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Good Quality And Affordable Imaging In A Light Polluted Area

astrophotography
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#1 NewBAstro

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Posted 06 June 2020 - 12:01 PM

I live in an area with light pollution that reduces limiting magnitude by 2.   I am interested in doing astrophotography in my backyard.  Currently I am considering f4 6 - 8 inch reflectors, f10 Cassegrain, f9 ritchey chretien telescopes.  

 

What would be the best choice or any other telescopes within the price range in a light polluted area considering following factors?

 

1. Price

2. Exposure Time

3. possibility of using focal reducer with additional cost

4. possibility of using guiding with additional cost (guiding camera and scope)

5. Light Pollution

6. HEQ5 and EQR6 Pro mounts

7. Mount Weight Capacity

8. Image Quality



#2 Chicoyne

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Posted 06 June 2020 - 12:08 PM

https://www.youtube....h?v=3RH93UvP358

 

Take a look, sound good to me ...



#3 orlyandico

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Posted 06 June 2020 - 12:55 PM

Aggressive filtering is the way to go. This greatly lengthens exposure times, which in turn means you need a high-dollar mount. To lower exposure time, use the fastest OTA you can get. This is going to be a newtonian.

 

A 6" f/4 newtonian with a coma corrector is the least cost option. It has the bonus of being light enough that an entry-level mount can carry it. You can further reduce it to f/2.8 with the Keller corrector, but that corrector is very expensive and you would need to upgrade the rest of the scope (carbon fiber tube, high-end focuser) because at f/2.8 the slightest miscollimation or sensor tilt will cause funny stars, so the OTA will have to be as stiff as possible.

 

If you think you will be using the Keller corrector in the future, you might as well buy one of those 6" f/4 carbon fiber imaging newtonians up front.

 

Even on an EQ6, I would prefer a 6" f/4 over an 8" f/4 - the bigger tube is a much bigger sail, and much more challenging to guide properly.



#4 TareqPhoto

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Posted 06 June 2020 - 01:11 PM

I agree with Orlyandico about 6" F/4 Newtonian, i got one recently not long time ago [last month] and i trust it will do a great job in my LP Bortle 7-9 sky.



#5 nimitz69

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Posted 06 June 2020 - 01:22 PM

If you want to learn AP a short, fast APO triplet refractor is the ticket on a quality mount. Something in the 60mm - 80mm range with a FF and reducer. You want to keep your Fl under 500mm while you are learning.

You haven’t said what your budget is but the mount is far and away the most important thing . I’m not aware of a mount suitable for AP that is under $1,000. Look no farther than th E6R—-pro if it fits your budget.

For camera starting out with a DSLR is probably the easiest if you already have a suitable one. If not the Nikon D5300 is the lowest noise DSLR out there. They can be had on eBay for $350 every day. If you have teh budget than A dedicated, cooled astro camera like the ASI 294MC pro is a great choice

#6 Ryou

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Posted 06 June 2020 - 07:50 PM

If you want to learn AP a short, fast APO triplet refractor is the ticket on a quality mount. Something in the 60mm - 80mm range with a FF and reducer. You want to keep your Fl under 500mm while you are learning.

You haven’t said what your budget is but the mount is far and away the most important thing . I’m not aware of a mount suitable for AP that is under $1,000. Look no farther than th E6R—-pro if it fits your budget.

For camera starting out with a DSLR is probably the easiest if you already have a suitable one. If not the Nikon D5300 is the lowest noise DSLR out there. They can be had on eBay for $350 every day. If you have teh budget than A dedicated, cooled astro camera like the ASI 294MC pro is a great choice

I'm going to second this and even suggest you get a RedCat (or one of the other colors) for the scope. It's nice and compact, has pretty good optics, built in field flattener, and a very forgiving focal length of 250mm. At f/4.9 it's also relatively fast even if not blindingly so like a RASA or Newt.

 

The mount may be king, however in light pollution I feel like filters are your queen. Narrowband is going to cut through it like a hot knife through butter, though even some base light pollution filters will help contrast of the DSO with a color camera. Just be warned you may not see them in a single frame depending on your target and setup. They are there, just faint, so have to stack to get them to show.



#7 NewBAstro

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Posted 08 June 2020 - 03:42 PM

Thank you all!  I will consider all the options to work around light pollution issue.


Edited by NewBAstro, 08 June 2020 - 03:42 PM.


#8 Ryou

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Posted 09 June 2020 - 12:57 AM

Thank you all!  I will consider all the options to work around light pollution issue.

Although I do not have data on the same target for a direct 1:1 comparison, I just tried out narrowband (Ha) for the first time last night and I have to say I was really blown away by just how much it cut through light pollution. There was basically no gradient (which is how light pollution shows in images) in the image whatsoever, and I started imaging when the target was fairly low to the horizon.

 

Here is a link to a single sub from that session, with just an auto stretch on it:

get.jpg?insecure

 

Meanwhile here is a single sub from a DSLR with similar height above the horizon and auto stretch, however with a broadband light pollution filter (IDAS NGS1).

lp.jpg

The filter leaves a slight green cast in un-calibrated/processed subs even with a background neutralization performed, however you can see the gradient I am talking about fairly clearly. Also the only thing that changed between these two images was the camera/filter. The mount and scope remained the same.



#9 Peregrinatum

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Posted 09 June 2020 - 05:25 PM

mono camera LRGB and NB filters, get Pixinsight and get good and removing gradients, slowest scope your equipment and you can handle



#10 cuivienor

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Posted 10 June 2020 - 02:55 AM

I'm in Tokyo. Light pollution is unfortunately my way of life.

 

I've started a Youtube channel that lays out a lot of what I face and how I deal with is ( https://www.youtube....CuivTheLazyGeek ), including the theoretical basics about noise in astrophotography, equipment choice, optimal exposure times, etc. You may find it useful, I have some organized playlists in there, including one ongoing one about starting astrophoto for lazy people, including choice of scope, camera, mount, etc. depending on the user's goals and after imparting proper understanding of FOV, sampling, and challenges to be faced.

 

As a TL;DW, it is possible to get good broadband pictures in Tokyo, even with an OSC camera, for some object types (bright galaxies and globular clusters come to mind).

 

It is possible to get very good pictures in Tokyo, using Narrowband imaging on emission nebulae. It however is not a cheap solution if you want to get the best filters possible (recommended for Bortle 8-9). Astrophotography really is a Pay to Win hobby in many respects!

 

Good luck!


Edited by cuivienor, 10 June 2020 - 02:55 AM.


#11 Ryou

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Posted 10 June 2020 - 10:46 AM

I'm in Tokyo. Light pollution is unfortunately my way of life.

 

I've started a Youtube channel that lays out a lot of what I face and how I deal with is ( https://www.youtube....CuivTheLazyGeek ), including the theoretical basics about noise in astrophotography, equipment choice, optimal exposure times, etc. You may find it useful, I have some organized playlists in there, including one ongoing one about starting astrophoto for lazy people, including choice of scope, camera, mount, etc. depending on the user's goals and after imparting proper understanding of FOV, sampling, and challenges to be faced.

 

As a TL;DW, it is possible to get good broadband pictures in Tokyo, even with an OSC camera, for some object types (bright galaxies and globular clusters come to mind).

 

It is possible to get very good pictures in Tokyo, using Narrowband imaging on emission nebulae. It however is not a cheap solution if you want to get the best filters possible (recommended for Bortle 8-9). Astrophotography really is a Pay to Win hobby in many respects!

 

Good luck!

I saw your channel from the NINA thread recently and have to say that you do have some good stuff there, and definitely being in Tokyo for light pollution? Highly echoing what you said about your channel and also the TL;DW.

 

Narrowband definitely is not cheap, especially with a mono camera, as you're now looking at 7 filters to buy for a complete SHO LRGB setup, and some of the higher end/narrower SHO stuff can be pricey (I'm looking at you Astrodon/Chroma). My image I took earlier was taken with a 6nm Astronomik which ran about 200 USD. A 3nm Astrodon is slightly above 550 USD. I'd personally argue even in heavy light pollution you may not need a 3nm, it would definitely cut through the light pollution even more though, however I would not go higher than 6nm really.

 

I'm right near the red/orange zone on darksitefinder.com so definitely not the best skies.On the bortle scale it's somewhere around a 6-8, which I realize is a large difference however when I look at images used to determine the scale I get one thing, then some tools show another, and then comparing the estimated sky brightness from clear outside to the scale yields ANOTHER result (which is also different from the one they display in the app). I personally think it's closer to a 7 based on my actual images compared to this image, though I could also see 8 depending on if you're looking at the sky brightness or number of stars in the image or a combo thereof.

 

Edit: Also when talking bortle scale I am not talking about with the light pollution filter I had in the other image I posted and rather my results straight out camera


Edited by Ryou, 10 June 2020 - 10:47 AM.



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