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Post pics taken with Celestron Evolution scopes

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#26 lenrabinowitz

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Posted 27 November 2015 - 11:27 AM

Are you guys shooting through an eyepiece or any filters?  I have begun experimenting with that.

 

You guys are to be congratulated on turning out some good shots, (above).  :bow:  :bow:

 

Perhaps bear in mind though, that "shooting" is only a lesser part of the overall technique where, if the captured image has potential, processing will pay a very major roll in exploiting this.

 

In my view, I think the essentials are:

 

1) Whether you take your shots at prime or a-focus is irrelevant, but try to accumulate a reasonable number of frames for stacking. This will increase your signal to noise ratio and thus produce a smoother, "cleaner" image for processing.

 

2) If possible, use a software package rather depend purely on any DSLR camera to accumulate your selected number of frames or video. By its use, .you can see now much better the image appears on the "widescreen" before capturing it, (i.e. its brightness, contrast, colour, focus etc.) and thus be in a position to adjust easily, any one or more of these properties should it be necessary.

 

3)  Decide and concentrate upon getting a good image of one perhaps two objects only on any given night. Flitting from object is not to be recommended as I recall to my own cost !

 

4) Learn the basics associated with stacking and processing.

 

Registax is an ideal tool for stacking and processing lunar and planetary frames, while DSS, (Deep Sky Stacker), is great for DSOs. Both of these packages are free while to enhance the final, stacked image, Photoshop offer their excellent CS2 version as an equally free download.

 

Registax and DSS however, do not offer any DSO capture capability unlike Amcap, Sharpcap, Craterlet etc. do for planetary and lunar landscape frames. For this purpose, I personally use "Nebulosity" supplied by Stark Labs. but I gather there are other programs available depending on how much one wants to spend. Nebulosity costs, I believe, about $60 nowadays.

 

So, exampling Pugsx's lunar landscape above, which includes the crater Tycho, the attached gives some indication of what CS2 alone can do.

 

I hope it meets with your approval and that the above post may help you to increase your skills in astrophotography.

 

Best regards and keep 'em coming ! :waytogo:

Tel

Great stuff Tel- Thanks!

 

Not sure I agree on one thing.  In music, when recording (another hobby of mine), the more you play the thing right in the first place, the less you have to do later, and the better off you tend to be.

 

Wouldn't that also hold true in AP?  Get a good initial shot?

 

All thoughts appreciated.  Thanks!


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#27 Tel

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Posted 27 November 2015 - 12:35 PM

Hi Len,

 

No, because your aim, whether using a webcam, a DSLR or a CCD camera, is to reduce the inherent electronic noise generated by chip heat.

 

When capturing therefore, the effective way to carry this out is to take a reasonable number of frames at the same exposure which effectively raises the signal, (that which you want) to noise, (that which you don't want) ratio, to produce a well resolved image.

 

You will probably have noticed, that single frame images are normally somewhat grainy. Taking a number of frames of the same object and stacking them will largely remove this and also enhance resolution although in many cases you will probably need to combine these "Lights", as they are known, with "Darks" *, (which is another "story") ! 

 

And I still maintain that most of what can be derived from the image lies in the post capture. Just try it for yourself !   :waytogo:

 

Best regards,

Tel  :gramps:

 

* Darks. Frames taken with the 'scope capped off. This has the effect of highlighting only those "hot" pixels on the camera chip and again, once stacked, can be "subtracted" from the "Lights", thus basically removing these "hot spots".


Edited by Tel, 27 November 2015 - 12:37 PM.

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#28 lenrabinowitz

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Posted 27 November 2015 - 01:37 PM

Ok.  So it's more about capture signal, and get rid of noise later.

 

Would that include star trailing?  I've been assuming that I can't really go more than 30 seconds for ap with the Evo mount, but maybe that's not true?

 

You are the best Tel!  Thanks!  I'll give it a shot.



#29 Ekyprotic

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Posted 27 November 2015 - 01:45 PM

Stacking is the key- Tel is right.  Actually you cant go more than 30 seconds at wide angles with a tripod and no tracking mount, with the SE mount you can do 60 seconds or so.



#30 Ekyprotic

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Posted 27 November 2015 - 01:46 PM

Stacking reduces noise by a factor of the square root of the number of frames- stack 9 frames and the noise is 1/3, 25 frames and it's 1/5



#31 mclewis1

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Posted 27 November 2015 - 03:06 PM

Thanks for the feedback Mark!  I already have all of that stuff.  I think I am actually just going to try the new Evo Wedge.  Any thoughts on that, or wedges in general?

 

I am just barely a beginner in this.  Taken me eight months to get anything even remotely worth looking at.  Just now starting to think about processing.

Are you sure that the Evo OTA would fit on the VX?  If you look at the VX on Celestron's website, the bar looks to me a lot larger.

 

Also, I'm not sure you can get the VX mount without the tripod, or if the mount alone works with the Evo tripod.

 

All feedback appreciated.  Thanks! Len

Wedges are interesting creatures. They make the setup of an alt az scope more complicated (level tripod, mount wedge, add mount to wedge, add ota to mount). The adjustments are essentially the same as the physical alt az adjustments on a gem (the lattitude and azimuth or rotation adjustments). The difference is that there are a few more bolts to handle (for example one on each side of the altitude axis). You are also bolting the mount to wedge at an angle so you have to support the mount as you bolt it up, something you don't do with the alt az setup. This is going to be relatively easy with the Evolution ... you out to see what this is like with a large C11 and dual arm fork mount (GPS or CPC), that's 68lbs or so that you have to support at an angle while getting at least one of the 3 bolts in the base attached ... really fun in the dark. It will be much easier to just attach the Evo mount to the wedge and then add the ota.

 

So they are more "fiddly" (a highly technical term) to setup and that usually means more time before you are viewing/imaging. They also move the center of gravity around a bit and so you need to pay more attention to balance and being careful when bumping into the tripod. The other area to be careful of is balance of the ota. Folks who have a Hyperstar configuration with a camera hanging off of the front of the scope where the secondary mirror was have to be particularly careful not to release the altitude clutches and let the scope freely tip forward (the camera hits the base and this can break the corrector).

 

Once you are setup and have done a polar alignment you are essentially using a gem style mount ... only without any counterweights (very cool). Yes viewing around the pole is problematic (the base of the mount is in the way) but unlike the gem the fork/wedge combination will track across the sky with no meridian flip required (something serious imagers really appreciate).

 

For someone moving from an alt az oriented scope to wedge mounting you'll likely find the motions strange up/down and left/right are now really angled and often a bit disorienting when you are slewing around looking for an object. On the other hand when you move back and forth from a map you'll start to appreciate the EQ orientation.

 

Then of course there's the big benefit of smooth accurate tracking of any object (assuming a good accurate polar alignment has been done). Point at something, center it and then start shooting, the object will stay put and your images can now go beyond 30-45s without any concern about field rotation and such.

 

Overall like most things with these scopes/mounts you'll find thing get much easier and more accurate with some practice .... experience is one of the most valuable things you can acquire.

 

--------------

 

Yes I'm sure about the EVO  dovetail bar fitting the AVX saddle. There are two popular bar/plate styles ... the narrower CG-5/Vixen ones and the wider flatter Losmandy D style plates. The AVX uses a CG-5/Vixen saddle. You will likely see different thickness Vixen bars and there is a strange flat style one (a lot of folks don't initially think it's a dovetail bar when they first see it) that is often used on low end gem style mounts (it often comes with the mount). This flatter bar is still a CG-5/Vixen compatible and will usually fit in any CG-5/Vixen compatible saddle. You may also see wider saddles on AVX mounts ... ADM makes a really nice dual saddle which is a wider saddle with cutouts for both CG-5/Vixen and D style bars/plates.

 

Celestron uses extruded orange dovetail bars (for either size setup) that look a little different than a solid bar ... but the important dimension (1.75" at it widest point) is still the same as other CG-5/Vixen bars.

 

------------

 

You really want the AVX tripod, it's a nice solid model with 2" steel legs and that helps with overall stability (important with a gem style mount because of swinging the counterweight around). What would be really cool is if you could use both the Evo and AVX mounts on the AVX tripod (this would be possible only with some form of adapter). For now though it's two separate tripods.


Edited by mclewis1, 27 November 2015 - 04:18 PM.

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#32 John59

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Posted 27 November 2015 - 04:44 PM

Here is a good review on the EVO 9.25 to include the use of a wedge.

He shows an unguided photo with 2.5 minutes of exposure.

 

http://astronomynow....on-9-25-review/



#33 johnoelliott

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Posted 27 November 2015 - 05:18 PM

Here is my first ever attempt. from my balcony in Toronto

Evo 9.25 f/6.3

Canon 60D and BYEOS

54 x 20 sec lights

5 darks

Used DSS to stack and Photo Shop

 

Orion First Attempt

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#34 mclewis1

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Posted 27 November 2015 - 05:29 PM

John, That's a wonderful image ... and even more so as a first attempt.

 

DSLR - check

SCT reducer - check

camera control/image acquisition software (BYEOS) - check

stacking software (DSS) - check

image processing software (Photoshop) - check

stacking shorter exposures in alt az mode - check

 

Further proof that you can indeed get great images from a good alt az setup.


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#35 lenrabinowitz

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Posted 27 November 2015 - 05:49 PM

Actually my music a analogy holds but I had it wrong.

The camera isn't the sound coming out of the speaker- it's the mike I front of it recording the sound. And yes you want as much gain as possible and you eliminate any noise later. So Tel wins!

#36 Jim4321

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Posted 27 November 2015 - 07:19 PM

Outstanding work, y'all!  I doubt I'll ever venture into these waters, I just don't have the patience for post processing.  Besides, I'm spending my few moonless clear nights doing visual.  

 

Jim H.



#37 pastortim

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Posted 27 November 2015 - 10:31 PM

here is an image of M2 taken from my driveway with a street light at the end of drive

 

5-40sec processed with registack

 

fr 6.3,  8" evo,  mllincam micro ex

 

M2

Edited by pastortim, 28 November 2015 - 10:33 AM.

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#38 lenrabinowitz

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Posted 28 November 2015 - 08:14 AM

Very pretty!  Sometimes I like this sort of image better then the "blow you away" ones.



#39 lenrabinowitz

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Posted 30 November 2015 - 06:24 AM

The Pleiades last night.  Single shot unprocessed, 20 second exposure at 800 ISO.

 

Questions:  Do any of you guys attach the camera to a lens and use filters?  I'm curious about that- I tried it the other night but not enough light getting through.  What setting do you use?

 

Thanks!

 

Len

Attached Thumbnails

  • IMG_9853.JPG

Edited by lenrabinowitz, 30 November 2015 - 06:24 AM.

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#40 mclewis1

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Posted 30 November 2015 - 09:34 AM

Len,

 

The Pleiades is huge, to image it all you want a field of view in the one degree + area ... that's only something you can usually get using a telephoto lens or a smaller refractor and a camera with a relatively large sensor (~800mm focal length with an APS-C sensor camera for example). The nebula in the cluster is also a reflection type (why it's quite blue) and quite tough to image well, it gets easily knocked down by light pollution and most filters also have a tough time with it.

 

Generally you want less glass in the optical path so going afocal (camera with a lens connected to an eyepiece) isn't the preferred setup when you are going after faint stuff ... for small bright planets or lunar/solar details it works fine but for most DSOs it usually isn't a good idea. Afocal usually magnifies the image too much creating too small a field of view.

 

- connect a camera without any lens in place directly to your scope (no eyepiece either). T thread adapters or 2" barrel type are popular for DSLR type of cameras. For cameras with smaller sensors (video cameras or similar) then 1.25" barrel attachments are popular.

- lower your f ratio as much as possible/practical - use a focal reducer. This speeds up the whole setup (more sensitive so less exposure time is required) and shortens the focal length (makes it easier on the mount tracking wise). Also remember that with faster f ratios/shorter focal lengths the objects will be smaller and that can make it tough to image smaller objects (planetary nebulae, smaller galaxies, etc.). This is all a trade off (fast speed vs. smaller object imaging) so many folks will use a variety of scopes (with different focal lengths) to go after a variety of objects. If you don't have the luxury of multiple scopes you'll need to match the type of object to your particular setup. 

 

So for example your 8" SCT isn't going to be a good wide field scope for big extended objects like the Pleiades, or M31 but will be a good choice with a focal reducer for many globular clusters, many galaxies and popular nebula like M42, M7, M8, etc.

 

If you want to plan some of potential targets with an idea about the field of view I'd download a copy of CCDCalc and setup the program with your particular telescope (aperture and focal length), focal reducer and camera sensor data (you need to know the number of and size of the pixels). I think you'll find it really interesting matching various configurations to the popular DSOs.


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#41 lenrabinowitz

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Posted 30 November 2015 - 02:33 PM

What a great detailed response!  Thank You!  A couple of things:

 

1.  Should have mentioned that I was using a focal reducer- the cheaper Celestron one.  Can't remember the specs.  For this I was using a Canon 60d attached with a t ring.  

 

2.  The less glass the better.  Got it.  Like recording music- the less in the signal path the better.

 

3.  So if I want to try something like M31 or planetary nebulae would it be better without the focal reducer?

 

4.  I'll look at the website.  Thanks!

 

5.  What about just using filters like say a light pollution reducer, or an O III?

 

6.  I will look at the website, but can anyone make a suggestion about a galaxy to try?  M31 is the only one I've seen; but right now its straight overhead; I can't get there!  

 

Thanks!


Edited by lenrabinowitz, 30 November 2015 - 02:37 PM.


#42 lenrabinowitz

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Posted 30 November 2015 - 02:35 PM

I have a Rokinon 35mm manual focus lens.  I think I will try the Pleiades by just attaching that to the camera, maybe some of the galaxies too.  I can mount the camera on the telescope.



#43 lenrabinowitz

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Posted 30 November 2015 - 02:47 PM

One more question:  I was using the Evolution with a Canon 60d.  20 to 30 second exposures, 800 or 1600 iso both depending on object.  With an alt az setup, would I be better off using shorter exposures with higher iso, say 10-15 seconds, 1600 to 3200 iso?  Thanks!



#44 Tel

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Posted 01 December 2015 - 06:23 AM

Hi Len,

 

Do, as Mark recommends and download the "New Astronomy Press CCD calculator. It will definitely give you an insight into what will fit into the fields of view your 'scope can produce with and without your focal reducer combined with your DSLR camera.

 

Here's the link:

 

http://www.newastro....camera_app.html

 

Secondly, experiment with exposure times with and without the reducer in place. I doubt though that you will be able to exceed ca.30 seconds by much before field rotation becomes obvious but at least you'll know how far you can push your set-up.

 

Thirdly, if you regard yourself as a novice imager, then use the reducer as much as possible and if you are at present only capturing single frames, use a low, rather than high, ISO setting. True, the resolution will be greater the higher the ISO number but equally so, the single frame will be electronically noisy, (very grainy).

 

If you want to use a higher ISO number with its accompanying better resolution, then take something like 20 frames at the same exposure time, stack them and process them, using, for example, the free downloads,. Deep Sky Stacker followed by Photoshop CS2. Once used to this, we can then talk "Darks" and if necessary the additional taking of "Flats" but for now, try to familiarise yourself just with stacking and a little processing.

 

Fourthly, forget filters at this stage. Try to concentrate on exposure times versus field rotation, multi-frame stacking and processing. The basics are easily learned and the results will give you a lot more satisfaction than hitherto. 

 

Best regards,

Tel

 

BTW. If you download the CCD calculator, you'll see that there's no way M31 is going to fit your set-up in its entirety, with or without a focal reducer, but then that's the beauty of the calculator !


Edited by Tel, 01 December 2015 - 06:24 AM.

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#45 lenrabinowitz

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Posted 01 December 2015 - 06:53 AM

Thanks Tel!  Will do and will get back to you.  As one of your fellow Brits said "It's getting better all the time!"

 

Len



#46 lenrabinowitz

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Posted 01 December 2015 - 06:55 AM

Actually the last time out I took about 20 images of each.  Haven't tried stacking yet.  I did take a set of darks as well.



#47 Tel

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Posted 01 December 2015 - 07:17 AM

Bravo, Len !

 

It all sounds like it's coming together nicely !

 

Incidentally in what format are you capturing your images ? 

 

I know that you have to "post" them here on CN in Jpeg format but capture, followed stacking, should be made in RAW (FITS) format.

 

It may not however be possible to Photoshop process in FITS without going through "FITS Liberator" software, but the way around this is to capture and stack your DSOs in FITS format and then convert the stacked image to Tiff format in Registax for further process it in Photoshop.

 

I'm afraid there are a few basic little "tricks" to be learned in this facet of our hobby, but, as they say, "Once you know 'em, you never forget 'em" !

 

Best regards,

Tel


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#48 lenrabinowitz

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Posted 01 December 2015 - 11:53 AM

Thanks Tel!  Yeah, it is coming together.  (Ok now I have "come together" in my head!). 

 

The camera takes pictures in RAW and jpg simultaneously.  I post the jpgs.

 

With 20 30 second images I did notice them moving in the field of view, so I am considering getting the Evo wedge.

 

All help appreciated!



#49 lenrabinowitz

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Posted 01 December 2015 - 11:56 AM

I have DSS.  I couldn't find photoshop CS2.  Anyone have a link?  Thanks!



#50 WarmWeatherGuy

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Posted 01 December 2015 - 12:01 PM

Different parts of the sky have different field rotation rates. Pick targets that are east or west. The highest rate is directly overhead.




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