Cardiac arrest - Page 2

LewisM · #21 31-03-2018, 09:04 AM

You are an arc-sec snob Suavi

Slawomir (Suavi) · #22 31-03-2018, 10:34 AM

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 (Dunk) · #23 31-03-2018, 10:49 AM

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

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

Paul Haese · #24 03-04-2018, 12:19 PM

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 · #25 03-04-2018, 01:56 PM

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

. It's like comparing apples to granite boulders.

Slawomir (Suavi) · #26 03-04-2018, 02:24 PM

Where is the promised graph in arcseconds?

multiweb (Marc) · #27 03-04-2018, 02:31 PM

Quote:

Originally Posted by LewisM

It's all academic, considering this mount won't carry such a beast

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 · #28 03-04-2018, 03:38 PM

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

multiweb (Marc) · #29 03-04-2018, 03:50 PM

Quote:

Originally Posted by 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

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

Camelopardalis (Dunk) · #30 03-04-2018, 03:57 PM

Quote:

Originally Posted by 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 if you’re using the same guide scope and camera, that’s not all that surprising

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