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Equipment advice for moving to EAA/OAP, and on to AP

EAA equipment imaging astrophotography
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#1 adg

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Posted 17 May 2019 - 03:27 AM

Hello all:

 

I am a newcomer to CN, looking for advice on equipment.  I hope this is the correct forum for that. [Edit: Originally posted in the general CN equipment forum, but later moved to the correct EAA forum.]

 

Background: I have done visual (eyepiece) astronomy for years, using very basic equipment (90mm achromatic refractor and a basic mount).

 

Goals:  Invest on new equipment to switch to EAA / OAP, and eventually also get into AP.

 

Main interest:  DSO.

 

Requirements and limitations:

 

a) Light pollution:  Observing/imaging from my Bortle class 6 backyard

 

b) Lightweight equipment (I have some difficulty carrying heavy items)

 

c) I prefer equipment (mount/control, camera, guiding camera) that are compatible with free software and linux as much as possible (EQMOD, ASTAP, INDI library, etc)

 

Plan:  My equipment investment plan, for a total of ~$4000:

 

  - Scope, an 80mm f/6 triplet ED APO CF, e.g.:
      Orion ED80T CF 6lbs 80mm f/6 FPL53 triplet APO:  ~$950 (2nds $750)
      Or: Explore Scientific ED80 CF 80mm f/6 FCD1 triplet APO:  ~$850

 

  - Camera, a CMOS OSC TEC (color needed for  EAA?, cooling needed for AP):
      ZWO ASI 294 MC Pro:  ~$1000
      Or:  ZWO ASI 183 MC Pro:  ~$800

 

  - Mount, capable for future AP:
      Orion Sirius EQ-G goto, 30lbs payload, ~$1050
      Or:  Sky-Watcher HEQ5 Pro goto, 30lbs payload, ~$1150

 

  - Accessories (filters, reducers, adaptors, rings):
      LPR filters, reducers, tube rings, dovetail bar, T-adaptors:  ~$500

 

  - Guider (optional for EAA, needed for AP):
      Orion Magnificent Mini Deluxe AutoGuider package:  ~$400

 

Does the above look like a good plan for my goals?

 

Specifically I have the following questions:

 

Q1. [Rephrased] I am mostly interested in wide field DSOs, but it would be great to get fine details on some small DSOs.  The 80mm f/6 + 294MC (my initial choice) will be excellent for large DSOs with a FOV of 2.3x1.6 degs, but its 2''/px image scale is too course to detect the remarkable M87 jet, as this CN thread seems to indicate.

 

Getting a larger scope or adding a second finer-pixel camera (e.g. 183MC has 2.4um px size, compared to the 4.6um of the 294MC) would be great solutions to this dilemma, but the cost would be too much for me.

 

So I am thinking of two low-cost approaches, while keeping the 80mm f/6 scope:

 

- Get the 183MC camera ($200 less than the 294MC), and add a strong focal reducer:  Use the reducer for wide views, and exploit the finer pixel size of the 183MC (1''/px image scale with the 80mm f/6 scope) for finer details of smaller DSOs.  This combo is known to detect the M87 jet.

 

- Or, conversely, keep the 294MC and add a high quality 2x barlow.  My guess is that under good conditions the barlow will add significant finer detail (image scale becomes 1''/px) and the 294MC will then be able to detect the M87 jet, but I could not find any hard confirmation.

 

So my question is: Does any of this make sense?  For the 80mm f/6 scope above, are there strong reducers suitable for AP (without back-focus issues)?  Or, will good quality 2x barlows work for AP?

 

Q2. Since my payload won't exceed ~10lbs, can I use a lighter 20lbs-payload mount to do AP (like Orion SkyView Pro Eq GoTo, or Sky-Watcher EQM-35 GoTo)?

 

Thanks!


Edited by adg, 17 May 2019 - 03:11 PM.


#2 bobzeq25

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Posted 17 May 2019 - 07:45 AM

Forgive me if this is somewhat blunt, I'm trying to maximize information.

 

That's a good starter setup for learning AP of DSOs.  The EAA folks can help you better on that, from what I've seen, they generally like bigger scopes.

 

Q1.  The 183 (I have one) is a tricky camera in a few regards.  Perhaps the biggest is that those tiny pixels need to be fed well, with longer total imaging time.  While most beginners use inadequate total imaging time (I do at most one target per night, my best work takes multiple nights on the same target, using platesolving to get pointed back to it).  I strongly recommend the 294C as a better camera for starting out.

 

Also when starting out, closer to 2 arc sec per pixel is better than 1 (for much the same reasons).  1 will only get you better resolution if a whole lot of other things go well, 2 is more "forgiving", will give you a better signal to noise ratio no matter what.

 

This image is 2.8.  Enough detail?

 

https://www.astrobin...6074/B/?nc=user

 

Click on it, note the salt and pepper noise on the dim stuff.  That was because this was only 2 hours of data, would have been much worse (would have occurred everywhere) at 1 arc sec per pixel, or even at 1.7, which was where I would have been with the 183.

 

Major point.  You'll learn faster/better/cheaper on big targets.  Detail in small galaxies is advanced work, can wait.  Think months, not weeks.

 

Minor point.  I got the M87 jet with an SV70T.  And four years of experience, which was far more important.  Take one of my favorite sayings to heart.  Dustin Johnson's clubs will not put you on the PGA tour.  Get this book.

 

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

 

Imagers hardly ever use Barlows.  For beginners, that should be never.  They slow down the optics, doubling the F number.  That hurts signal to noise ratio, which is as least as important as resolution.  You might as well just crop.  Imagers use reducers, not Barlows.

 

Here's the reducer.  Spacing it correctly is one of a great many skills you'll need to learn.

 

https://www.highpoin...efractor-s20200

 

Q2  One of the two most common beginner mistakes is skimping on the all important mount.  Your first choices are _far_ better than these alternatives.  (The second mistake is getting too big a scope, your 80mm is a fine choice for starting AP.)  Even the first choices are adequate, no more.  I started with a zeq25, in the same class as those, now use a CEM60.  Imagers always want a better mount.

 

By the way, we share your characteristics 1 and 2.  Bortle 7 here, can't carry much (why I got the CEM60, the lightest "good" mount).   As far as 3 goes, you're making your life somewhat harder, there's more image capture software for a Windows laptop, and it's less fussy.  A Mac/Linux is fine for processing.  Which is more than half the game in AP.  That was the key to getting the jet.

 

Get the book.  It can build your absolutely crucial knowledge base (much of AP is just not intuitive) far better than any number of short posts here.


Edited by bobzeq25, 17 May 2019 - 08:23 AM.

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#3 han59

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Posted 17 May 2019 - 10:41 AM

If your interested in wide field deep sky, you should look for a telescope with a flattener included or astrograph to have sharp stars in the image edges. It will be very frustrating if the stars in the image corners are oval shaped due to curvature. An opening between 65 and 100 mm will be fine as long it is F/5 or  F/6.

 

I personally would go for a cooled monochrome camera as a first camera. Monochrome is much more sensitive and works better with an H-alpha filter.  Using an H-alpha filter will allow making nebula images while the Moon is shining, so it doubles your clear sky nights. Furthermore stacking and processing of monochrome images is easier and less cumbersome compared with stacking colour images. Using a colour sensor, light pollution will quickly generate a green or orange background you have to remove while preserving the faint nebula colours.  In addition to a monochrome camera you could use an additional secondhand low cost DSLR for making colour images.

 

I would not be too worried about pixel size. In most cases they are too small en you could just bin x2 them after converting to colour or straight from the beginning using a monochrome sensor. More important is the sensor size/diagonal.  As usual, the bigger the better.

 

Han


Edited by han59, 17 May 2019 - 11:45 AM.

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#4 Stelios

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Posted 17 May 2019 - 01:45 PM

Moving to EAA for a better fit.


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#5 adg

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Posted 17 May 2019 - 04:22 PM

bobzeq25,

 

Many thanks for your very valuable and detailed response, with crucial information and links.  It answers all my questions from the imaging/AP viewpoint.

 

I am awaiting response from the EAA folks:  May be an 80mm scope is too small for EAA?

 

 

 

Forgive me if this is somewhat blunt, I'm trying to maximize information.

 

That's a good starter setup for learning AP of DSOs.  The EAA folks can help you better on that, from what I've seen, they generally like bigger scopes.

 

. . .

 



#6 RazvanUnderStars

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Posted 17 May 2019 - 08:06 PM

It will be fine for objects with a larger angular size (nebulas) and too small for others (small DSOs such as global clusters or smaller galaxies, for which aperture will make a difference). By "too small" I don't mean that you won't see them, you will but they won't be as spectacular as in larger scopes. For example, I've seen the ever popular M13 through the two scopes I use for EAA (the Orion 80mm triplet apo and an Evolution 8" SCT) with the same camera, ASI 294 MC Pro. The view through the latter shows more stars, with more details. 

 

You can simulate the view for a given equipment via http://www.blackwate...ging-toolbox/. 

 

In the end there's no perfect set up for all the objects so depending on your preferences, but today there's a lot of choice to be happy with - we live in good times for astronomy except the light pollution.

 

I am awaiting response from the EAA folks:  May be an 80mm scope is too small for EAA?


Edited by RazvanUnderStars, 17 May 2019 - 08:10 PM.

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#7 DSO_Viewer

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Posted 17 May 2019 - 10:09 PM

It will be fine for objects with a larger angular size (nebulas) and too small for others (small DSOs such as global clusters or smaller galaxies, for which aperture will make a difference). By "too small" I don't mean that you won't see them, you will but they won't be as spectacular as in larger scopes. For example, I've seen the ever popular M13 through the two scopes I use for EAA (the Orion 80mm triplet apo and an Evolution 8" SCT) with the same camera, ASI 294 MC Pro. The view through the latter shows more stars, with more details. 

 

You can simulate the view for a given equipment via http://www.blackwate...ging-toolbox/. 

 

In the end there's no perfect set up for all the objects so depending on your preferences, but today there's a lot of choice to be happy with - we live in good times for astronomy except the light pollution.

An 80 mm scope is fine and works very well for EAA and it all depends on what object you are trying to view. Try viewing the North American nebula in an 8" sct and see if it fitswink.gif

 

Steve


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#8 adg

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Posted 18 May 2019 - 01:25 AM

RazvanUnderStars and DSO_Viewer (Steve):

 

Thanks for your feedback --- they give me more confidence in my gear selection and investment. Heavily leaning toward the 80mm ED APO triplet + ASI 294 MC Pro + Sirius EQ-G mount.


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#9 Startex

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Posted 20 May 2019 - 06:40 PM

I have searched and can't find the definition for OAP. 



#10 Vondragonnoggin

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Posted 20 May 2019 - 07:19 PM

I have searched and can't find the definition for OAP. 

Observational Astro-Photography

 

Over the course of a few years some have been unhappy with EAA which was formerly Video Astronomy. EAA was coined to be inclusive of all Electronically Assisted Astronomy forms of observation. Also because more and more members were moving on from Video Cameras to other cameras with CMOS tech or CCD tech still, but not in the traditional Video formats like the older security cameras used that were modified like the Mallincams, AVS, Stellacam, etc.

 

Several members have have attempted to change the terms by just continually using their own coined terms and hope it catches. Another forum uses EEVA (Electronically Enhanced Visual Astronomy)

 

Electro-Telescopes was used consistently by one member, OAP used consistently by another member.

 

Interesting term but find it is only inclusive of camera based EAA and excludes Night Vision EAA which does not require a camera and has nothing to do with Astro-Photography unless one couples an image intensifier device to a camera which can be done but not required.

 

If camera technology grows to be sensitive enough and minimal noise for live view astronomy with good results, then the term OAP would also not apply to it, but it fits camera based EAA right now and could be interchangeable with EAA in reference to camera use. Probably not inclusive of the older Near Real-Time Video (NRTV) that used to be a standard of the Video Astronomy forum that some still use because they still use video cameras for observation like the Revolution Imager II

 

Some feel EAA too broad a term since it can include just mounts that use electronics or similar non-observational impact equipment. 

 

At at least that’s my take on it and explanation of OAP term.

 

undecided.gif


Edited by Vondragonnoggin, 20 May 2019 - 07:43 PM.

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#11 Don Rudny

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Posted 20 May 2019 - 07:36 PM

I have searched and can't find the definition for OAP. 

I think someone on this forum uses OAP instead of EAA for who knows what reason.  I think it means observational astrophotography in contrast to traditional AP.  I guess it’s like reinventing the wheel and calling it RT for round thing.  There were many threads here about a better name for EAA, but I think most everyone agreed to leave it EAA.

 

Added note:  I think Von and I were responding at the same time trying to say the same thing.  He gave a more detailed explanation.


Edited by Don Rudny, 20 May 2019 - 07:38 PM.

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#12 Startex

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Posted 20 May 2019 - 08:00 PM

I suppose I should throw my acronym out there, SEAP. Short Exposure Astrophotography. I figure if you're standing there looking at images coming in sub 1 second up to 5-10 seconds it is video astronomy. But lets face it as much as "real APers" would frown on this, if I'm capturing an image at 1-2 seconds up to 10-15 seconds or even a little more, then stacking and processing it, I'm doing astrophotography. So I further define it with "short exposure".


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#13 Vondragonnoggin

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Posted 20 May 2019 - 08:29 PM

I suppose I should throw my acronym out there, SEAP. Short Exposure Astrophotography. I figure if you're standing there looking at images coming in sub 1 second up to 5-10 seconds it is video astronomy. But lets face it as much as "real APers" would frown on this, if I'm capturing an image at 1-2 seconds up to 10-15 seconds or even a little more, then stacking and processing it, I'm doing astrophotography. So I further define it with "short exposure".

Sure why not. smile.gif

 

Some might confuse it with SAEP though (Spherical Aberration of the Exit Pupil) and you might get someone that comes along in a year with a post saying “What is SEAP? I searched and could not find a definition only a definition of SAEP”

 

wink.gif



#14 Startex

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Posted 20 May 2019 - 08:55 PM

Well, as long as we're out there under the stars and enjoying ourselves, who cares what we call it.


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