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First shot with SkyGuider Pro and D850

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#1 ET_PhoneHome

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Posted 08 August 2020 - 12:02 PM

Got to play with my Skyguider last night and took a stab at M101 (Pinwheel).  I'm guessing maybe this isn't the easiest one to start with, or maybe it is, and I just don't know what I'm doing, haha.  Anyway, I'm wondering how much is possible with the Skyguider and my DSLR (I used the 200-500 lens for this one, at 300mm).  I took 30s subs x 40.

 

Some issues I see are

  • the galaxy is very small in the frame, so I had to crop way, way down
  • I had to raise exposure in post by a couple stops, so I'm assuming I underexposed and should've used a longer exp. than 30s
  • The stars are not pinpoints (so exposure was too long or tracking was not good enough).  Focus might be slightly off, too

I think I did a good polar alignment, so I'm just wondering, is this about what I can expect from the SkyGuider?  Do I need an autoguider to get longer exposures?  Maybe some of this is due to using my 200-500 lens instead of a telescope?  I know the lens isn't as sharp in the corners as the center, so even with perfect tracking, the edges will be blurred a bit.

 

I guess I was expecting the wrong thing from stacking.  Being a total newb to it, I figured the purpose was to make the final image much brighter.  However, it seems that the real goal is to get less noise (by getting a better SNR).  The final stacked image basically looks just as dark as the individual RAWs, and it needs a lot of processing to get it looking reasonable.  I pushed and pulled on the file much more than I usually do with my regular photography.

 

Thanks for any thoughts/tips/advice!

 

 

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#2 PhilA

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Posted 08 August 2020 - 12:45 PM

Hi ET,

 

A good first go at it. You got the pinwheel in the frame and that isn't always easy, so you are on the right track.

 

Were you guiding or was this just the tracker? Zoom in on the stars and you can see they are oval shaped. Your goal is to keep them nice and round which will come from a good polar alignment, good focus, and choosing your exposure time - polar align and take some time with it to get it close. The longer the exposure and the longer the focal length the better it needs to be. Then take some test shots and limit your exposure time to where the stars are still round.

 

Processing, for me, is as big as collecting the subs. It can get very involved and the longer you work on it the more detail you will be able to pull out of the images. 

 

For a good, in depth intro to working with trackers, check out Peter Zelinka's YouTube channel and his website. It is specific to trackers and he will take you step by step through the whole process, get you set up guiding (which will make thing that much better with deep sky targets), and then walk through processing with Photoshop. His Deep Sky tutorial is worth the money too. I have no connection with him other than I learned a lot. Also take a look at Trever and his sidekick Rudy at Astrobackyard on YouTube. His imaging is mostly done with bigger telescopes, but I think he is also very good with Photoshop processing. He goes down a little different road than Peter, but he does some very nice work and you can learn a lot. Experiment, experiment, experiment - there are literally thousands of settings in Photoshop and other processing software and there is no "right" way to do it. It is was works for you. But given that, these guys can get you headed in a direction you can grow with. There are also other ways to go other than Photoshop, but if you have a good grasp of PS anyway, it is a good start.

 

After that it is all about the details, both in shooting the frames and the processing. Be patient and it just gets better and better!

 

pa


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#3 Gene3

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Posted 08 August 2020 - 01:06 PM

Hi Phil & ET,

I am testing out my new Skyguider Pro.

My first issue is that it does not seem to want to slew. I have power and battery is charged, but when I press the left or right arrow button it does not slew.

I must be doing something wrong

Any thoughts?

 

Thanks,

Gene


Edited by Gene3, 08 August 2020 - 01:06 PM.


#4 ET_PhoneHome

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Posted 08 August 2020 - 01:52 PM

Hi Phil & ET,

I am testing out my new Skyguider Pro.

My first issue is that it does not seem to want to slew. I have power and battery is charged, but when I press the left or right arrow button it does not slew.

I must be doing something wrong

Any thoughts?

 

Thanks,

Gene

I am totally new to the Skyguider as well.  All I can think of offhand is, is the clutch tightened?


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#5 ET_PhoneHome

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Posted 08 August 2020 - 01:57 PM

Hi ET,

 

A good first go at it. You got the pinwheel in the frame and that isn't always easy, so you are on the right track.

 

Were you guiding or was this just the tracker? Zoom in on the stars and you can see they are oval shaped. Your goal is to keep them nice and round which will come from a good polar alignment, good focus, and choosing your exposure time - polar align and take some time with it to get it close. The longer the exposure and the longer the focal length the better it needs to be. Then take some test shots and limit your exposure time to where the stars are still round.

 

Processing, for me, is as big as collecting the subs. It can get very involved and the longer you work on it the more detail you will be able to pull out of the images. 

 

For a good, in depth intro to working with trackers, check out Peter Zelinka's YouTube channel and his website. It is specific to trackers and he will take you step by step through the whole process, get you set up guiding (which will make thing that much better with deep sky targets), and then walk through processing with Photoshop. His Deep Sky tutorial is worth the money too. I have no connection with him other than I learned a lot. Also take a look at Trever and his sidekick Rudy at Astrobackyard on YouTube. His imaging is mostly done with bigger telescopes, but I think he is also very good with Photoshop processing. He goes down a little different road than Peter, but he does some very nice work and you can learn a lot. Experiment, experiment, experiment - there are literally thousands of settings in Photoshop and other processing software and there is no "right" way to do it. It is was works for you. But given that, these guys can get you headed in a direction you can grow with. There are also other ways to go other than Photoshop, but if you have a good grasp of PS anyway, it is a good start.

 

After that it is all about the details, both in shooting the frames and the processing. Be patient and it just gets better and better!

 

pa

Thanks, Phil!  This was just the tracker without guiding.  I wonder how much accuracy is possible that way?  This was only at 300mm, and my lens goes to 500, which would be even trickier.  Another thing is, I shot this at 400 ISO, so I could probably boost that a bit to get shorter exposures.  It's a learning experience, that's for sure.  Much harder than "regular" photography!

 

For my post work, I normally use Lightroom.  Hopefully, that's flexible enough to give me decent results.  We'll see.  I'll keep at it cool.gif



#6 Gene3

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Posted 08 August 2020 - 02:30 PM

I am totally new to the Skyguider as well.  All I can think of offhand is, is the clutch tightened?

You can get yours can slew by just pressing the left or right button correct?



#7 spereira

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Posted 08 August 2020 - 05:11 PM

Moving to DSLR ...

 

smp



#8 Jaluca

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Posted 08 August 2020 - 06:43 PM

You can get yours can slew by just pressing the left or right button correct?

Left and right buttons should slew along RA.  Keep the button pressed for a second...sometimes it takes a sec for the gear to engage, and when it does, the movement is very slight.  And yes, make sure the clutch is tight.  You should also hear the motor when slewing.  It's not loud, but it should be audible.


Edited by Jaluca, 08 August 2020 - 06:44 PM.


#9 Jaluca

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Posted 08 August 2020 - 06:56 PM

Got to play with my Skyguider last night and took a stab at M101 (Pinwheel).  I'm guessing maybe this isn't the easiest one to start with, or maybe it is, and I just don't know what I'm doing, haha.  Anyway, I'm wondering how much is possible with the Skyguider and my DSLR (I used the 200-500 lens for this one, at 300mm).  I took 30s subs x 40.

 

Some issues I see are

  • the galaxy is very small in the frame, so I had to crop way, way down
  • I had to raise exposure in post by a couple stops, so I'm assuming I underexposed and should've used a longer exp. than 30s
  • The stars are not pinpoints (so exposure was too long or tracking was not good enough).  Focus might be slightly off, too

I think I did a good polar alignment, so I'm just wondering, is this about what I can expect from the SkyGuider?  Do I need an autoguider to get longer exposures?  Maybe some of this is due to using my 200-500 lens instead of a telescope?  I know the lens isn't as sharp in the corners as the center, so even with perfect tracking, the edges will be blurred a bit.

 

I guess I was expecting the wrong thing from stacking.  Being a total newb to it, I figured the purpose was to make the final image much brighter.  However, it seems that the real goal is to get less noise (by getting a better SNR).  The final stacked image basically looks just as dark as the individual RAWs, and it needs a lot of processing to get it looking reasonable.  I pushed and pulled on the file much more than I usually do with my regular photography.

 

Thanks for any thoughts/tips/advice!

Hey there, I'm a SGP user as well.  This looks like inaccurate tracking to me, which is easy to do with the SGP, especially if you're doing polar alignment with the built in scope and an app, as opposed to the iPolar scope.  

 

At 300mm and 30" subs, you'll be able to get better results with some practice. One thing I struggled with in the beginning was messing up what I thought was good polar alignment by flipping the DEC bracket around, mounting my camera, and lining up my shot.  It doesn't take much to bump yourself out of alignment with this mount, especially on a lightweight tripod.   I commonly shoot with a small refractor and crop sensor DSLR at about 570mm and it can be very challenging on the SGP.  Still, I've gotten round stars at 90" before, though it felt more like luck than anything.

 

Oh, also make sure your tripod is level and as stable as possible.

 

More thoughts:  How heavy is that zoom lens?  And are you using the DEC bracket and counterweight?  If so, make sure you're load is balanced, and very slightly over-balanced on the Eastern side.  That way the gear will always have positive pressure as it moves your payload around.  Payload weight can quickly become an issue on a mount this size.


Edited by Jaluca, 08 August 2020 - 07:00 PM.


#10 ChristopherBeere

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Posted 08 August 2020 - 06:57 PM

If you want to shoot galaxies then this is simply the wrong hardware.

 

An autoguider will not help at all as the right ascension tracking is very accurate on modern mobile trackers.

 

Periodic error is largely irrelevant compared to the declination drift from innacurate polar alignment.

 

Thats the key, accurate polar alignment, an autoguider on a mobile rig is not worth bothering with.


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#11 17.5Dob

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Posted 08 August 2020 - 08:18 PM

Got to play with my Skyguider last night and took a stab at M101 (Pinwheel).  I'm guessing maybe this isn't the easiest one to start with, or maybe it is, and I just don't know what I'm doing, haha.  Anyway, I'm wondering how much is possible with the Skyguider and my DSLR (I used the 200-500 lens for this one, at 300mm).  I took 30s subs x 40.

 

Some issues I see are

  • the galaxy is very small in the frame, so I had to crop way, way down
  • I had to raise exposure in post by a couple stops, so I'm assuming I underexposed and should've used a longer exp. than 30s
  • The stars are not pinpoints (so exposure was too long or tracking was not good enough).  Focus might be slightly off, too

I think I did a good polar alignment, so I'm just wondering, is this about what I can expect from the SkyGuider?  Do I need an autoguider to get longer exposures?  Maybe some of this is due to using my 200-500 lens instead of a telescope?  I know the lens isn't as sharp in the corners as the center, so even with perfect tracking, the edges will be blurred a bit.

 

I guess I was expecting the wrong thing from stacking.  Being a total newb to it, I figured the purpose was to make the final image much brighter.  However, it seems that the real goal is to get less noise (by getting a better SNR).  The final stacked image basically looks just as dark as the individual RAWs, and it needs a lot of processing to get it looking reasonable.  I pushed and pulled on the file much more than I usually do with my regular photography.

 

Thanks for any thoughts/tips/advice!

#1: Expecting to be able to shoot anything with just 20 min total exposure is impossible...you need to think in hours of time..not minutes. But you are completely correct., stacking does not make things brighter. Your stack will be no brighter than your subs.

#2: Besides Andromeda, you need a lot more focal length to shoot galaxies, 1000mm +...you need to select more suitable targets.

#3: You should be able to get better results at 300mm, but it's still just a glorified "camera tracker" meant to be used with under 200mm focal for best results....adding an autoguider to try to shoot longer focal lengths is like putting lipstick on a pig. It was never designed for it. Stick to 85mm - 200mm and you'll be a lot happier...especially if you get rid of the zoom and start shooting primes at f4 of faster. THAT's what these little trackers were designed for...short exposures with fast optics.
 


Edited by 17.5Dob, 08 August 2020 - 08:19 PM.

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#12 NatureKnyt

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Posted 08 August 2020 - 11:56 PM

Got to play with my Skyguider last night and took a stab at M101 (Pinwheel).  I'm guessing maybe this isn't the easiest one to start with, or maybe it is, and I just don't know what I'm doing, haha.  Anyway, I'm wondering how much is possible with the Skyguider and my DSLR (I used the 200-500 lens for this one, at 300mm).  I took 30s subs x 40.

 

Some issues I see are

  • the galaxy is very small in the frame, so I had to crop way, way down
  • I had to raise exposure in post by a couple stops, so I'm assuming I underexposed and should've used a longer exp. than 30s
  • The stars are not pinpoints (so exposure was too long or tracking was not good enough).  Focus might be slightly off, too

I think I did a good polar alignment, so I'm just wondering, is this about what I can expect from the SkyGuider?  Do I need an autoguider to get longer exposures?  Maybe some of this is due to using my 200-500 lens instead of a telescope?  I know the lens isn't as sharp in the corners as the center, so even with perfect tracking, the edges will be blurred a bit.

 

I guess I was expecting the wrong thing from stacking.  Being a total newb to it, I figured the purpose was to make the final image much brighter.  However, it seems that the real goal is to get less noise (by getting a better SNR).  The final stacked image basically looks just as dark as the individual RAWs, and it needs a lot of processing to get it looking reasonable.  I pushed and pulled on the file much more than I usually do with my regular photography.

 

Thanks for any thoughts/tips/advice!

As an owner of a SGP/Redcat 51 combo, I generally agree with others that this is really stretching what these trackers were meant to do. Can you pull it off? Sure, but it's a lot tougher than other easier targets. Perhaps your biggest challenge will be framing - I got lucky one night and framed Whirlpool in one try. Ran out out the battery and when I switched it out, took me over an hour to get it reframed. Def got a dummy battery after that. If you are determined to get these longer FL targets, you're going to want GOTO. For an example of Pinwheel on an SGP, here is one (using an astrocam and guiding): https://www.astrobin...87lwg5/?nc=user

 

 

If you want to shoot galaxies then this is simply the wrong hardware.

 

An autoguider will not help at all as the right ascension tracking is very accurate on modern mobile trackers.

 

Periodic error is largely irrelevant compared to the declination drift from innacurate polar alignment.

 

Thats the key, accurate polar alignment, an autoguider on a mobile rig is not worth bothering with.

I definitely agree this is not the strength of this kind of setup (my whirlpool shots are pretty sad, heh). However, when I moved to autoguiding with my SGP and Redcat 51, I've been able to get 10, even 15 minute subs with round stars on more appropriate targets like Veil and NA nebula. No way I could get that with just manual polar scope before, and that's using the upgraded WO latitude base and brackets. The ASIair Pro helps tremendously with simplifying this and will even dither in RA. But yes, I tend to stick to easier targets than Pinwheel and Whirlpool. Without GOTO, it's just an exercise in frustration trying to frame targets.

 

#1: Expecting to be able to shoot anything with just 20 min total exposure is impossible...you need to think in hours of time..not minutes. But you are completely correct., stacking does not make things brighter. Your stack will be no brighter than your subs.

#2: Besides Andromeda, you need a lot more focal length to shoot galaxies, 1000mm +...you need to select more suitable targets.

#3: You should be able to get better results at 300mm, but it's still just a glorified "camera tracker" meant to be used with under 200mm focal for best results....adding an autoguider to try to shoot longer focal lengths is like putting lipstick on a pig. It was never designed for it. Stick to 85mm - 200mm and you'll be a lot happier...especially if you get rid of the zoom and start shooting primes at f4 of faster. THAT's what these little trackers were designed for...short exposures with fast optics.
 

See above, agreed a full GOTO mount is the way to go for long focal lengths. But autoguiding can definitely make a huge difference even on a SGP.


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#13 lakeorion

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Posted 09 August 2020 - 09:23 AM

Get an 85mm f1.2, stop it to 2.8 and don't worry about galaxies (except Andromeda).  Or a 35mm f1.8, stop it to 3.5 and get entire constellations, example here, Cassiopiea. (Note: not taken with a SkyGuider, but a cheap GEM, iOptron SmartEQ - but similar price and quality.)

2015-09-19 Cassiopeia post.jpg
2015-09-19 Cassiopeia annotated post.jpg

 

It's the same concept as hand held telephoto.  If it's difficult hand held past 200mm, it's difficult tracking unguided past 200mm.
 
My two cents.  I wanted to get a Sky Watcher Star Adventurer for my upcoming work trip but you guys bought them all.  By the time I decided there was no stock left.  Next year...

Edited by lakeorion, 09 August 2020 - 09:27 AM.


#14 ET_PhoneHome

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Posted 09 August 2020 - 11:56 AM

Hey there, I'm a SGP user as well.  This looks like inaccurate tracking to me, which is easy to do with the SGP, especially if you're doing polar alignment with the built in scope and an app, as opposed to the iPolar scope.  

 

At 300mm and 30" subs, you'll be able to get better results with some practice. One thing I struggled with in the beginning was messing up what I thought was good polar alignment by flipping the DEC bracket around, mounting my camera, and lining up my shot.  It doesn't take much to bump yourself out of alignment with this mount, especially on a lightweight tripod.   I commonly shoot with a small refractor and crop sensor DSLR at about 570mm and it can be very challenging on the SGP.  Still, I've gotten round stars at 90" before, though it felt more like luck than anything.

 

Oh, also make sure your tripod is level and as stable as possible.

 

More thoughts:  How heavy is that zoom lens?  And are you using the DEC bracket and counterweight?  If so, make sure you're load is balanced, and very slightly over-balanced on the Eastern side.  That way the gear will always have positive pressure as it moves your payload around.  Payload weight can quickly become an issue on a mount this size.

Thanks!  I did do polar alignment using an app to get Polaris' position, and then I used the built-in scope.  Is the iPolar scope that much better?

 

Also, I may have bumped the mount a little.  The problem is, I can't polar align with the camera attached, since during the intial setup, I flipped the dec. bracket around (like people suggest for heavy cameras) so the camera is mounted closer to the axis.  The problem I found with this is, the internal polar finder is upside down, and it won't illuminate, either.  So what I did was, do the alignment, then rotate the bracket 180 degrees to mount the camera.  Maybe there is a better way?

 

The camera is a D850 with 200-500 lens, so it's hefty.  I could probably use a second counterweight to help balance, but it's pretty good as is.  Maybe 500mm with this sort of setup is going to be a lost cause.  I also have a 300mm f/4, and 70-200 f/4 that are much lighter.  And then if I want to go wide, I have a 50mm f/1.8 and a 85mm f/1.8.

 

Finally, maybe I should save the small DSOs for when I'm more experienced, and try using different gear.  Aside from the Skyguider, I also have a Celestron 6SE SCT and mount.  Should I even try imaging with that mount since it's AltAz?  I am getting a SW EQM-35 mount, so maybe that would be my best option for imaging, even better than the Skyguider?  As far as scopes go, I have the 6SE and am getting a SW 100ED Evostar.  I'm thinking maybe the best combo for imaging would be either scope on the EQM-35?  Maybe the refractor for larger objects, and the SCT for stuff like M101?



#15 Jaluca

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Posted 10 August 2020 - 12:03 PM

Thanks!  I did do polar alignment using an app to get Polaris' position, and then I used the built-in scope.  Is the iPolar scope that much better?

 

Also, I may have bumped the mount a little.  The problem is, I can't polar align with the camera attached, since during the intial setup, I flipped the dec. bracket around (like people suggest for heavy cameras) so the camera is mounted closer to the axis.  The problem I found with this is, the internal polar finder is upside down, and it won't illuminate, either.  So what I did was, do the alignment, then rotate the bracket 180 degrees to mount the camera.  Maybe there is a better way?

 

The camera is a D850 with 200-500 lens, so it's hefty.  I could probably use a second counterweight to help balance, but it's pretty good as is.  Maybe 500mm with this sort of setup is going to be a lost cause.  I also have a 300mm f/4, and 70-200 f/4 that are much lighter.  And then if I want to go wide, I have a 50mm f/1.8 and a 85mm f/1.8.

 

Finally, maybe I should save the small DSOs for when I'm more experienced, and try using different gear.  Aside from the Skyguider, I also have a Celestron 6SE SCT and mount.  Should I even try imaging with that mount since it's AltAz?  I am getting a SW EQM-35 mount, so maybe that would be my best option for imaging, even better than the Skyguider?  As far as scopes go, I have the 6SE and am getting a SW 100ED Evostar.  I'm thinking maybe the best combo for imaging would be either scope on the EQM-35?  Maybe the refractor for larger objects, and the SCT for stuff like M101?

You are the same journey with this mount that I was, my friend.

 

Re: iPolar.  Not sure, since I haven't used it.  I've gotten decent results without it, so I haven't invested in one.  Also, for me, the whole point of this mount was portability and minimal peripheral equipment.  The iPolar brings a laptop back into the mix, so I'm not as interested in it for that reason as well.

 

Flipping the DEC bracket is the right call, imo, but as you have noted comes with the downside of having the polar scope upside down in the mount housing.  I love my SGP, but this is one of the major design flaws it has and I hope iOptron fixes this in future editions of the mount.  The fix for this is, well, not ideal.  You can disassemble the mount and re-orient the polar scope using these instructions: http://www.ioptron.u...opeRotating.pdf

 

The process linked above looks worse than it is.  I was able to complete it in about an hour with no issues and it has greatly improved my experience with the mount, ease of set up, and consistency with good alignment.  Now I just mount my camera and scope, align, and I'm off to the races.  No awkward flipping of the DEC bracket or mounting gear after alignment.  If you're comfortable with minor electronics repairs, it's a fairly simple process, but as with anything, you do run the risk of messing something up inside the mount, so I completely understand why someone wouldn't want to do this with a new $400+ piece of equipment.

 

And lastly, yes, what others have said in this thread about galaxies/tiny DSOs is spot on.  The SGP wasn't made for that kind of imaging.  However, there are TONS of great targets that are within its range.  Moreover, I would actually argue that 500mm focal lengths, while challenging, are not out of the question for the SGP.  But I've learned that starting with the most forgiving targets (wide field Milky Way, large nebulae, etc.) and then working your way towards the limits of the mount will yield a far better imaging experience and will be less frustrating overall.

 

Despite its quirks, I'm an SGP fan and am happy to chat about it anytime.  Good luck and clear skies!!



#16 PhilA

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Posted 10 August 2020 - 01:21 PM

If you want to shoot galaxies then this is simply the wrong hardware.

 

An autoguider will not help at all as the right ascension tracking is very accurate on modern mobile trackers.

 

Periodic error is largely irrelevant compared to the declination drift from innacurate polar alignment.

 

Thats the key, accurate polar alignment, an autoguider on a mobile rig is not worth bothering with.

Agree, it may not be the BEST hardware, but if that is what you have it will surely work. Having messed with guiders for a several years I can assure you a guide scope with a good polar alignment makes a significant difference. 3 min subs with crisp round stars are easily do able and longer sometimes if everything is perfect. 600mm lenses are possible, but weight becomes an issue if they aren't lightweight versions.

 

A guider is intended as a mobile rig and that is generally how they are used. I don't think I have ever seen one used on a pier - just on tripods of various suitability.

 

You use what you have in this hobby and learn from pushing it as far as you can.



#17 PhilA

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Posted 10 August 2020 - 01:30 PM

Jaluca,

 

I have an iPolar on an iOptron CEM40Ec mount and it works fine, but it does tie you to a computer which is something you may not want with a tracker. Another option is to get close with the built in polar scope and then finish up with either your camera or a guide scope. You can use Sharpcap  or the software on an AsiAir for the final alignment.  They both have similar functionality and will get you closer than the built in scope.

 

Thanks for the link to rotating the scope. That will be a big help - I didn't know you could do it.



#18 ET_PhoneHome

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Posted 10 August 2020 - 02:37 PM

You are the same journey with this mount that I was, my friend.

 

Re: iPolar.  Not sure, since I haven't used it.  I've gotten decent results without it, so I haven't invested in one.  Also, for me, the whole point of this mount was portability and minimal peripheral equipment.  The iPolar brings a laptop back into the mix, so I'm not as interested in it for that reason as well.

 

Flipping the DEC bracket is the right call, imo, but as you have noted comes with the downside of having the polar scope upside down in the mount housing.  I love my SGP, but this is one of the major design flaws it has and I hope iOptron fixes this in future editions of the mount.  The fix for this is, well, not ideal.  You can disassemble the mount and re-orient the polar scope using these instructions: http://www.ioptron.u...opeRotating.pdf

 

The process linked above looks worse than it is.  I was able to complete it in about an hour with no issues and it has greatly improved my experience with the mount, ease of set up, and consistency with good alignment.  Now I just mount my camera and scope, align, and I'm off to the races.  No awkward flipping of the DEC bracket or mounting gear after alignment.  If you're comfortable with minor electronics repairs, it's a fairly simple process, but as with anything, you do run the risk of messing something up inside the mount, so I completely understand why someone wouldn't want to do this with a new $400+ piece of equipment.

 

And lastly, yes, what others have said in this thread about galaxies/tiny DSOs is spot on.  The SGP wasn't made for that kind of imaging.  However, there are TONS of great targets that are within its range.  Moreover, I would actually argue that 500mm focal lengths, while challenging, are not out of the question for the SGP.  But I've learned that starting with the most forgiving targets (wide field Milky Way, large nebulae, etc.) and then working your way towards the limits of the mount will yield a far better imaging experience and will be less frustrating overall.

 

Despite its quirks, I'm an SGP fan and am happy to chat about it anytime.  Good luck and clear skies!!

Thanks for the advice waytogo.gif  As far as the polar scope flipping, I did stumble across that pdf the other night, and was thinking about it.  I thought it would be simple, LOL.  I think I can probably manage it, so maybe I'll give it a shot.  I'm planning on always using the dec bracket in this config, so it would make more sense to rotate the polar scope.

 

So it sounds like I'm getting a little carried away.  I will try for some larger objects instead of the tiny stuff.  Although, I did manage to get a quick shot of the Whirlpool last night with a single, 30s exposure.  If I played with the file, I could vaguely tell what it was, but obviously not even close to the "good" photos I've seen.  I'm not sure how limited I will be by light pollution, but we'll see.

 

I am actually planning on getting a decent EQ mount for my 4" refractor, and I may throw my 6" SCT on it sometimes, too, so once I get more experienced, that may be what I use for astro shooting.

 

I snagged a shot of M13 last night.  I think it was 10s x 6, 800ISO, 300mm, f/4.  The one odd thing I noticed is the brighter stars are round, but they have a line through the middle.  I'm guessing it's something to do with the optics of my lens?  It's a Nikon PF (phase fresnel) lens, so maybe that's why?  Only downside of shooting at 300mm is I had to crop a ton!  Imagine if I could fill the frame with M13 at 45MP grin.gif   If only!

 

https://www.flickr.c...eposted-public/



#19 tebarton

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Posted 11 August 2020 - 10:35 PM

Hi Phil & ET,

I am testing out my new Skyguider Pro.

You are doing the same thing I did probable. You need to engage the clutch. 

I found this out as it didn't do anything when I first set it up. But the I put the camera and weights on it, tighten the clutch and it worked. 

Cheers


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#20 Gene3

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Posted 11 August 2020 - 10:46 PM

You are doing the same thing I did probable. You need to engage the clutch. 

I found this out as it didn't do anything when I first set it up. But the I put the camera and weights on it, tighten the clutch and it worked. 

Cheers

Right same here as well as motor reboot

http://www.ioptron.u...motor_reset.pdf



#21 ET_PhoneHome

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Posted 11 August 2020 - 11:03 PM

OK, so I went through that procedure to rotate my polar scope 180 degrees (basically took the whole mount apart, LOL).  Anyway, now I can do the polar alignment with the camera in place and the weight pointed down (in this position, the 12 o'clock position is now at the top in the scope.  Yay!).

 

While I was at it, I checked the alignment of the polar scope with the RA axis, but it was off by a decent amount.  If I centered a target and rotated the axis, the target didn't stay in the center.  After some tweaks, it's pretty close now.  The weird thing is, as I rotate the axis, the center of the reticle still doesn't stay in the center.  However, the target stays centered under the reticle as it wobbles around the axis.  So I guess as long as the target e.g. star stays centered under the reticle while rotating, I'm good?  When aligning to Polaris, I rotated the axis and it seems to (more or less) stay withing the inner ring.

 

The good news is, I think all this helped a bit.  I did a quick test tonight and was able to get 30s subs with reasonable stars.  Not perfectly round, but pretty good unless you zoom in and pixel peep.  Here's an example:

https://www.flickr.c...eposted-public/

 

Finally, am I going to be really limited by light pollution and what DSOs I can image?  In the example above, the sky in a single 30s exposure looks extremely bright and washed out.  I'm guessing this can't be good when trying to see nebula and other faint objects?  Here's one exposure with no processing:

 

Attached Thumbnails

  • 2.jpg

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#22 vidrazor

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Posted 12 August 2020 - 12:15 AM

Got to play with my Skyguider last night and took a stab at M101 (Pinwheel).  I'm guessing maybe this isn't the easiest one to start with, or maybe it is, and I just don't know what I'm doing, haha.  Anyway, I'm wondering how much is possible with the Skyguider and my DSLR (I used the 200-500 lens for this one, at 300mm).  I took 30s subs x 40.

 

Some issues I see are

  • the galaxy is very small in the frame, so I had to crop way, way down
  • I had to raise exposure in post by a couple stops, so I'm assuming I underexposed and should've used a longer exp. than 30s
  • The stars are not pinpoints (so exposure was too long or tracking was not good enough).  Focus might be slightly off, too

I think I did a good polar alignment, so I'm just wondering, is this about what I can expect from the SkyGuider?  Do I need an autoguider to get longer exposures?  Maybe some of this is due to using my 200-500 lens instead of a telescope?  I know the lens isn't as sharp in the corners as the center, so even with perfect tracking, the edges will be blurred a bit.

 

I guess I was expecting the wrong thing from stacking.  Being a total newb to it, I figured the purpose was to make the final image much brighter.  However, it seems that the real goal is to get less noise (by getting a better SNR).  The final stacked image basically looks just as dark as the individual RAWs, and it needs a lot of processing to get it looking reasonable.  I pushed and pulled on the file much more than I usually do with my regular photography.

 

Thanks for any thoughts/tips/advice!

Yeah tracking is off on that. I've had 25 second subs with a 360mm on an M4/3 body, giving me 720mm full frame equivalent FOV and motion blur. You should be able to get about 40-50 seconds clean at 300mm full frame.

 

Once you get the hang of aligning with the unit that's about what you'll get out of the box, but autoguiding with it will certainly give you a significant improvement in sub times, contrary to other opinions on it.

 

But shoot with the unit as is and get the hang of it, especially the alt-az mount, that has a significant amount of backlash. Getting the hang of the alt-az mount will make life easier when you try autoguiding. You should be able to balance the rig in both RA and DEC. Have a look at this fellow's page and video so you can see the differences you can get out of your SkyGuider Pro with autoguiding: https://www.peterzel...e-skyguider-pro


Edited by vidrazor, 12 August 2020 - 12:24 AM.


#23 chanrobi

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Posted 13 August 2020 - 03:07 AM

Has nothing to do with 30s exposures, and more to do with total integration time.

 

This isn't film days and you aren't using a 20 year old digital camera. 2 x 30s is going to be pretty much the same as 1 x 60s. Way less subs to throw out anyways.



#24 ET_PhoneHome

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Posted 13 August 2020 - 01:44 PM

Has nothing to do with 30s exposures, and more to do with total integration time.

 

This isn't film days and you aren't using a 20 year old digital camera. 2 x 30s is going to be pretty much the same as 1 x 60s. Way less subs to throw out anyways.

Maybe to an extent, but there should be an optimal time for subs, otherwise they will be over or under exposed.  If I shot 1s x 60, I'd have to boost the exposure a ton in post, and exposure can only be pushed by so much.  There must be some advantage to using longer exposures, or everyone would just shoot 30s x a huge number of shots and not bother with all the fancy autoguiding equipment.

 

My main concern is how much is light pollution going to screw me up.  For example, even if I can get 5 minute subs, is it going to be possible to image nebula and things like that?  I shot the Veil Nebula last night (total time about 45 mins), and it's there, but very, very faint, and I'm going to have to process the heck out of the image to get anything sort of worthwhile.



#25 DubbelDerp

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Posted 13 August 2020 - 02:08 PM

For me, longer subs are a really nice thing. If I'm going to get 6 hours on a target, I'd much rather stack 72 300-second subs as opposed to 720 30-second subs. Would they produce similar images? Perhaps, but you'll get to a calibrated stack a lot faster with only 72 subs.

 

I do all my imaging with a Skyguider, and recently switched to autoguiding. I don't like having a laptop in the field, and am in the process of switching over to Astroberry, but there are just too many benefits for guiding my tracker to not use it. Longer subs, smaller, more round stars, and it tames some of the erratic tracking I see from my tracker throughout a session. Works great out to 360mm focal length on an APS-C sensor.

 

The background is pretty bright in the sub you posted... must have a decent amount of light pollution? If your camera is modded, you might consider a dual narrowband filter for shooting emission nebula. It blocks a LOT of light, making framing that much more difficult. But isolating the wavelengths you care about really cuts through all kinds of light pollution. I can shoot emission nebulae in full moonlight with mine.

 

45 minutes isn't going to get you much on the Veil nebula. I got 15 hours on it, and I'm going to get some more narrowband data as soon as I get a chance. You definitely don't want to process 15 hours of 30-second subs...

 

Edit - Oh, and putting the histogram peak on the back-of-camera histogram 1/4 - 1/3 from the left really is a good rule of thumb. I'm guessing that its much farther over to the right in the sub you posted? (Don't tell anyone, but I'll sometimes shoot for well over the 50% point on the histogram if I'm going after something really dim and don't care about star colors so much.)


Edited by DubbelDerp, 13 August 2020 - 02:10 PM.

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