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Help with framing and other dumb questions

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#1 PrisonMike

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Posted 21 January 2021 - 09:13 PM

Ok so I'm still new to astrophotography and getting familiar with my heq5 and redcat. Getting better at polar alignment and im able to get up to 4 minute exposures with no star trails still with no guiding. My first dumb question is after i star align and slew to my target i usually check something that i can see easily on the live view like orion nebula so i know that its centered after alignment. Its always dead center so ill slew to my target such as m31 take a 90 second test shot to make sure im still centered and itll be centered but more towards the top of the frame. So what is my next step after this, if i recenter it with the hand controller will the mount just start tracking that as the new coordinates or do i have to start my star alignment process over. i know its a dumb question but i still have no idea what im doing sorry



#2 jonnybravo0311

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Posted 21 January 2021 - 09:20 PM

Not sure what mount you've got... so I'll tell you how I do it with my CEM40 using just the hand controller... no guiding, no plate solving.

 

  1. Do a good, accurate polar alignment. With the CEM40, I can just use iPolar. Typically, I use SharpCap Pro. This is the only step requiring a laptop (unless you are using a dedicated cam from ZWO, QHY, etc or a program like BackyardEOS).
  2. With the hand controller do a 1, 2 or 3 star alignment depending on how accurate you want it.
  3. Slew to your intended target.
  4. Is it centered? If yes, you're done.
  5. If not centered, use the hand controller to perform a sync.
  6. Use the arrow keys to center your target.
  7. Confirm it's synced.

That's it. The CEM40, once you slew to a target begins tracking it.



#3 bobzeq25

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Posted 21 January 2021 - 09:27 PM

Ok so I'm still new to astrophotography and getting familiar with my heq5 and redcat. Getting better at polar alignment and im able to get up to 4 minute exposures with no star trails still with no guiding. My first dumb question is after i star align and slew to my target i usually check something that i can see easily on the live view like orion nebula so i know that its centered after alignment. Its always dead center so ill slew to my target such as m31 take a 90 second test shot to make sure im still centered and itll be centered but more towards the top of the frame. So what is my next step after this, if i recenter it with the hand controller will the mount just start tracking that as the new coordinates or do i have to start my star alignment process over. i know its a dumb question but i still have no idea what im doing sorry

Just recenter.  The mount will start tracking.

 

If you're not autoguiding yet, you should start.


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#4 sbharrat

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Posted 22 January 2021 - 08:34 AM

Ok so I'm still new to astrophotography and getting familiar with my heq5 and redcat. Getting better at polar alignment and im able to get up to 4 minute exposures with no star trails still with no guiding. 

You already have the answers to your original question. But I had to comment on this: You get 4m (!!) good subs without guiding? That is incredible. I have the equivalent of the HEQ5 (Sirius EQ-G) and I was starting to see elongation at 30s. That's a really big disparity in PE among these similar class mounts....


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#5 PrisonMike

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Posted 22 January 2021 - 05:14 PM

You already have the answers to your original question. But I had to comment on this: You get 4m (!!) good subs without guiding? That is incredible. I have the equivalent of the HEQ5 (Sirius EQ-G) and I was starting to see elongation at 30s. That's a really big disparity in PE among these similar class mounts....

They were a little over saturated bc I’m still waiting on my l enhance so I was filterless but the stars were still looking good at 4 minutes. I just got my modded t3i so I’m finally going to give guiding a shot tonight now that I have a dslr that’s compatible with the asiair 


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#6 PrisonMike

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Posted 22 January 2021 - 05:15 PM

Not sure what mount you've got... so I'll tell you how I do it with my CEM40 using just the hand controller... no guiding, no plate solving.

 

  1. Do a good, accurate polar alignment. With the CEM40, I can just use iPolar. Typically, I use SharpCap Pro. This is the only step requiring a laptop (unless you are using a dedicated cam from ZWO, QHY, etc or a program like BackyardEOS).
  2. With the hand controller do a 1, 2 or 3 star alignment depending on how accurate you want it.
  3. Slew to your intended target.
  4. Is it centered? If yes, you're done.
  5. If not centered, use the hand controller to perform a sync.
  6. Use the arrow keys to center your target.
  7. Confirm it's synced.

That's it. The CEM40, once you slew to a target begins tracking it.

Another stupid question. Step 5. Can you elaborate on this?



#7 PrisonMike

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Posted 22 January 2021 - 05:16 PM

Just recenter.  The mount will start tracking.

 

If you're not autoguiding yet, you should start.

Tonight will be my first attempt with guiding


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#8 jonnybravo0311

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Posted 22 January 2021 - 05:46 PM

Another stupid question. Step 5. Can you elaborate on this?

Not stupid at all. The CEM40 hand controller has a menu option to "sync to target". You use this to manually correct any targeting error. It is used after you have told the mount to slew to target. Here's an example of what I mean.

 

I setup and polar align my mount. Once that's done, the next step is to perform a star alignment. You can do a 1-star, 2-star or 3-star alignment. The more stars you align to, the more accurate your mount's slewing/targeting will be. Ok, let's say you've done a 2 star alignment. The next step is to tell your mount to slew to a target. Let's say you've chosen M31. You enter M31 in the hand controller (under slew to target menu) and the mount will rotate around the RA/Dec axes until it thinks it's pointing right at Andromeda.

 

Look at what your camera sees. Is Andromeda really centered? If it isn't, you would choose the "sync to target" menu item. This allows you to manually move the mount using the arrow keys on the hand controller until Andromeda (or whatever target you chose) is perfectly centered in your camera's view. When you're satisfied, you hit the enter/OK button.

 

So, when does the mount start tracking? As soon as you slew to a target. So, in my case, after I polar align and I start the star alignment. As soon as I choose a star and the mount slews to it, that's when it's tracking. When I manually adjust the mount using the arrow keys... it's tracking. When I sync... you guessed it... it's tracking :).


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#9 PrisonMike

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Posted 22 January 2021 - 06:41 PM

Not stupid at all. The CEM40 hand controller has a menu option to "sync to target". You use this to manually correct any targeting error. It is used after you have told the mount to slew to target. Here's an example of what I mean.

 

I setup and polar align my mount. Once that's done, the next step is to perform a star alignment. You can do a 1-star, 2-star or 3-star alignment. The more stars you align to, the more accurate your mount's slewing/targeting will be. Ok, let's say you've done a 2 star alignment. The next step is to tell your mount to slew to a target. Let's say you've chosen M31. You enter M31 in the hand controller (under slew to target menu) and the mount will rotate around the RA/Dec axes until it thinks it's pointing right at Andromeda.

 

Look at what your camera sees. Is Andromeda really centered? If it isn't, you would choose the "sync to target" menu item. This allows you to manually move the mount using the arrow keys on the hand controller until Andromeda (or whatever target you chose) is perfectly centered in your camera's view. When you're satisfied, you hit the enter/OK button.

 

So, when does the mount start tracking? As soon as you slew to a target. So, in my case, after I polar align and I start the star alignment. As soon as I choose a star and the mount slews to it, that's when it's tracking. When I manually adjust the mount using the arrow keys... it's tracking. When I sync... you guessed it... it's tracking smile.gif.

Thank you so much. This has been a big learning curve but proving to be worth all the headaches.


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#10 kathyastro

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Posted 22 January 2021 - 06:59 PM

As others have noted, you don't have to do anything after re-centering the object.  The mount is already tracking, and it will just continue to do so.

 

Step 5. [perform a sync]  Can you elaborate on this?

In your situation, there is no need to perform a sync.  However, in some situations, it can be a useful thing to do.  A sync adds another alignment star/object to the ones you already used for your goto alignment.  So if you did a 1-star alignment, after the sync, it will be a 2-star alignment.  If you did a 3-star alignment, it will become a 4-star alignment.

 

My manual is a few years old, so the procedure may have changed some.  Skywatcher calls the sync function "Pointing Accuracy Enhancement (PAE)".  You slew to a known object in the normal way, and then re-centre it as required using the arrow keys.  Then, you hold the ESC key for 2 seconds.  After ensuring that the named object is dead-centre, you hit ENTER.  That adds it to the sky model, and future gotos in that area of the sky will be more accurate as a result.  Check PAE in your manual to confirm the current procedure.

 

When I was using a DSLR that I needed to focus with a Bahtinov mask, I found the sync function very useful.  With an eyepiece installed, I would slew to my target and centre it.  I would do a sync, to ensure that the mount had exact coordinates for the target.  Then I would slew away to a bright star.  I installed the camera and used my Bahtinov mask to focus it.  I then slewed back to the target.  Because this final slew was "blind" (no eyepiece), I relied on the extra accuracy of the sync point on the target to go back to the original framing.


Edited by kathyastro, 22 January 2021 - 07:00 PM.

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#11 fewayne

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Posted 23 January 2021 - 02:04 PM

I don't know if you're using a computer to do your imaging. Ignore this if not. But if you add plate solving to your software repertoire, it can make this whole process pretty easy. I don't bother with aligning my mount per se any more, I tell the software "I want to go to M31". It shoots an image of wherever it's currently pointing, solves it to figure out the exact coordinates, syncs the mount so it knows too, slews to target, then repeats the process until the target is precisely centered.

 

It's really slick. And with the right imaging stack, it's pretty simple to set up, too.



#12 sbharrat

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Posted 23 January 2021 - 03:02 PM

As others have noted, you don't have to do anything after re-centering the object.  The mount is already tracking, and it will just continue to do so.

 

In your situation, there is no need to perform a sync.  However, in some situations, it can be a useful thing to do.  A sync adds another alignment star/object to the ones you already used for your goto alignment.  So if you did a 1-star alignment, after the sync, it will be a 2-star alignment.  If you did a 3-star alignment, it will become a 4-star alignment.

 

My manual is a few years old, so the procedure may have changed some.  Skywatcher calls the sync function "Pointing Accuracy Enhancement (PAE)".  You slew to a known object in the normal way, and then re-centre it as required using the arrow keys.  Then, you hold the ESC key for 2 seconds.  After ensuring that the named object is dead-centre, you hit ENTER.  That adds it to the sky model, and future gotos in that area of the sky will be more accurate as a result.  Check PAE in your manual to confirm the current procedure.

 

When I was using a DSLR that I needed to focus with a Bahtinov mask, I found the sync function very useful.  With an eyepiece installed, I would slew to my target and centre it.  I would do a sync, to ensure that the mount had exact coordinates for the target.  Then I would slew away to a bright star.  I installed the camera and used my Bahtinov mask to focus it.  I then slewed back to the target.  Because this final slew was "blind" (no eyepiece), I relied on the extra accuracy of the sync point on the target to go back to the original framing.

Kathy very helpfully gave me this advice when I was having this exactly same problem. And it worked. I used this for a few weeks. But then I got NINA and plate-solving to work and would never go back. It REALLY is worth the effort to get plate solving working. It literally cut my the framing start up time from >30m to 10s of seconds. Well worth your time. (For me, the time involved running a USB cable through my house wall but it was STILL well worth it!)

 

Cheers


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#13 WoodlandsAstronomer

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Posted 23 January 2021 - 03:04 PM

Or you could skip all the goto stuff and use software that platesolves and perfectly centers your target every time! We live in an age where you don’t have to goto! Praise the ASIAIR overlords
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#14 WoodlandsAstronomer

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Posted 23 January 2021 - 03:04 PM

Or you could skip all the goto stuff and use software that platesolves and perfectly centers your target every time! We live in an age where you don’t have to goto! Praise the ASIAIR overlords


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