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Please share your Esprit 100 filter offsets.


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I am having some issues with setting up my filter offsets on my Esprit 100 I keep ending up with slightly bloated red channel when I average focus based on HFR.

I would appreciate it of anyone with an Espirt 100 could share their offsets for comparison, I know mine will be different so its just a wet finger in the air thing.

Mine are currently set as:

Lum = 4

Red = 7

Green = 0

Blue = 0

 

Thanks,

Adam

Edited by Adam J
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On 07/05/2020 at 23:27, Adam J said:

I am having some issues with setting up my filter offsets on my Esprit 100 I keep ending up with slightly bloated red channel when I average focus based on HFR.

I would appreciate it of anyone with an Espirt 100 could share their offsets for comparison, I know mine will be different so its just a wet finger in the air thing.

Mine are currently set as:

Lum = 4

Red = 7

Green = 0

Blue = 0

 

Thanks,

Adam

Hi Adam

Whilst I don't have an Esprit 100, I do own an Esprit 150 which is set up for automated imaging using filter offsets.  I explored the details of this a couple of years ago and understanding the theory a little more greatly improved my results. So,  you might want to take a look at this post: 

 

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I have a Esprit 100 and use a ZWO EFW. I have a Sesto Senso electronic focuser but have not needed to refocus when switching filters.  

I really don't see how you can compare one persons step count with anothers. There is a big difference in how different s/w apps allow you to set the desired  acceptable FWHM variance when focussing.  Then add to that the different focusers people use each with a different step count for moving the same distance.

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I have Esprit 150s on a dual rig  with autofocus running in SGP. I run the focus routine at the start of every filter change on the colour camera, and refocus the Lum camera at the same time, so I don’t use offsets. In my experience, the results are not consistent enough to do it any other way, but that may be due to the relatively short imaging sessions that I have managed since setting it up.

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I have an Esprit 100 but I must be honest all my filters are Baader and all same thickness so I assumed if focussed on one filter it was okay for all of them.  I have not inspected all filter images to the nth degree but they look okay for focus but will check a bit closer to make sure

I did do a bit of messing about with auto-focussing in APT quite recently and as I could focus same filter anther time and the actual position would differ slightly anyway each time, that is  the final position would go back and forth ever do slightly but the focus still looked okay to my eye I left it as it was and all same for all filters. This is more me being a relative newbie and not quite getting how to focus exactly and get it absolutely spot on.

O really would like to go into this more as obviously I have no compensation for temperature though my session and just rely that it stays pretty much in focus throughout the night.

Steve

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On 11/05/2020 at 14:16, wornish said:

I have a Esprit 100 and use a ZWO EFW. I have a Sesto Senso electronic focuser but have not needed to refocus when switching filters.  

I really don't see how you can compare one persons step count with anothers. There is a big difference in how different s/w apps allow you to set the desired  acceptable FWHM variance when focussing.  Then add to that the different focusers people use each with a different step count for moving the same distance.

You can't but in general if red is longer than greeñ and blue on one scope it will be the same on another. 

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On 11/05/2020 at 12:51, MarkAR said:

What's your red channel look like with out the filter offset and does it move 7 steps from green and blue all the time?

 

My auto focus is reasonably consistent. So the range on each filter if you repeat it is no more than 3-4 steps if you exclude rare outliers. 

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55 minutes ago, Adam J said:

You can't but in general if red is longer than greeñ and blue on one scope it will be the same on another. 

Not sure that is correct different scopes have different lenses/optics and focus different wavelengths differently so you are still comparing apples and oranges IMHO.

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Hi Adam.... with my Esprit 100/ASI1600 I focus on each filter using SGPro same exposure for LRGB 3 seconds binned 2x2 (I use 10seconds with NB)..  FWHMs on red are nearly always slightly worse than blue and green - about 10-15%.    I've checked the offsets and they aren't very large and are in line with yours directionally.  Maybe try focus on filter if your software allows

HTH 

Dave

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I spent many hours messing about with filter offsets and in the end I gave up.

What I did learn was that my scope (Tak 106 EDX IV) is VERY temperature sensitive and I got much better results by telling SGP to refocus on every filter change and again with every 0.5 degree temperature change. It is more time consuming but I have kept an eye on what the offsets would be if I was to use them and they vary by =/- 80% !!! Almost entirely dependant on temperature.

Not sure that this helps but its an observation that might be worth thinking about.

 

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22 hours ago, Laurin Dave said:

Hi Adam.... with my Esprit 100/ASI1600 I focus on each filter using SGPro same exposure for LRGB 3 seconds binned 2x2 (I use 10seconds with NB)..  FWHMs on red are nearly always slightly worse than blue and green - about 10-15%.    I've checked the offsets and they aren't very large and are in line with yours directionally.  Maybe try focus on filter if your software allows

HTH 

Dave

Yes the red channel is worse on mine too even with refocusing. Sometimes gives faint red rings around blue stars. 

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