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'First light' for EQ6/Astrotortilla


Demonperformer
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'Frustrating' does not begin to describe last night. I had been planning on getting out of Mon evening, but the wind was rather strong, so decided I couldn't be bothered. Last night conditions were much better, so I embarked upon using the new mount.

Many of my problems stemmed from not realising I had failed to spread the legs of the tripod fully until I came to screw-in the plate. I had levelled the tripod, added the head and screwed that in (managing to lose a washer in the garden in the process when the lower lock-knob fell off unexpectedly - to be looked for this morning). When I tried to fit the plate, it wouldn't go, and that was when I realised the legs were not fully spread. At this point I made a tactical error. With hindsight, I should have removed the head and started again. What I actually did was fully spread the legs fully and try to re-level the setup using the tiny little bubble-level on the head.

My next problem was that I found the polar scope totally unusable. Despite having the tripod almost fully extended (and that had the scope so high up, I could get the 4" on it, but would never have managed to lift the 8" onto it successfully), I could barely get into a position where I could see through it at all. And when I did, I encountered the far more serious problem of not being able to see a thing through it. Actually, I could faintly make out what appeared the be the 'big dipper' shape, but it was too dim to be of any use. And there was no sign of anything resembling a star. And it was hurting my back bending into the awkward position necessary to look through it at all. Can't help feeling it needs to be illuminated with a small red led (like a reticle eyepiece).

Anyway, following the old marine 'AIO' mantra (Adapt, Improvise, Overcome), I figured that as the scope was in the 'park position' I could use the telescope itself (4" f6.5 refractor) as a rough polar scope. And, to an extent, it worked. I managed to locate it into the centre of the reticle cross-hairs and (maybe not surprisingly) it pretty much stayed put. So I chalked that up as a 'rough polar alignment' and proceeded to think about refining it using Astrotortilla (AT).

Well, the good news is that I managed to get AT communicating with the mount: it was showing the correct telescope position and when I pressed 'capture and resolve' it did so - in about five minutes. Seemed a little long to me, but then I checked the settings. I was using a 180 degree search field and had the size set as 1.5 - 2 degrees wide. So, using output from my first successful solve, I changed the search field to 45 degrees (that is a figure I have seen recommended by other AT users) and changed the size to 1.79-1.8 pixels per arc second.

Tried a small slew, using CdC, to Alkaid. The mount duly moved and, although it was way off, it had not moved in the wrong direction or by a vastly inaccurate (2x or 0.5x) amount. Well, this is what AT is for.

Capture and resolve. You must be joking!

The program gave me a massive readout in about 8 seconds, containing a mass of (to me) gobbledegook, talking about me being weird for calling a file 'none' and it wasn't working. There then followed a thirty minute period, during which I tried everything I could think of to get it working to no avail. Every attempt I made to use AT produced this same readout. The only thing I was achieving was getting more and more frustrated. Finally decided I could take no more so, taking a copy of the log a screen-print of my settings and a final image through APT to prove it wasn't the camera, I packed up. To add insult to injury, the laptop chose the moment I decided to switch it off to display the 'I am now installing updates - do not unplug or switch off'. At this point Bill Gates, together with all the other writers of windows software, received a rather unfair aspersion on their ancestry.

An hour later, I was still rather hyped-up, so I got the laptop out again and started putting files together for the 'Why doesn't it work?' post i was intending to make. As part of the process I converted my final APT shot from cr2 to jpg and decided to see if AT would now work. It didn't, but I did have another closer look at my settings and nearly threw the laptop across the room. I had set the 'size' to 1.79-1.8 aecsecperpix instead of arcsecperpix. Put that right and it accurately resolved my final pic in about three minutes. Think there may be room there for a 'drop down box option' in the 'units' settings. Will have to suggest that as an improvement for the next version.

OK. Despite the frustration, try to pull together a few positives from the evening.

  • I now know that the legs of the tripod are 'stiffer' than I anticipated and it is easy to not spread them fully, so check that at the start of every session before levelling.
  • I now know that when fully extended, the tripod legs produce a setup that is too high to use with comfort. Ideally I will try to have it so that one leg is not extended at all, next time, with the other two only extended far enough to make the tripod level. That should also make the setup more stable (not that it wasn't stable anyway). As long as I can see Polaris over the neighbour's roof, it shouldn't be a problem, particularly as the polarscope is (based on last night's efforts) not worth attempting to use.
  • I now know that AT is talking to the rest of the software on my laptop and it will take a picture and resolve it IF i have settings that make sense. I also know to leave the settings pretty much alone if I can as spelling mistakes can cause frustration!

So, the plan for next time? Well, the forecast is not hopeful for the rest of the week, but when I do get out again, the goal for the evening will be to successfully polar align using AT. I think that, as long as I get the scope pointing in roughly the right direction, I won't worry too much about centring Polaris in the scope itself before letting AT have a go.

As AT tells you by how many degrees you need to adjust the azimuth and altitude bolts (as i understand it), does anyone actually know how many turns on these bolts make up one degree? Will probably have worked out a rough figure by the end of my next session anyway, but if anyone knows and can tell me this, there seems little point in 'reinventing the wheel'.

Thanks.

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It's from these evenings we grow. Just at it again! Regarding the polar scope on the NEQ-6, there is a setting to turn down the red light, I've never had to since I always located polaris pretty quick, but some people are really helped by it. Be careful with your alt bolts as they're prone to bending. Best of luck!

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Hi,

The polar scope looks though the altitude axis, there is a hole in the shaft that histo be lined up to use the polar scope. When you remove the cap you can see the shaft, rotate the alt until the hole aligns by looking back through the hole in the top.

Robin

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Thank you both for your responses.

Re-reading the instruction booklet, it does say "rotate the mount in declination axis so that the hole in the shaft is in front of the polar scope". I hadn't noted that and so didn't do it. This may explain why I could see nothing. I will have a play when I get the time (hopefully) later today.

Carl - are you saying that the polar scope is illuminated by a red light? I certainly did not see one last night.

I think the problem is still going to remain about actually going through the contortions required to look through the polar scope at all, but if I am able to see what is going on, it would probably still be faster getting Polaris 'roughly' in position than using the main scope. I am firmly convinced, however, that AT is the way to go for precise PA.

Does anyone know what the fov of the polarscope is? If the diagram in the manual is anything like accurate, it would be about 7.8 degrees (based on the size of the 'Polaris circle' about 5mm radius for 41' from NCP x 58mm diameter of polarscope). If it is that big, then I should certainly be able to position the mount so that Polaris is within the fov first time.

Based on all this, I think it is a case of not giving up on the polarscope completely at this stage. Play a bit more and see where I get. At least next time I will be going in with last night's experience behind me. And who knows, "rotating the mount in dec axis" might make a world of difference.

I am aware of the alt-bolt problem and so replaced them with the Astrodevelopments improved version before I set up the mount for the first time.

Thanks.

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Hi,

The etching of Ursa Major on the polar scope is for orientation and you aren't supposed to be able to see all of those stars. The polar scope is quite narrow and the large circle at the centre is the track of Polaris around the centre of earth's axis. Polaris is 45 arc minutes from the centre, so the large circle is about 1.5 degrees across.

To correctly polar align you have to adjust the mount (RA) until Ursa Major is in the correct position and then centre Polaris over the small circle using the mount adjuster bolts, which are usually very stiff to operate. There are a few guides on here and on line about polar aligning, perhaps a search will show a few up. Without the Dec axis aligned you will just see the Ursa Major reticule. The brightness of the reticule is adjustable from the handset, but if you can just see it, it is probably about correct.

Precise polar alignment is only really required for astrophotography, if it is just visual it is usually good enough to set your latitude on the scale (51N) and point it north. For sure there will be a small error, but it probably won't be noticeable.

For example, for photographing the planets, I don't polar align, but since I use a pier, my mount and scope goes back in the nearly the same place every time. As for looking through the polar scope, I usually sit on the ground and look up, but again my pier makes it slightly easier.

As for lifting a scope on to an EQ6, I managed to lift my C11 (around 11Kg) on without too much problem. I have the scope in the home position (pointing towards Polaris), lift the scope on to the saddle plate, hold it with one hand whilst I do up the dovetail locking screws. I also have a dovetail safety clamp from Astro-developments (http://www.axio35.dsl.pipex.com/astrodevelopments/Losmandy%20Cables.htm ), which is left on the scope all of the time. These just clamp round the dovetail and allows me to slide the scope in to the saddle, the clamp then positions the scope and takes some of the weight whilst I do up the saddle bolts.

Hope this helps?

Robin

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One moe thing you may find helpful is regarding the stars listed for aligning the mount ready for goto operation. There is a pdf on line (I found it easy via google) which lists all the stars with the constelation they are in, and also has charts with all of the stars marked on. I don't think many people will know where all the stars are, however experienced they may be. Regards, Paul.

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Since you've got astrotortilla, you're obviously connecting to a computer and use EQMOD. Use the EQMOD polar align routine. Don't worry about them or read them beforehand, just follow the instructions step by step, it makes it work really simply.

http://eq-mod.sourceforge.net/docs/PolarScopeAlignment.pdf

Yes, there is a red light illumination of the polar scope.

Yes you do have to rotate the mount in DEC (and extend the counterweight bar) to be able to see through the polar scope in the first place - obvious when looking "the wrong way" as there is a hole in the bar.

Once you get Polaris in the polar scope it's usually really obvious.

Edited by dmahon
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Carl - are you saying that the polar scope is illuminated by a red light? I certainly did not see one last night.

Yes, my NEQ6 polar scope is illuminated as soon as it is powered on. And the synscan handset contains a setting for the strength of the illumination. Even with full illumination you can make out polaris.

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Thank you all for your responses and suggestions.

Photography is my main intention for purchasing this mount, so getting AP as accurate as possible will be important for me. For (occasional) visual sessions, I would probably stick with the alt-az mounts I have been using until now [that may change as I get more capable with the eq6].

I've looked at various options (including the eqmod option) and my impression is that none of them are easier than the 'take 4 photos and let the computer tell you what changes you need to make'. Again, I may change that opinion with experience. It's just a question really of how close I need to get to PA to get that to work.

I am not sure how valuable setting a 'home' setting will be as I will be setting up each time. I can understand that in a permanent setup, or on a fixed pier that is always identically aligned, that would be an advantage. But with the inevitable variations of tripod set up I'm not sure how it would be an advantage.

The problem with lifting the scope was on the basis of the fully extended tripod I had last night. The dovetail plate was virtually at head-height, which I could manage with the light refractor, but would not be happy doing with the SCT. Looking on the net at piers, it seems they tend to be about 1m high. So it seems to me that it would make sense to use the tripod at the same height. There would be no problem fitting the SCT at that level, I envisage.

That safety clamp sounds interesting. The site has no picture, but presumably it is attached below the dovetail at the 'front' end of the scope and sort of 'hooks' over the front of the mount? [not a brilliant description of what i am thinking, but i hope it makes sense]

Polar scope illumination: all i can do is repeat that i noticed no such illumination last night, but will watch out for it next time. The comments that it is adjusted on the handset makes me wonder if this is an option that is only on the synscan. Mine is syntrek version, which has a very simple handset. I have checked the manual and there is no mention of reticle illumination in that. Any thoughts from other syntrek users would be valuable.

Alignment stars: I'm pretty sure that with EQMOD you are not limited to what objects you can use for alignment - just click on the object in CdC, slew to it and sync it - unless I've got it wrong. Can't be totally sure as I didn't get that far last night.

So much further to go!

Thanks.

Edited by Demonperformer
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Yeah look into the fact that you're not getting light in your polar scope. If you cannot get the reticle illuminated you're going to have a bad time polar aligning. The work arounds are either drift alignment, polar alignment via EQmod and cameras or shining a weak red light down the bore to manually illuminate the scope.

No chance of borrowing a SynScan from a friend or society-member to rule out the syntrek?

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Right, I have now had a chance to do a quick setup indoors, to investigate the polar scope a little more.

First off, I definitely had the dec axis in the wrong place last night, which would explain why I could see nothing. Secondly, that "nothing" included the red light which, contrary to everything I have said previously in this thread, DOES EXIST and is actually clearly visible when the hole in the axis is lined up. All I can put this down to is the suggestion that maybe the led is above the axis, and so the light from it was cut off by not having the hole open. It may still require a few contortions to get to see through it, but at least it is going to be more useable than I thought originally.

So, reassessing last night:

Polar scope problem at least partially fixed, will need to find the most comfortable height for ease of setting up scope/ease of polar scope use.

Tripod legs - remember to spread them properly at the start and that will fix that problem

Check spelling on AT settings and I should have no further problems there

And, the cherry on the top, I found the washer that fell off last night.

All-in-all I am feeling a lot more positive about last night's session than I was 10 hours ago.

Thanks to everyone who has helped me work through these issues.

[i will no doubt be back with lots more issues after the next clear night!]

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Hi,

That is good to hear. It can be annoying, you get some new kit and then just can't get going with it. I must admit when I bought an EQ6 I went through a dummy set up in the daylight to make sure I understood everything.

Depending on your scope weight you will want to keep the tripod as low as possible to avoid flex in the tubes. I know that this makes the polar scope hard to see through, but it will be worth the effort. Sorry I misunderstood earlier that you wanted to do AP, of course good polar alignment will be required, but so will guiding if your exposures are over 60 seconds. To a great extent, guiding overcomes polar and 3 star alignment issues.

It is a steep learning curve.

Robin

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It certainly is, Robin.

But then, I keep forgetting how much trouble I had with the SE mount in the early days, when I just could not see the red dot in the rdf. Eventually sold it and bought a wixey, after which it became plain sailing.

Guiding is "in hand". I have all the gear, but want to make sure I have the basics running before I start introducing any more variables. Even with only 60s unguided, it will still be 3x what I was regularly achieving on the SE. For once, I am trying not to run before I can walk [like that's going to last very long!]

Thanks.

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I struggled for ages not wanting to "get your knees dirty" when polar aligning. I now put a small tarp on the ground and sit/lie down. it's so much more comfortable and its only for a short time :). it may seem daunting but i'm sure in no time you'll look back and wonder what all the drama was about.

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Since AP is your eventual goal, you ought to consider building a permanent pier for your Mount.

Perhaps a Roll Off Roof Obsy and pier, which would make life very much easier. Polar Alignment can be set, then forgotten about.

When your session has ended, Park the scope, switch off close the roof, lock it down, Close the Obs up, then go to bed :grin: .

Resuming next time out is then a doddle, weather permitting of course.

Sounds Good Heh? Well, It is, as long as your wife, or partner agree to the building of said Obs. in the first place.

That is usually the stumbling block for most guys, as the Mrs thinks it will spoil the garden, which is rubbish really.

Done Properly, it can actually enhance your Garden.

Best of British anyway :icon_salut:.

Ron.

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I have a pier and concrete base but no obs. That still speeds up the operation and my scope is never far from polar alignment each time. My Mrs has just given me permission for a very small [robotic] dome, trouble is it is looking like my scope won't fit and she is saying no to a 2m dome. Talk about egging you on only to kick you back down.

Point is, not everyone can have an obs. If you can't have a permanent set up then I suggest marking where the tripod legs go and put the mount/tripod back in the same place. As long as the mount hasn't been moved off the tripod it won't be very far out and you won't need to mess with the legs to get the thing level, it will save you 15 - 20 minutes of set up time.

Robin

Edited by DrRobin
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Thanks everyone for your comments.

Not so worried about dirty knees, but I have received advice on another webcam that does the job, and for the one-off cost of £7.99 on Amazon, together with a short 'fitting' job, compared to having to scramble around on my knees every time I set up, particularly for those of us who are "no longer as young as we were" ....

I would love to have a permanent obsy, but there are two main problems. One is that I observe from both sides of the house, one side gives me south and west (and plenty of streetlights), the other gives me north and east (but less LP). No one location for an obsy would fully meet my needs. Secondly, the front (S/W) which is my preferred location has three feet of garden, two feet of path and another three feet of garden, which would be a bit limiting for placing one.

However, I have wondered about a permanent pillar - or, indeed, two permanent pillars. If I was able to get it right, I should be able to get them so that there would be very little alignment to do, even moving from one to the other, and certainly when going back to the same one.

I see what you mean, Robin, about keeping the mount on the tripod and putting the legs in the same place. One issue with the front garden is that it is not flat and so the tripod legs are of different lengths. That would lead to issues with storage between sessions.

I think the way I am going to go initially is to get the webcam and try the adaption. If that works as well as it appears to, and if AT does the job of final adjustment as well as I hope, then PA will not be an issue. As Scott put it, I will "wonder what all the drama was about". In the longer term, I may well think about installing a pillar in the front, and either another one in the back, or use the tripod there. No need to hurry to make a decision on that yet.

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