Avalon Linear Fast reverse with Star-Go. How is the guiding?

[Broke Astronomer]

For those of you who have the Linear, what are your experiences with guiding?  What software do you use for guiding?  What gear are you using and what settings are you using?   I had the chance to use one recently and I have had mixed results with the guiding.  Sometimes really great and other times I can't buy a round star for anything.  Could use some advice from others that have used the Linear recently.  

[DrRobin]

Hi,

I have the Avalon M-Uno and would imagine they are similar.  I use CDC, ASCOM and PHD and it guides just fine.  I wouldn't say it is any better than the EQ6 I had, but as the M-Uno is obs mounted and the EQ6 wasn't generally it performs better.

Hope this helps

Robin

[swag72]

I use Maxim to guide with my Linear Fast reverse, with an OAG. I have tried imaging at 2.3m of focal length and also 329mm (so from one extreme to another) - The guiding has been excellent under both circumstances. I also use EQMOD pulse guiding - The settings do need to be changed between both focal lengths - It may be that you just need to tweak some settings.

I can honestly say that I haven't dropped subs due to the mount since I got it - It happens due to my own stupidity at times!! If I need 7 subs for example, I set Maxim to take 7 subs as I know that they will be spot on.

[Broke Astronomer]

I use Maxim to guide with my Linear Fast reverse, with an OAG. I have tried imaging at 2.3m of focal length and also 329mm (so from one extreme to another) - The guiding has been excellent under both circumstances. I also use EQMOD pulse guiding - The settings do need to be changed between both focal lengths - It may be that you just need to tweak some settings.

I can honestly say that I haven't dropped subs due to the mount since I got it - It happens due to my own stupidity at times!! If I need 7 subs for example, I set Maxim to take 7 subs as I know that they will be spot on.

That is good to hear and I am sure the issue is on my end.  Are you using Star-Go?  What do you have the RA and DEC guide speed set to?  I was told RA30, DEC25.    I had really good results when I was guiding using an OAG(ZWO120mm) through my 80mm refractor but if I go to a longer focal length OTA I can not seem to get the guiding to smoothen out.  Of course it could also be that I have incredibly bad seeing right now.   What I am experiencing is the graph going smooth for a bit and then there will be some instability where the error peaks at over 2 arc seconds and then it goes back to under an arc second for a while.  Obviously trying to do long exposure at F/10 isn't ideal but I would think that I should get 10 minute exposures using an OAG without a problem. 

What firmware are you using?   Any settings or advice would really help.   I am finding that I am spending way too much time tinkering with settings trying to smooth things out.

[Barry-Wilson]

Like Sara, I use the free EQMOD software and use pulse guiding (not ST4 cable) with PHD2.  As there is virtually no backlash in either of the mount's axes, I set the DEC backlash to zero in eqmod, with guide rates set to 0.2 x sidereal for both RA and DEC.  In PHD2, I use 3 sec subs and a low hysteresis setting of 3 with RA aggressiveness of 90%.  I change Min Motion to either 0.15 to 0.05 depending whether I'm using my ST80 ot 50mm finderguider.  I am able to achieve very reliable 1200s subs with less than +1" to -1" peak-to-peak in RA (DEC tends to be quite flat) and total RMS of 0.16.  Not yet tried 1800s and may still tweak guide settings.  Perfect balance is important and do not set east-heavy, as is a good PA of course.  My longest focal length is 740mm.

Your settings may well be different, but I hope the above helps you refine your guide settigs for the characteristics of your set up.

HTH.

Barry

[swag72]

I've not come back to this as I've not been out since the post and so I can't remember what settings I use!

I know that aggressiveness is set to 10 in Maxim on both axis as per Avalons recommendation. When I'm up and running I'll have a look and come back to this.

[Elio]

As one of the first user of Avalon my experience is more than positive.

I imaged at different focal lenght and with several OTA as you con see on my astrobin gallery or my website, for example guiding 900s perfect subs during one night, with Vixen Visac @/f6.3  and Canon 60D-CDS, and guiding "only" with a 50/f5 finder with Lacerta MGen, a stand-alone guiding system, because I don't like computer on the field.

I tried also with my C11HD @f/10 and taken 1200s subs, but using a OAG system, I think very long focal need off axis guiding.  

My suggestion is try with low guide speed and do a good balancing in both axis and put the guide-ccd with orthogonal axis with the mount, if the system have to correct in mixed direction it could guide worse.

I hope to read good news from you soon, good luck 

[ollypenrice]

I use AstroArt 5 for guiding. It is messy to set up but very adjustable in real time, without stopping, once running. I like it.

I use a guide speed of 0.125 sidereal and set the backlash to zero. I experiment with sub length but generally disagree with the maker's advice to go for long subs. Fairly short ones seem to work best for me, around one second. The mount does seem to like to be recalibrated for each shoot. I can't explain this. Wherever I am in the sky with the Mesu I just use the same settings. It works. I can't explain that either!

The Avalon is giving very consistently 'good to acceptable' guiding and I think I'm pushing the limits of the belt drive because it is carrying a TEC140. This is not over payload but the OTA is very long indeed, with high mass items at both ends. (Triplet up front, mighty flattener and full frame CCD and wheel at the other.) This gives a huge polar inertia. The elasticity is very evident and it's quite surprizing, quite honestly, that it guides as well as it does. Walking past the mount gives a spike in the trace but this is corrected very quickly. Result images are good and I like the consitency. In fact I like the mount very much but it is an oddball used with a long scope. It is probably at its best with short catadioptics of low polar inertia and long focal length. It can certainly guide them.

Olly