Confused - HEQ5 Pro GoTo

[Sabalias]

Hi everyone,

I'm a bit confused about the tracking on my HEQ5 Pro. This is the process I follow after setting up (including balancing and starting in home position)

• I try to accurately polar align the mount
• Carry out an 2 or 3 star alignment
• Do a test slew to a known, visible object (last time it was Vega) and the object is nice and central in the eyepiece
• I even carry out a PAE with a star close to where I am imaging

Now I'm ready to look for a DSO that I can image but the object winds up far from centre (and in some cases not in the field of view at all). The only thing that has changed is the very careful replacement of the eyepiece with a camera (weight is different but not significantly so); is that likely to knock the alignment off?

Many thanks,

Stu

Edited July 21, 2021 by Sabalias

[PeterCPC]

What is the field of view of the EP compared to the camera? Weight could also be an issue.

[carastro]

It sounds like you are doing everything correctly, especially since Vega is ending up in the eye piece. 

A few comments.

The point of focus will be very different to the eyepiece with a camera, can you see stars with the camera but just the wrong ones?  I would suggest you find your target with the eyepiece first, then change to the camera and then re-focus.

Also depending on what camera you are using, if it is a colour camera again depending on the model, they are generally not good for seeing what you are looking at in live view, you may need to do an exposure of several seconds to see what you are looking at with a camera. 

However this may not be the problem.   It might just be a case of your mount not going to the target as you say.  Fiddling around with changing eyepiece to camera can knock the alignment off a bit.  

I have been imaging for around 11 years and even now I sometimes have the occasion when the mount doesn't GOTO where I want it to despite alignment.  These days I tend to only do a 1 star alignment on a star close to my target and find that works much better than 2 and 3 star alignments.

Hope some of this might give you some food for thought.

Carole 

[michael8554]

1 hour ago, Sabalias said:

I even carry out a PAE with a star close to where I am imaging

That should allow an accurate GoTo a nearby Target.

From what I've just read, getting a PAE is not straightforward:

"On the SynScan menus, the nearest equivalent of that sync function that I've discovered is called "PAE correction" (PAE being an acronym for Polar Alignment Error). 

It's two layers down on the "Utility" Menu: Utility>PAE>PAE correction.

So, if you've used the Go-To and have an object selected but not centered, you'll need to go back up the menu ladder with the ESC key, select the Utility Menu, then down two steps, center the object and tap "Enter."

I thought I would at least be able to choose the Utility menu just by using the "Menu" button, but alas, that is not the case.

That button does nothing whatsoever unless I've gone to the top of the menu ladder with the ESC key."

Edited July 21, 2021 by michael8554

[Sabalias]

57 minutes ago, PeterCPC said:

What is the field of view of the EP compared to the camera? Weight could also be an issue.

Thanks for responding Peter. The eyepiece is 68 degrees but I'm not sure about the camera - it's an EOS 600D

Regards,

Stu

Edited July 21, 2021 by Sabalias

[Sabalias]

52 minutes ago, carastro said:

It sounds like you are doing everything correctly, especially since Vega is ending up in the eye piece. 

A few comments.

The point of focus will be very different to the eyepiece with a camera, can you see stars with the camera but just the wrong ones?  I would suggest you find your target with the eyepiece first, then change to the camera and then re-focus.

Also depending on what camera you are using, if it is a colour camera again depending on the model, they are generally not good for seeing what you are looking at in live view, you may need to do an exposure of several seconds to see what you are looking at with a camera. 

However this may not be the problem.   It might just be a case of your mount not going to the target as you say.  Fiddling around with changing eyepiece to camera can knock the alignment off a bit.  

I have been imaging for around 11 years and even now I sometimes have the occasion when the mount doesn't GOTO where I want it to despite alignment.  These days I tend to only do a 1 star alignment on a star close to my target and find that works much better than 2 and 3 star alignments.

Hope some of this might give you some food for thought.

Carole 

Thanks Carole,

I'm referring in particular to a session where I was trying to image the veil nebula but it didn't appear to be in the camera field of view at all (taking a 10 and 20 second, high ISO exposure to see). I switched to the dumbbell nebula and found that the object was way off to the side of the camera FOV; at that point I stopped the tracking, centred on the nebula and then started tracking again before initiating guiding. It's reassuring to hear that this sort of thing just happens and that it's likely to be my ham-fisted efforts at switching eyepiece for camera.

Stu

[M40]

Have you tried slewing to a known object eg vega with the camera installed then looking at vega using live view of the camera? Is vega centered on the camera display?

[PeterCPC]

19 minutes ago, Sabalias said:

Thanks for responding Peter. The eyepiece is 68 degrees but I'm not sure about the camera - it's an EOS 600D

Regards,

Stu

Try them both during daylight and you will be able to see how they compare.

[Sabalias]

15 minutes ago, M40 said:

Have you tried slewing to a known object eg vega with the camera installed then looking at vega using live view of the camera? Is vega centered on the camera display?

Good idea. I'll give that a try next time I'm out

Stu

[Sabalias]

1 hour ago, michael8554 said:

That should allow an accurate GoTo a nearby Target.

From what I've just read, getting a PAE is not straightforward:

Hi Michael,

I can attest to the relative complexity of the process 😂 but I believe those are the steps that I followed. I'll have to give it another go and make absolutely sure next time.

Stu

[Sabalias]

13 minutes ago, PeterCPC said:

Try them both during daylight and you will be able to see how they compare.

I'll do that Peter 👍.

Thanks,

Stu

[malc-c]

Just my 2p worth

If you have good alignment and can slew to a bright star near the target, then chances are the mount won't be off in the goto.  For example if you centre Vega and then slew to the ring nebula it should still be within the FOV as any goto error won't be large enough to make it well outside the FOV.  I would put my money on one of two things.  Either you've forgotten to refocus through the camera, or you're on target, but you are expecting to see something in live view and the target is just not bright enough to register.

Having done your alignment routine, remove the eyepiece and insert / attach the 600D.  Place a Bahtinov mask for the scopes focal length on the scope and take a 20s exposure.  Adjust focus until the middle line is central and equidistant between the other intersecting lines to get focus.  Remove the mask and now select the target.  Depending on the target, a 30s exposure might confirm position (such as the bright core of a galaxy), or better still, do a two or three minute exposure which will confirm the target is in the FOV.  Once you have the target confirmed proceed with guiding and then run whatever plan you have set in APT / Backyard EOS / NINA or whatever app you use.

Good luck

[michael8554]

I find that LiveView works on a bright star with a Bahtinov mask, no need to take long exposures.

To verify that the GoTo after PAE has put the target in FOV, take a 30 second exposure at maximum ISO.

[Sabalias]

18 hours ago, malc-c said:

Just my 2p worth

If you have good alignment and can slew to a bright star near the target, then chances are the mount won't be off in the goto.  For example if you centre Vega and then slew to the ring nebula it should still be within the FOV as any goto error won't be large enough to make it well outside the FOV.  I would put my money on one of two things.  Either you've forgotten to refocus through the camera, or you're on target, but you are expecting to see something in live view and the target is just not bright enough to register.

Having done your alignment routine, remove the eyepiece and insert / attach the 600D.  Place a Bahtinov mask for the scopes focal length on the scope and take a 20s exposure.  Adjust focus until the middle line is central and equidistant between the other intersecting lines to get focus.  Remove the mask and now select the target.  Depending on the target, a 30s exposure might confirm position (such as the bright core of a galaxy), or better still, do a two or three minute exposure which will confirm the target is in the FOV.  Once you have the target confirmed proceed with guiding and then run whatever plan you have set in APT / Backyard EOS / NINA or whatever app you use.

Good luck

Thanks Malcolm,

I managed to get the dumbbell nebula in the FOV of the camera but my concern was that it wasn't close to central - I completely lost he veil but that might be because it's a fainter object. I've ordered a Bahtinov mask now though as focusing seems to be a challenge through a camera.

Stu

[Sabalias]

14 hours ago, michael8554 said:

To verify that the GoTo after PAE has put the target in FOV, take a 30 second exposure at maximum ISO.

Hi Michael,

Sadly, I couldn't get anything other than a washed out image at max ISO 😄 - the skies were still too bright. As the year progresses I hope to be able to follow this process though.

Cheers,

Stu

Edited July 22, 2021 by Sabalias

[michael8554]

Understood, full moon is not an ideal testing condition !

Michael