Questions about Avalon Linear

[Andyb90]

On 26/07/2016 at 17:40, swag72 said:

I know that Avalon are no longer selling the Synscan.... so if anyone does have them then they've been on the shelf for some time..... Could be used as a bargaining chip?

I got a reply from the Widescreen centre. They don't have the Synscan. They just haven't updated their website to reflect that.

Andy.

[Beeko]

On 26 July 2016 at 16:41, Andyb90 said:

Interestingly, the Synscan version of the Linear is still listed here. The site let me add it to the basket.

https://www.widescreen-centre.co.uk/astronomy-mounts-and-tripods/avalon-instruments-mounts/avalon-instruments-m-linear-fast-reverse

Maybe the website hasn't been updated.

I've emailed Avalon to see if the Synscan option is still produced.

Andy.

Hi Andy,

Let me know what the outcome of this is - I'm curious. Are you still interested if the only option is the stargo? Did the widescreen say they have one in stock? If so, you've saved me a phone call. I've had an email from Luciano (maker of the mount) this morning to say that he will be at the next Astrofest - wondering about waiting for a deal or whether to go for it now. At the minute, I've got my hands full learning SGP and how to plate solve so not absolutely urgent. I am sold though, this is the mount I'm going for either now or next Feb .

 

[Andyb90]

I've replied back to Widescreen centre to see if they have one in stock.

I'm still interested with the Star Go. 

I did still have some concerns about impacts of wind, because of wanting to image from a remote site, but found this post on CN very useful.

"I've read about the potential wind susceptibility of the Avalon/belt drive mounts. I can tell you that in modest steady wind (10MPH or less) I've had no issues. The one night I tried to image at FL 2350 with steady winds 15 MPH with strong gusts, the guide star bounced around the chip to the point where imaging was impossible because I kept losing the guidestar. But I suspect under these conditions that any light to mid weight mount would have trouble, and even heavy duty high end mounts can't overcome the poor seeing under windy conditions. So if you plan to image in very windy conditions with a belt driven mount, get a tank like a Mesu or put the setup in an observatory."

I think it's a good point made above that with more wind seeing would probably become an issue anyway.

"The elasticity may be a theoretical concern but objectively seems to be an advantage. Even on nights with relatively "poor" guiding per my PHD graphs, the corrections snap back on pixel so quickly that round stars are the norm even when my my guiding looks like a polygraph tracing."

Above is exactly the point Olly made about the fast reverse getting things back on track very quickly. Really like that.

I'm now pretty much ready to go with the Linear too.

Andy.

[ChrisLX200]

There's one on UKABS at the moment...

ChrisH

[schmeah]

20 hours ago, Andyb90 said:

I've replied back to Widescreen centre to see if they have one in stock.

I'm still interested with the Star Go. 

I did still have some concerns about impacts of wind, because of wanting to image from a remote site, but found this post on CN very useful.

"I've read about the potential wind susceptibility of the Avalon/belt drive mounts. I can tell you that in modest steady wind (10MPH or less) I've had no issues. The one night I tried to image at FL 2350 with steady winds 15 MPH with strong gusts, the guide star bounced around the chip to the point where imaging was impossible because I kept losing the guidestar. But I suspect under these conditions that any light to mid weight mount would have trouble, and even heavy duty high end mounts can't overcome the poor seeing under windy conditions. So if you plan to image in very windy conditions with a belt driven mount, get a tank like a Mesu or put the setup in an observatory."

I think it's a good point made above that with more wind seeing would probably become an issue anyway.

"The elasticity may be a theoretical concern but objectively seems to be an advantage. Even on nights with relatively "poor" guiding per my PHD graphs, the corrections snap back on pixel so quickly that round stars are the norm even when my my guiding looks like a polygraph tracing."

Above is exactly the point Olly made about the fast reverse getting things back on track very quickly. Really like that.

I'm now pretty much ready to go with the Linear too.

Andy.

Hi Andy. That was an M Uno that I was referring to but the the concept should apply to any of the belt driven Avalon's. I don't set up in strong wind, but that would be the case regardless of the mount. The wind issue is a non issue IMO. Olly's point about scopes with a long moment arm however is well taken. My scopes, both SCT and refractor, are fairly compact.

Derek

[Beeko]

Just rang the Widescreen Centre and they've 'just' sold their last Linear which was a non stargo model. I'm curious Andy, was that you? 

A little frustrated that I can't go and see one in the UK with a stargo to answer a few questions I have. Think I'll just have to bite the bullet unless I can visit someone in the UK with one?

[Andyb90]

No, it wasn't me. When they told me the Synscan version was no longer available they also said they had no remaining stock.

Ideally I would also like to see the mount before buying.

Andy.

[schmeah]

I'm pretty happy with StarGo. I had issues early after its initial release, but Avalon was very responsive in addressing all issues. It is simple, very functional and adaptable IMO. It has been rock stable since I last upgraded my firmware several months ago.

 

Derek

[ollypenrice]

Tomorrow night I'll be helping one of our robotic owners to set up a used Avalon Linear Fast Reverse in the Observatoire Per Frejvall. It is an EQ6- specced version. It will be my second 'hands on' experience with an Avalon so I'll let you know how we get on with it. I'm always happier commenting on products of which I've seen more than one example. For the moment it is sitting there in its box unopened.

Olly

 

[Beeko]

Oh, yes please Olly. Thank you. I was about to do my order yesterday but some urgent things came up and I stalled. Also still want a proper Polemaster bracket and have been told by Lucianno that they are looking into it. 

[Beeko]

By the way, am I right in thinking that the polar scope comes pre-aligned/collimated t o the mount?

[ollypenrice]

16 hours ago, Beeko said:

By the way, am I right in thinking that the polar scope comes pre-aligned/collimated t o the mount?

It does, with a certificate signed by the person who aligned it. Peter, who's coming today to set up, has also bought a Polemaster which he said can be fitted using double sided tape in the absence of a bracket. He'd seen a U tube video about this.

Olly

[Beeko]

Olly, do you have a link to the you tube video? Looking forward to seeing how you get on. If possible, could you upload a pic so I can see the positioning. 

[ollypenrice]

48 minutes ago, Beeko said:

Olly, do you have a link to the you tube video? Looking forward to seeing how you get on. If possible, could you upload a pic so I can see the positioning. 

Peter got here very tired and has gone to bed but we'll be fiddling tomorrow and I'll keep you posted. He'll know where the video is. I'm curious as well!

Olly

[StuartJPP]

I wouldn't let a bracket for the PoleMaster keep you from moving forwards, it can literally be placed anywhere as long as it has a clear view of Polaris when rotated in RA. Mine gets attached to the Dec dovetail where the pink camera is in the attached image...I obviously can't monitor PA during an imaging session because I have slewed away from NCP but then again I am not too bothered about that.

Maybe one day I will attach it to one of the white 'L' brackets....

[ollypenrice]

18 hours ago, StuartJPP said:

I wouldn't let a bracket for the PoleMaster keep you from moving forwards, it can literally be placed anywhere as long as it has a clear view of Polaris when rotated in RA. Mine gets attached to the Dec dovetail where the pink camera is in the attached image...I obviously can't monitor PA during an imaging session because I have slewed away from NCP but then again I am not too bothered about that.

Maybe one day I will attach it to one of the white 'L' brackets....

I don't know this gadget, Stuart, and it has been delayed, due tomorrow. Does it not have to be highly orthogonal with the polar axis? I'm wondering how it deals with cone error, if it does? (And for your system to work I suspect it must be able to do so?)

Olly

[StuartJPP]

3 hours ago, ollypenrice said:

I don't know this gadget, Stuart, and it has been delayed, due tomorrow. Does it not have to be highly orthogonal with the polar axis? I'm wondering how it deals with cone error, if it does? (And for your system to work I suspect it must be able to do so?)

Olly

Olly, it doesn't have to be orthogonal to the polar axis, of course that isn't strictly true, it obviously has to point in the same direction and be close but all it does it determine the centre of rotation of the mount in RA...theoretically it can be some degrees off and as long as you are still covering the NCP area during rotation in RA you can still find the centre of that rotation.

It then uses a template for the user to place over Polaris and a few other alignment stars to find the actual NCP. Since the focal length and pixel size is constant it doesn't need to do any plate solving.

 

[ollypenrice]

9 minutes ago, StuartJPP said:

Olly, it doesn't have to be orthogonal to the polar axis, of course that isn't strictly true, it obviously has to point in the same direction and be close but all it does it determine the centre of rotation of the mount in RA...theoretically it can be some degrees off and as long as you are still covering the NCP area during rotation in RA you can still find the centre of that rotation.

It then uses a template for the user to place over Polaris and a few other alignment stars to find the actual NCP. Since the focal length and pixel size is constant it doesn't need to do any plate solving.

 

Brilliant. Thanks Stuart. If the delivery people can be bothered to come up here with the PoleMaster tomorrow we'll be good to go. To be fair, they have got to know us and seem quite pleased to see us when they get here! I guess it breaks their daily routine: There's this English nutter in the middle of nowhere with a million telescopes and loads of visitors in the middle of winter...etc.

Olly

[Beeko]

Olly. You'll love the Polemaster. Alignment better than a drift alignment in under 5 mins. So messing about with polar scopes, red torches, aspa routines, turning your mount on and off. It just works really well. 

[ollypenrice]

28 minutes ago, Beeko said:

Olly. You'll love the Polemaster. Alignment better than a drift alignment in under 5 mins. So messing about with polar scopes, red torches, aspa routines, turning your mount on and off. It just works really well. 

I'll be happy to recommend it to guests when I've had hands on experience but it cannot work better  than drift alignment, can it? Drift alignment is a direct measurement entirely free of calculation. However, it can work faster than drift alignment if it does what it says on the tin, and that I will happily accept. As is well known, I'm a bit stone age in my methods. If I can do it myself I rather like to do it myself, but I'm observatory based and if this device can help people get up and running quickly then I'm in favour. I must say, though, that next week I'll be welcoming a group of 'old guard' Dutch/Belgian astrophotographers (two of whom are a lot younger than I am!) and they set to with their polarscopes, tik-tak, and knock out world class images for the rest of the week.

Olly

[StuartJPP]

The PoleMaster can definitely beat a drift alignment if you only spend 5 minutes doing each

5 Minutes of PoleMaster    better than    5 minutes of Drift Align.
30 minutes of Drift Align    better than     Any minutes of PoleMaster.

I wouldn't have thought that anything would beat a proper drift alignment. The PoleMaster is good to get you mostly there (100% good enough for my focal length) but it certainly won't beat a drift alignment. What would make PoleMaster more accurate would be to do like I do...swap the 25mm lens of the PoleMaster for a 130mm miniGuideScope after you have done the initial PoleMaster alignment...NOTE - you read that here first!!!

 

 

From a previous post of mine:
I used the PoleMaster again for polar alignment and it was pretty spot on, DEC guiding had about 6 correction pulses over the entire ~3 hour session which is the best I have ever had.

 

[ollypenrice]

OK, at last the 'new' used Avalon is up and running in the robotic shed. It all went together sweetly and, after a single calibration run in PHD (without use of the refining Guide Assistant) soon settled down to a very agreeable RMS of 0.15. It's carrying a Tak Baby Q and QSI CCD with OAG, plus a hefty boxload of robotic gubbins on top of the scope. The elasticity I feel in mine with a long OTA is not really present to any significant degree in this case. So my admiration for Avalon mounts has deepened. Getting it to communicate with the robotic installation may not prove quite so easy, but the mount is very nice.

The Polemaster was ordered from the UK on express delivery at a cost of £45  from DHL. It arrived a day late, but it didn't arrive here. Oh no, the driver left a message on our answer phone to say he'd dropped it off at a bar five miles away. Our guest is, understandably, furious and is demanding his £45 back in full. Quite right too. Locally it seems that all couriers bar UPS subcontract final delivery to the same gang of feral teenagers in white vans.

But the Polemaster is convincing! Peter simply stuck it onto the RA housing (Avalon Linears are admirably rectilinear in shape) with double sided tape and ran one interation of the procedure after I'd cribbed the polar scope view from our Avalon and set his to match.

So as far as I'm concerned, 'Avalon yes, Polemaster yes!'

Olly

[sloz1664]

Toatally agree on both the Avalon & Polemaster fronts. Also, it seems parcel companies are now using the Ryanair philosophy. Offering the basic price point low and as you add the "essentials" the prices become ridiculously expensive. I would certainly demand payment in full.

 

Steve

[Southcoaster]

I know this thread has been running for a while, but I thought I would add my experiences.
I own an observatory based Avalon Linear mount with the StarGo software since last February.
The mount itself is beautifully designed & engineered. It comes in a strong cardboard padded box and has a handle for easy carrying, so would be a good choice for remote imaging.

I have experienced two issues with the StarGo software.
1) A problem slewing in the PHD2 azimuth drift alignment routine to 0,0.
2) The mount would not perform a meridian flip when using SGP.
Both these problems have now been fixed (Ascom driver V6.8.1.94), and I have found Luciano at Avalon very responsive when I have reported any problems.
I was the friend that Sara referred to back in July, but since Luciano fixed my Ascom driver problems, I have always had reliable meridian flips.

Agreed the StarGo is not as feature rich as the Synscan, but if this was the same board that is used in the AZ-EQ6 GT then I have managed to quickly blow one up when the power dropped below 12v, so it’s not bomb-proof.

Like others, I have found the Linear is sensitive to wind (I have a Vixen AX103S scope which is a long refractor plus a separate guide scope).
In calm conditions my PHD2 guiding the other night was down to 0.52 arc sec RMS total. In a wind that’s noticeable, this can deteriorate to nearer 1.00.
This is still below my 1.36 arc sec/px resolution so I am happy with the Linear’s performance. I think any windier than this, then I probably would not image with my Vixen.

I use a Lakeside focuser to handle the focusing for me, so I never have to go near the mount.

I also have a Polemaster and I found it very easy and quick to obtain good polar alignment. Later checking the PA against PHD2 drift alignment, I found it spot on in azimuth and only a few pixels out in altitude which was easily corrected in PHD2.
I attached my Polemaster with a fabricated acrylic plate by removing the handle.
I did have to make sure the Polemaster, mount & pier were earthed together, as when I went to adjust the azimuth bolts this connection was broken and it froze the Polemaster’s output for some reason.

I generally use 20min exposures for narrow band imaging. I have tried 30 min exposures but they seemed to add little to the 20 min and I could get more images with 20 min. To date generally the only sub’s I have lost are self-inflicted.

I hope this helps. It’s a shame Beeko you are not located down on the south coast of the UK as you would be welcome to come and see my set-up.

[Beeko]

Southcoaster, thanks for your input. Curious about how you mounted the acrylic plate, did you drill into the mount. Definitely going with this mount - ready to order now but keep flitting between now and waiting. I'm worried about getting to Astrofest next year and seeing £250-£500 off as a special offer.