Having fun with old equipment


Roland Christen
 

Hi Astronuts,

Having recently purchased a ZWO CMOS camera and putting it thru its paces, I am impressed with how much easier it is to take great images. Download times are very fast, resolution is unreal. However, this camera produces such large files that it makes processing a real bear. Just trying to combine a large number of files causes my laptop to give up the ghost.

I have had an old SBIG STL11K sitting here unused for a long time, so I thought I would dust off this old monster to see what it could do. We do not have great conditions here for deep sky, so I have to image the brighter objects, like M57. I put it on the 17" F8 astrograph and immediately discovered that the tiny internal guide chip just won't show any stars in the star-poor regions away from the Milky Way. Can't use a guide scope with the 17" due to focal length, flexure etc. The solution for me was to fire up APCC and do a point map.

Easier said than done. Although the software is straight forward, the old STL11K has a hugely long download time, even binned 2x2. So to do a mapping run of 190 points took about 2 1/2 hours of precious dark sky. In the end it was worth it. Starting image runs at midnight, I still had another 2 + hours of imaging before the first hints of dawn. Fortunately the almost full Moon was far south, so I didn't have much in the way of gradients.

How did the scope track with APCC modeling with the 1600 encoder mount? Round stars at 4 minute and even 6 minute exposures for the duration of the session. And that's at 3454mm focal length at 0.5 arc sec per pixel. The mount drifted about 8 pixels during that entire session. Hats off to Ray Gralack for this wonderful program.

Take a peek:
https://www.astrobin.com/full/wqa9yw/0/?mod=&real=

Rolando

(I did make one error at the beginning when I entered the wrong pixel scale. Old age or?)

--
Roland Christen
Astro-Physics


Dean Jacobsen
 

APCC modeling is definitely the way to go.

I had an STL 11K back in the day.  I got some pretty good shots with it on my Epsilon 160.  It was a real PITA to use with the USB 1 downloads.  Getting a decent number of flats took a loooong time.

Your M57 looks nice.
--
Dean Jacobsen
Astrobin Image Gallery - https://www.astrobin.com/users/deanjacobsen/


M Hambrick
 

Great image Roland That 17-inch has some serious resolution. 

How long is the download time for the old STL11K ?

And your ZWO camera, is it a color or mono version ?

Mike


Roland Christen
 

STL11k takes about 30 seconds to download.

We have both a color and mono version of the 35mm full frame ZWO.

Roland

-----Original Message-----
From: M Hambrick <mhambrick563@...>
To: main@ap-gto.groups.io
Sent: Fri, Jun 17, 2022 5:17 pm
Subject: Re: [ap-gto] Having fun with old equipment

Great image Roland That 17-inch has some serious resolution. 

How long is the download time for the old STL11K ?

And your ZWO camera, is it a color or mono version ?

Mike

--
Roland Christen
Astro-Physics


Patrick Sparkman
 

Quick question about your model Roland.  Was that an all sky 190 point model, or did you do a Dec-Arc model around the Dec of your target?  Just wondering what you settings were for the model.  I am still trying to get a handle on the Dec-arc vs just Enable Tracking Correction.  I have not been able to get consistent unguided results like you describe with my AP1600AE, and am wondering if there are some guidelines on the settings needed for particular focal lengths.  I know that a while back that George had a post with some guidelines, but I couldn't find it.

BTW - Nice image of M57.  You did a good job processing it to maintain the colors.


Roland Christen
 

It was an all-sky model, 10 degree Dec spacing, 10 degrees RA spacing, 4.5 hours either side of the meridian.
It's important to have no mirror shift or flex in the scope - my 17" has an ultra-light weight quartz mirror that does not move (hardly affected by gravity). The secondary mirror is also light weight quartz and the secondary holder and spider vanes are very rigid.

The mount is on a heavy ATS pier, sitting on a 6 ft deep concrete block. It is not perfectly polar aligned and there is some natural drift consisting of atmospheric refraction and PA error. In the area I was shooting the drift ranged from 75  to 20 arc sec per hour as the object rose higher in the sky. With the model activated the drift was reduced to around 4 arc sec per hour, so a 5 minute exposure would produce about 1/3 arc sec drift. That's good enough for a night where the seeing was between 1.5 and 2 arc sec FWHM.

When we designed this 17" scope we wanted to make sure that it would not be a source of error. We wanted a setup to allow us to measure the mount errors without having them influenced by a floppy scope system. People sometimes forget that the scope can also be a source of significant pointing errors that are random in nature and can prevent precise pointing/tracking.

Rolando

-----Original Message-----
From: psparkman via groups.io <psparkman@...>
To: main@ap-gto.groups.io
Sent: Sun, Jun 19, 2022 9:46 pm
Subject: Re: [ap-gto] Having fun with old equipment

Quick question about your model Roland.  Was that an all sky 190 point model, or did you do a Dec-Arc model around the Dec of your target?  Just wondering what you settings were for the model.  I am still trying to get a handle on the Dec-arc vs just Enable Tracking Correction.  I have not been able to get consistent unguided results like you describe with my AP1600AE, and am wondering if there are some guidelines on the settings needed for particular focal lengths.  I know that a while back that George had a post with some guidelines, but I couldn't find it.

BTW - Nice image of M57.  You did a good job processing it to maintain the colors.

--
Roland Christen
Astro-Physics


Jeff B
 

In the vein of having fun with old equipment, here is a mix of old and new.  My "old" AP 178 pre-ED Starfire on an 1100 mount.  A very effective combination and the "old" 178 F9 still packs a young visual punch.

Jeff

On Mon, Jun 20, 2022 at 11:36 AM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
It was an all-sky model, 10 degree Dec spacing, 10 degrees RA spacing, 4.5 hours either side of the meridian.
It's important to have no mirror shift or flex in the scope - my 17" has an ultra-light weight quartz mirror that does not move (hardly affected by gravity). The secondary mirror is also light weight quartz and the secondary holder and spider vanes are very rigid.

The mount is on a heavy ATS pier, sitting on a 6 ft deep concrete block. It is not perfectly polar aligned and there is some natural drift consisting of atmospheric refraction and PA error. In the area I was shooting the drift ranged from 75  to 20 arc sec per hour as the object rose higher in the sky. With the model activated the drift was reduced to around 4 arc sec per hour, so a 5 minute exposure would produce about 1/3 arc sec drift. That's good enough for a night where the seeing was between 1.5 and 2 arc sec FWHM.

When we designed this 17" scope we wanted to make sure that it would not be a source of error. We wanted a setup to allow us to measure the mount errors without having them influenced by a floppy scope system. People sometimes forget that the scope can also be a source of significant pointing errors that are random in nature and can prevent precise pointing/tracking.

Rolando

-----Original Message-----
From: psparkman via groups.io <psparkman=me.com@groups.io>
To: main@ap-gto.groups.io
Sent: Sun, Jun 19, 2022 9:46 pm
Subject: Re: [ap-gto] Having fun with old equipment

Quick question about your model Roland.  Was that an all sky 190 point model, or did you do a Dec-Arc model around the Dec of your target?  Just wondering what you settings were for the model.  I am still trying to get a handle on the Dec-arc vs just Enable Tracking Correction.  I have not been able to get consistent unguided results like you describe with my AP1600AE, and am wondering if there are some guidelines on the settings needed for particular focal lengths.  I know that a while back that George had a post with some guidelines, but I couldn't find it.

BTW - Nice image of M57.  You did a good job processing it to maintain the colors.

--
Roland Christen
Astro-Physics


Roland Christen
 

Nice looking setup.

Roland

-----Original Message-----
From: Jeff B <mnebula946@...>
To: main@ap-gto.groups.io
Sent: Mon, Jun 20, 2022 11:08 am
Subject: Re: [ap-gto] Having fun with old equipment

In the vein of having fun with old equipment, here is a mix of old and new.  My "old" AP 178 pre-ED Starfire on an 1100 mount.  A very effective combination and the "old" 178 F9 still packs a young visual punch.

Jeff

On Mon, Jun 20, 2022 at 11:36 AM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
It was an all-sky model, 10 degree Dec spacing, 10 degrees RA spacing, 4.5 hours either side of the meridian.
It's important to have no mirror shift or flex in the scope - my 17" has an ultra-light weight quartz mirror that does not move (hardly affected by gravity). The secondary mirror is also light weight quartz and the secondary holder and spider vanes are very rigid.

The mount is on a heavy ATS pier, sitting on a 6 ft deep concrete block. It is not perfectly polar aligned and there is some natural drift consisting of atmospheric refraction and PA error. In the area I was shooting the drift ranged from 75  to 20 arc sec per hour as the object rose higher in the sky. With the model activated the drift was reduced to around 4 arc sec per hour, so a 5 minute exposure would produce about 1/3 arc sec drift. That's good enough for a night where the seeing was between 1.5 and 2 arc sec FWHM.

When we designed this 17" scope we wanted to make sure that it would not be a source of error. We wanted a setup to allow us to measure the mount errors without having them influenced by a floppy scope system. People sometimes forget that the scope can also be a source of significant pointing errors that are random in nature and can prevent precise pointing/tracking.

Rolando

-----Original Message-----
From: psparkman via groups.io <psparkman=me.com@groups.io>
To: main@ap-gto.groups.io
Sent: Sun, Jun 19, 2022 9:46 pm
Subject: Re: [ap-gto] Having fun with old equipment

Quick question about your model Roland.  Was that an all sky 190 point model, or did you do a Dec-Arc model around the Dec of your target?  Just wondering what you settings were for the model.  I am still trying to get a handle on the Dec-arc vs just Enable Tracking Correction.  I have not been able to get consistent unguided results like you describe with my AP1600AE, and am wondering if there are some guidelines on the settings needed for particular focal lengths.  I know that a while back that George had a post with some guidelines, but I couldn't find it.

BTW - Nice image of M57.  You did a good job processing it to maintain the colors.

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics


Brian McFarland
 

I have the 6" version of that telescope, and I love it.

- Brian