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Bobby1970

EEVA set up/workflow

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I want to use my AzGti, 72mm Frac and ZWO 178 for some EEVA. I also have sharpcap and APT 

Given this equipment what should my set up procedure and subsequent navigation using Goto on the AzGti be?

So:-

Alignment - how many stars for alignment from the synscan app? Can I or should I be using platesolving via Sharpcap or APT to improve each alignment stars accuracy? 

Or should I just eyeball the alignment stars then try and use platesolving for each subsequent target after alignment? 

 

Sorry if it seems a dumb question but I just wondered what others do with similar set up. 

Many thanks

 

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I’m not sure I’ve come across anyone using plate-solving for EEVA, but I might be wrong.

It seems to me that EEVA is more observing-like than imaging-like, so some manual navigation is not unnatural.  I certainly use go-to mounts, usually in combination with software like Stellarium, so just use whatever you need to get near enough (within FOV, for example) and then manually browse around.   I do sometimes use guiding if my exposures are more than 15 seconds, or so, but mostly so that I can dither to improve the noise with live stacking.  It’s so quick to do that it doesn’t really get in the way of spontaneous enjoyment of the view.

However, there’s really no right or wrong, just what’s easy for you  

Tony

Edited by AKB
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1 hour ago, AKB said:

I’m not sure I’ve come across anyone using plate-solving for EEVA, but I might be wrong.

It seems to me that EEVA is more observing-like than imaging-like, so some manual navigation is not unnatural.  I certainly use go-to mounts, usually in combination with software like Stellarium, so just use whatever you need to get near enough (within FOV, for example) and then manually browse around.   I do sometimes use guiding if my exposures are more than 15 seconds, or so, but mostly so that I can dither to improve the noise with live stacking.  It’s so quick to do that it doesn’t really get in the way of spontaneous enjoyment of the view.

However, there’s really no right or wrong, just what’s easy for you  

Tony

As I say. Maybe I've got it all wrong. But if I want to ensure I get to view several targets, without panning around for them if the goto is slightly off, I was assuming platesolving could be used to improve the accuracy of the Goto. My ZWO has a smaller fov than my DSLR, which I knew when I decided to get it, so just wondering what others do. Maybe next time I will use a focal reducer. See if that helps. 

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I always follow the same setup with my AzEQ6 mount in alt-az mode. 

1. Perform 2-star alignment

2. While I have the second bright star still on the monitor, slap on the Bhatinov mask to focus.

3. (sometimes) check alignment by going to a brightish DSO in the vicinity and use PAE to try to improve things (although I find it doesn't make a lot of difference, so maybe I'm not doing it correctly)

That's all. Most nights the objects are not exactly centred on my small chip (Lodestar X2 mono) at 800mm focal length,  but they're always in the FOV, and I just centre them if I feel like it, or don't bother if they're close enough. 

Concerning GOTOs, quite often I'm looking for objects that are not in the mount's database so I just enter the RA/Dec manually. What really helps (especially for objects like quasars or dim galaxy groups that are too faint to see on individual subs) is to have deep enough charts and to be able to freely rotate the incoming subs to match the charts exactly. I don't use plate-solving.

Martin

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I have a similar setup with a similar mount, the AZ GTe in EQ mode with a wedge and counterweight. I started off using the ZWO camera to do a static polar alignment with SharpCap's polar alignment feature. Then I aligned 3 alignment stars using Synscan Pro on a laptop connected my Wifi to the mount and USB to the camera. I used the reticule feature in SharpCap to get them in the centre. Then I use the latest version of Stellarium with ASCOM support to move around the sky.

I've not yet managed to get it that accurace, it's accurate enough to get targets in the frame, and tracks well for live stacking, but not enough to get them totally in the centre so I've got something wrong. I'm not worried about backlash, as I'm sure Synscan Pro takes care of that, but I am worried about other mechanical issues, my mount is the AZ GTe so doesn't have clutches to tighten up, and I'm using the Star Adventurer wedge so that is probably over it's weight limit, the Sky Watcher tripod has a bubble level on it but so does the AZ GTe mount and they don't agree. It's hard for me to balance the AZ GTe mount as it doesn't have clutches, and I'm not sure where to measure the zero points for RA and Dec so all that is probably putting me off more than my alignment. I think I will upgrade to the AZ GTi at some point.

It seems to be working well enough, and I'm going to try to make it better as I learn more. I tried Synscan Pro's align on sync command with SharpCap and it didn't really work as I expected. I think it will work if you look at the 3 stars Synscan Pro want to align to and do a plate solve near them. I'll try that on the next clear night. :clouds1:

I did try getting it working with EQMod. I can connect EQMod to the scope over a Wifi virtual serial port that seems to get a good connection, and be able to send and receive commands but something is well off - probably the gear ratios, as the mount crashed into the central tripod post when commanded to move just a few degrees off  celestial North. :confused3: EQMod will support easier alignment by plate solving. Hopefully EQMod will be updated to automatically detect this mount soon, as the AZ GTi and EQMod combination should be portable, easy to use, and accurate.

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Hi Bobby,

My setting is similar to yours, ASI224 + SW72ED or SW130p on a AZGTI. I  often use plate solving from SharpCap to refine my gotos and to adjust the alignment (plate solving and adjusting before "confirming" the star aligned in the Synscan Pro PCc app...). It is quick and works.

Maybe if I better level the mount before or play longer with start alignment I may need less plate solving later, don't know... The truth is I usually want to get to a target quickly and to be completely honest, I really enjoy to see the magic of plate solving in action and see the object sliding into (the rather small) view of my camera.

In AZ mode with a quick and not perfect alignment I can still do EAA, stacking 5 to 10 secs subs for few minutes without problem. I'm about to try the EQ mode of the GTI, maybe things are getting even better, let's see.🤞

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9 hours ago, Deflavio said:

Hi Bobby,

My setting is similar to yours, ASI224 + SW72ED or SW130p on a AZGTI. I  often use plate solving from SharpCap to refine my gotos and to adjust the alignment (plate solving and adjusting before "confirming" the star aligned in the Synscan Pro PCc app...). It is quick and works.

Maybe if I better level the mount before or play longer with start alignment I may need less plate solving later, don't know... The truth is I usually want to get to a target quickly and to be completely honest, I really enjoy to see the magic of plate solving in action and see the object sliding into (the rather small) view of my camera.

In AZ mode with a quick and not perfect alignment I can still do EAA, stacking 5 to 10 secs subs for few minutes without problem. I'm about to try the EQ mode of the GTI, maybe things are getting even better, let's see.🤞

So, you platesolve on your alignment stars, rather than aligning "by eye" then platesolving your target? 

I think I will try your method myself next time I'm set up. 

I'm also planning on trying EQ mode with the AzGti at some point. But I want to make some sort of adaptor for my iPolar to attach to the AzGti to use for polar alignment. Then maybe some longer stacks during EEVA or some "proper" astrophotography. 🙂

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My basic procedure is the one described by Martin. After the 2 star alignment I then GOTO a third star in the region that I plan to do my EAA and sync on that third star. I then insert the camera, sort out focus and after that the objects will be in the fov. Sometimes I will re sync on an object with the camera still in if I feel things are a little off.

I have also learnt the hard way that when using my equatorial mount it is always worth spending the time getting it level and then to spend further time getting it polar aligned (manually, do not have any fancy software to do it for me) as accurately as I can.

If using my AZ mount, I make the effort to get it level, then 2 star align, off to the third star and just as before. Mike

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On 01/02/2020 at 01:16, Deflavio said:

Hi Bobby,

My setting is similar to yours, ASI224 + SW72ED or SW130p on a AZGTI. I  often use plate solving from SharpCap to refine my gotos and to adjust the alignment (plate solving and adjusting before "confirming" the star aligned in the Synscan Pro PCc app...). It is quick and works.

Maybe if I better level the mount before or play longer with start alignment I may need less plate solving later, don't know... The truth is I usually want to get to a target quickly and to be completely honest, I really enjoy to see the magic of plate solving in action and see the object sliding into (the rather small) view of my camera.

In AZ mode with a quick and not perfect alignment I can still do EAA, stacking 5 to 10 secs subs for few minutes without problem. I'm about to try the EQ mode of the GTI, maybe things are getting even better, let's see.🤞

Hi do you still use this method and setup?  especially the SW 130p?  do you live stack using sharpcap? or do you view using some other software?  do you do live broadcasts?   any chance of seeing your results?   have same set up and tryign to get EAA going but having a few problems   mainly with the actual goto accuracy. 

thanks 

 

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Hi Keltoi,

Yes, this is my main setup for most of my observations, I alternate between ED72 and 130p. Just last night I did some EAA using the 72ED + ASI224 and AZ GTi in EQ mode.  It was a pleasing and fun night with everything working well. I recently added the SW focuser + HitecAstro DC controller to improve my focus and I can see the difference. 

My software combination is SynScan app on windows, together with Sharpcap, HitecAstro focuser software and Cartes du ciel. It is a bit overkill but the long term goal for me is to learn how to control everything remotely.  As basic setup you only need Sharpcap and SynScan app.

About Goto and tracking accuracy, I have to admit, with the EQ mode, once you get the polar alignment done, everything seems a bit more reliable and easy than in AZ but need to do more testing on that. Still, I have used AZ quite a bit and once aligned you can always plate solving if your goto is a bit off and automatically recenter. SharpCap plate solving is quite forgiving allowing up to (I think) 11 degrees error, which is a lot! The main issues I have found in my case is more about good tracking after a goto...and this may be due to levelling errors. I have the impression for AZ a good levelling is even more critical than in EQ. In EQ once you are aligned to the earth axis, you are all set. 

 

Here some images from yesterday, SW London, Bortle 8. Please note I'm still learning a lot about EAA myself...just to give you an idea what can be achieved with this setup. I'm sure other people can do much better than that.  Yesterday I was trying to squeeze from the little ASI224 a better color balance and sharper stars.

 

M27  (Gain 349, 5sec x 90 frames, ED72 + ASI224 + Astronomik L-3 UV+IR) - EQ mode

M27.thumb.jpg.da2ce6f0a4affd6878197ac396191e5e.jpg

 

M57  (Gain 349, 5sec x 54 frames, ED72 + ASI224 + Astronomik L-3 UV+IR) - EQ mode

M57.thumb.jpg.d8319f357a8653db8761dd7babad7caf.jpg

 

and M71 (Gain 299, 10.4sec x 33 frames, ED72 + ASI224 + Astronomik L-3 UV+IR) - EQ mode

M71.thumb.jpg.77e3371aafd7d0f1d5fb94534a78ded9.jpg

 

Edited by Deflavio
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...and here some old images using the 130p and AZ-GTi. This was a couple of years ago so that was just basic setting (Sharpcap, SynScan and manual focus).  I'm now trying to get the SW focuser working on the 130. Hopefully that would improve things further.

 

M51 (Gain 350, 15sec x 40 frames, SW130p + ASI224) - AZ mode

M51.thumb.jpg.bdc505ba5f201c6d7f37b79270a538f5.jpg

and  the firework galaxy

NGC6946 (Gain 373, 5sec x 80 frames, SW130p + ASI224) - AZ mode

Firework.thumb.jpg.aaa14c27d37476279833e4e023ecdb6e.jpg

 

Edited by Deflavio
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Personally I find levelling and accurate polar alignment essential. I even level accurately my GOTO Dob. Mike

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3 hours ago, Mike JW said:

Personally I find levelling and accurate polar alignment essential. I even level accurately my GOTO Dob. Mike

I agree, now that I have seen the improvement using the GOTO on EQ I can see the value of good alignment. Although I'm still not sure if just levelling with the bubble on the AZ-GTi is precise enough for AZ...That's why I'm never got mad about it. I mean the bubble is always within the marks but how good is it?  On a EQ mount aligning to polar seems to me more objective and quantitative (especially using SharpCap or similar tools).

If I got it right, with a good polar alignment, levelling becomes more about stability of the scope but it is not really affecting goto or tracking because RA just need to rotate around the polar axis and declination is orthogonal to RA. On the contrary, on AZ a bad levelling is directly affecting both axes.  

So, on simple AZ mounts like GTi what would be the best way for levelling?

 

Edited by Deflavio

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I've only ever used my mount in alt-az mode although it does have EQ. I just get the bubble roughly in the centre by eye. I don't really know how critical it is. Most of the time I observe on a less-than-optimal suspended wooden terrace anyway which most likely changes its level as it cools... and certainly does as the dog wanders around.

In the same way I don't know how critical getting the stars dead centre during 2-star alignment it, but I always aim for as close as possible (within a few pixels?) in that case and my gotos are usually on the chip somewhere which is good enough for me given how small the FOV is (0.4 degrees). I don't plate solve.

Deflavio, you seems to have a well-adjusted setup judging by your images. I most likely have some camera/filterwheel induced tilt and twisted spider vanes which I've been meaning to do something about for about 5 years now... EEVA is pretty forgiving though (which is why I haven't!).

Martin

 

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I use 3 star alignment on my AZ GTi because I read somewhere that it was better than 2 star but after reading the posts in this thread I'm beginning to have doubts - what are your thoughts ?

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A few confused thoughts as I am not particularly technical.

Using my Alt/Az ioptron mini tower: - level as accurately as I can using the bubble, then the next step is accurately align it to south (use compass), finally put scope in vertical position (use a mini spirit level ), again accurately. Then do one star alignment choosing star in the area I am interested in and hit GOTO. When I have taken the time to be accurate it has often surprised me how close the first star is. Use finder to get accurately in the centre of fov/ reticule eyepiece. Then swop over to camera.

Personally I think it pays off to be accurate in the setting up. When I head off to somewhere else then I will sync in that area before going to more DSOs.

Using my iOptron EQ45, - equatorial mode. Again I have often proved that accurate levelling (I use mini levels and the level on the polar scope as the bubble level is way out) and then accurate polar alignment makes a big difference in locating and tracking. With this mount after the first two star alignment I look at the read out and if it indicates that the alignment is poor I go back to the zero position and adjust accordingly, then follow up with another 2 star alignment before heading off for the targets. Again I will always sync to additional local stars as  I move around a given area. It is a right pain but when I make this effort I get the reward of those tiny faint DSOs that you see me post.

Dob - levelling very accurately seems to help with the two star alignment procedure. Then head off to the area of interest. Sync to a local bright star and often then head off to a fainter star (I use SAO numbers) before then confidently going to the object of interest - absolutely have to do this for SHKs, many of the VVs, Palomars. Again it is a pain but the rewards are worth it.

I have tried 3 star alignment on the iEQ45 - not sure it made any improvement compared to the 2 star procedure.

Agree with Martin that EEVA is very forgiving. Remember EEVA is not about getting wonderful images (that is for the serious imaging techniques). EEVA is about finding the object and then observing it/researching it......

I don't plate solve - do not have the software to do this and most of the time I don't need to. Just now and again it would be useful to have this facility when I am after a small, very faint object in a sparse star area but then the fun of the chase kicks in........EEVA is about enjoying the objects and having fun.

Mike

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