Cardiac arrest

[LewisM]

Seems my SXP has died... flatline at 20:56 on 29/03. :P

OK, OK, I keep on going on about it, but this always brings a smile to my dial after fighting a few mounts over the years. The fact this Vixen SXP KEEPS doing this, session after session just awes me.

And just for the Polish naysayer, see, not guiding on a hot pixel :lol:

OK, I still have it set to pixel RMS, but go tell someone that cares :rofl:

Let's see which smarty can figure out the target based on that guide image :lol: :lol:

[LewisM]

At 0239, a slight murmur was encountered... :lol:

[Logieberra]

Nice. What are you guiding with - your Tak 7x50 finder-guider?

[Slawomir]

That's very good that you are pleased with your mount Lewis :thumbsup:

For the record, I never suggested that you guide on a hot pixel ;)

But I recall you promising that the next graph will have a meaningful scale in arcseconds... :rolleyes:

EDIT: With a 7x50 finder scope and Lodestar image scale would be about 10 arcseconds per pixel. Going for the graphs, total RMS error is about 0.08 pixels x 10 = about 0.8 arcseconds total RMS guiding error. This is more than enough when imaging at about 2.5 arcseconds per pixel, so the mount is perfect for the job.

[Atmos]

I’ll have to measure mine some time Lewis. I know I can imagine at 1.15”/pixel with 600-900s subs and round stars ;)

[Camelopardalis]

So what are you implying Lewis? That you get better seeing than the rest of us :P :lol:

[Lognic04]

0.8 arcseconds??? My CGEM gets that! :lol:
:D

[multiweb]

+1.10asp? My coffee grinder has better PE. :P Lewis we want to see you lift your skirt now. :lol:

[LewisM]

OK Sauvi, OK...BUT...

I just tried changing the plot settings to Arc-secs, and that option is greyed out. Suggestions?

I can select Arc-secs on THIS computer (the non-imaging one [Win10], but all software installed anyway), but NOT on my Win 7 imaging laptop.

It selects Pixels just fine, and that is the ONLY selectable unit.

[Slawomir]

Page 376 in the manual states that this option is greyed out as a safety feature when guiding is really bad, so that the user does not get a real cardiac arrest :lol:

But more seriously, I believe you need to provide your autoguider's pixel size and guidescope's focal length somewhere in the settings to be able to select arcseconds instead of pixels. Or perhaps the software (phd2?) needs to be updated.

[LewisM]

Running 2.6.4dev9. PHD acquired the pixel size etc itself.

Same setup both computers yet i cannot use arc sec on the imaging one. I reset the cam settings now and rebuilding dark libraries again.

Your fault if my guiding goes to poop :lol:

[LewisM]

Success - arc sec y plots enabled. Had to delete the old config file

[Slawomir]

Good work Lewis. I'm glad we could help.

Now we all impatiently await a new super flat guiding graph with arc-seconds on the vertical scale :thumbsup:

[LewisM]

It'll probably guide diagonally now

[multiweb]

Russian mountains. :lol:

[codemonkey]

Make sure to set the Y-axis to a reasonable scale as well... it's easy to make it look flat at 16" - I set mine to 2" from memory

[Slawomir]

IIS Betting is back online and taking bets now...

Anyone recons the total rms will be below 0.8”? :prey:

[LewisM]

You are gonna have to wait till that big lumen maker disappears.

[bert]

Auto Guiding.... thats cute. I remember the days when I used to guide.:rofl:

Picture is unguided and pec disabled.

Hey remember that eq5 you sold me? It now does 10 minute exposures unguided. I did have to modify it a bit though, and added some stuff to it.

[Slawomir]

Another graph with a scale in pixels?:rolleyes:

To be honest, the graphs that Lewis presented, also in pixels, are MUCH more flat :lol:

[LewisM]

You are an arc-sec snob Suavi :P

[Slawomir]

A graph without a proper scale can be quite limited in what it conveys. That was taught in maths in primary schools back in the days when Poland was a communist country...

[Camelopardalis]

Yeah Lewis, you’re just selling snake oil... :P

Even my lowly EQ6 guides comfortably below 0.5” on a good night.

[Paul Haese]

Hmmm, Lewis, I'd be impressed if that was at a long focal length with a small image scale. Guiding with a wide field refractor either OAG or just as a guide scope will produce those sort of results often. If not you have the wrong settings and you need to fine tune the mount. When I was using the FSQ with OAG on the PME it would flat line like that all the time. Now I have a 12" f4 at 0.92" on that mount it does not look really flat anymore. A long focal length will show up the errors in the mount and the guiding real quick.

[LewisM]

It's all academic, considering this mount won't carry such a beast (I carry this mount out to the side yard with a tripod each and every time - it's not some pier mounted permanent set up PME...), so why even need to mention it? For what this mount was designed for and what it does, it's pretty darned decent. Did the same with my f/8 TSA-102.

This mount carries a 15kg payload...so a 12" Newt is not even an option :lol:. It's like comparing apples to granite boulders.

[Slawomir]

Where is the promised graph in arcseconds? :tasdevil:

[multiweb]

It's not about the weight. What Paul meant was long FL will change the image scale. The only way to put this one to bed is to give the focal length of your guider and your guiding camera pixel size. Then you can deduct the error in seconds of arc which is what Suavi's after. 1px will then be X seconds of arc.

[LewisM]

Guidescope FL is 180mm and the Lodestar is 8.3um by memory.

The SXP did the same graphing with the f/5.3 FSQ85 as with the f/8 TSA (and the TSA with extender at f/12). I posted a graph a long while back with the TSA at f/12.

But seriously comparing a PME to an SXP is rather silly :lol:

[multiweb]

I have 8.2um for the old lodestar so you're at ~9.5 seconds of arc per pixel.

[Camelopardalis]

But if you’re using the same guide scope and camera, that’s not all that surprising :shrug:

The larger scopes will just show up any real errors in more detail :D