Jump to content


Photo

Imaging with the Celestron AVX?

  • Please log in to reply
40 replies to this topic

#1 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1194
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 01 July 2013 - 12:08 PM

I've had my eye on the AVX since it came out. I'm thinking of getting this mount while it's on sale.

What would be a good scope to pair with this mount, to do mainly deep space imaging with a DSLR?

#2 CounterWeight

CounterWeight

    Cosmos

  • *****
  • Posts: 8237
  • Joined: 05 Oct 2008
  • Loc: Palo alto, CA.

Posted 01 July 2013 - 12:35 PM

just wanted to ask a question back. DSO include both in our galaxy and outside it. In our galaxy are the beautiful nebula(HII regions, emission, reflection), clusters, asterisms. Outside it are the other galaxies and galaxy groups. So when you say DSO it still requires a bit more thinking.

Deciding on a scope best for the objects considered I just want to recommend the two parameters to consider are 'fast' focal ratio, and 'flat'. Scope sometime are one without the other, and getting the 'flat' part requires another piece of the puzzle.

That said - there's learning to image ;), and my standard recommendation is a short fast widefield refractor (with a field flattener) and any/all adaptors, rings, extender tubes. That and an autoguider like the Orion miniguider/SSAG using PHD software.

#3 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1194
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 01 July 2013 - 12:46 PM

just wanted to ask a question back. DSO include both in our galaxy and outside it. In our galaxy are the beautiful nebula(HII regions, emission, reflection), clusters, asterisms. Outside it are the other galaxies and galaxy groups. So when you say DSO it still requires a bit more thinking.


Well, both but I do understand that different FOV requirements require different scopes (or significant cropping, and thus lower resolution). If I had to prioritize, I'd say that other galaxies > local DSOs. For larger DSO's maybe I could just throw my camera on the mount with the 70-200 f/4 lens. With the 1.4x telextender I can get 280mm at f/5.6. Not sure how that compares to a widefield refractor - but I guess that lens *is* a widefield refractor :grin:

#4 Madratter

Madratter

    Fly Me to the Moon

  • *****
  • Posts: 7150
  • Joined: 14 Jan 2013

Posted 01 July 2013 - 01:29 PM

In my opinion, the AVX is decidely non-optimum for galaxy imaging. I did this with the CG-5 and although the AVX is somewhat better, it still does not have roller bearings in the declination axis.

That makes guiding at longer focal lengths problematic unless your polar alignment is very good (which is what I did with the CG-5).

I got an Atlas and the difference is large. However, if portability is a concern, an Atlas is portable only in the loosest sense.

#5 cn register 5

cn register 5

    Viking 1

  • -----
  • Posts: 760
  • Joined: 26 Dec 2012

Posted 01 July 2013 - 02:46 PM

Condemning a mount, untried, because of some prejudice about its construction with experience of what it can do seems deeply irrational to me.

The reality, from someone who has used it, is that the AVX guides excellently, far better than the CG-5. The improvements that Celestron have made allow this.

The largest mount I've used is a 6" F/9 RC with a ST80 piggybacked as a guider, total weight 25lbs.

Chris

#6 Jeff2011

Jeff2011

    Vanguard

  • *****
  • Posts: 2010
  • Joined: 01 Jan 2013
  • Loc: Sugar Land, TX

Posted 01 July 2013 - 02:47 PM

I can add to what the Madratter is saying in that I encounter a lot of problems during guiding with the declination. I finally had to resort to finding which way it was drifting in Dec and set PHD to send commands only in the opposite direction. This helped a lot, but I agree that this mount is not optimal for longer focal length scopes.

I don't know how the Orion Sirius mount stacks up, if you are looking for a more portable mount. Perhaps someone with experience with this mount can comment.

Edit:
I agree that this mount is not optimal for a beginner with longer focal length scopes.


#7 WarmWeatherGuy

WarmWeatherGuy

    Surveyor 1

  • *****
  • Posts: 1914
  • Joined: 27 Aug 2011
  • Loc: Orlando, FL 28° N, 81° W

Posted 01 July 2013 - 03:01 PM

I've had my eye on the AVX since it came out. I'm thinking of getting this mount while it's on sale.

What would be a good scope to pair with this mount, to do mainly deep space imaging with a DSLR?


The AT72ED. You might want to also get a field flattener after you get some experience taking and processing the images.

https://www.astronom...scope-black_...

Here is a picture I took with that scope.

http://www.astrobin.com/25052/

The scope is relatively small and light, fast (f/6), and has a wide field of view (focal length = 432mm). These things make it easy to get great pictures. There are many targets that require such a scope so it is not like training wheels where you discard them when you're done. This will be a scope you will want to keep even after you decide to use longer lenses.

#8 CounterWeight

CounterWeight

    Cosmos

  • *****
  • Posts: 8237
  • Joined: 05 Oct 2008
  • Loc: Palo alto, CA.

Posted 01 July 2013 - 03:03 PM

Steve that is a great point. I remember something though about was it the 72 that had no accommodation for a finder / miniguider out of the box? If I am incorrect please let me know. There are many 80mm scopes that do.

#9 Jeff2011

Jeff2011

    Vanguard

  • *****
  • Posts: 2010
  • Joined: 01 Jan 2013
  • Loc: Sugar Land, TX

Posted 01 July 2013 - 03:09 PM

Jim,

You are correct. I added a synta/orion style finder mount from Scope Stuff to my AT72ED.

The iphone pic is a little fuzzy, but here is my setup with the 72. The mini came with a finder mount, but the Scope Stuff one fit better.

Also, I had some issues with some focuser droop, so I added a 2" extender so that I don't have to draw the focuser back that far.

Attached Files



#10 WarmWeatherGuy

WarmWeatherGuy

    Surveyor 1

  • *****
  • Posts: 1914
  • Joined: 27 Aug 2011
  • Loc: Orlando, FL 28° N, 81° W

Posted 01 July 2013 - 03:11 PM

Steve that is a great point. I remember something though about was it the 72 that had no accommodation for a finder / miniguider out of the box? If I am incorrect please let me know. There are many 80mm scopes that do.


Yes, that is true, and it is certainly an obstacle to overcome. I use a side-by-side system and hadn't thought of that. Thanks for reminding us.

#11 Madratter

Madratter

    Fly Me to the Moon

  • *****
  • Posts: 7150
  • Joined: 14 Jan 2013

Posted 01 July 2013 - 03:54 PM

Condemning a mount, untried, because of some prejudice about its construction with experience of what it can do seems deeply irrational to me.

The reality, from someone who has used it, is that the AVX guides excellently, far better than the CG-5. The improvements that Celestron have made allow this.

The largest mount I've used is a 6" F/9 RC with a ST80 piggybacked as a guider, total weight 25lbs.

Chris


I guess I'm going to have to stick with that irrational label. For what it is worth, I have read considerably about the mount including posts by you before coming to this conclusion.

At the end of day, however, it is just an opinion.

EDIT: I'll add that I read the AVX mount threads with a great deal of interest since I wanted to get something that was better suited for imaging than my CG-5. I ended up buying the Atlas despite the fact it meant a much bigger outlay in money. And the money certainly was a consideration. So in this particular case, my opinion, although apparently irrational, did directly influence my own behavior. In other words, I put my additional money where my mouth is.

#12 JoseBorrero

JoseBorrero

    Gemini

  • *****
  • Posts: 3210
  • Joined: 04 Sep 2009
  • Loc: Puerto Rico Island

Posted 01 July 2013 - 06:31 PM

Look great! just need to survive dew :waytogo:

Jim,

You are correct. I added a synta/orion style finder mount from Scope Stuff to my AT72ED.

The iphone pic is a little fuzzy, but here is my setup with the 72. The mini came with a finder mount, but the Scope Stuff one fit better.

Also, I had some issues with some focuser droop, so I added a 2" extender so that I don't have to draw the focuser back that far.



#13 Jeff2011

Jeff2011

    Vanguard

  • *****
  • Posts: 2010
  • Joined: 01 Jan 2013
  • Loc: Sugar Land, TX

Posted 01 July 2013 - 11:21 PM

Two other accessories I forgot to mention. A 7 inch vixen dovetail bar and a 7.5 lb counter weight. The dovetail bar provided for better balancing, and the 11 lb weight that came with the mount was too heavy for this configuration. I got the 7.5 lb weight from Orion.

#14 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1194
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 02 July 2013 - 09:22 AM

The largest mount I've used is a 6" F/9 RC with a ST80 piggybacked as a guider, total weight 25lbs.


The two recs I got here so far (AT6RC and AT72ED) were the two I was looking at. I guess I'm on the right track. Didn't find too many posts on the RC, though... Maybe I was looking in the wrong place? Where do those users hang out? Or is it not very popular because it is so specialized?

#15 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1194
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 02 July 2013 - 09:27 AM

We all know there are bigger, better mounts for more money. I asked a specific question and I'd love to hear (and see images) from people who already use the AVX for astrophotography.

Not going to spend 3x for an Atlas.

#16 Madratter

Madratter

    Fly Me to the Moon

  • *****
  • Posts: 7150
  • Joined: 14 Jan 2013

Posted 02 July 2013 - 09:43 AM

That is of course your choice. But my comments were and are directed at the question you asked. Specifically, the mount will be a good match for the AT72ED. However, in my opinion, it is not a good match for galaxies and it is not a good match for an AT6RC at F/9.

If you ask for advice, don't shoot people when they give it to you, whether it is what you want to hear or not.

You can go to the Mount forum today and read a message from someone who has this mount that wishes it had roller bearings on the declination axis. I'll save you the effort of finding it. See the post by ETXuser here:

http://www.cloudynig...5945171/page...

In addition, with the AT6RC you are going to be pushing the weight. Although the mount is rated for 30 pounds, the rule of thumb is those weights are for visual use. For imaging the rule is you normally chop it in half. Once you add in the other equipment like cameras, etc., you will probably be well over the 15 pounds that would be half.

That is not to say it can't be made to work. Specifically, any wonkiness (technical term) in the declination axis can always get fixed with better polar alignment. But in my opinion, you are setting yourself up for some grief, especially if you tear down and setup every night.

EDIT: As for images, see this link for various examples on Astrobin:

http://www.astrobin....on-advanced-vx/

#17 Jeff2011

Jeff2011

    Vanguard

  • *****
  • Posts: 2010
  • Joined: 01 Jan 2013
  • Loc: Sugar Land, TX

Posted 02 July 2013 - 10:23 AM

At a focal length of 430mm the AT72ED is meant for wider angle shots like nebulas. To get good nebulas, you will need a modded DSLR or a CCD.

I originally had plans to get an AT6RC. At 13 lbs plus accessories the mount should be able to handle the weight just fine assuming you go with the mini guide scope option. The problem I have with that scope is its slow speed at F9. Since this scope has been out of stock it has given me time to think and I have now ordered an AT6IN (Imaging Newt). At F4 it is very fast. Coma comes into play, but I already have a baader coma corrector. The focal length is still short at 610mm, but I think this scope is a good compromise. Last I looked Astronomics still has these in stock and at a price less than what I paid for my guide camera. As an initial learning scope the AT72ED is the way to go. Plus I use my AT72ED as a grab and go and at my clubs outreach events. It is a good all around scope.

The Dec problem with the AVX that Madratter talks about is a real issue that I have encountered. I have been able to mitigate this by configuring PHD only to send guide commands in the direction opposite of the drift. Before I did this the Dec swung wildly. When switching directions in Dec the mount took so long to react that it messed up PHD.

All of the following images were taken with my AVX mount. I am just a beginner, so take that into consideration.

http://www.flickr.co...57633228178182/


#18 Holltim4103

Holltim4103

    Explorer 1

  • *****
  • Posts: 81
  • Joined: 25 Feb 2013
  • Loc: Plattsburgh, NY

Posted 02 July 2013 - 11:10 AM

I absolutely love my AVX mount. I primarily use an Orion 8 inch Newtonian F3.9 with a Canon XSI (450D - not modified). It is a heavy setup however I can regularly get 180 second unguided subs with a good polar alignment. (I use BYEOS to get a precise polar alignment with the ASPA in the hand controller) I can image galaxies but I especially love imaging nebulas with this setup. I also have an Orion PIAG but haven't used it much because I find it more of a pain to use as I am still learning how to use it.

#19 John Miele

John Miele

    Surveyor 1

  • *****
  • Posts: 1966
  • Joined: 29 May 2005
  • Loc: North Alabama

Posted 02 July 2013 - 12:58 PM


The largest mount I've used is a 6" F/9 RC with a ST80 piggybacked as a guider, total weight 25lbs.


The two recs I got here so far (AT6RC and AT72ED) were the two I was looking at. I guess I'm on the right track. Didn't find too many posts on the RC, though... Maybe I was looking in the wrong place? Where do those users hang out? Or is it not very popular because it is so specialized?


Hmmm...as other have noted, these are two VERY different scopes for VERY different types of imaging goals. As a beginner I'd get the AT72 and then later compliment it with the AT6 after you know what you are doing and have vetted out your mount and guiding skills...John

#20 WarmWeatherGuy

WarmWeatherGuy

    Surveyor 1

  • *****
  • Posts: 1914
  • Joined: 27 Aug 2011
  • Loc: Orlando, FL 28° N, 81° W

Posted 02 July 2013 - 02:06 PM

Jim,

You are correct. I added a synta/orion style finder mount from Scope Stuff to my AT72ED.

The iphone pic is a little fuzzy, but here is my setup with the 72. The mini came with a finder mount, but the Scope Stuff one fit better.

Also, I had some issues with some focuser droop, so I added a 2" extender so that I don't have to draw the focuser back that far.


How did you attach the guider to the OTA? On my AT72ED there is only a single, very tiny, screw which looks like it is meant to hold the telescope together, not to attach something to it with.

If it is from ScopeStuff could you provide a link?

Thanks.

Attached Files



#21 Jarrod

Jarrod

    Apollo

  • *****
  • Posts: 1194
  • Joined: 20 Jan 2013
  • Loc: SE USA

Posted 02 July 2013 - 02:19 PM

If you ask for advice, don't shoot people when they give it to you, whether it is what you want to hear or not.


I do appreciate the advice about imaging galaxies. However, I've seen what I consider good results coming from even the older CG5 mount.

Case in point:

http://www.astrobin.com/42164/

Look familiar? ;) Perhaps over time my tastes would change and I'd wish for a better mount. Probably. Isn't that how it works? :grin:

You can go to the Mount forum today and read a message from someone who has this mount that wishes it had roller bearings on the declination axis. I'll save you the effort of finding it. See the post by ETXuser here:


And I wish the Atlas cost half as much, weighed half as much, and still had the same performance :grin:

At some point, there has to be a compromise - everything is a compromise. Mine was that I wouldn't pay more than $800 for a mount that could do "respectable" AP.

I was wrong about the Atlas costing >$2k (must have been thinking of the new EQ/AltAz combo). In reality, it is "only" twice the price of the AVX. That's actually not as bad as I was thinking. But still, I could have the AVX, the AT72ED *and* the AT6RC (or a C6, which I've been waiting for someone to mention) for the price of an Atlas. If I get good at drift aligning with the AVX, I believe I could get good results even with longer focal lengths. Am I wrong?

#22 Jeff2011

Jeff2011

    Vanguard

  • *****
  • Posts: 2010
  • Joined: 01 Jan 2013
  • Loc: Sugar Land, TX

Posted 02 July 2013 - 02:20 PM



http://www.scopestuff.com/ss_rdpb.htm

Edit(It was RDPT an M6 screw). Yes there is only one hole. The screw is a 6mm, so it is fairly strong. The screw that comes with it was a bit long, but you can cut it or get another screw from a home improvement store. The pamplet that came with the scope (if you bought it new), shows where a finder can be mounted. There are two places you can mount it. One on the tube where I mounted it and one on the part that rotates the focuser, just behind where I mounted it.

#23 WarmWeatherGuy

WarmWeatherGuy

    Surveyor 1

  • *****
  • Posts: 1914
  • Joined: 27 Aug 2011
  • Loc: Orlando, FL 28° N, 81° W

Posted 02 July 2013 - 02:36 PM

http://www.scopestuff.com/ss_rdpb.htm

Edit(It was RDPT an M6 screw). Yes there is only one hole. The screw is a 6mm, so it is fairly strong. The screw that comes with it was a bit long, but you can cut it or get another screw from a home improvement store. The pamphlet that came with the scope (if you bought it new), shows where a finder can be mounted. There are two places you can mount it. One on the tube where I mounted it and one on the part that rotates the focuser, just behind where I mounted it.


Wow, that's great. You have a complete auto-guiding system without breaking the bank.

I guess I should have looked at the manual.

https://www.astronom... at72ed manu...

It says those holes are for mounting stuff.

Thanks for the link to ScopeStuff, and for the picture of your gear. A picture IS worth 1,000 words.

#24 Madratter

Madratter

    Fly Me to the Moon

  • *****
  • Posts: 7150
  • Joined: 14 Jan 2013

Posted 02 July 2013 - 02:56 PM

If I get good at drift aligning with the AVX, I believe I could get good results even with longer focal lengths. Am I wrong?


If you have an observatory, you absolutely can using drift aligning to take the declination out of the issue to some level of tolerance.

Alternatively, you might find that all star polar align will get you close enough for some equipment.

I found my CG-5 would start to give somewhat useable results if I was within a minute or two of the pole. The AVX probably can do somewhat better than that.

For example, I was able to get 10m guided Ha at 2x2 binning with my Celestron C8 and f/6.3 focal reducer at 1260mm.

Here is an example: http://www.astrobin....233/0/?mod=none

However, it is also correct to say that I struggled with this equipment and lost more frames than I liked because of it. Part of that was declination issues, part of that was due to too much weight on the mount (which would be an issue with the AVX too), part of it was periodic error being somewhat irregular, part of it was wind gusts, part of it was vibration damping.

What I can say for sure is that when I went to the Atlas, my pictures instantly improved. I'm sure I would have seen "some" improvement with the AVX. But at the end of the day, after reading a boatload on the new mount, I decided the Atlas was the way for me to go.

On the other hand, if I was imaging with a 72 ED, I'm positive the CG-5 (let alone an AVX) would have been more than good enough for it.

And the Atlas is certainly not a grab and go mount, at least for me. I wouldn't even consider it without an observatory.

Also, you might want to consider the iOptron Z mount. I'm hearing good things about it and the cost is only slightly higher than the AVX. There is a ton of info on it over in the mount forum.

#25 Jeff2011

Jeff2011

    Vanguard

  • *****
  • Posts: 2010
  • Joined: 01 Jan 2013
  • Loc: Sugar Land, TX

Posted 02 July 2013 - 02:57 PM

Steve,

Glad to help. Makes me feel good to be able to help out after all the great help I have received from this forum.

While you are ording from ScopeStuff, you might want to pickup one if these if you don't already have one. Remember the focuser droop I spoke about. This adapter seems to solve that.

http://www.scopestuff.com/ss_eet2.htm

The #ET35 is all you should need.

Disclaimer: I am not affiliated with ScopeStuff. I just think they have great stuff!






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics