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EQ6-R Pro and APT Plate Solving - Newbie Configuration Question

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#1 Eddie_42

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Posted 12 January 2019 - 01:47 AM

Hey all,

 

I have APT configured to use plate solving via the PlateSolver2 and the All Sky Plate Solve (ASPS) interfaces. I have uploaded a few of my M42 subs and they solve appropriately. What I'd like to ask, because I am a newbie, is what the proper sequence is for aligning my mount/scope for the nights images. My first night out ran into a hiccup of not having plateSovler2 installed, and thus required the hand controller. Luckily I brought it with me to the site. Since that night, I got the software, tested as mentioned, but have yet to find a night worthy of the setup. But that will come, eventually.

 

I am guessing a sequence akin to:

1 - polar align my mount, currently just using the built in polar scope and a smart phone app. I don't have a pole-master or other such device (its on my wishlist).

2 - set the scope to a "home" positions, roughly in the Polaris direction.

3 - Slew to an object using the GOTO feature within APT

4 - take a shot

5 - plate solve

6 - sync

7 - ______

 

or 4.1 use the AUTO feature in APT, it does it all 4 through 7

 

Does this align the scope, or just provide a correction to the local object. I don't image chasing more than one object a night (still sorting out battery life issues). But if I chase a second, thats just a plate solve and correction away.  I'd love any and all advice towards a successful night out using the laptop and APT as the primary driver, no hand controller.

 

The one and only night I've gone out (recall, im a newbie) I didn't have plate solver installed on my laptop, and to revert to the hand controller.  No guidance scope or other drivers, just the FOV and a plate solve.

 

Thanks for the tips!



#2 ks__observer

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Posted 12 January 2019 - 04:16 AM

I am a bit if a newbie here myself on this topic:

I just bought the EQ6R a few weeks ago, and I only got plate solve going recently.

My understanding is you need to do at least a one star align so APT knows the mount position.



#3 Mert

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Posted 12 January 2019 - 05:22 AM

If I'm not mistaking, APT has platesolving but that is used in Pointcraft and automated

meridian flip. ( Version 3.62 )

I use Astrotortilla for finding and centering objects, no finder scope is used.

First do your polar alignment as good as possible ( if using a polarscope then use

for example the EQMOD function that will show you Polaris in the correct

rotation, then adjust the mount )

 

1) I just slew the scope to some desired object using CDC, then activate 

capture and solve in Astrototortilla with the Re-slew to target and sync options selected.

This will get the scope centered on the object.

2) Using Pointcraft from within APT you solve the frame taken and then you can use

the AIM and GOTO++ to move the scope tiny bits to get the framing you like.

 

 

Hope this helps a bit!


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#4 Eddie_42

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Posted 12 January 2019 - 10:25 AM

Definitely think I can do it all in APT. I am just not sure how to work it through, need some field experience.

 

The "star align" approach seems almost on par with a "DSO and plate solve" in terms of accuracy.  From what I've read, the Star align is a GOTO, with a manual correction to center the thing. Perk that its likely a brighter star, so I could take a moment to get the Focus Mask on and tweaked at the start of the night.

 

I have also seen some threads where people take a Shot and Plate Solve from the home position, before any slew. Again, unsure of the plus and minus, but seems intriguing.

 

From the APT manual regarding Planetariums - Currently supported are Cartes du Ciel (CdC), Computer Aided Astronomy (C2A), SkytechX, Hallo Northern SKY (HNSKY) and Stellarium. Thats just a layer of complication I dont want to tackle at this stage. One trick at a time.



#5 AhBok

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Posted 12 January 2019 - 01:27 PM

You don’t need a planetarium program in APT to get started, but once you get the hang of platesolving, you will want to add a planetarium app. I use CdC.

After polar aligning, I go to objects in APT and choose a bright star near my object of interest and slew. Since I do not do a star alignment, I’m generally off target. Then I do a blind solve in Pointcraft and when solving is complete I click sync. The I slew to the star again and it is generally in the center of the field. I then use my Bahtinov mask to fine focus and the in the object locator choose my object and slew to it.
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#6 Eddie_42

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Posted 12 January 2019 - 10:52 PM

Awesome!! Thats about how I envisioned it, but I wanted to make sure I wasn't missing something.



#7 the Elf

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Posted 13 January 2019 - 05:06 AM

To use the polar scope you have to adjust the reticle first as described in the manual. Did you do that? Can easily be performed at daytime with some target nearby. Next you have to make sure the tripod is level. The bubble level in my EQ6-R is way off so I use a big bubble level in the center of the tripod and put the mount on after that. Next you have to rotate RA so that the reticle is level. Adjust it to some edge of a house or a tower. Mark the position with a black felt pen!

At night look to the sky and identify polaris (alpha UMI) and kochab (beta UMI). The direction of kochab in the sky is where polaris needs to be in the reticle. No need for a smart phone app. When you enter date, time and position in the hand controller it tells you the position of polaris on the clock dial. No matter if you get the correct positon from some app, from kochab, from the controller or elsewehre: it only works if the reticle is centered and level! I'm doing 15 min subs with manual polar alignment without any trails.

Find a few photos here:

https://www.cloudyni...date-avx-eq6-r/

 

I recommend you train PEC (peridoic error correction). If you get an autoguider soon you can do it with that. If you don't you can either find a fellow astronemer who has got one or you can even train manually using a cross hair eyepiece. The correction is stored permanently in the mount.


Edited by the Elf, 13 January 2019 - 05:10 AM.


#8 ks__observer

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Posted 13 January 2019 - 08:59 AM

Re Polar Align:

Sharpcap is so easy and accurate that it seems most reccomend that for PA.

PA tolerance is function of several factors:

http://celestialwond...xErrorCalc.html

Re bubble level: hadn't thought about cone error before but agree.



#9 Eddie_42

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Posted 13 January 2019 - 10:42 AM

Thanks for the PA tips, though I am not sure what prompted it???  I was not aware of the natural alignment with UMI Beta. Learn something new every day...and i havent even had my coffee yet.

 

My mount bubble level is decently close, ive used it in the living room with a shop level, just to test. I do want to pick up a small one to put in my parts box for nights i venture away from the house.  Geometry wise though, perfect level doesnt change the quality of the alignment, any better or worse than slightly off. Having the polar axis of the mount pointed to the right spot is the critical part, a level mount just provides a good base, and the adjustment knobs are more intuitive to use (left right up down) versus some diagonal value. Level does help stability and tipping problems, for certain, but you'd have to be pretty far off for that.

 

alignment of my reticle is good out of the box, I can twist 180deg around with Polaris in the ring and it stays in the ring. Pretty happy i didnt have to touch that part.  I do wish i could change the hour angles in the reticle when at 'home' position. Right now, my 'home' 12 oclock is more around 1:30 or 2o'clock. Good idea to find vertical in the day light and sharpie the scope. I have struggled with that in the dark, trying to know how "up" is "up", while cranking my neck sideways and standing on my head trying to get polaris in the reticle. A chair helps some, but the **** tripod is right in the way.  One day i will get a big-boy toy for that, and it wont be an issue.



#10 ks__observer

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Posted 13 January 2019 - 10:53 AM

Geometry wise though, perfect level doesnt change the quality of the alignment, any better or worse than slightly off. Having the polar axis of the mount pointed to the right spot is the critical part, a level mount just provides a good base, and the adjustment knobs are more intuitive to use (left right up down) versus some diagonal value. Level does help stability and tipping problems, for certain, but you'd have to be pretty far off for that.

NS tripod does not have to be level but EW off level will cause cone error.


Edited by ks__observer, 13 January 2019 - 11:35 AM.


#11 Eddie_42

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Posted 13 January 2019 - 11:01 AM

More of a question here - my understanding of cone error is the quality of parallel between the RA axis and the optical train, most commonly in the clamping plates?



#12 ks__observer

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Posted 13 January 2019 - 11:38 AM

Note edit: "NS ... does not …"

The saddle and the clamps can cause cone error.

Just imagine if the tripod was 30deg tilted E or W -- the RA axis will not turn about the celestial NS pole axis.



#13 Eddie_42

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Posted 13 January 2019 - 03:33 PM

Note edit: "NS ... does not …"
The saddle and the clamps can cause cone error.
Just imagine if the tripod was 30deg tilted E or W -- the RA axis will not turn about the celestial NS pole axis.


Polar alignment means the central axis of the mount is pointed to the NCP, and thus parallel to the earth rotation axis.

To quote a user from a thread on this topic dec 2016 "It's as crucial as the quality of the bubble levels that come with mounts".

Wholly concur that level makes things easy. And leveling is quick. But the crucial part is the alignment, getting that axis parallel. Should a user get 30deg off in east west...i would argue that they aren't in alignment.

#14 ks__observer

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Posted 13 January 2019 - 04:32 PM

I agree that the affect of being slightly off level is probably minor.



#15 MikeECha

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Posted 13 January 2019 - 08:03 PM

Hey all,

 

I have APT configured to use plate solving via the PlateSolver2 and the All Sky Plate Solve (ASPS) interfaces. I have uploaded a few of my M42 subs and they solve appropriately. What I'd like to ask, because I am a newbie, is what the proper sequence is for aligning my mount/scope for the nights images. My first night out ran into a hiccup of not having plateSovler2 installed, and thus required the hand controller. Luckily I brought it with me to the site. Since that night, I got the software, tested as mentioned, but have yet to find a night worthy of the setup. But that will come, eventually.

 

I am guessing a sequence akin to:

1 - polar align my mount, currently just using the built in polar scope and a smart phone app. I don't have a pole-master or other such device (its on my wishlist).

2 - set the scope to a "home" positions, roughly in the Polaris direction.

3 - Slew to an object using the GOTO feature within APT

4 - take a shot

5 - plate solve

6 - sync

7 - ______

 

or 4.1 use the AUTO feature in APT, it does it all 4 through 7

 

Does this align the scope, or just provide a correction to the local object. I don't image chasing more than one object a night (still sorting out battery life issues). But if I chase a second, thats just a plate solve and correction away.  I'd love any and all advice towards a successful night out using the laptop and APT as the primary driver, no hand controller.

 

The one and only night I've gone out (recall, im a newbie) I didn't have plate solver installed on my laptop, and to revert to the hand controller.  No guidance scope or other drivers, just the FOV and a plate solve.

 

Thanks for the tips!

Hello there

 

To answer your question, that just makes a correction to the sky map.

 

I am somewhat new too and with my modest understanding of how all these works this is what I see.

 

You are going to be imaging withou guiding. Nothing wrong with that. Just that limits your exposure time. That also means you will be depending on first, the unguided tracking capabilities of you mount and then your manual polar alignment thru the polar scope.

 

Very good polar aligment is the key for maximazing your unguided exposure time before star trails appear. You have very little to nothing you can do about the mount quality. It is what it is (do not know your mount). The better the polar aligment the longer the unguided exposures without star trails before the tracking quality of your mount becomes the dominant factor.

 

The polar aligment is where you can make the difference. If your mount works like mine, this is what works for me.

 

Before you polar align at night, make sure you polar scope if perfectly aligned with your mount RA axis and that the recule is oriented straight up when the counterweight is pionting straight down to the floor. This is a one time adjustment better done during daytime. Just point at a distant point and adjust the polar scope such that the reticule rotates concentrically with the point when you loosen the RA clutch and rotate the mount manually. Your mount may have a specific procedure for that. At night, you start your set up by leveling the top of tripod the best you can. Put the mount on the tripod and balance it.

 

Now, the manual polar aligment part is easy. Use the az and alt knobs to put polaris on the reticule according to you location and time as accurate as you can. From here you should refine your polar aligment. Your mount/hand controller shoud have a procedure specifically for polar aligment using a specific stars. Just follow it.

 

Also check that Polaris is visible on you DSLR LCD screen when you see it thru the polar scope. If not, adjust the telescope, not the polar scope.

 

Noticed that I have not mentioned plate solving yet. That is because plate solving has a different purpose. Plate solving is done to improve the map of the sky for gotos. BUT, all those goto coordinates are referenced to the celestial pole. Thus the importance of good polar aligment.

 

I also use APT and it only takes me one or two solved image to get every star i goto right in the middle of my dslr screen.

 

I hopes this helps. 



#16 Eddie_42

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Posted 13 January 2019 - 09:29 PM

Hey,

 

Gear details in the signature - Using the Skywatcher EQ6-R Pro, very capable mount. I have gone upto 5min on a single sub in some testing, but the sky pollution is too much for that (bortle 6 in my area). Havent really pushed the longest max i can due to the background issues.  My one and only long integration time shot I used 150sec exposures. Tracking wasnt a thing. 

 

Your comments on APT and plate solve are what I am after, the point, shoot, correct, shoot, correct.....twiddle thumbs for hours.  About what I expected, just wanted to make sure i wasnt skipping over a vital step.  I just need my skies to cooperate, and I can go test this theory.



#17 the Elf

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Posted 14 January 2019 - 12:56 AM

For the .... leg: you can undo the az bolt on the tripod base and put it on the other side if you like the gap between two legs under the polar scope. There is a hole and a thread on the opposite side.

For the polar alignment the position of the mount does not matter. But if you have a mark on the mount where the reticle is level that only works if the mount itself is level. If you have a different option to turn the reticle to the correct position (like a building nearby) or if you use any other method of polar alignment no need to worry about a level tripod. The bubble level is recommended over the mounts internal level as loosening a tripod leg with the mount on top is risky. 

I picked up the topic as it was point 1 in your list. It is the only point that needs a physical adjustment and the only one that cannot be calculated away.



#18 Eddie_42

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Posted 14 January 2019 - 11:16 AM

I picked up the topic as it was point 1 in your list. It is the only point that needs a physical adjustment and the only one that cannot be calculated away.

Ah, no worries, sparked a fun conversation about geometry anyhow. 

 

I have not dug into the tripod to see about that reversal, I might have too. Its rather uncomfortable currently to get my eye in postion for the PA scope. Not impossible, just a pain (and Im lazy, i like simple).  How does this reversal effect the POST (black spire) that the mount pushes against on the tripod platform? or is that the "az bolt" you refered to? I will look at the mount later tonight.



#19 the Elf

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Posted 14 January 2019 - 11:43 AM

IMG_6039.JPG

 

Sorry, I'm not a native speaker. This is the thing I'm tasking about. Just put in the hole on the other side and the leg is gone.



#20 Eddie_42

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Posted 14 January 2019 - 02:13 PM

oh man...they made that REALLY complicated didnt they.   lol.gif

 

No language issues, if anything its a limited vocabulary on my end.  Vielen Dank!




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