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Choosing astrophotography equipment

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#1 tboss70

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Posted 29 November 2020 - 01:51 PM

I am trying to correctly choose the appropriate astrophotography equipment for my Takahashi FC-100DZ. I think I have an idea of what I want/need but would like to get some other eyes on it to be sure. I currently have a Tak FC-100DZ and intend to use it with the FC-35 reducer as well as the Tak flattener. Native the Tak is f/8 so 100mm lens and 800mm fl. The flattener is 1.04x (f/8.32) and the reducer is .66x (f/5.3). Astronomy tools shows this seems to cover me for average to good seeing. Of course with good seeing the limiting factor will likely be the telescope resoltuion.

 

I've been on the fence about whether or not I should purchase a monochrome or color camera and have been leaning toward the ASI-2600MC but I could be persuaded otherwise. I only lean that way for convenience but like the idea of monochrome and the other things I can use it for. One of the things Im not sure about is back focus.  The ZWO website talks about how to get the proper back focus (55mm) for most telescopes but how do I figure that out for my fc-100dz?

 

Any other thoughts or suggestions as I go through this? In town where I live, and using DarkSkyFinder, the skies are bright yellow. I have a farm about 30 minutes away and the skies are dark blue there, so much better.



#2 Huangdi

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Posted 29 November 2020 - 02:02 PM

I would most certainly get the reducer. F8 is painfully slow. That means you'll have to take many more hours than a fast scope to get the same level of signal
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#3 bobzeq25

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Posted 29 November 2020 - 02:11 PM

I am trying to correctly choose the appropriate astrophotography equipment for my Takahashi FC-100DZ. I think I have an idea of what I want/need but would like to get some other eyes on it to be sure. I currently have a Tak FC-100DZ and intend to use it with the FC-35 reducer as well as the Tak flattener. Native the Tak is f/8 so 100mm lens and 800mm fl. The flattener is 1.04x (f/8.32) and the reducer is .66x (f/5.3). Astronomy tools shows this seems to cover me for average to good seeing. Of course with good seeing the limiting factor will likely be the telescope resoltuion.

 

I've been on the fence about whether or not I should purchase a monochrome or color camera and have been leaning toward the ASI-2600MC but I could be persuaded otherwise. I only lean that way for convenience but like the idea of monochrome and the other things I can use it for. One of the things Im not sure about is back focus.  The ZWO website talks about how to get the proper back focus (55mm) for most telescopes but how do I figure that out for my fc-100dz?

 

Any other thoughts or suggestions as I go through this? In town where I live, and using DarkSkyFinder, the skies are bright yellow. I have a farm about 30 minutes away and the skies are dark blue there, so much better.

Thoughts.  Mostly trying to explain what the priorities here are.  This ain't visual.

 

The most important part of a DSO setup is the mount.  Buy the best you can afford and carry.  No one in DSO imaging ever regrets buying "too good" a mount.  Thing to understand.  It's all too easy for _tracking_ to be the limiting factor in resolution.  And seeing (atmospheric turbulence) is at least as iimportaant.  Did I mention this isn't visual?  <smile>

 

Whatever mount you get, you'll want an autoguiding system to make a necessary improvement.

 

That may set your budget for the camera.  The 533 is on sale now for $799, it would be a good choice.  Not a critical choice, like the mount.  So, get whatever camera you want.  Mono plus filters is a good, but expensive choice.  If it knocks you down a class on the mount, that's not good.

 

Spacing things correctly is simply a basic skill to learn.  There are no cookbooks.  Most of us have a drawer full of spacers.

 

But "equipment" needs a broader definition than you may think.

 

This will be the best $50 you ever spend in getting into DSO AP.   Knowledge is key, and you'll never learn all you need to know from short posts here.  We're excellent for specific questions, you need to build a strong knowledge base.

 

https://www.amazon.c.../dp/0999470906/

 

This will be the best $150 you ever spend getting into DSO AP.  Processing is at least half the game, saving a few bucks here is ill-advised.  APP both stacks and processes, has an excellent gradient reduction tool for reducing the effects of light pollution.  But the _big_ thing is that it's laid out logically, doesn't have many "gotchas".  So, it will actively _help_ you learn processing.  And, indirectly data acquisition.

 

https://www.astropixelprocessor.com/

 

The last beginner I recommended APP to called it a "lifesaver".  <smile>  Beats the whatever out of trying to use DSS and warp a terrestrial program like Photoshop into doing astro.


Edited by bobzeq25, 29 November 2020 - 02:19 PM.

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#4 idclimber

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Posted 29 November 2020 - 02:20 PM

In case you are not aware of this, the back focus will be set and specified by the reducer. You will need to look up the spec for that specific model.  55mm is just a common one. 


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#5 tboss70

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Posted 29 November 2020 - 02:54 PM

Thanks all.  I have a EQ6R Pro mount and auto guiding with it has been descent so for now I think I am good on the mount.

I can work with TakahashiAmerica on the back focus items but they need to know what camera first so I guess I need to decide that.

I should mention I've already done some basic imaging with a DSLR and the ASI224MC but its really more for planetary.

I used DSS and Gimp/GLimpse rather than Photoshop but I would like to find a better program for this.

It sounds like I need to decide on color vs monochrome, then go from there.



#6 Stelios

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Posted 29 November 2020 - 03:19 PM

Thanks all.  I have a EQ6R Pro mount and auto guiding with it has been descent so for now I think I am good on the mount.

I can work with TakahashiAmerica on the back focus items but they need to know what camera first so I guess I need to decide that.

I should mention I've already done some basic imaging with a DSLR and the ASI224MC but its really more for planetary.

I used DSS and Gimp/GLimpse rather than Photoshop but I would like to find a better program for this.

It sounds like I need to decide on color vs monochrome, then go from there.

 Probably they just want to tell you what back-focus will cover the image circle your camera needs. Most manufacturers give you the distance at which you have the *largest* corrected circle, and most manufacturers aim to have that distance be 55mm because a DSLR + T-ring is 55mm. 

 

I think your best camera buy is the ASI294MM-Pro, or the QHY equivalent (while being aware that there will be extra cost in filter wheel and filters). Here's my reasons:

 

The 294 *mono* camera gives you *TWO* pixel-size options: 2.3mm and 4.6mm. These are very well suited to your optics with the two different reducers (whether you buy them now or later):

1) 2.3mm pixels with 530mm: 0.9"/px, pretty much ideal. 

2) 4.6mm pixels with 832mm: 1.14"px, also pretty much ideal (you could also try, if your seeing is good, the 2.3mm pixels that would give you 0.57"/px--that would be a great setup for imaging smaller objects with the excellent Takahashi optics). 

Also the 294 mono is an 4/3rds sensor, only slightly smaller than APS-C, and significantly larger than the 183 and 533 sensors. 


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#7 drd715

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Posted 29 November 2020 - 03:20 PM

In addition to the 533 being on sale now, also the 2600 is on sale. The 2600 is a very nice camera for osc. I am hesitating for now on getting a mono camera as I'm not impressed with the offerings. Maybe if an APS-C mono camera with back illuminated sensor were to be marketed and reported to be good by experienced narrow band imagers i might add that to the mix. But for now I'm sticking with the 2600.

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#8 bobzeq25

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Posted 29 November 2020 - 03:25 PM

Thanks all.  I have a EQ6R Pro mount and auto guiding with it has been descent so for now I think I am good on the mount.

I can work with TakahashiAmerica on the back focus items but they need to know what camera first so I guess I need to decide that.

I should mention I've already done some basic imaging with a DSLR and the ASI224MC but its really more for planetary.

I used DSS and Gimp/GLimpse rather than Photoshop but I would like to find a better program for this.

It sounds like I need to decide on color vs monochrome, then go from there.

The only real drawback to mono is the expense.  If that's not a deterrent, mono is better.  How much so depends on circumstances, and what you want to image.  One shot color is much cheaper, and, with modern OSC cameras, the gap to mono has closed.

 

How much light pollution you have is a big deal.  Gathering data faster improves signal to noise ratio, and your ability to separate out light pollution, with a number of techniques.

 

There are two good ways to fight light pollution with mono.  For emission nebulae, you can do narrowband imaging.  Ha, O(III) and S(II) filters are the most common.  For other targets you can do LRGB imaging.  That's a clever trick, based on the fact your eyes see detail in the luminance part of the image, not the chrominance.  So, you use the L filter to basically record the target.  The use the RGB data to color it, like paint.  Very efficient in gathering data, compared to the terrestrially oriented Bayer matrix filter used in OSC cameras.

 

There are other good techniques.  Ha images in black and white can be very nice, there are some on my astrobin, like this.

 

https://www.astrobin.com/dzrgl2/

 

For emission nebulae I like HaRGB.  Combines some of the detail of Ha, with the natural color of RGB.  The processing is difficult, though.

 

https://www.astrobin.com/285813/B/

 

There are many fewer mono cameras though, most people either don't want to spend the money, or fear the complexity, which is not all that bad.

 

Note that the reducer also gathers data faster.  Lower F numbers are good.  The loss in resolution can be less than simple theory predicts, or even nonexistent, depending on seeing.


Edited by bobzeq25, 29 November 2020 - 03:32 PM.


#9 tboss70

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Posted 29 November 2020 - 04:24 PM

 Probably they just want to tell you what back-focus will cover the image circle your camera needs. Most manufacturers give you the distance at which you have the *largest* corrected circle, and most manufacturers aim to have that distance be 55mm because a DSLR + T-ring is 55mm. 

 

I think your best camera buy is the ASI294MM-Pro, or the QHY equivalent (while being aware that there will be extra cost in filter wheel and filters). Here's my reasons:

 

The 294 *mono* camera gives you *TWO* pixel-size options: 2.3mm and 4.6mm. These are very well suited to your optics with the two different reducers (whether you buy them now or later):

1) 2.3mm pixels with 530mm: 0.9"/px, pretty much ideal. 

2) 4.6mm pixels with 832mm: 1.14"px, also pretty much ideal (you could also try, if your seeing is good, the 2.3mm pixels that would give you 0.57"/px--that would be a great setup for imaging smaller objects with the excellent Takahashi optics). 

Also the 294 mono is an 4/3rds sensor, only slightly smaller than APS-C, and significantly larger than the 183 and 533 sensors. 

Thanks all.  The only thing with this camera is I read reflections can be an issue similar to the 1600. One poster toward the bottom of the thread said it was not limited to just reflectors: https://www.cloudyni...mono-edgehd-11/



#10 tboss70

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Posted 29 November 2020 - 04:30 PM

In addition to the 533 being on sale now, also the 2600 is on sale. The 2600 is a very nice camera for osc. I am hesitating for now on getting a mono camera as I'm not impressed with the offerings. Maybe if an APS-C mono camera with back illuminated sensor were to be marketed and reported to be good by experienced narrow band imagers i might add that to the mix. But for now I'm sticking with the 2600.

Sent from my SM-N950U using Tapatalk

I think I agree with this.  Does anyone know if there are plans to release a 2600 mono in the future? I'd like to know more about the reflections in the 294 before going that route.



#11 idclimber

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Posted 29 November 2020 - 07:03 PM

I think I agree with this.  Does anyone know if there are plans to release a 2600 mono in the future? I'd like to know more about the reflections in the 294 before going that route.

Both QHY and ZWO should have versions with that sensor out first part next year. I assume once orders can be placed the discussion about them will increase dramatically. 


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