Re: PREVIEW: New Tutorial on calculating your Image Scale
Good tutorial and information but I am confused.? Shouldn't you enter your auto-guider information and not your imaging scope if you intend to use PEMPro?
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Hi Jamie,
Sounds like you care for the mount as I do, I keep it covered when in the field and not in use. When it is not in use it is stored in the house also covered. If you do this and you have used SuperLube on the mount bearing you can go many years without needing to clean and lube again. Of course if you get caught in a sand storm - it depends. If you have SuperLube the lube itself will never wear out in this application. But contamination is the problem and it takes years to accumulate unless exposed during an unusual severe event like a sandstorm. But even then if the mount is well covered and protected chances are good it will be fine for many years.??
??
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Chip Louie - Chief Daydreamer Imagination Hardware
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Sounds well cared for Jamie.
I'd be inclined to not worry for 5 years.
The minimal motion use of our mounts is really very light duty to the lube.
And I believe it is a synthetic, so it should retain it's lubricity for many years in your ideal type circumstances.
I know Brian has mentioned what Scott uses for the mounts. Hopefully he will weigh in again.
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SonnyE
(I suggest viewed in full screen)
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Re: [Gemini-II_io] PREVIEW: New Tutorial on calculating your Image Scale
Thanks for the input Paul!
On Mon, Jul 6, 2020 at 5:45 AM Paul Kanevsky < yh@...> wrote: Very good tutorial, Brian!
Wanted to mention that variations of a few 1/100s of an arcsecond in pixel scale between predicted and measured are really insignificant. In most cases this is way smaller than the error introduced in an astrometry solution by the position errors in the star catalog, seeing conditions, and tracking/guiding. Even a tiny difference in distance between the reducer and the sensor can result in a much larger image scale change, so best not to obsess over getting it right to more than 1 decimal place, especially for PEC training :)
Regards,
? ? -Paul
-- Brian?
Brian Valente portfolio
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Re: [Gemini-II_io] PREVIEW: New Tutorial on calculating your Image Scale
Very good tutorial, Brian!
Wanted to mention that variations of a few 1/100s of an arcsecond in pixel scale between predicted and measured are really insignificant. In most cases this is way smaller than the error introduced in an astrometry solution by the position errors in the star catalog, seeing conditions, and tracking/guiding. Even a tiny difference in distance between the reducer and the sensor can result in a much larger image scale change, so best not to obsess over getting it right to more than 1 decimal place, especially for PEC training :)
Regards,
? ? -Paul
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Thanks, I'm using a newer GM811G, maybe a year old or so. I store it indoors, and? take it in before I go to sleep, so it's got minimal exposure to the elements. Seems like I've got some time.?
Jamie
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Like all things it depends on your use, care and conditions. Also depends on your mount, older straight drives are more exposed to the elements than later tucked servo OPW mounts. But once a year seems excessive to me. Maybe every 2-5 years depending as above.?
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Chip Louie - Chief Daydreamer Imagination Hardware
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Re: [Gemini-II_io] PREVIEW: New Tutorial on calculating your Image Scale
I should also mention this tutorial is a basic one that just covers how to calculate ?your image scale ? ? If you already know this and are comfortable with your process, please feel free to skip it. ? I get a lot of questions about image scale, and it¡¯s a good thing to know, especially at the start of something like periodic error correction ? ? ? Thanks ? Brian ? Brian Valente Losmandy Astronomical ? Losmandy.com Tutorials and vids at ?
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From: [email protected] [mailto: [email protected]] On Behalf Of Brian Valente Sent: Sunday, July 5, 2020 5:43 PM To: [email protected]; [email protected]Subject: [Gemini-II_io] PREVIEW: New Tutorial on calculating your Image Scale ? This isn¡¯t yet published, but I wanted to pass this along to this special group of folks and see if there¡¯s any feedback ? It¡¯s Part 1 of Practical PEC for your Gemini ? It was supposed to be a short ¡®here¡¯s how to calc your image scale¡¯ but it ended up 18 minutes long ? ? ? Thanks ? Brian ? Brian Valente Losmandy Astronomical ? Losmandy.com Tutorials and vids at ?
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PREVIEW: New Tutorial on calculating your Image Scale
This isn¡¯t yet published, but I wanted to pass this along to this special group of folks and see if there¡¯s any feedback ? It¡¯s Part 1 of Practical PEC for your Gemini ? It was supposed to be a short ¡®here¡¯s how to calc your image scale¡¯ but it ended up 18 minutes long ? ? ? Thanks ? Brian ? Brian Valente Losmandy Astronomical ? Losmandy.com Tutorials and vids at ?
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Someone was telling me that years ago they had a g11, and found that they needed to clean and re-lube once a year. Is this recommended??
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Re: Going Auto with N.I.N.A
Roman,
I forgot to drop this link for you to verify your Losmandy Gemini 1 RS232 cabling. ?
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Chip Louie - Chief Daydreamer Imagination Hardware
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Re: Going Auto with N.I.N.A
Hi Roman,
Get a good directly from ATEN. Many of us have been using these for many years and they work very well an are reliable and known to work. Then just use your existing cable if you know it is wired correctly.??
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Chip Louie - Chief Daydreamer Imagination Hardware
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Re: Best Way To Determine Periodic Error?
Hi Sonny
UI really think what you are seeing is field rotation due to polar misalignment - it's not about the quality of the guiding, although i suspect your guiding is reasonably good
as your target moves across the sky, it is tracked, but the polar misalignment causes your framing to rotate. when you image for extended perior?of time, that can be quite a lot.?
I mentioned this before, but there's an easy way to visualize this if you re-stack your images with Maximum integration mode instead of average.
?
On Fri, Jul 3, 2020 at 10:43 AM, Michael Herman wrote:
Have fun and continued progress and success.
?
Michael
Hi Michael, Thank You for the reply.
I certainly hear you about the Orion (lack off) Quality issue. My Orion G3 was a POS out of the box, then things got worse. It's so dead now it can't be used at all, but the freakin fan runs.
Please correct me if I'm wrong, but the soul purpose of a guide camera is to find a single star, lock onto that star, then the guiding (PHD2) sends the guiding pulses to the mount to guide on that single star. (In a nutshell)
Since I'm a dolt about getting things right, I was wondering about that Smeartation I was seeing. (My word. I made it up. Makes as much sense as "Sticktion", a WW2 terminology)
I almost always just use the Auto in PHD to pick a star for guiding. The latest version has a nifty picker button that gets the guiding on right away. Love that improvement. Makes my life much simpler and quicker to get to imaging.
I do like the USB3 attributes, and hunkier connectors. But my USB cable (for one thing) is a USB 2 configuration. So no need for a USB3 camera, because it's going to get knocked back to USB2 anyway. Of course, no need to let a $9 cable spoil the party. If I can find a 15' USB3 cable, I'll buy it just to have my USB3 Star Tech hub connected to my Baby Dell at it's USB3 port. Can't hurt to give it as much speed from the hub at the telescope, to the computer. Even if my cameras are USB2.
Oh! This mud is thick!
?
--
SonnyE
(I suggest viewed in full screen)
-- Brian?
Brian Valente portfolio
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Re: Best Way To Determine Periodic Error?
On Fri, Jul 3, 2020 at 10:43 AM, Michael Herman wrote:
Have fun and continued progress and success.
?
Michael
Hi Michael, Thank You for the reply. I certainly hear you about the Orion (lack off) Quality issue. My Orion G3 was a POS out of the box, then things got worse. It's so dead now it can't be used at all, but the freakin fan runs. Please correct me if I'm wrong, but the soul purpose of a guide camera is to find a single star, lock onto that star, then the guiding (PHD2) sends the guiding pulses to the mount to guide on that single star. (In a nutshell) Since I'm a dolt about getting things right, I was wondering about that Smeartation I was seeing. (My word. I made it up. Makes as much sense as "Sticktion", a WW2 terminology) I almost always just use the Auto in PHD to pick a star for guiding. The latest version has a nifty picker button that gets the guiding on right away. Love that improvement. Makes my life much simpler and quicker to get to imaging. I do like the USB3 attributes, and hunkier connectors. But my USB cable (for one thing) is a USB 2 configuration. So no need for a USB3 camera, because it's going to get knocked back to USB2 anyway. Of course, no need to let a $9 cable spoil the party. If I can find a 15' USB3 cable, I'll buy it just to have my USB3 Star Tech hub connected to my Baby Dell at it's USB3 port. Can't hurt to give it as much speed from the hub at the telescope, to the computer. Even if my cameras are USB2. Oh! This mud is thick! ? -- SonnyE (I suggest viewed in full screen)
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Re: Sawtooth pattern in DEC
Thanks, Brian, I set the period to the G11 worm period once I realized what was happening. I think at one point, it went all the way up to 900s! Next time, I'll try starting with a lower DEC backlash number and go from there. I did check to see if there was any slop in DEC and couldn't find any, And like I said, the DEC guiding was quite good regardless of what the assumed backlash number was.
Thanks for all your help so far. Feel much more confident now that I can get good results with this mount even with a longer f/l.
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Re: Sawtooth pattern in DEC
yeah seems high
you might put it at 3500 just to see what happens, but also reset the starting point to around 800ms
sometimes when it gets that high it takes a while for it to correct back, if it needs correction
I started with 1500, it went to 1500.
So I took it to 2000, it went to 2000.
I ended the night at 2500, and it went to 2500.
-- Brian?
Brian Valente portfolio
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Re: Sawtooth pattern in DEC
I started with 1500, it went to 1500.
So I took it to 2000, it went to 2000.
I ended the night at 2500, and it went to 2500.
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Re: Sawtooth pattern in DEC
Hi Arun
>>>I kept increasing the backlash number and PHD2 kept going to the max.
what was the max you were operating at?
>>Also wondered why PHD2 kept increasing the period length in RA and then saw that I had checked auto calculate period.
That's the nature of the algorithm, it attempts to identify periodicity in your results, without knowing anything about your mount's PE. Personally i set it at the 239.34 sec of the G11 (or whatever your mount is) and uncheck the auto. But whatever results are best
So an update on this... almost all good.
Tightened the clutches a bit, make sure the polar alignment was good - Polemaster is not as reliable as you think - used PPEC and enabled backlash comp in DEC. Got the best guiding I've gotten so far on what looked to be a poor night. Consistently averaging around 0.7" RMS, I am sure it would have been lower with better seeing. DEC was basically +/- 0.5" RMS fluctuations along the mean, all tightly bound. Predictive was 30%, Reactive as 80%, 2 second corrections. Very nice and exactly what I wanted to see.
However - it seems like PHD2 thinks there is significant DEC backlash. I kept increasing the backlash number and PHD2 kept going to the max. It didn't seem to affect the guiding though, what I set it, so not sure what's going on here. Also wondered why PHD2 kept increasing the period length in RA and then saw that I had checked auto calculate period.? Overall, very promising. Looking fwd to using the mount on the Newtonian.
-- Brian?
Brian Valente portfolio
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Re: Sawtooth pattern in DEC
So an update on this... almost all good.
Tightened the clutches a bit, make sure the polar alignment was good - Polemaster is not as reliable as you think - used PPEC and enabled backlash comp in DEC. Got the best guiding I've gotten so far on what looked to be a poor night. Consistently averaging around 0.7" RMS, I am sure it would have been lower with better seeing. DEC was basically +/- 0.5" RMS fluctuations along the mean, all tightly bound. Predictive was 30%, Reactive as 80%, 2 second corrections. Very nice and exactly what I wanted to see.
However - it seems like PHD2 thinks there is significant DEC backlash. I kept increasing the backlash number and PHD2 kept going to the max. It didn't seem to affect the guiding though, what I set it, so not sure what's going on here. Also wondered why PHD2 kept increasing the period length in RA and then saw that I had checked auto calculate period. ?Overall, very promising. Looking fwd to using the mount on the Newtonian.
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Re: Going Auto with N.I.N.A
Hi Chip ,?
I found that pages for settings in Gemini.Net?
We all remember this pages and never forget :(
My USB/Serial adapter is very very old and do not let me choose any COM port and all ports settings are invalid : COM port?
Need to order new one?
Thanks?
Roman?
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Chip Louie
Paul Kanevsky
Jamie Amendolagine
Roman Kulesza