The chad EQ5 vs The almighty AVX

[LR Watanabe]

Okay, hi.

I need to ask a question–

Is imaging with a Evostar 72ED on a SW EQ5 even feasible?

So I recently I just bought myself the EQ5 and a SW 150 PDS, and after browsing through countless forums, etc., I realised how big of a mistake it was to get the 150 PDS– I thought it'd be able to take fantastic astro-images of faint DSOs, and boy I was wrong! My imaging set up, when placed on the 150 PDS, will literally exceed 7kg– far above the recommended 5 kg!

And so I chose to do the only logical-seeming choice– saving up money in order to add 2 dual axis motor drives and a SynScan GOTO for the EQ5!

But alas, I'm thwarted by 2 options once more– do I wait one year, for the end-of-the-year sale, and upgrade the naked EQ5 or do I wait one year, sell my EQ5, and get myself a Celestron AVX?

I'm really leaning towards the upgrading of my EQ5, but you lads are far more superior when it comes to Astro-imaging setups.

Just know that I'll probably be imaging with the Evostar 72ED.

 

Some other questions are–

If I choose to go the EQ5 way, how many minutes of exposure will my mount manage before star trails obliterate my astro-images? (Using the 72 ED, of course.)

Same question, but instead of using the 72ED I use the 150 PDS.

 

P.S. I can't buy the HEQ5 here in Japan, they don't sell it!

P.P.S After the upgrading of the EQ5/the purchasing of the AVX, I'll start saving up money for the ultimate EQ6R.

 

Clear skies,

Leon.

?

 

[JRWASTRO]

2 hours ago, LR Watanabe said:

Some other questions are–

If I choose to go the EQ5 way, how many minutes of exposure will my mount manage before star trails obliterate my astro-images? (Using the 72 ED, of course.)

Same question, but instead of using the 72ED I use the 150 PDS.

The answers to the above questions are involved andPolar_Alignment_Barrett.pdf may be found by referring to the work of Frank Barrett :-

Determining Polar Axis Alignment Accuracy (2nd Edition 9/21/2016)

Equation 12 is a "good start" Equation 13  tells us about field  rotation.

Attached are the works of Barrett and Richard N. Hook of the BAA which was referred to by Barrett.

Jeremy.

Polar_Alignment_Hook.pdf

[LR Watanabe]

I appreciate your effort, but sadly, a 12 year old can't handle so much maths.

Either way, I took a peak through the PDFs and grasped a slight understanding.

Thanks for helping out, JRWASTRO!

[catburglar]

Leon

I think it’s difficult to answer your questions precisely because each EQ5 and drive set will  have been machined/assembled to a different level of accuracy. Also, the size of the pixels in the camera you are using will have an impact because if you’ve got a camera with large pixels the errors in the drive may be less apparent than if you’ve got small pixels.

 

I’m guessing that you’re using a DSLR and that you don’t have a guide scope/camera in your setup. I think you’d be lucky to get much longer than two-3 minute exposures with the ED72 (focal length is 420mm) and probably around half that with the SW150 (focal length is 750mm).

if you can get rally good polar alignment and your drives have low periodic error then you may do better, but the only way to know for sure is to give it a try.

 

Good luck

john

[LR Watanabe]

Oh, forgot to mention–

I WILL be using an autoguider– a shop made 60mm F/4 and a ZWO ASI 120mm MINI mono

How much of a difference will that make?

 

P.S. Is the 4.3 macrons on the Canon Rebel T3i small?

[cletrac1922]

Leon

I am running a ED80 on EQ5 mount, with SynScan

I would not throw money at your existing EQ5 mount, rather updating to HEQ6 mount

The attached pic was taken a solar viewing day with my club, shows my ED80 on EQ5 mount

In background is another ED80 on a HEQ5 mount

I also use my EQ5 mount with my Coronado SolarMax 11

John

 

 

 

[LR Watanabe]

I would, but they don't sell the HEQ6, too.

Only thing near that is a EQ6R.

Can't afford it though.

Not for now.

 

Clear skies,

Leon.

 

btw nice setup

[cletrac1922]

Lean

Perhaps can order from Australia

Link to my local astronomy retailer

http://www.astroanarchy.com.au/mounts.html

Cheers

John

 

[Adam J]

7 hours ago, LR Watanabe said:

I would, but they don't sell the HEQ6, too.

Only thing near that is a EQ6R.

Can't afford it though.

Not for now.

 

Clear skies,

Leon.

 

btw nice setup

He meant HEQ5 pro there is no HEQ6 only NEQ6.

Am I correct in saying that your current mount does not have any tracking / motors? If so then I would sell it rather than add drive motors to it yourself. 

If it was a EQ5 pro and already had duel axis drives then I would say that an Evostar 72 ED would be a great choice of scope to get started in imaging. A much better choice on a low budget than a 150PDS that is going to be tricky for a beginner even if you had a HEQ5 pro mount.  

I would sell your current EQ5 mount, I would not upgrade it. 

For use with the Evostar 72 I would then suggest a true EQ5 Pro or a EQM-35 or a AVX mount if you can afford it.

If you want to use the 150PDS....and I dont recommend it for a beginner, then the AVX may scrape it, but I would want a HEQ5 pro myself.  

As you are probably starting to appreciate aperture is not as important in imaging as it is for visual work. I would wait and go with the best mount you can get in the next 12 months.  

There is always the second hand market if you want to save money....

 

Adam