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Order of operations for alignment, polar align, guide, etc?

Astrophotography Beginner Celestron EQ Imaging Polar Alignment Software Mount Equipment
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#1 Nathan_2448

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Posted 03 October 2022 - 10:57 PM

Hello, this is my first ever post. I’m new to astrophotography and need a bit of help from the more experienced astronomers. I am using a celestron 9.25 SCT with an evolution goto/nexstar mount on a wedge to make it an EQ Mount, an f/6.3 reducer, Asi662 mc camera, 50mm guide scope and camera. I know what steps need to be taken but I’m not sure which order would be best. Should I do it in this order?

1) polar align (using either cpwi or sharp cap)

2) 2 star align (using cpwi)

3) add a few reference/calibration stars (cpwi)

4) plate solve (sharp cap)

5) auto guide (with PHD2) 

 

Any/all feedback/information/advice is greatly appreciated. Thanks a lot and clear skies everyone! 

 

 


Edited by Nathan_2448, 04 October 2022 - 06:00 AM.


#2 D_talley

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Posted 03 October 2022 - 11:25 PM

IF you are setting up every night then the first thing is to Polar Align.

you can do a one or two star alignment next.

I would just plate solve since that would tell the scope and your astronomy software where the scope is pointing.

Go and auto guide on your target.


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#3 joshman

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Posted 03 October 2022 - 11:56 PM

  1. (SharpCap) Get rough focus - close enough for plate solving to work
  2. (SharpCap) Polar Align
  3. (PHD2) Slew close to Celestial Equator and Calibrate guiding (if required)
  4. (Imaging Software / SharpCap) Slew to target
  5. (Imaging Software/Manually) Change to imaging filter (if required - only if filter drawer or EFW)
  6. (PHD2 or Imaging Software) Start Autoguide
  7. (SharpCap or Imaging Software) Properly Set focus
  8. (Imaging Software) Start Imaging.

Edited by joshman, 03 October 2022 - 11:57 PM.

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#4 blazek

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Posted 04 October 2022 - 01:51 AM

Well, your setup is quite challenging for imaging, so the first and most important is to be very patient and not to give up at the first problem . I do not want to discourage you , not at all , especially because I also started on similar hard way.

With this camera and the focal length of your scope you will have extremely small field of view. So you'll be limited to planetary imaging (you do not need guiding for that) and some very small DSOs (like planetary nebulae, small galaxies, ..).

If you have DSLR camera, consider as an alternative to your 662. Also , guiding of scope with such focal length by small guiding scope is challenging. 

So what to do: 

Fix your guiding scope as good as you possibly can

Align your guiding scope with your main scope as accurate as you possibly can . You can do that during the daylight aiming at some distant object like communication tower or any fixed point far away . Align it as precise as you possibly can as you might be using you guiding scope for star alignment or plate solve . 

Next steps should be done during the night without the wind

-do polar align .either use Sharpcap (you need paid license for polar alignmen) or use NINA software which is free and has excellent 3 point polar alignment. If your polar alignment fails , use your guidescope to do polar alignment . Of course condition is that the main scope and guiding scope are very precisely aligned. Either way make sure that you put proper focal length into the software setup, whichever software you use

-after polar align , you could try to do 3 star alignment . With your setup it will be challenging to get the star into the view at you main scope. You can use your guiding scope if well aligned with the main scope to do 3star alignment. Far better is that you do plate solving instead of 3star alignment. By using any planetarium software point your scope to the desired object. It is assumed that you downloaded plate solving software (ASTAP, Astrotortilla, or any other. ) and belonging index files.

By imaging software initiate plate solving process, enabling synchronization with the mount. The routine will take the image, will try to plate solve and correct your mount, and will repeat it until the object is in the center of your scope. Due to small field of view , plate solve might fail. Use your guiding scope instead of the main scope. If they are aligned well, you will get your object in the center of both scopes. 

-start PHD2, connect equipment, point your scope to close to celestial meridian and equator. Let software finds guiding star and initiate calibration . 

- go back to your desired object and if not in the field of view, initiate plate solve again. 

-start guiding , initiate your imaging sequence

 

-If you wish to avoid many frustrations do the following 

Consider camera with larger sensor

Consider OAG (one with large prism) instead of guiding scope

because the small sensor of your camera, combined with small pixel and long focal length could be the source of frustration


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#5 Nathan_2448

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Posted 04 October 2022 - 02:05 AM

Thanks for the replies! Does anyone know if SharpCap will be able to communicate with the Evolution Mount? I’ve read some forums saying it will be able to work easily and others saying it’s impossible to polar align with sharpcap because sharpcap won’t be receiving any data from the Mount/cpwi. 



#6 F.Meiresonne

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Posted 04 October 2022 - 02:08 AM

Hello, this is my first ever post. I’m new to astrophotography and need a bit of help from the more experienced astronomers. I am using a celestron 9.25 SCT with an evolution goto/nexstar mount on a wedge to make it an EQ Mount, an f/6.3 reducer, Asi662 mc camera, 50mm guide scope and camera. I know what steps need to be taken but I’m not sure which order would be best. Should I do it in this order?

1) polar align (using either cpwi or sharp cap)

2) 2 star align (using cpwi)

3) add a few reference/calibration stars (cpwi)

4) plate solve (sharp cap)

5) auto guide (with PHD2) 

 

Any/all feedback/information/advice is greatly appreciated. Thanks a lot and clear skies everyone! 

You can skip the 2 star alignment if you are using plate solving.


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#7 Nathan_2448

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Posted 04 October 2022 - 02:23 AM

I appreciate the detailed response Blazek, I plan to buy the zwo asi294mc pro camera sometime soon which has a much larger sensor. Combined with the focal reducer I think the field of view should be sufficient for some great deep space imaging (until I buy a Hyperstar). I ended up getting the 50mm guidescope as it was being sold for a very good price, thought I should try it and if it doesn’t work I’ll pick up a celestron OAG. I hope that my Mount won’t have much trouble communicating with any softwares like Nina, sharpcap, etc. but I’ll give them a try. I’m expecting clear skies here in upstate New York this Wednesday, I’ll experiment with everything you guys have mentioned. 
 

Anyone with more input, feel free to add onto this thread! 
 

- Nathan 



#8 c131frdave

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Posted 04 October 2022 - 07:23 AM

Having started almost exactly the same way you are, save yourself some grief and keep the scope you have in the garage.  Pull it out to look at planets and what not visually from time to time.  Impress the neighbors.  Then go and get a decent EQ mount and short refractor.  

 

I realize you are going to ignore this post.  I did.  That's fine.  Just remember it 2 months from now.


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#9 danny1976

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Posted 04 October 2022 - 07:49 AM

Thanks for the replies! Does anyone know if SharpCap will be able to communicate with the Evolution Mount? I’ve read some forums saying it will be able to work easily and others saying it’s impossible to polar align with sharpcap because sharpcap won’t be receiving any data from the Mount/cpwi. 

If I’m not mistaken Sharpcap doesn’t need a connection with the mount to perform polar alignment. I only have the guidescope+cam connected and the polar alignment routine works just fine.

 

Then I open APT for imaging and all the rest.


Edited by danny1976, 04 October 2022 - 01:25 PM.

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#10 idclimber

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Posted 04 October 2022 - 07:59 AM

I appreciate the detailed response Blazek, I plan to buy the zwo asi294mc pro camera sometime soon which has a much larger sensor. Combined with the focal reducer I think the field of view should be sufficient for some great deep space imaging (until I buy a Hyperstar). I ended up getting the 50mm guidescope as it was being sold for a very good price, thought I should try it and if it doesn’t work I’ll pick up a celestron OAG. I hope that my Mount won’t have much trouble communicating with any softwares like Nina, sharpcap, etc. but I’ll give them a try. I’m expecting clear skies here in upstate New York this Wednesday, I’ll experiment with everything you guys have mentioned. 
 

Anyone with more input, feel free to add onto this thread! 
 

- Nathan 

I do not recommend the 294mc. Instead you should look at a 533mc or the 2600mc. But I question your entire plan....

 

You are on a very difficult road with that mount and that scope. That mount is simply not precise enough to match the image scale you will get out of any modern CMOS camera. The SCT is fine but much more suitable to an experienced imager. 

 

Your talk of Hyperstar is equally concerning. You are in my humble opinion making the classic beginner mistake. You are focused on the large fancy scope and not the mount or learning AP. If you really want to image well with a 9" or larger scope you need at a minimum a CEM70 mount. 

 

I speak from experience and was right where you are now just a few years ago. I started with a 12" SCT. 

 

By far the most important piece of equipment in imaging is the mount. This is the one place where it is almost impossible to go too big or too expensive. In order to get my 12" SCT imaging well I purchased a Paramount MX+, which is not an insignificant investment. 

 

The standard recommendation is an 80mm refractor. Pair that with the best equatorial mount you can afford. Either an GEM28 HEQ5 on the entry level price range or CEM70 if you want to be able to image with the SCT, or more if your budget allows.

 

You can do this with a larger scope but the budget will be higher. You will also have less room for any error. To image at sub arc second image scales requires everything to be running perfectly. This includes guiding, tracking, polar alignment, focusing, backspacing, tilt, collimation and about a dozen other things. If any are not perfect your images can and will be a frustrating mess. 

 

Then there is the practical side. Most of imaging is limited by seeing conditions. This limits effective resolution to about an arc second. My 4" refractor is not far off from that and my 6" is over that line. My SCT is 0.33 arc seconds and well below the typical seeing limit. There is little if any effective increase in resolution between the 6" scope and the 12. So even after you get your 9.25" SCT working perfectly on a good equatorial mount your images are only marginally more detailed than someone with an Esprit 120. And the Esprit can image much larger targets than you can because of the much larger field of view. 

 

Even with an observatory and a very capable mount, I image most of the time with the refractor. The SCT only comes out in the spring during galaxy season. With my new SVX152 it will come out even less for that if at all. 


Edited by idclimber, 04 October 2022 - 08:00 AM.

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#11 VincenzoZito

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Posted 04 October 2022 - 08:03 AM

Hi,

1) polar align

2) plate solve

3) auto guide.


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#12 fewayne

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Posted 05 October 2022 - 12:00 AM

Second idclimber's comments. Please don't feel we're knocking your choices or your judgement -- as Bob likes to say, this is not at all intuitive. I moved to a long-focal-length catadioptric scope only after getting a couple years of wide-field refractor imaging under my belt, due to advice on this and other fora.

 

SO GLAD I did that. Believe me, the 8" scope was quite the challenge, even with that experience. For a simple example, trying to polar align via plate solving through the main scope was a PITA, because with a 30' field of view the necessary adjustments were invariably outside the FOV and so I had to repeat the alignment process again and again until it was close. I think your FOV will be even smaller than mine. I'm running an iOptron CEM70  mount and I still struggle with getting decent stars at that tiny image scale.

 

A Hyperstar would increase the FOV (and ameliorate the really slow scope), but those come with their own problems -- it's a rig that demands a lot of precision and fine-tuning know-how.


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#13 Nathan_2448

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Posted 05 October 2022 - 09:03 AM

Hello all! I just checked this thread and noticed all of the responses, a bit of a bummer but nonetheless much appreciated. As a beginner I am starting to realize my silly beginner mistakes but with your help I am getting on the right path. For reference - I decided on this setup as I was mainly focused on planetary imaging with some deep sky visual observation. My first night out I was able to capture some great photos of jupiter and it instantly got me hooked. I spent many more amazing nights out learning and exploring but quickly came to realize that as much fun as planetary imaging is, I am limited to a finite number of objects and will soon want to dive deeper into space. Now I am faced with the challenge of imaging DSO with an entire setup that does not want anything to do with that. Although not ideal, this will be a great learning experience and I feel I am up for the challenge. Tonight is forecasted to be ideal seeing conditions with 0% cloud coverage, 1mph wind, 10+ mile visibility, low humidity, and cool temperatures. Upgrading to a quality EQ mount is inevitable for the future, but not something that will happen within these next few months. For now I will make the best with what I have and give it my best shot! If it ends up being a complete disaster I can use this as an opportunity to further improve my skills/understanding of planetary imaging while I save money/decide on an EQ mount and smaller scope. For anyone that's interested, I will make a follow-up post tomorrow evening with an update on how things went and *hopefully* share some images of my results. This will be my complete setup tonight ----

 

Clestron 9.25 SCT

Evolution mount with HD Pro Wedge

Celestron F/6.3 focal reducer

ZWO ASI662MC

105mm backfocus spacers 

Orion 50mm guidescope

Orion Starshoot Autoguider

Bahtinov mask

Nina, CPWI, PHD2, ASTAP


Edited by Nathan_2448, 05 October 2022 - 09:10 AM.

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#14 Nathan_2448

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Posted 06 October 2022 - 07:56 AM

I’ve just come back in from the cold as the sun was rising and the stars faded away. I ran into many problems such as the wedge and Mount not wanting to align, drift, incorrect backfocus, and my guide cam didn’t arrive yesterday as expected so I tried out my backup which was no good ( Svbony SV105). Since everything was out of focus and not tracking/guiding correctly I wasn’t able to stack any of my images. It was a mess but it’s always an amazing night when I’m out under clear skies, was a great time! This is what I was able to scrape up from my first night of deep sky imaging. Not good by any stretch of the imagination, but it’s a start! Any advice? I’m starting to look at actual EQ mounts and better DSO cams.

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#15 idclimber

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Posted 06 October 2022 - 08:05 AM

Well, it looks like the trapezium so you definitely win there. All the stars look round and you have some nice color. I assume your exposure were short and you were live stacking??

 

These are the kind of photos that got me hooked and looking at better mounts, etc. You will get similar results during galaxy season in the spring. A lot of good targets then for this type of imaging. 


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#16 Jay6879

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Posted 06 October 2022 - 08:28 AM

Hello, this is my first ever post. I’m new to astrophotography and need a bit of help from the more experienced astronomers. I am using a celestron 9.25 SCT with an evolution goto/nexstar mount on a wedge to make it an EQ Mount, an f/6.3 reducer, Asi662 mc camera, 50mm guide scope and camera. I know what steps need to be taken but I’m not sure which order would be best. Should I do it in this order?

1) polar align (using either cpwi or sharp cap)

2) 2 star align (using cpwi)

3) add a few reference/calibration stars (cpwi)

4) plate solve (sharp cap)

5) auto guide (with PHD2) 

 

Any/all feedback/information/advice is greatly appreciated. Thanks a lot and clear skies everyone! 

 

Here's how I roll..

 

 

 

1) run an autofocus routine

2) take my flat frames

3) check focus on guide scope

4) polar align

5) go to object and check framing/rotation and adjust as needed 

6) do a guiding calibration

7) start imaging 

 

I prefer to do the polar aligning after I've done anything that would require me touching the setup


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#17 bbasiaga

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Posted 06 October 2022 - 10:39 AM

Hello all! I just checked this thread and noticed all of the responses, a bit of a bummer but nonetheless much appreciated. As a beginner I am starting to realize my silly beginner mistakes but with your help I am getting on the right path. For reference - I decided on this setup as I was mainly focused on planetary imaging with some deep sky visual observation. My first night out I was able to capture some great photos of jupiter and it instantly got me hooked. I spent many more amazing nights out learning and exploring but quickly came to realize that as much fun as planetary imaging is, I am limited to a finite number of objects and will soon want to dive deeper into space. Now I am faced with the challenge of imaging DSO with an entire setup that does not want anything to do with that. Although not ideal, this will be a great learning experience and I feel I am up for the challenge. Tonight is forecasted to be ideal seeing conditions with 0% cloud coverage, 1mph wind, 10+ mile visibility, low humidity, and cool temperatures. Upgrading to a quality EQ mount is inevitable for the future, but not something that will happen within these next few months. For now I will make the best with what I have and give it my best shot! If it ends up being a complete disaster I can use this as an opportunity to further improve my skills/understanding of planetary imaging while I save money/decide on an EQ mount and smaller scope. For anyone that's interested, I will make a follow-up post tomorrow evening with an update on how things went and *hopefully* share some images of my results. This will be my complete setup tonight ----

 

Clestron 9.25 SCT

Evolution mount with HD Pro Wedge

Celestron F/6.3 focal reducer

ZWO ASI662MC

105mm backfocus spacers 

Orion 50mm guidescope

Orion Starshoot Autoguider

Bahtinov mask

Nina, CPWI, PHD2, ASTAP

This may not be a popular opinion, but it has been my experience so I'll share.  Hyperstar is a pretty darned good cure for a lot of the listed ills.  Imaging at F/2, exposures get very short.  Stuff starts to saturate well before you get in to exposures that require guiding.  This also means general mount errors/PEC etc don't get the same chance to affect the image.  Your image scale is also smaller (wider field of view) so again some errors in tracking and alignment are less noticeable.  

 

Its expensive, but its expensive for a reason!  

 

Before I took a 10year detour into building big dobs, I was imaging with a C11 with hyperstar.  I got some decent results (for a beginner).  All while I was blissfully ignorant to the fact that on paper my mount was undersized and wasn't even aware that autoguiding was a thing.

 

You still have to deal with collimation, mirror shift, etc., that come with SCT territory.  And I'm not trying to convince you to rush out and get hyperstar.  I'm just saying its a way to start with short focal length photography with the scope you have, and with some advantages (faster f ratio) than a short refractor.  

 

In the long run, you may still want a better mount for your OTA, and you'll find much of the rest of the advice will still apply to some of the things you want to image.  

 

-Brian


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#18 mooresaw

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Posted 24 October 2022 - 09:56 AM

I'm new so posting this to get constructive criticism.

 

 

1. Setup and plug everything in

2. Power up - Open CPWI Connect celestron CGEM II through hand mount

3. CPWI will ask for an alignment I'll usually select load last alignment and tell it the scope is in index

4. Pick a suggested star and slew to it.

5. While slewing open ASCOMM Device Hub connect telescope via ASCOM.CPWI

6. Open NINA -> load profile, connect Device hub telescope, connect camera and start cool down

7. By now the scope has slewed to the star, I'll use ASTAP plate solver in NINA to ensure its centered. Once centered I tell CPWI I'm aligned

8. Starting from current position I use NINA 3 point polar align, sometimes I do two passes to get a rough one down to <10 arc minutes and then again to get to <2 or so

9. Go back to CPWI pick a star like Vega to slew to, plate solve if I have to

10. Don't have an autofocuser yet so I use a Bhatinov mask to check focus

11. Go to Sky atlas pick a target set it up for framing and simple sequencer

12. Once slewed and center - connect guider

13. Start guiding, start sequence




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