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Gaining experience but so many questions!

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#1 jtf_ie

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Posted 18 June 2021 - 09:37 AM

Hi All,

 

Firstly, my apologies in advance for a long post and for posting so many questions in one thread.

I recently bought my first "proper" telescope and mount having previously owned a Skywatcher Explorer 130 on an EQ2 mount ( see new equipment below) which wasn't really very useful for imaging.

 

I just (even more recently) introduced guiding and automated image acquisition and polar alignment with NINA, PHD2 and Sharpcap and after some teething problems I think I have finally gotten everything up and running but I have so many questions! Apologies again for dumping so much in one post but figured it better than spamming the forum with a bunch of separate posts.
My equipment:
Mount: Skywatcher HEQ5 Pro
Scope: Skywatcher Evostar ED80
Main camera: Canon 100d (unmodded)
Guide camera: ZWO ASI130 MC-S
Guide scope: ZWO mini guide scope

 

And so to my questions:
1. How does dew impact calibration frames? I assume it impacts flats, in particular. I don’t have any dew heater bands yet (I know, I need to get them)! So often towards the end of a sequence of light frames dew has collected on the telescope lens. Therefore the calibration frames are taken while there is dew on the lens.
2. I live at 53 degrees north and so only have about 2 hours of astronomical darkness at the moment. So what is the minimum number of light frames that should ge taken for stacking. With guiding I could go for 5 min subs (for example, but could only get about 12 frames in a night at the moment) so for now am I better off taking, say, 3 min subs to get more frames for stacking?
3. I am imaging exclusively at home so connecting to mains power. For those of you using mains power, how do you power everything? At the moment I have the mount, the laptop and a dummy battery for the DSLR plugged in, but I know I need to get dew heaters for the scope and guide scope soon also, so wondering how people manage having so many things to power with mains.
4. Is there a way to get the mount to slew back to the home position without having to switch it off (park)?

5. How do you frame/rotate the camera when framing a target? I'm using the framing assistant in NINA, but often the camera would need to be rotated. I assume you should focus after each time you rotate the camera (I'm not using any rotator - rotating manually). I find this can take a lot of time, because (depending on the target) there may not be a bright star to focus on in the frame and I find it easier and quicker to use a bright star and just use the live view on the camera, so have to slew to a bright star and back, and then check rotation again, etc.
6. I would love to get peoples input on general setup and workflow for the night.

 

I have been doing the following:
- level and balance setup.
- rough polar align with polar scope
- polar align with sharpcap (using guide camera)
- set mount back to home position
- do a 1 star alignment with the hand controller, really just so I can focus the main camera using the live view on the back of the camera.
- park scope, switch off mount and switch on again, making sure it’s in the home position (see 4).
- open NINA and PHD2 and connect equipment.
- search for target in NINA sky atlas.
- set for framing assistant.
- slew to target from framing assistant
- check framing and set as sequence target.
- set up a sequence with just one shot to plate solve (since the plate solving in the sequence tab uses the target, but the plate solving in the imaging tab uses the current coordinates).
- start the guiding in PHD2 including calibration.
- set up the full sequence for light frames in NINA and off we go.

Sorry again for the long post and thanks in advance for any advice and for taking the time to read it all!
Regards,
Brendan.



#2 ChiTownXring

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Posted 18 June 2021 - 10:31 AM

I am new to the hobby and wanted to take a crack at your questions knowing more experienced APers will chime in..

 

1. I would imagine dew can make things change constantly as far as the sharpness of your images and focus and so I would imagine your flats would be effected. But since you are just starting out and will get a dew heater I wouldn't worry about it for now. You can try the disposable handwarmers and some Velcro and see if that helps..

2. I know one can get excited about stacking your subs to see what you are getting but in the end the more acquisition time on a target the better so if your setup can handle 5 min subs with round stars that are not blown out then stick to that and wait until you have as many subs as possible even if that means it takes several nights. The minimum subs is up to you and how much detail you want your pictures to have and if there is a min that is required in the stacking program you use.

3.   I am using a quality surge power strip for now to plug in everything but do have a Pegasus Power Box on the way : )

4. In NINA I use the sequence feature and in the lower right hand corner is the park scope after the sequence is done..

5. Before I got my EAF I would slew to a bright star near my target and use a bahtinov mask to focus then slew to my target. I only rotated my camera to make sure the target is framed right and then I just leave it that way until I am done with that target and let my stacking software line everything up and then crop as needed.

Your work flow seems like it will work.


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#3 kathyastro

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Posted 18 June 2021 - 11:02 AM

1. The dewy flats will properly calibrate the dewy lights.  The calibration of dry lights will be wrong.  The best solution is not to get dew.  Darks will be fine.

 

2. You should aim to get 10 or more subs for noise reduction.  More is better.  The important thing is the total integration time.  Only in very specific circumstances does more time per sub give a real benefit.  Don't bust a gut trying to get longer subs.

 

3. Use a heavy-duty (15A) extension cord and you won't have to worry about overloading anything.  Not that you likely would, but it's a good practice.  Get a 6-outlet surge-suppressing power bar.  It gives you plenty of outlets for all the devices. 

 

Most astro devices run on 12 volts DC.  Get a good 12v power supply that can supply lots of amps.  You can then run a lot of your devices off it.

 

4.  That is very mount-dependent.  Why would you want to send it home if you aren't going to turn it off?  The mount only needs to be in the home position before you start your n-star alignment.

 

5. Personally, I always keep my camera oriented so north is up prior to the meridian flip, which post north down after the flip.  That way, I always know the orientation of my images.  One good reason is diagnosing star trails.  I can easily tell if any un-round stars trail in the RA or Dec direction.  Any targets big enough to not fit in that format are usually big enough that they'd need a mosaic anyway.


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#4 jtf_ie

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Posted 18 June 2021 - 02:28 PM

1. The dewy flats will properly calibrate the dewy lights.  The calibration of dry lights will be wrong.  The best solution is not to get dew.  Darks will be fine.

 

2. You should aim to get 10 or more subs for noise reduction.  More is better.  The important thing is the total integration time.  Only in very specific circumstances does more time per sub give a real benefit.  Don't bust a gut trying to get longer subs.

 

3. Use a heavy-duty (15A) extension cord and you won't have to worry about overloading anything.  Not that you likely would, but it's a good practice.  Get a 6-outlet surge-suppressing power bar.  It gives you plenty of outlets for all the devices. 

 

Most astro devices run on 12 volts DC.  Get a good 12v power supply that can supply lots of amps.  You can then run a lot of your devices off it.

 

4.  That is very mount-dependent.  Why would you want to send it home if you aren't going to turn it off?  The mount only needs to be in the home position before you start your n-star alignment.

 

5. Personally, I always keep my camera oriented so north is up prior to the meridian flip, which post north down after the flip.  That way, I always know the orientation of my images.  One good reason is diagnosing star trails.  I can easily tell if any un-round stars trail in the RA or Dec direction.  Any targets big enough to not fit in that format are usually big enough that they'd need a mosaic anyway.

Thanks!

I don't really want to "park" the scope but rather return it to the home position. Perhaps I was doing something wrong, if you look at my workflow, I do the 1 star alignment to focus on a bright star. When I tried to then use NINA to slew to a target it didn't seem to recognise that I wasn't starting from the home position and was way off. So I figured if I first bring the scope back to the home position before switching back to NINA to slew to the target I wouldn't have that problem. I was also afraid that if I manually bring the scope back to the home position then the mount itself be get "confused". 

Also, it just seams like a reasonable thing to want to do! :) 



#5 sbharrat

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Posted 18 June 2021 - 03:11 PM

Thanks!

I don't really want to "park" the scope but rather return it to the home position. Perhaps I was doing something wrong, if you look at my workflow, I do the 1 star alignment to focus on a bright star. When I tried to then use NINA to slew to a target it didn't seem to recognise that I wasn't starting from the home position and was way off. So I figured if I first bring the scope back to the home position before switching back to NINA to slew to the target I wouldn't have that problem. I was also afraid that if I manually bring the scope back to the home position then the mount itself be get "confused". 

Also, it just seams like a reasonable thing to want to do! smile.gif

If you have NINA connected already, you should REALLY see if the built in driver supports your Canon (I had a Canon 1000d and it did). If you get that working, then you use NINA to platesolve and sync to the scope and you never need to go do the alignment again. 

 

Absent that, how are you doing this star alignment? Through the hand controller? And your eqmod is connected to the mount how? 



#6 kathyastro

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Posted 18 June 2021 - 03:37 PM

When I tried to then use NINA to slew to a target it didn't seem to recognise that I wasn't starting from the home position and was way off.

That suggests that there is an issue with your goto alignment.  The 1-star alignment (or 2-star or 3-star) is intended to align the goto system.  If you are only using it to find a bright star for focusing, finding the wrong star will serve your purpose just fine.  But aligning on the wrong star will cause the goto system to go to the wrong targets.

 

So, I would recommend putting a bit more effort into getting the goto alignment right.  Start in an accurate home position when you power on.  Select a three-star alignment, and make sure you centre on the correct three stars.  You should then be able to go to a bright star for focusing, and then go directly to your target without going back to home.



#7 jtf_ie

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Posted 19 June 2021 - 04:24 AM

Thanks for the replies... much apprecated.

 

If you have NINA connected already, you should REALLY see if the built in driver supports your Canon (I had a Canon 1000d and it did). If you get that working, then you use NINA to platesolve and sync to the scope and you never need to go do the alignment again. 

 

Absent that, how are you doing this star alignment? Through the hand controller? And your eqmod is connected to the mount how? 

I don't "need" to do the star alignment, I only do it so I can pick a bright star to focus on. NINA does support my canon, so there is no issue there. NINA platesolves fine. I also tried to use NINA to slew to the star to focus on, but I don't see any individual stars in the sky atlas in NINA and even if I did, the platesolving would fail because the camera would be so out of focus.

I'm doing the star alignment with the hand controller (1-star alignment). I'm not using the ST4 cable, I have the mount connected through the hand controller via USB to the laptop (new HEQ5 mount - has a USB connection on the hand controller). Now I downloaded ASCOM and got all of that working with NINA, etc. I tried to install the EQMOD controller so I could control the mount from the laptop outside of NINA, but couldn't get it to work. No idea why and I didn't look to much in to it because I didn't need to use it.

 

That suggests that there is an issue with your goto alignment.  The 1-star alignment (or 2-star or 3-star) is intended to align the goto system.  If you are only using it to find a bright star for focusing, finding the wrong star will serve your purpose just fine.  But aligning on the wrong star will cause the goto system to go to the wrong targets.

 

So, I would recommend putting a bit more effort into getting the goto alignment right.  Start in an accurate home position when you power on.  Select a three-star alignment, and make sure you centre on the correct three stars.  You should then be able to go to a bright star for focusing, and then go directly to your target without going back to home.

I don't thing that was the problem. When I did the star alignment with the hand controler it found the correct star but went back to NINA, NINA seemed to think the mount was still in the home position, so when NINA tried to slew to the target it was way off. Interestingly, plate solving then corrected NINA and it eventually found the right target, but I feel I must have done something wrong and that NINA and the mount should somehow be in sync. Or at least if I can just go back to the home position with the hand controller then NINA works fine.



#8 kathyastro

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Posted 19 June 2021 - 05:21 AM

How are you connecting to the mount?  Are you using EQMOD?  Is the cable from the PC connected directly to the mount itself, or is it connected via the handset?


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#9 lkannard

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Posted 19 June 2021 - 08:58 AM

Dew is your enemy.
Temporarily, you can use painter’s blue tape to attach some hand warmers around the objective lens and diagonal.
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#10 dghent

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Posted 19 June 2021 - 09:18 AM

There is an entire menu called Manual Focus Stars in NINA that lists bright stars that are visible from your location, ordered by altitude with a handy slew button to skew the mount to the one you select. This is in the documentation

Edited by dghent, 19 June 2021 - 09:19 AM.

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#11 Phishin_phool

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Posted 19 June 2021 - 10:11 AM

I don't thing that was the problem. When I did the star alignment with the hand controler it found the correct star but went back to NINA, NINA seemed to think the mount was still in the home position, so when NINA tried to slew to the target it was way off. Interestingly, plate solving then corrected NINA and it eventually found the right target, but I feel I must have done something wrong and that NINA and the mount should somehow be in sync. Or at least if I can just go back to the home position with the hand controller then NINA works fine.

 

You need to sync the mount (EQMOD) and NINA also your planetarium software if using one.

this may help

https://www.cloudyni...-and-eq6-mount/

 

this also may help

https://www.youtube....h?v=lAMyEpBcLV4


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#12 sbharrat

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Posted 19 June 2021 - 11:41 AM

There is an entire menu called Manual Focus Stars in NINA that lists bright stars that are visible from your location, ordered by altitude with a handy slew button to skew the mount to the one you select. This is in the documentation

Agreed. To OP, this is the way you slew to bright stars. I use this to put a bright star in FOV to focus using the Bahtinov mask. I have never needed to do a star alignment outside of NINA after learning about this.


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#13 jtf_ie

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Posted 19 June 2021 - 02:17 PM

How are you connecting to the mount? Are you using EQMOD? Is the cable from the PC connected directly to the mount itself, or is it connected via the handset?


I’m connecting via the hand controller but using USB not the ST4 cable. My mount (HEQ5) does not have another USB port. Only on the hand controller.

#14 jtf_ie

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Posted 19 June 2021 - 02:20 PM

There is an entire menu called Manual Focus Stars in NINA that lists bright stars that are visible from your location, ordered by altitude with a handy slew button to skew the mount to the one you select. This is in the documentation


This is a game changer!! Thanks.
I just had a look and found it. It never occurred to me that this functionality would be anywhere except in the sky atlas and I couldn’t find it there.
This will make a big difference for me.

#15 jtf_ie

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Posted 19 June 2021 - 02:21 PM

Agreed. To OP, this is the way you slew to bright stars. I use this to put a bright star in FOV to focus using the Bahtinov mask. I have never needed to do a star alignment outside of NINA after learning about this.


Thanks. I have a bahtinov mask ordered. So that will help too once it arrives.

#16 sbharrat

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Posted 19 June 2021 - 06:24 PM

I’m connecting via the hand controller but using USB not the ST4 cable. My mount (HEQ5) does not have another USB port. Only on the hand controller.

Ok, this works. Though some have pointed out that it sometimes is unreliable. Just for your info, you can get a cable to directly connect to the mount (removing the hand controller). See for example https://www.amazon.c...e?ie=UTF8&psc=1 (one I use). Then you no longer need the handcontroller at all. 




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