3853 replies to this topic

[Bagwell]

Maybe you could replace the screen protector with a new fresher one.  May or may not help.  

[EastAnglian]

It’s a thought, because I think I’ve got a spare to hand. Will update. 

[Evil510]

I tested early this morning from my east facing balcony using David's EQ alignment suggestions (except doing another alignment after polar) and came up with these. I think I can do about 2.5mins @ 200mm. These are 100% screenshots after a little bit of adjustment in LightRoom.

 

Arctus @ 124sec, ISO100, f5.6

 

Arctus @ 211sec, ISO100, f5.6, can see star trails

 

Great Cluster in Hercules @ 153sec, ISO100, f5.6

 

Few thoughts/questions...

1. For every object I would GoTo, I would have to recenter manually. Is this normal? It seemed like it was always lower in frame (live view). Even going back to the same object.
2. The Sky-Watcher EQ mount isn't that great when doing the Polar Alignment step, loosening/tightening the Alt locking nut, the alignment changes.
3. After doing the 2 or 3 star alignment, why is it necessary to do a Polar alignment? Doesn't the mount know where it is after doing the star alignment?

[Bagwell]

I could be mistaken but it seems to me that #3 doing polar alignment after star alignment is to dial in the polar alignment from your first step which would be to roughly aligning the eq wedge to polaris. 

 

Since this mount doesn't have a way to use a polar scope to align it close to exact, you must do the 2 or 3 star alignment first and then do the polar alignment but use the wedge adjustments to align polar alignment to the 2 or 3 star alignment you just did.   

 

I'm not sure if that makes sense, but it seems like the way to fine tune the mount's alignment doing star alignment, then polar alignment and then again star alignment.  Dials it in real fine.  Each step makes it even more aligned.  

[davidparks]

Tracking isn’t perfect in any mount.  An Alt-Az mount needs to track in both axis.  Even a poorly aligned EQ mount would need to track in both axis.  Tracking with a properly aligned (polar) EQ mount will reduce the error down to just one axis, so it should be a bit better. 

 

The first Star Alignment gives the mount a sky model which allows the mount to GoTo a star (relatively close) for Polar Alignment.  After adjusting the base, the mounts sky model is slightly off, because you “moved the rug out from under it” by the very act of adjusting it.  The Star Alignment after Polar Alignment gives the mount an accurate sky model again.  Without the last Star Alignment, the mount’s sky model is still set to the first Star Alignment, so the GoTo’s will be slightly off (by approximately the amount you adjusted your base), and more importantly the tracking calculations would also be from the first Star Alignment... basically using the 2-axis motor movements of the previously poorly aligned mount.   The Star Alignment at the end gives the mount a new sky model and tracking calculations based upon the now accurately polar aligned mount.

 

Of course all of this depends on the precision of each step... but hopefully this helps 

[Evil510]

Thanks Bagwell and David. It makes sense and helps. Need a lot of patience with this hobby, not being able to try things right away after reading the forum during the day.

 

Tracking with a properly aligned (polar) EQ mount will reduce the error down to just one axis, so it should be a bit better. 

So for non-guiding folks like me, a regular EQ mount would be better? Or would you expect similar results to what I got in the photos above? BTW, how are my photos, do I have a good baseline?

 

I meant to type "wedge" instead of mount here. Are your experiences the same with the Sky-Watcher EQ wedge? 

The Sky-Watcher EQ mount wedge isn't that great when doing the Polar Alignment step, loosening/tightening the Alt locking nut, the alignment changes.

Thanks again.

[davidparks]

I can’t say that I would recommend one or the other in general, a regular EQ mount or an Alt/Az mount on a wedge... it all depends on weight of the gear, how portable you want to be, and focal length of the lens/scope.  Different Strokes.   I do think you have a good setup.  Also your pictures are great!  You can get a lot in just a few minutes or less.  I usually do 1 or 2 minute exposures, stacked for an hour or more.   I would expect the same results with either an Alt/Az/Wedge or EQ mount.  With unguided tracking your exposures will be limited by your polar alignment accuracy and the mounts gear precision.  (Also your star alignment accuracy, just be sure to center your stars). Also remember to always approach the center in the same direction, up and right.

 

I agree, the Skywatcher EQ Base can be less than stable...  I found the iOptron wedge much more stable and easier.  The altitude fork is shorter and wider.  Others have reported they like they Skywatcher better, so I guess it’s personal preference, but if you ask me, the iOptron wins hands down.

[Evil510]

Also remember to always approach the center in the same direction, up and right.

Is approaching the center in the up and right direction to take up the gear lash? The app seems to flash one of the arrows before you can complete the GoTo. With more use, I'll be able to remember which arrow slews the mount in the correct direction.

 

I agree, the Skywatcher EQ Base can be less than stable...  I found the iOptron wedge much more stable and easier.  The altitude fork is shorter and wider.  Others have reported they like they Skywatcher better, so I guess it’s personal preference, but if you ask me, the iOptron wins hands down.

I read the same things about the Skywatcher, so I ordered that one. I'll give the iOptron a try if I can return the Skywatcher.

 

Thanks.

[davidparks]

Is approaching the center in the up and right direction to take up the gear lash? The app seems to flash one of the arrows before you can complete the GoTo. 

Correct, to eliminate backlash.  You’ll notice on GoTo’s the mount will always try to approach by going up/right, even if it has to overshoot, and then “come back”.

[jeffry7]

Hi Folks,

 

Last night I was out using the SkyWatcher az-gti on the moon. At the time, from 11 to midnight, the moon was nearly directly overhead. The syncscan app did not list the moon in the goto menu. I was using it in Alt/Az.

 

It occurred to me that this might be a an alt/az problem rather then a SkyWatcher problem.

 

I was able to manually point it, but it didn't like it. I am pretty sure the clutch slipped along the way. I had other technical difficulties and so packed it in, but wanted to come here and see if someone knew what happened to me, and what the work around would be. Thanks!

[EastAnglian]

Hi Jeff

You should find Moom under Star/Solar Sytem. Yes, everyone agrees it’s odd! Re technical difficulties, it seems most of os get those, but if you’re more specific there’s people on here can help. 

Max

p.s. I’m only just getting familiar with this myself!

[jeffry7]

Hi Jeff

You should find Moom under Star/Solar Sytem. Yes, everyone agrees it’s odd! Re technical difficulties, it seems most of os get those, but if you’re more specific there’s people on here can help. 

Max

p.s. I’m only just getting familiar with this myself!

Hi East,

 

I went to that menu. All it had was Uranus.

 

As for the technical issue, I have this T-Mount camera lens I was trying to use. It is an old Rexatar 750 mm catadioptric. It has a really stiff focusing action. In fact it has a little lever in the focus ring which presumably is to help with the stiffness. When I was out last night, it was right around freezing in my part of the world. The focus lever just would not budge. And no, I wasn't against the focus stop.

 

In trying to get critical focus I not only bumped the mount, I shifted the angle the camera was mounted to the dove tail plate on.

 

So I was freezing, and I was looking at having to do another alignment, even supposing I could get the focus right. It wasn't a wasted night. This was my 3rd try with alignment and the first time I got it where I could slew to a target and get it within the FOV. Also the second try with my red dot finder. Just need more practice.

 

If I try this particular lens again, I think I will try to get the focus ready on a ordinary tripod, and then transfer to the AZ-GTi and do my alignment rather then the other way around. I know once the focus is set, it isn't going to budge. I am really grateful for the enthusiasm to help on this list and on cloudynights in general. I just didn't want to bog the thread down with an issue that had nothing to do with the mount.

[davidparks]

 At the time, from 11 to midnight, the moon was nearly directly overhead. The syncscan app did not list the moon in the goto menu. 

Look under the Settings Menu > Altitude Limit.  You may need to increase the limit to 90, which is straight over head.  Also, you can turn the catalog for objects outside your limits on and off.  Likely the Moon was higher than your limit, and Catalog Filter was turned on.

 

Just be sure your gear can swing without crashing into your tripod!

[maxsid]

Object which are in "unsafe" positions will not be shown.

There's "Altitude Limit" setting in Settings of SyncScan app. Whatever object is higher then that limit will not be shown in any of the object lists.

 

 

Hi East,

 

I went to that menu. All it had was Uranus.

 

 

[maxsid]

You beat me by 2 minutes.. : )

 

Look under the Settings Menu > Altitude Limit.  You may need to increase the limit to 90, which is straight over head.  Also, you can turn the catalog for objects outside your limits on and off.  Likely the Moon was higher than your limit, and Catalog Filter was turned on.

 

Just be sure your gear can swing without crashing into your tripod!

Edited by maxsid, 21 January 2019 - 11:47 AM.

[Evil510]

Hello,

I went out and tested tonight, but couldn't get the exposure length I was getting the other night. I could only get 20 sec exposures before star trails, the other night I got upto 150 sec, both at 200mm. I'm not sure what went wrong. I feel I was doing everything the same but with more care.

 

I have a question regarding the Polar Alignment step. When I'm recentering the stars using the EQ base knobs, the star doesn't recenter in either lat/long. It's off by a little bit. Should I use the arrow keys to center it exactly for each lat and long step? Or should I be able to center the star exactly in lat/long only using the knobs?

Polar alignment in EQ mode is fairly simple just using the SynScan app on your mobile device.  You will first need to do a 2 or 3 star alignment from the alignment menu.  I'd recommend 3 star for more accuracy.  Then you can do a Polar Alignment.  Synscan will let you choose a star, to which it will slew to, and ask you to center it using the arrow keys.  It will then move your mount slightly and ask you to re-center the star using your EQ Base adjustment knobs, first in latitude, and then in longitude.  You should then do another 2 or 3 star normal alignment.  If your DSLR has a live view, you can use that to assist with centering stars, or use a finder scope, laser pointer, or other previously aligned tool.

I did get the Orion Nebula using 60, 20sec subs, stacked in Lynkeos (no dark frames or flats) and edited in Lightroom. I should remove the light streaks.

 

Any comments/thoughts about improving alignment or of the photo is appreciated.

Thank you.

[EastAnglian]

Help!

I think I’m going mad. I’m unable to get my unit to align outside ! Today, not for the first time I brought my setup into my lounge to see if I could get it to align. I did this because last time out it refused to align outside, having worked fine in my lounge. So today, with the prospect of a clear night ahead, I wanted to check if I could get it to align, and it did. I was puzzled but just accepted that something odd had happened. So tonight out I go, and with the same setup, attempt to align. But again no! I chose, as I had done indoors, level north method. The first chosen star was Pollux, so it started off and stopped, azimuth wise, approximately near, but when it rose in altitude past zenith I switched off in frustration and disbelief. I repeated the whole procedure one more time with the same result. On the third attempt I decided not to stop the rotation but see how far it would go. It completed more than one revolution before I gave up in frustration. I can’t for the life of me see why this works fine indoors but refuses point blank to work outside! What am I missing?

[davidparks]

Help!

 What am I missing?

All I can suggest is that you take it step by step:

Assuming you are using this in AZ mode, and you are mindful of which firmware you are using (Left or Right Mounted OTA)

Also Assuming you have your time/location correct.

  1. Create a User Object, Terrestrial, with Axis1 = 0, Axis2 = 0

  2. GoTo this User Object

  3. Loosen both clutches and physically move your OTA to the proper left or right mounted north level position

  4. Tighten both clutches

  5. Reset Alignment

  6. Perform your North-Level Alignment

 

If this doesn't work, try re-applying the firmware.

Edited by davidparks, 24 January 2019 - 01:52 PM.

[EastAnglian]

All I can suggest is that you take it step by step:

Assuming you are using this in AZ mode, and you are mindful of which firmware you are using (Left or Right Mounted OTA)

Also Assuming you have your time/location correct.

  1. Create a User Object, Terrestrial, with Axis1 = 0, Axis2 = 0

  2. GoTo this User Object

  3. Loosen both clutches and physically move your OTA to the proper left or right mounted north level position

  4. Tighten both clutches

  5. Reset Alignment

  6. Perform your North-Level Alignment

 

If this doesn't work, try re-applying the firmware.

Hi David

Many thanks for taking the time to answer. Firstly I can confirm that I am using this in alt/az mode. But before I go any further can I say that today I had another go at alignment indoors, although this time in the annexe where my scope lives at the moment. Exactly the same thing happened as did yesterday indoors; it aligned perfectly first go! Now I’m guessing it has to be just extraordinary coincidence that this is happening, but one thing is for sure, it’s very frustrating!

I’ve not been able to check it outside as it’s not only cloudy, it’s raining. 

I may go ahead and update to the latest firmware, but from what I can see in the release notes the updates don’t address anything related to my problem. I’ll try the sequence of steps you suggest if you really think it’ll help. 

Thanks again

Max

[Bagwell]

I think some have experienced occasional issues due to other wifi signals interfering.  Others in here correct me if I am wrong.  I read some about it in this thread somewhere I believe.

Vaughn

[EastAnglian]

Hi Vaughn

That’s actually an interesting point, because my observation position is further away from my router, but may be nearer my neighbours. I’l try and check this out later. 

Cheers

Max

[EastAnglian]

Vaughn, it looks like you cracked it!! I just checked and found at least another six WiFi signals at my observation point; for some reason I don’t understand, it’s a WiFi hotspot! I’m clearly going to have to rethink my observing position with this head at home. The only good news to come from this is that it looks as though it’s going to be fine for bundling into the car and travelling to dark country spots, for which was its intended purpose.  

Will update again once I’ve doubly confirmed this. 

Very many thanks 

Max

[Bagwell]

I think I remember people having more of a problem with the mount in close proximity to other signals such as inside a house with 1 or more wifi signals going on.  There may be some kind of fix for it.  It may be worth checking with Skywatcher or doing some research online to find if anyone has solved the problem without simply moving to an area without the signals.  If you do find more information be sure and post it here as a resolve.  I would love to see some kind of problem and resolve page for this mount where the information is able to be fond fairly easily without having to search the internet for it all.  I think it would be great to organize all astronomy equipment info where it could be found actually.      

 

Clear Skies, 
Vaughn

[EastAnglian]

Hi again Vaughn

Yes, I had heard about the indoor WiFi problem, which is why I didn’t catch on quickly when it worked indoors, but wouldn’t work outside! I will do an ‘away from it all’ test as soon as I can. The actual built-in WiFi I’ve found is more powerful than I expected. I thought it might only work in very close proximity, just a few feet, but it’s much better than that. I’m still puzzled as to why I’ve got a whole bunch of signals exactly on my observation site, and it’s unfortunate that it’s the best dark site with reasonable views. I have another site with much better all round views, but it’s on the front of my property and brightly lit with various street lamps. I think what it means is that I’ll have to hurry up the repair to my ETX 105 and use that instead, keeping the AZ+GTi for car trips. A shame, but there it is. 

I think your idea of having a problem page is a good one, but would take a bit of collating and organising. Watch out the moderator doesn’t get back to you    

Thanks again

Max

[jeffry7]

I wonder if using a handset might resolve the WiFi issue. Although comments from earlier suggest the handset is expensive.