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Will a single axis motor drive suffice for entry level astrophotography?

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#1 12345678910

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Posted 19 August 2019 - 11:16 AM

Hello,

 

I'm probably missing something obvious but i wanted to known if a single axis drive (right ascension) would be sufficient for very entry level photos of easy deep sky objects such as Andromeda galaxy, Hercules cluster, and Orion nebula. I recently bought a ZWO ASI224MC Cmos camera that is rated excellent for planetary imaging and very good for dso. With this camera i have taken OK pictures of jupiter and the moon (the pictures should get better the more i do it). Currently i have a celestron 127eq 5 in telescope with a manual mount. If i get the single axis motor drive and take relatively short exposures and stack a lot of them would this be enough to get half decent images of bright dso?

 

What Im really trying to get at is I don't want to buy a 1000 dollar mount😁


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#2 GoldSpider

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Posted 19 August 2019 - 11:34 AM

Hello,

 

I'm probably missing something obvious but i wanted to known if a single axis drive (right ascension) would be sufficient for very entry level photos of easy deep sky objects such as Andromeda galaxy, Hercules cluster, and Orion nebula. I recently bought a ZWO ASI224MC Cmos camera that is rated excellent for planetary imaging and very good for dso. With this camera i have taken OK pictures of jupiter and the moon (the pictures should get better the more i do it). Currently i have a celestron 127eq 5 in telescope with a manual mount. If i get the single axis motor drive and take relatively short exposures and stack a lot of them would this be enough to get half decent images of bright dso?

 

What Im really trying to get at is I don't want to buy a 1000 dollar mount

A lot of the answers you'll get to this question will depend on what your personal taste of "half decent" is.  

 

Before I answer your question about the mount, I'll point out the ASI224MC's small sensor won't be able to capture very much of the larger objects on your list such as Andromeda or Orion Nebula.  To get an idea what I mean, take a look at this useful FOV calculator:  https://astronomy.to.../field_of_view/

 

For the mount, in theory, if your polar alignment is good, you could probably do 30 sec. unguided exposures with the single-axis motor drive.  I certainly wouldn't try any longer than that to start with.  It could be an inexpensive way to work on learning the fundamentals of long-exposure DSO astrophotography, which I'd never discourage.  However the setup has a fairly low performance ceiling, so the key to enjoying it will be setting realistic expectations and enjoying the learning process.



#3 jerahian

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Posted 19 August 2019 - 11:38 AM

Well, I just deleted everything I was typing because Adam said what I was going to say, but better and more concisely.  So, +1 to Adam's post.



#4 airscottdenning

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Posted 19 August 2019 - 11:39 AM

Answer depends on

 

1) Your focal length, and

2) The precision of your polar alignment

 

Most of us start with wider fields than your 5-inch reflector will produce. With a DSLR and wide-angle lens or even a 135 mm you can absolutely get by with a single-axis tracker (iOptron SkyTracker or Vixen Polarie, for example). It's a great way to get started and learn about exposures, calibration frames, stacking, processing, etc. 

 

The trouble is that if you have a long enough focal length to do planetary imaging, you're going to magnify every tiny error in your DSO images. It would take exquisite polar alignment to get decent tracking at a focal length of 1000 mm.

 

I think for starting in this hobby you should choose between planetary (requires long focal length) and DSOs (best with short focal length). Keep your 1000 mm reflector for visual and planets.

 

Get a cheap wide-angle lens and star tracker to get your feet wet with DSOs.


Edited by airscottdenning, 19 August 2019 - 11:40 AM.

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#5 ericthemantis

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Posted 19 August 2019 - 12:03 PM

I've got an iOptron SkyGuider Pro, and a Celestron CG-4. Both are unguided, so they only track in RA. I did get the dual motor drive for convenience and to make my mount seem more "complete", but it currently does not improve my imaging (no autoguider). I've been getting really good wide-angle stuff with my DSLR and focal lengths in 18-100mm. I've struggled with longer for DSO's, but have learned some tricks that should help (better polar alignment, shorter exposures).

 

The CG-4 has a 1000mm focal length refractor on it. I just took some of my best planetary images with it. But again, this was after getting a polar alignment scope for it, and the frames are really short for planetary (I was doing between 1/60" and 1/125").



#6 Galaxyhunter

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Posted 19 August 2019 - 12:21 PM

The short answer, YES.  The real answer - it all depends on your expectations.  All the above replies are spot on.  The only thing I can add is the say that Astrophotography  has a HUGE learning curve. I'm not one to try to squash anybody enthusiasm,  but you need to be realistic when you are starting out. I have seen it many time where a newbie get frustrated right away & says the heck with it. Remove your OTA, mount your DSLR to your mount & start shooting wide angle.  This will give you decent results right away & then you can start making small steps. The one tip I give all newbies,  Write down everything you do, That way you will see what works & what doesn't, and it will keep you from making the same mistake over & over.  Good Luck



#7 PirateMike

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Posted 19 August 2019 - 12:29 PM

Check out the Orion SkyView Pro Equatorial GoTo mount - $799.00

 

I have no experience with this mount but the specs do say "guiding" and the price is under $1000.

 

There are probably other makes and models available to fit your budget.

 

 

Miguel   8-)

 

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#8 PirateMike

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Posted 19 August 2019 - 12:34 PM

iOptron CEM25P - $898

 

This is a decent mount for a light weight scope and guider setup.

 

 

Miguel   8-)

 

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#9 Hesiod

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Posted 19 August 2019 - 12:41 PM

Theoretically yes, since only the RA drive is required (the so called "star trackers", which are designed for deep sky widefield photography, have just the RA drive); however, pay attention that your camera is quite different from DSLRs.

First, you have a very small sensor, so need extremely short focals for big fields (there is no way you can fit Andromeda in your sensor with your 127/1000 powerseeker); second, your camera has very small pixels, meaning that every kind of tracking error will be "magnified" if compared to DSLRs.

Another set of issues arises from the telescope itself: as far as I remember the Powerseeker does not have the polarscope, so more than intrinsic tracking error would be the lack of accuracy in the alignement to the pole the true limit of your exposures; furthermore, the optical tube itself has a rather slow focal ratio and a long focal (with these premises one would likely wish for a very fast lens/optical tube, with a short focal length)

 

Anyway, while I wold never suggest to purchase a setup such as yours fro deep sky AP, since already own all the pieces think that the best option is just to try.



#10 cmooney91

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Posted 19 August 2019 - 12:42 PM

The 1 axis drive should technically work, but as others have said, with the small sensor and longer scope it will be hard to find and center objects.

 

Check out  SharpCap Live stacking.

With the ASI224 you can use short 4-16 second exposures which are very forgiving to tracking errors.  You can also set it up to auto reject bad frames. 

 

It would be beneficial to use a cheap 0.5X focal reducer for both a wider FOV and shorter exposures, If you can still reach focus with it.

The small sensor is very tolerant of focal reduction.

 

Also check out OnStep. You can convert your EQ-5 to full GoTo with WiFi/BluTooth/USB for less than the basic 1 axis DC drive costs. With a computer you could even plate solve to land DSO on the small sensor if needed. (I've never needed to)

 

I use a 224 knockoff camera, with a 4.5" F4 newt on an Onstep converted old Super Polaris.  I use it for EAA, I don't expect APoD quality, I just want  to see more than I can visually, and it's nice to have some pictures I can share with friends. I am  really happy with the results.

 

I usually use 8 second exposures. I've never felt it necessary to guide.  I even have a second 290 mono cam with a wide field lensesthat i could guide with, but i'd rather use it as a second wide field FOV for fun.

 

I started out with short f.l. fast 25-50mm F1.4 C-mount lenses on a stationary tripod to get the hang of live stacking, then I moved to the small newt on a GEM.  Currently planing to OnStep my 10" Dob for EAA.

 

 

That 224 sensor is amazing for short exposure live stacking, you will succeed one way or another. 



#11 PirateMike

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Posted 19 August 2019 - 12:42 PM

A Sky-Guider   https://www.youtube....8&v=LaxEYTBeSp8

 

 

Miguel   8-)

 

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#12 17.5Dob

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Posted 19 August 2019 - 10:22 PM

Your 224 is a micro chip sized camera. I wouldn't even try using it for DSO's . Keep it for lunar /planetary use and just buy a small camera tracker ($299) and a dSLR and kit lens ($700 or less) for DSO's.


Edited by 17.5Dob, 19 August 2019 - 10:23 PM.



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