axis guider set for 10 second exposures and let the guider nudge the mount every once in a while to keep it on track.

Drift is complex when imaging close to the horizon and the tracking rate changes from minute to minute as the mount moves Westward and the object begins sinking into the southern horizon. You can get a simple model to work well for 5, 10 or even 15 minutes, but long 1 hour exposures are not going to work when imaging at or near 1 arc sec per pixel image scale.

In my second image, which was taken from several hours past the meridian, the guide star drifted 15 arc seconds in both axes due to atmospheric refraction in that 1 hour time frame.

Rolando


-----Original Message-----
From: Khushrow Machhi via groups.io <kmachhi@...>
To: main@ap-ug.groups.io
Cc: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Thu, Aug 27, 2020 2:18 pm
Subject: Re: [ap-gto] [ap-ug] Pillars of M16

Is the 1hr sub unguided with the Mach2? 

Khushrow

On Aug 27, 2020, at 11:17 AM, Roland Christen via groups.io <chris1011@...> wrote:


Hi Astronuts,

The recent M16 image that Ignacio posted presented me with a challenge to see what could be achieved here in Northern Illinois, using a 160EDF refractor. Challenge indeed it was. The object is only about 30 degrees above the horizon, directly over a huge mall and auto dealer complex, the Moon was quite nearby. Seeing down near the horizon is quite iffy in the best of nights. Plus, we still have smoke in the skies from out west. temperature was in the mid-80's so my camera would not cool down to below about -15C.

Even though i was shooting thru a narrowband H-a filter, I didn't know what to expect. On top of that I decided to go for broke and do 1 hour subs, two of them were combined in the images I just posted:

https://www.astrobin.com/full/7bqswe/0/
Full Res:
https://www.astrobin.com/full/7bqswe/0/?real=&mod=

While you may think this was insane, before you open the links, take a look at my sky conditions in the photo below:

<dummyfile.0.part>



Re: APPM and color cameras #APCC

Nick Iversen
 

Regarding the IMX571 it has a "75ke full welll" and 16 bit output. But 75k doesn't fit into 16 bits. How do you think they handle the extra 10k?

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