Avalon Linear Night 3.

[ollypenrice]

As it was getting too light for imaging in the wee hours of Saturday I did a dirft alignment of sorts, not a very long one, but clearly this improved my 'polarscope only' PA. With the short nights (we get about 4 hours of full astronomical darknesss on June 21st) I didn't want to spend dark sky time on this since it is working well anyway. So for the Sat into Sun session, with the improved PA came improved performance. Here's the trace in AA5;

Note that this screenshot came from the end of the session so the scattergraph at the top is showing every single giude correction position from an all night run. Not one single bad hit has been recorded. I'm sure I can improve the Dec trace even more but it is hardly at the top of my priority list! Also note that the target was the Trifid which, even for us, is a bit of a horizon skimmer so the seeing cannot ever be as good as it is higher up. And finally, because of this, the scope was almost horizontal and could pass the Meridian without collision. By the end of this session the counterweight was high in the air. As you can see, this had no effect whatever on the guiding. I often run past the Meridian but it is rare not to see any fall-off in the tracking accuracy on gear driven mounts.

A couple of other observations; I don't normally recalibrate the guiding between nights in AA5 if there is no change in target. (On the Mesu I don't recalibrate it at all, I just switch it on 'as is.') However, the Avalon seems to like a recalibration each time. Not a problem but just worth remembering for me.

(Having an easier time of it up in Cepheus the Mesu ran an all night trace of an almost supernatural 0.02 on one axis and 0.03 on another.)

The elastacity issue is there with the Avalon. It takes a second or so longer to settle after touching for focus, for instance. (I should get an electric one, yeah, I know...) and you don't want to be clumping around near it. It might be less confident in the wind, too.

But the hard reality is there in that all night guide trace. I'm happy.

Yves has sussed out all sorts of software wonders to automate his Avalon with a plate solved auto meridian flip, control through CDC etc. He'll be here in the not too distant future so my next phase will be to let him sort me out on all of that!

Olly

[gingergeek]

Olly, please can you detail the next automation phase that Yves performs for you. Some of us would like to know how to go about setting up automation after only being manual driven from the handset.

Those graphs do look sweet indeed and clearly have benefited from drift alignment, glad this mount was plug and play.

[ollypenrice]

Olly, please can you detail the next automation phase that Yves performs for you. Some of us would like to know how to go about setting up automation after only being manual driven from the handset.

Those graphs do look sweet indeed and clearly have benefited from drift alignment, glad this mount was plug and play.

Will do. I'm going to wait for Yves rather than plough through the stuff from scratch myself. He's just a tad more IT savvy than I am as well...    

Olly

[Thommy]

I know that a user of the Linear here in Denmark has reported problems when it's windy (and it is always windy in Denmark - that's why we have some funny face expressions). He had to put up some further wind shield. The problem could be the elasticity of the belts.

/Thommy

[ollypenrice]

Yes, I think that wind is likely to be the weak point. If you are exposed to a lot of it this might not be the optimal mount for you, I suspect.

I've just processed a first light image from ours, though, and it's looking very good. I'll post it shortly.

Olly

[Tinker1947]

Wind i suspect will make its presence know what ever the mount, just depends how deep one's pockets are.....

[ollypenrice]

Wind i suspect will make its presence know what ever the mount, just depends how deep one's pockets are.....

True, but in weighing up your mount choices you might want to consider this aspect of the belt drive system.

In fact at our site the wind's effect on the mounts is less damaging than its effect on the seeing, which it wrecks, so no mount in the world can get round that. What we do on these windy nights, which are not common, is stick to shorter focal lengths and shoot colour. A good luminance layer then sorts out the resolution.

Olly

[Dave_D]

my guide window usually looks like M13

[PNJ]

Hi Olly

Glad you like the Avalon Mount.   I have had mine now nearly 2 years come September,  and lately have been using a 8 inch Edge Hd telescope,  and my typical readings in guiding from just a quick polar alignment in my back garden, as i got to have a complete new setup every time i use it.  (have to get a shed lol ) is around 0.5 / 0.9 in my traces, which is great.   I suspect if it was a permanently setup, with accurate Polar alignment i could improve on this.

I have to make a comment here on the wind issue..   I live in the North East of England, and do get a lot of wind and breezes, off course heavy gusts of wind can have an effect, but normally, i not noticed it been an issue with my mount.

No more than i had with a previous EQ6 and also my EM400 mounts.  

i see that Avalon have brought out there own Star go system,  any thought on this Olly,  Do you think it might be worth a upgrade !!

cheers

Paul J

[fwm891]

I know that a user of the Linear here in Denmark has reported problems when it's windy (and it is always windy in Denmark - that's why we have some funny face expressions). He had to put up some further wind shield. The problem could be the elasticity of the belts.

/Thommy

Yes it is susceptible to wind gusts but it's the spring loaded belt tensioner rather than the belts themselves that is the problem.

Love my Avalon Linear but a big ish scope and gusty conditions do cause headaches.

With an 8 inch f8 RC and calm conditions I get traces of around 0.2 and 0.3 with my altair 115 frac traces are much lower

[ollypenrice]

Interesting. I wonder if there might be any way to beef up the tensioner or back it up with a fixed jockey not permanently in contact but imposing a maximum deviation. Under normal conditions the sprung jocky would be the one doing the work.

Olly

[perfrej]

Open her up!

/per

[ollypenrice]

Only in contact with Luciano, who has been great to talk to on the phone. We are having a week of down time in our mad busy season so it won't be this week!!!

Olly

[famax]

 Hello,

Sorry to says that, but that kind of graph isnot  useful information since there's no scale on it ..

[ollypenrice]

 Hello,

Sorry to says that, but that kind of graph isnot  useful information since there's no scale on it ..

Isn't there? I specified the effective pixel size and focal length and the graph shows a pixel either side. It is easy enough to work out the errors in arcseconds if you want to but most of us just mentally scale up to our imaging pixel scale to see if we are going to remain sub pixel. Multiplying the deviation by about four to bring it into line with the imaging scope would still leave me sub pixel.

Such is my reasoning but fire way by all means.

Olly

[famax]

oooops, just saw that you give the info on the part 2 of the review... should be nice to repeat the scale information here too...

[famax]

So olly, the info is onthe part two right? (or maybe i'm to tired to find the info on the first post...)

So : lodestar binnedx2 with a 400mm FL guide scope.

Off topîc, i go south in two days, near your place Olly (APT, Luberon) how is the seeing/ haze in these days ?

Thanks

francois

[famax]

So : average guiding in RA is 0.66 " if the above post information is correct.

Very good guiding for small to middle range FL imaging.

If the seeing is very good a 0.33" guiding average can be expected, and so the FL imaging can be upgraded...

Avalon  is a very good brand with a nice middle range mount policy.