Dual Esprit 150 imaging rig

[Davey-T]

Can't see from your pictures but have you got any safety stops, I've got them both ends of the dual bar and at the front of the scope dovetails. better safe than sorry 

Dave

[Tomatobro]

Re safety stops a good idea will add them.....

[Davey-T]

Just now, Tomatobro said:

Re safety stops a good idea will add them.....

I just use bolts with a rubber grommet to cushion them.

Dave

 

[tomato]

Thanks for that, none currently in place,  we are very careful, but it would only need one mishap...

The centre dovetail is  now bolted directly to the Mesu so one clamp arrangement has been eliminated.

[Jonk]

Just a thought... have you checked the scopes sit that close together with cameras and focus motors fitted?

[tomato]

34 minutes ago, Jonk said:

Just a thought... have you checked the scopes sit that close together with cameras and focus motors fitted?

Yes, that’s all good. There is a G2-8300 with an internal filter wheel on scope #1, and an Atik 383 with external filter wheel on the other. One scope still has a manual focuser, the other focuser was designed and built by @Tomatobro, and is quite a tight arrangement.

[Jonk]

Ok, reason I mention it was because I wanted to move my 2 smaller scopes closer together than I had originally intended, but they will still be a 100mm gap between the OTA bodies unless I have the focusers vertically with respect to the base plate? Hmmm... I'll think about that.

[Jonk]

In theory, this would be the closest I could get them (not much to be gained by switching the motor to the other side on the 2nd scope) so the vertical focusers is more appealing.

This depends on the camera widths, I'll look into that next.

 

 

[tomato]

The bracing plate was installed last night and a few test subs taken. 
 

The first thing is I managed to do was align the cameras 90 degrees out, I wrongly assumed that Moravian and Atik orientated the sensors in the same way relative to the power and USB ports on the camera body, not so, but this hasn’t affected the test. 

Tightening of the bracing plate had to be done very carefully as expected, uneven tightening of the bolts could impart a bigger deflection  than those made with the adjustment saddle.

The good news is that no flex or sag was observed on the test, so far so good.

Guided Scope

 

Slave Scope

Edited January 16, 2020 by tomato

[Jonk]

Any progress is good progress. Glad I found this thread, as it's helped me to plan my dual rig.

Here's what I have in mind...

I can't get them closer in this orientation unless I remove the focus knobs I suppose, plus I still need to locate the guidescope...that's next to draw followed by whatever securing mechanism I feel is best.

 

[Davey-T]

34 minutes ago, Jonk said:

I can't get them closer in this orientation unless I remove the focus knobs I suppose, plus I still need to locate the guidescope...that's next to draw followed by whatever securing mechanism I feel is best.

I don't think there's a big need to have the scopes that close together, I have my three canted with the focusers upwards at an angle still need enough room to rotate the cameras to frame things.

Is that just an artist impression as the plate is restricting a lot of movement, it could end between the focusers and the rear tube rings.

Dave

Edited January 16, 2020 by Davey-T

[tomato]

In my case the main driver for putting them as close together as possible is the limited aperture width of the Pulsar dome. 
 

 

[ollypenrice]

On 10/01/2020 at 18:03, Jkulin said:

That was exactly what was going through my mind Olly, I know it means an extra mount and pier, but surely would be far more accurate and less problematic?

When we set up the original dual rig (2 x Tak106/Atik 11000) on a Mesu using guidescope and Cassady T-GAD tilt-pan adjuster it just worked from day one and never missed a beat, literally never. Not a single sub lost out of thousands. This was at 3.5"PP. The exercise was a total success.

With the present dual TEC, working a little either side of 1"PP (Atik 460 and Moravian 8300) we sometimes see minor trailing on one side but it mostly works fine. The fact that the focusers are both good may have a lot to do with it. One of the TECs has a TEC focuser and one has a Feathertouch.

My system is rather old-school and manual so labour is saved by the dual rig. Someone running fully automated systems might find two mounts easier than a dual rig. This ignores the cost! (It's always best to ignore the cost in this game...)

Olly

[jjosefsen]

On 08/01/2020 at 17:33, Jonk said:

SGPro 4 is planned to include dual scope dithering, evidently very difficult to achieve but they say they’re working on it.

N.I.N.A. has syncronized dithering (experimental feature, but as far as I know it works) if you aren't married to SGP. Haven't used it myself as I don't have a dual rig (yet!).

[Laurin Dave]

12 minutes ago, ollypenrice said:

(It's always best to ignore the cost in this game...)

Olly

Definitely! 

[gorann]

Regarding dithering, my impression is that it is something that makes a difference with noisy cameras and many dead/bright pixels. With my cooled ASI CMOS cameras I have never seen a need to do it. Hot pixels are effectively removed using the stacking routines in PI. Or am I missing something? At least I would not attempt to do it on my dual Esprit rig.

[Jonk]

If you have a hot pixel in the same place on all subs in a stack, then it would probably not be removed.

You must have some natural drift or other movement going on if they don’t appear in the same place on each sub.

I would always dither at least a few pixels.

[ollypenrice]

4 hours ago, Jonk said:

If you have a hot pixel in the same place on all subs in a stack, then it would probably not be removed.

You must have some natural drift or other movement going on if they don’t appear in the same place on each sub.

I would always dither at least a few pixels.

I stack in AstroArt which, like most stacking routines, has a hot pixel filter. I find it very effective. Because I've been using dual rigs for ages I haven't been dithering and, honestly, I can't say I've missed it. Being lazy, I tend to think that a bit of polar misalignment (within reason!) doesn't do any harm. What does intrigue me is why my 'noisy' old Atik 11000 produces a far cleaner background sky than my 'low noise' Atik 460 with Sony chip. But it does, believe me.

Olly

[tomato]

5 hours ago, ollypenrice said:

This ignores the cost! (It's always best to ignore the cost in this game...)

Olly

 

5 hours ago, Laurin Dave said:

Definitely! 

Many years ago when myself and Tomatobro were active participants in motorsport, there was an advertising slogan from a certain American performance exhaust supplier which went, ‘Why waste your money on food and rent when all I need are my Hooker Headers’ , now substitute Mesu mounts, ED 150s, etc etc.😊

[gorann]

18 hours ago, Jonk said:

If you have a hot pixel in the same place on all subs in a stack, then it would probably not be removed.

You must have some natural drift or other movement going on if they don’t appear in the same place on each sub.

I would always dither at least a few pixels.

If I image for several hours I always have a small drift, at least several pixels, so maybe that helps, but I also think that the image integration routines in PI are very effective in remving hot pixels, just like the ones Olly @ollypenriceare using in Astro Art. In any case, after I moved from Nebulosity to PI for my stacking some years ago, I never notice hot pixels in my images (just like all satellite trails are magically gone).

Edited January 18, 2020 by gorann

[wimvb]

On 17/01/2020 at 15:38, Jonk said:

If you have a hot pixel in the same place on all subs in a stack, then it would probably not be removed.

You must have some natural drift or other movement going on if they don’t appear in the same place on each sub.

I would always dither at least a few pixels.

Cosmetic correction in both DSS and Pixinsight can take care of this. Otoh, you need very good tracking for ordinary pixel rejection not to work. 

I guess that AstroArt's hot pixel filter has similar functionality. 

Edited January 18, 2020 by wimvb

[tomato]

Tried to set up the two ASI 178s tonight, so 3 ZWO cameras coming down the cables to a single laptop. The idea was to have SGP running one for RGB, PHD connected to the ZWO 120 mini, and Sharpcap running the other 178 shooting Lum.

We could not overcome the USB port conflicts, the software just wanted to connect to one camera, and I had a corrupted copy of PHD which would not recognise a ZWO camera. Interesting, as one laptop would run 3 cameras (but all different) no problem on the previous set up.

So, a second laptop was brought into play, PHD re-installed and success, all three cameras communicating. We then encountered auto focus issues with SGP, and then the so called clear night gave out with persistent high cloud.

Still, a bit more progress made.

[Laurin Dave]

1 hour ago, tomato said:

Tried to set up the two ASI 178s tonight, so 3 ZWO cameras coming down the cables to a single laptop. The idea was to have SGP running one for RGB, PHD connected to the ZWO 120 mini, and Sharpcap running the other 178 shooting Lum.

We could not overcome the USB port conflicts, the software just wanted to connect to one camera, and I had a corrupted copy of PHD which would not recognise a ZWO camera. Interesting, as one laptop would run 3 cameras (but all different) no problem on the previous set up.

So, a second laptop was brought into play, PHD re-installed and success, all three cameras communicating. We then encountered auto focus issues with SGP, and then the so called clear night gave out with persistent high cloud.

Still, a bit more progress made.

I think to do this on one laptop you'll need to have the ASCOM as well as the native ZWO ASI drivers installed..  in SGPro or PHD you'll then get a choice of more than two cameras to connect to (ie  two as ASCOM nd two as ZWO )

Dave

[ampleamp]

For sheer ease i went with two computers - cheap NUC-type boxes - as i got too many conflicts with trying to run two rigs from the same box. I know it is possible and some do it very well, but i couldn't. I have one of those HDMI blanks in each which apparently tricks the computer into thinking it has a screen attached and then I just link through by Anydesk. If you are on the same network, which presumably you would be, it is very quick. 

I've never bothered with dithering though i do tend to shoot L/H through both scopes before tasking the slave to RGB. If a nb target, i would shoot HOS equally through both scopes. If Cosmetic Correction doesn't pull out the hot pixels, stacking does, and using data from two scopes does seem to improve the background noise significantly. Definitely worth thinking about with identical cameras. 

[tomato]

 

10 hours ago, Laurin Dave said:

I think to do this on one laptop you'll need to have the ASCOM as well as the native ZWO ASI drivers installed..  in SGPro or PHD you'll then get a choice of more than two cameras to connect to (ie  two as ASCOM nd two as ZWO )

Dave

Last night my version of SGP was saying it no longer supports ZWO native drivers. I must say in my experience  Sharpcap appears to have a more robust communication link with these cameras than SGP, but I do like the integrated features of the latter package.  

However, Sharpcap is catching up fast.....