Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Sky-Watcher Explorer 190MN DS-PRO + Celestron Off-Axis-Guider Deluxe + ZWO Camera ASI 294 MC Pro Color - Backfocus

  • Please log in to reply
15 replies to this topic

#1 jellyfish

jellyfish

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 17 Sep 2019

Posted 17 September 2019 - 11:32 AM

I'm wondering if any of you knowledgable people might know if the above setup will work. Not sure if the 190MN has enough back focus to allow the OAG and the Zwo camera.

 

Sky-Watcher Explorer 190MN DS-PRO +

Celestron Off-Axis-Guider Deluxe +

ZWO Camera ASI 294 MC Pro Color

 

Many thanks,

 

Michael



#2 John Miele

John Miele

    Gemini

  • *****
  • Posts: 3452
  • Joined: 29 May 2005
  • Loc: North Alabama

Posted 17 September 2019 - 01:08 PM

That should work ok.

 

I use an ASI071 with a Celestron OAG and it reaches focus just fine. My camera back focus is 17.5mm and the Celestron OAG (the way I have it configured) uses up about 40mm of back focus. There is plenty of travel left in the drawtube. Note I retrofitted a moonlite focuser so not sure if the drawtube travels is the same as the stock unit. I did not compare them.



#3 f300v10

f300v10

    Ranger 4

  • -----
  • Posts: 302
  • Joined: 16 Sep 2018
  • Loc: Marietta, GA

Posted 17 September 2019 - 08:07 PM

Michael,

 

I use that exact setup (MN190, Celestron OAG, ASI294-MC Pro) and it works fine.  Like John I have swapped the stock focuser for a moonlight, but I believe it would reach focus with the stock unit as well.

 

Scott



#4 jellyfish

jellyfish

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 17 Sep 2019

Posted 18 September 2019 - 02:38 AM

Thank you both. Very excited about this new set-up and with it arriving today and blue skies this morning, it's all looking a bit too good to be true! 

 

Is the Moonlight focuser the goto solution for this scope?

 

Tia,

 

Michael



#5 f300v10

f300v10

    Ranger 4

  • -----
  • Posts: 302
  • Joined: 16 Sep 2018
  • Loc: Marietta, GA

Posted 18 September 2019 - 06:43 AM

I could never get rid of some tilt using the stock focuser, nor did the single thumb screw do an adequate job holding the OAG/camera in a secure fashion.  Moonlight sells a mounting bracket specific to the MN190 that allows you to adjust the alignment of the focuser over the secondary, which is key to getting the MN190 to perform at its best.


  • jellyfish likes this

#6 jellyfish

jellyfish

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 17 Sep 2019

Posted 19 September 2019 - 10:47 AM

Hi f300v10,

 

Can you point me in the direction of the page for this product please. Having played with the kit last night I am more than a little concerned about the use of plastic and the movement in the fittings. Looking at the Moonlite website certainly feels like a good solution to attaching the OAG+camera.

 

How many inch travel did you buy?

 

Have you come across any other makes of focusers?

 

Thanks in advance,

 

Michael


Edited by jellyfish, 19 September 2019 - 10:53 AM.


#7 f300v10

f300v10

    Ranger 4

  • -----
  • Posts: 302
  • Joined: 16 Sep 2018
  • Loc: Marietta, GA

Posted 19 September 2019 - 12:54 PM

Jellyfish,

 

I don't see a way to link directly to the product page on the moonlight website ( https://focuser.com/products.php )

 

Select the CR 2 inch Format Newtonian Focusers from the menu on the top left.  I went with the 1.5 inch drawtube, Dual Rate Tri-Knob with lock shaft.  Once you have that in your cart, continue shopping and find the Universal Install Kit for CR Focusers.  On that page you will find an image of the install kit specific to the MN190.  Be sure and select that one (listed as Orion MN190) in the 'select telescope' dropdown at the bottom of the install kit page.

 

As for other focusers, I know FeatherTouch are quality, but I think most MN190 users go with the moonlight, as they have the custom install bracket.



#8 jellyfish

jellyfish

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 17 Sep 2019

Posted 19 September 2019 - 03:21 PM

Once again, thank you for your clear instructions!

 

I've got one more question which is niggling at me.

 

Having done the unboxing yesterday and played around extensively today, I do have some issues with the build quality as you mentioned.

 

My other niggle is the fastening bolts for the telescope fastening rings. Every time I adjust them I'm left with a pile of aluminium filings which is annoying. Also, I'm thinking that once things get colder, it might be nice not to have to adjust metal bolts in freezing weather.

 

I don't suppose you know of any suppliers of 3rd party bolts that are rubber / powder coated??

 

And lastly, I'd love a carry handle for the telescope. Don't suppose you have one of those you can recommend (can't quite see from your profile image on AstroBin)? I'm loving the dew heater too.

 

The images on AstroBin are superb and exactly where I'm aiming... You'll have to be careful because once I start getting data through from my camera I'm going to have a load more questions for you.

 

Thanks for the tips. At this stage, every little helps!

 

Michael



#9 f300v10

f300v10

    Ranger 4

  • -----
  • Posts: 302
  • Joined: 16 Sep 2018
  • Loc: Marietta, GA

Posted 23 September 2019 - 03:06 PM

Once again, thank you for your clear instructions!

 

I've got one more question which is niggling at me.

 

Having done the unboxing yesterday and played around extensively today, I do have some issues with the build quality as you mentioned.

 

My other niggle is the fastening bolts for the telescope fastening rings. Every time I adjust them I'm left with a pile of aluminium filings which is annoying. Also, I'm thinking that once things get colder, it might be nice not to have to adjust metal bolts in freezing weather.

 

I don't suppose you know of any suppliers of 3rd party bolts that are rubber / powder coated??

 

And lastly, I'd love a carry handle for the telescope. Don't suppose you have one of those you can recommend (can't quite see from your profile image on AstroBin)? I'm loving the dew heater too.

 

The images on AstroBin are superb and exactly where I'm aiming... You'll have to be careful because once I start getting data through from my camera I'm going to have a load more questions for you.

 

Thanks for the tips. At this stage, every little helps!

 

Michael

Sorry for the delay, just saw your latest post.  I have no idea on where you might find better bolts.  As for the 'carry handle' I moved the Vixen style dovetail that came on the scope to the top of the rings, and replaced it with a Losmandy style plate on the bottom that I use to mount the scope.  The top dovetail is my carry handle.  It's also a good secure place to mount a guide scope, though I have since switched to using an OAG and have removed the guide scope from my MN190.  The top dovetail remains as my carry handle.  One last piece of advice, get an autocollimator.  It has made all the difference for me and my MN190.  You use it as the final step on collimating the scope and it really helps nail it.


  • David_Ritter likes this

#10 David_Ritter

David_Ritter

    Viking 1

  • *****
  • Posts: 611
  • Joined: 31 Jan 2014
  • Loc: Edmonton, Alberta, Canada

Posted 23 September 2019 - 03:13 PM

... As for the 'carry handle' I moved the Vixen style dovetail that came on the scope to the top of the rings, and replaced it with a Losmandy style plate on the bottom that I use to mount the scope.  The top dovetail is my carry handle.  It's also a good secure place to mount a guide scope,..

This is exactly what I have done as well. And in my case the vixen bar on the top does indeed carry a guide scope.

 

As for the focuser, I ended up with a FeatherTouch. Starlite Instruments supplied me with a custom ring to adapt their 2" focuser to the existing base. The install was fast and easy.


Edited by David_Ritter, 23 September 2019 - 03:17 PM.

  • NorthField likes this

#11 jellyfish

jellyfish

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 17 Sep 2019

Posted 02 October 2019 - 01:54 PM

Michael,

 

I use that exact setup (MN190, Celestron OAG, ASI294-MC Pro) and it works fine.  Like John I have swapped the stock focuser for a moonlight, but I believe it would reach focus with the stock unit as well.

 

Scott

Hi Scott,

 

My Moonlight focuser has just arrived at home but I am away at the moment.

 

I have been trying to get the Celestron OAG + ASI294 to work with the stock focuser on the 190MN and I cannot get it to work. It seems I cannot get the OAG close enough to the scope to achieve focus (this was on distant objects during daylight - which means infinity focus needs to be even closer!)

 

I'm hoping that once I have the Moonlight in my hands all will be sorted!

 

In the meantime, would it be too much to ask for you to post a close-up picture of your focuser/OAG/camera attachments for me to see?? A good sideways view would be useful for me to get an idea of approximate distances...

 

I know it's a big ask, but you have my exact same system!

 

Thanks in advance,

 

Michael



#12 f300v10

f300v10

    Ranger 4

  • -----
  • Posts: 302
  • Joined: 16 Sep 2018
  • Loc: Marietta, GA

Posted 02 October 2019 - 06:13 PM

Hi Jellyfish,

 

I never tried to use the OAG with the stock focuser as I used a guide scope until about a month ago.  With the moonlight I can't remember if I was able to make it work using only the 11mm T2 ring, or if I had to use my even shorter T2 ring I got on amazon:

 

https://www.amazon.c...0?ie=UTF8&psc=1

 

I'm pretty sure it just worked with the 11mm T2 that came with the camera, so that is how I have configure it in the images that follow.  Here is the full setup attached to the MN190.  The focuser is pulled approximately to where it was when focused.  The ASI290mm mini guide camera is also inserted to where it was when para-focal.  It's way in there, and I had to remove the extender nose piece from the 290mm to get it to work.

Attached Thumbnails

  • IMG_2660.jpg

Edited by f300v10, 02 October 2019 - 06:20 PM.


#13 f300v10

f300v10

    Ranger 4

  • -----
  • Posts: 302
  • Joined: 16 Sep 2018
  • Loc: Marietta, GA

Posted 02 October 2019 - 06:15 PM

I use a 2" M48 camera adaptor, and screw my UV/IR block filter onto the front of the adaptor, so it doesn't take up any backfocus.  Note I added some electrical tape near the top.  This helps the compression ring of the focuser get a really good grip on the adaptor:

Attached Thumbnails

  • IMG_2661.jpg

Edited by f300v10, 02 October 2019 - 06:16 PM.


#14 f300v10

f300v10

    Ranger 4

  • -----
  • Posts: 302
  • Joined: 16 Sep 2018
  • Loc: Marietta, GA

Posted 02 October 2019 - 06:18 PM

Lastly I'm using the M42 male adaptor on the OAG, and screw the camera + 11mm M42 ring onto the OAG:

 

 

Attached Thumbnails

  • IMG_2662.jpg


#15 jsrj98

jsrj98

    Sputnik

  • -----
  • Posts: 34
  • Joined: 21 Feb 2008

Posted 02 October 2019 - 08:09 PM

Just a word on using a OAG on a MN scope. I have one of the original MN-55 scopes. It has a similar focal ratio of 5.5 vs yours at 5.3-- so I also have the issue of minimal backfocus. My scope came with a Feathertouch focuser, which I love-- but at one time I used a Moonlite with a MN-56 and it worked great (but I couldn't use a FW). I recently moved away from a guide scope on my MN-55 to using an ZWO OAG with my ZWO FW and ZWO 1600 Mono camera. Everything comes into focus, and I have 1/2 inch or so to spare of backfocus. When I first purchased the ZWO OAG I could only set the focus in the daytime. However, I recently purchased the new ZWO OAG Helical focuser. It's awesome, and I can now tweak the guider camera focus in real time. A great purchase for sure.

 

As a comparison to the Celestron OAG, a few years ago I used one on my 8" Edge with the focal reducer. Once you lock down everything tight on the ZWO OAG, it's very solid and I have no problems with it. While the Celestron is great, it's just too thick to use on a Newt or Mak-Newt with  FW. The beauty of the ZWO OAG with using a FW and the 1600 is that you have all the spacers required to get you exactly to 55mm backfocus if you use a refractor FF/FR-- which I also do. One of the reasons I went to the OAG is that I can leave the camera, FW and OAG all setup and just pop it on which ever scope I want to use. I have the ZWO 290 mini for my guider and it's VERY sensitive, and I have plenty of stars to choose from for guiding.

 

I hope this helps.


Edited by jsrj98, 02 October 2019 - 08:13 PM.


#16 jellyfish

jellyfish

    Lift Off

  • -----
  • topic starter
  • Posts: 8
  • Joined: 17 Sep 2019

Posted 03 October 2019 - 02:19 AM

Lastly I'm using the M42 male adaptor on the OAG, and screw the camera + 11mm M42 ring onto the OAG:

f300v10, Thank you so much for this. Also, jsrj98 for your helpful tips. The ZWO OAG has a mush slimmer profile but was lacking the ability to focus the guide camera separately / accurately. Now that you have pointed out the helical focuser, this does indeed look like a very nice solution.

 

I also completely agree about being able to have the cameras and OAG all 'set-up' and ready to go is a very useful feature.

 

Once I'm back home I will grab the Moonlight focuser and get setup on that to see what gives.

 

Thank you both once again!

 

Michael




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics