1392 replies to this topic

[dciobota]

Ok, for those of you wondering about the max payload of the skyguider pro.  I'm including an image of my setup with the at65edq and the 30mm guider kit. 

 

 

The AT65edq weighs about 7lbs with the guider on it, plus the camera is another pound or so.  I did manage to use just one counterweight.  It is slightly underbalanced, but probably ok.  I'll find out tonight, it's supposed to be clear so I'll do some guided and unguided test runs.

 

Btw, I'll also be using phd2 to gauge pec, but never done it before with that app.  So any pointers, much appreciated.  I'll read the manual, just in case.  ;-)

 

I believe this is about as much weight as you can safely put on it.  If you use a second counterweight, you might be able to do more, but stability I think will become an issue.

 

So, the ZS73 with an aps-c camera would at least balance ok.

 

Hope this helps

Edited by dciobota, 19 April 2018 - 07:04 PM.

[dciobota]

Well I did run some tests last night with the kit I mentioned above, and like I suspected, it struggled.  I took a series of 4 min unguided exposures then a series of guided exposures.  I had the scope pointed east and fairly low when I started.  The unguided run was first and I let it go for about an hour.  Then I switched guiding on and let it run for another 3 hours.  Unfortunately, I lost the phd guide log.  I'm not sure if it maybe got saved somewhere else. 

 

Here's a link to an album I created that has one typical unguided and one typical guided from each series:

https://photos.app.g...jTGrbspj4tz9TC3

 

As you can see, the unguided image has serious trailing as the mount is struggling to keep the speed going.  Guiding fixes that, nice round stars.  But even guiding was not all that great last night, the rms error varied between 1.2 and 1.6 arcsec, considerably worse than when I was running just the camera and lens.  I didn't think the scope was that badly unbalanced, but it was apparently. 

 

Still, the end result shows that if you do guide, you will do ok.  If you do unguided with this setup, you might get away with shooting 1 min exposures, or maybe use a second counterweight to balance.  I didn't try those two.

 

Btw, I did find the phd log from my previous night's run, when I was doing just the camera and lens.  I ran PECPrep, is that what you guys use to estimate PEC?  I'm not sure that tool is working right, it tells me the PEC is less than 1 arcsec, but how can it tell from the mount corrections?  I wish PHD2 had a tool that just observes star movement and generates a PEC estimate based on that.  That would be the most accurate way.

 

Anyways, for anyone interested, here is my guide log from that night.

 PHD2_GuideLog_2018-03-14_214641.zip   198.4KB   109 downloads

 

If you figure out how to use it and get a useful PEC value from it, please let us know.

 

Hope this helps.

[dciobota]

Ok, I did learn one thing today, and that I can get an unguided log by turning on guiding assistant in PHD2.  Had no idea.  So I guess that would give me the real PEC value.

Until next time.  Hopefully next time I'll be taking some real pics for a change.  ;-)

Edited by dciobota, 20 April 2018 - 09:40 PM.

[dciobota]

Some more musings on the skyguider pro. 

 

I had meant to try the setup pictured a couple of posts above, but with an additional counterweight, so I could get as good a balance as possible.  Which I did.  Tested the rig last night, but the unguided results still disappointed, a little less trailing but still unacceptable at 4 min.

 

I also tried the guiding assistant, in the hopes of capturing a guidelog that would help identify the mount PEC.  Well, no go.  There was no guide log produced, just a debug log, which couldn't be read by either of the tools I have.  So honestly, I still have no idea how to generate an unguided log.  If anyone can give me more specific instructions for PHD2, I'll be glad to try again, since I have some clear nights ahead and heading into a full moon (of course).

 

I did turn on guiding later on and let it run all night.  The guiding still works beautifully, nice round stars.  The 30mm miniguider kit I think is a perfect companion for this mount.  I use it not only as a guider, but for polar alignment as well.  Which is a must in my case, since my polar scope seems to be off still.

 

Hope this helps.

[leveye]

If you have nice round stars then thats your guide log yes? It's working. Post some results when you can. I'll have some new shots very soon to post. Many thanks.

Edited by leveye, 24 April 2018 - 12:46 PM.

[dciobota]

Yeah, but I was told I could use guide assistant with guiding turned off to get a log to calculate PEC.  I was asked to do that, and frankly I was curious too.  I posted a guidelog previously, and I used PEMPro as well as PECPrep to try and see if they gave me values for PEC, but the numbers I got from them were suspicious (like 1 arcsec peak to peak).  That didn't sound right.

 

Anyways, I left it to guide last night and pulled the guidelog from that session.  A total of 320 min until daylight (fell asleep).  Found the scope jammed into the tripod leg.  Tested it tonight and it seems ok.  We'll see.  Anyways, here's a screenshot of the PEMPro screen.  Shows a more believable (and more disappointing) number, 13.47 arcsec peak to peak.  I was hopeing for something under 10 arcsec. With that size PE, with my camera and 420mm scope the elongations would be around 7 pixels.  I honestly don't know if I should believe it's that bad, when I was testing at 200mm with the same camera I would get no visible trailing.  Maybe part of the large PE is the fact my guidecam wasn't orthogonal?  

 

Anyways, I'll post the guidelog in the next post, maybe someone else can make sense out of it.

[dciobota]

And here's the guidelog.

 PHD2_GuideLog_2018-04-23_225246.zip   381.58KB   50 downloads

 

I'll stack the guided images, but don't expect much.  It's just stars I had the scope pointing roughly east, without goto I'm lost in my back yard, I can see maybe ten stars.  Didn't even take flats.

Edited by dciobota, 24 April 2018 - 09:02 PM.

[cloudywest]

If it was true the PE 13.47", you'd be so excited.  Any tracker at this size with less than 20" should be very good.

[dciobota]

Thanks for the info Cloudywest.  Yeah, the PE is not that bad, but I believe the Astrotrac mounts are supposed to have around 5 arcsec PE.  I was hoping for this one to be comparable.  It may still be, the previous log from March indicated much lower PE.  Maybe the very heavy payload I used this time exacerbates movement due to PE.  It definitely made guiding worse.

[cloudywest]

Astrotrac is at twice the price as the Skyguider Pro. There is a site very informative about EQ mounts; they list the factory PE value of most manufactures. For example Star Adventurer is 25-50". EQ5 30-45", HEQ5 20-30", EQ8 12-25", and higher end EQ mounts less than 10". https://www.darkfram...rmance-charts-1.

[dciobota]

Thanks for that link, very informative.  Yep, the Astrotrac is a lot more expensive, but if you look at the innards of the SGP you will notice the build quality and design thought that went into it are pretty high.  It belt driven for one.  I know that doesn't help PE much, but still.  If you look at the chart you linked to, a lot of the iOptron mounts have less than 10 arcsec PE.  I was expecting this little mount to be the same.

 

If it's clear tonight, I'll give it one more shot, this time with a 200mm lens instead of the refractor.  Much lighter payload, so I won't use the DEC bar, just a simple geared head.  Hopefully this setup I can get a more accurate PE measurement. 

 

I may also try the smarteq pro.  I find it hard to believe they measured 40-60 arcsec PE, plus they list guiding at >2 arcsec.  On my worst guiding nights I was able to do under 2 arcsec.  I don't consider my mounts to be any better than average in their batch.  It could be I'm undersampling errors, guiding pixel scale is only around 4.5 arcsec.

[Msmst25]

I haven’t tried it without the battery grip on the 6d.  I’m planning to use the 6d with my new vixen sx2 mount and the zs73 and I’ll use the SGP with my Fuji XT2 and Xmount lenses.

Edited by Msmst25, 26 April 2018 - 02:35 AM.

[timmbottoni]

Just saw this new thread that answers how to see what your Periodic Error is with just a long exposure image taken.

 

Thought it was worth sharing here

 

https://www.cloudyni...e/#entry8541722

[dciobota]

Thank you very much Tim!  I think I finally figured out from that thread, I just need to turn off "output guide commands" in PHD.  Whew!  Who knew I had to use the "brain" lol.  They don't call it Push Here Dummy for nothing.

 

I'll give it one more try tomorrow night.  I have the smarteq pro out testing tonight, trying to iron out one issue with my plate solving.  So I did the unguided graph for it in PemPro logviewer, and it's pretty much what I expected:

 

I think iOptron advertises 30 arcsec peak to peak, and at the calculated value in the viewer, it's just under.  Hopefully the skyguider will be better.  One thing I do know is that the skyguider guides much better in RA than the smarteq pro, even carrying the same load (my refractor, which for the skyguider pro is definitely at the max limit).

 

So stay tuned for the skyguider PE tomorrow.  Too bad with the moon nearly full all I can do is test.

 

 

[dciobota]

Ok, last night was a bust, issues unrelated to the mount, but tonight I got everything working for testing.  I tested with the camera and 200mm lens mounted on a geared alt/az head, which actually works better than using the declination adapter and weights.

 

So I captured a guidelog the correct way, letting PHD2 record star movement while unguided, by turning off guide commands after calibration.  The results are encouraging, see pic and log:

 

 PHD2_GuideLog_2018-04-28_234450 SGP unguided.zip   87.87KB   74 downloads

 

Still not under 10 arcsec as I had hoped, but pretty close.  Interesting to note how much lower the PE is for this mount vs the Smarteq Pro.  It compares very well even against much more expensive mounts.

 

Note: in order to get an accurate PE reading, make sure the payload is balanced as well as possible.  This seems to make a significant difference in the result.  So the old adage, a balanced mount tracks well is a good adage to follow.  :-)

 

Hope this helps.

 

PS: the long drift arc in RA is due to polar alignment error (the scope swept across the meridian).  I didn't realign the mount after switching the dec adapter out, I should have done that.   Sorry about it.

Edited by dciobota, 29 April 2018 - 01:15 AM.

[KemalOz]

Ok, last night was a bust, issues unrelated to the mount, but tonight I got everything working for testing.  I tested with the camera and 200mm lens mounted on a geared alt/az head, which actually works better than using the declination adapter and weights.

 

So I captured a guidelog the correct way, letting PHD2 record star movement while unguided, by turning off guide commands after calibration.  The results are encouraging, see pic and log:

2018-04-28 SGP Unguided PEMPro.jpg

 

PHD2_GuideLog_2018-04-28_234450 SGP unguided.zip

 

Still not under 10 arcsec as I had hoped, but pretty close.  Interesting to note how much lower the PE is for this mount vs the Smarteq Pro.  It compares very well even against much more expensive mounts.

 

Note: in order to get an accurate PE reading, make sure the payload is balanced as well as possible.  This seems to make a significant difference in the result.  So the old adage, a balanced mount tracks well is a good adage to follow.  :-)

 

Hope this helps.

 

PS: the long drift arc in RA is due to polar alignment error (the scope swept across the meridian).  I didn't realign the mount after switching the dec adapter out, I should have done that.   Sorry about it.

You should try slightly east heavy balance. 

[leveye]

 One thing I do know is that the skyguider guides much better in RA than the smarteq pro, even carrying the same load (my refractor, which for the skyguider pro is definitely at the max limit).

 

 

This does not surprise me at all. Old Tech. I returned mine right quick. 

[Aaron_tragle]

I have used the iOptron SkyGuider Pro and WO Z61 to in my opinion a great deal of success. Most of the images on my flickr page were taken with one and I even got mentioned in an article which can be found here. The only limitation I found of this combo was the lack of dec guiding and goto at high focal lengths, 540mm with my Nikon D5300.

[bobzeq25]

Thanks for that link, very informative.  Yep, the Astrotrac is a lot more expensive, but if you look at the innards of the SGP you will notice the build quality and design thought that went into it are pretty high.  It belt driven for one.  I know that doesn't help PE much, but still.  If you look at the chart you linked to, a lot of the iOptron mounts have less than 10 arcsec PE.  I was expecting this little mount to be the same.

 

The numbers on the chart are the PE +/- out from the center, so they need to be multiplied by 2 to compare with your number.

 

Based on people's experience with 65 and 73mm scopes, I'm bailing on the SGP for my SV70T, getting a CEM25P for portable use.   I'll continue to use my Skytracker Pro with camera lenses.  By the time you look at everything needed, the SGP just wouldn't be that much more portable for me and the SV70T, with autoguider, tripod, laptop.

Edited by bobzeq25, 30 April 2018 - 05:16 PM.

[dciobota]

Awesome pics Aaron, great examples of what you can do with the mount.

Yeah some sort of way to point is needed at the longer focal lengths, I'm still searching for a way myself.  An rdf is probably good enough at dark sites if you know the sky well enough.  I haven't had much exposure to dark sites to learn the skies, and impossible in my back yard.  I tried using my android phone and the Skeye app as a push to system, with limited results.

 

The numbers on the chart are the PE +/- out from the center, so they need to be multiplied by 2 to compare with your number.

 

Based on people's experience with 65 and 73mm scopes, I'm bailing on the SGP for my SV70T, getting a CEM25P for portable use.   I'll continue to use my Skytracker Pro with camera lenses.  By the time you look at everything needed, the SGP just wouldn't be that much more portable for me and the SV70T, with autoguider, tripod, laptop.

Actually, I believe those are peak to peak values.  For the smarteq pro they list 40-60 arcsec which is acually higher than what I measured.  The eq5 and cg5 also match my past experience, about 30 arcsec peak to peak.

The cem25p is double the weight and price, not in the same category at all.  Definitely not a mount you'd put in a carry on bag along with the scope.  My whole kit including two cameras and assorted lenses fit in a backpack.  If i take out one camera and all but one lens I can fit the at65edq instead.  That includes two weights as well.  I don't believe that's possible with the cem25p.

 

PS:  I forgot to mention this also includes guider, stick pc, travel router and 9 inch tablet for remote access to guiding.  And one rechargeable li-ion battery to power everything but the mount, which has a built in battery.

 

Edited by dciobota, 30 April 2018 - 09:50 PM.

[timmbottoni]

Great thread - thanks everyone for contributing!

 

In case anyone is curious, my original worm gear for my iEQ45 was showing well over 60 arc sec, and quite erratic.  At the time iOptron had just started offering the newer, improved worm setup with better bearings, etc and iOptron offered me a set for free since it was so new.  It improved it to around 14 arc sec if my memory is correct, which I believe is quite good.

 

Of course guiding is now easy, but at it also allows me to get many keeper 2 min exposures with my ZS61, and 30 sec with my ZS103.

 

I didn't opt for the upgrade (which I would have had to pay for) to the iEQ45 PRO model which came out about a year or so later.

 

I really need to try recording the PEC again and see what that gives me.  Need some more clear night now!

 

Timm

Edited by timmbottoni, 02 May 2018 - 08:44 AM.

[leveye]

Here's a pretty good deal given the tripod is included. Snap it up.

 

https://astromart.co...cope-and-extras

[dciobota]

Chris I believe that's a skytracker?  It doesn't look like the skyguider.

[leveye]

Chris I believe that's a skytracker?  It doesn't look like the skyguider.

Yes but still an opportunity for someone looking to get into the hobby. 

[Hajfimannen]

Inspired by all the amazing images and videos here and on the other sites I have decided to give astrophotography a go. If I can only reach a fraction of that I’ll be happy. And CouldyNights seems to be the perfect place to start out.
My first “night out” was in March so you realize it is all new. But I was immediately hooked. After that I had 2-3 good nights with clear skies.
Having tried both stacked images and panorama nightscapes a couple of times I could not resist the temptation of a tracker. There seems to be several interesting alternatives on the market but eventually I decided to go with the Skyguider Pro.

The package arrived yesterday but I have not had time to open it yet shocked.gif . How ever I have decided to name it – Tina. Cause she’s quite a Turner…. Sorry bout that one.

Looking forward to absorb the knowledge here and eventually share some of my findings.

Here is my very first image. A self portrait taken by the old pilot station as I was waiting for the MW to rise. Jupiter at 2 o'clock and I guess a satellite passing right overhead.

 

 

 

Edited by Hajfimannen, 04 May 2018 - 04:02 PM.