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

ZWO ASI183MC Pro achieving focus with a TV-101

  • Please log in to reply
10 replies to this topic

#1 chuckscap

chuckscap

    Apollo

  • *****
  • topic starter
  • Posts: 1,104
  • Joined: 18 Jul 2009
  • Loc: Colorado Springs, CO USA

Posted 29 March 2020 - 05:37 PM

Hi, I am definitely a beginner imager.   Before this I took some DSO shots with the ASI1224MC with an alt/az mount but that's about it.  Igot my ZWO ASI183MC Pro two days ago.  It seems to be working with Sharpcap,  I can see the background change and the histograms move in response to gain and exposure settings.  Unfortunately I can't seem to get it to focus.   I tried my ZWO ASI1224MC with the included "fish eye" lens and then the ASI183MC   Got images with the ASI1224MC  but not with the ASI183MC.  I looked at the link below

 

https://astronomy-im...tions-55mm.html

 

Still confused.  I have my telescope pointed at tower about 5 miles out to try out initial focus.  I've used it before.  I'm guessing the optical train is too short?  I have the 

 

1 1/4" nosepiece -> 21mm extender -> ASI183MC

 

Any help appreciated.



#2 moxican

moxican

    Viking 1

  • *****
  • Posts: 826
  • Joined: 13 Nov 2011
  • Loc: Toronto, Canada

Posted 29 March 2020 - 05:50 PM

Were you able to achieve focus with the ASI224MC? The sensor distance is close (if the exactly) the same, thus the focus point for the 183 should be close to the same point for the focuser.

I use a mono version of that sensor. With filter wheel and 0.8x reducer I have to stretch the focuser out pretty far. Yours might differ but if it worked with the the 224 it should work with the 183 as well.



#3 ButterFly

ButterFly

    Viking 1

  • *****
  • Posts: 616
  • Joined: 07 Sep 2018

Posted 29 March 2020 - 05:58 PM

Try to get focus with an eyepiece first.  In the Paracorr Type 2, the ASI183MC Pro, use as a 2" eyepiece, focuses at around the A:45 position.  That should get you close enough with any eyepiece to see the disk of a star change as you rack in and out.



#4 RNSpeed

RNSpeed

    Mariner 2

  • -----
  • Posts: 242
  • Joined: 26 May 2005
  • Loc: San German, Puerto Rico

Posted 29 March 2020 - 05:58 PM

Not the same scope but in order for my ASI183MC-Pro to archive focus with my Stallarvue SV80 I had to buy a 50mm extension tube.



#5 Stelios

Stelios

    Cosmos

  • *****
  • Moderators
  • Posts: 8,968
  • Joined: 04 Oct 2003
  • Loc: West Hills, CA

Posted 29 March 2020 - 06:17 PM

While looking at the Sharpcap screen in the daytime (exposure should be just a few milliseconds) hold the camera and pull it outside the fully-racked-out focuser (while holding it as lined up as possible).

 

If the image gets sharper as you move back, then yes, you need an extension tube. AgenaAstro has several that are quite inexpensive. 



#6 chuckscap

chuckscap

    Apollo

  • *****
  • topic starter
  • Posts: 1,104
  • Joined: 18 Jul 2009
  • Loc: Colorado Springs, CO USA

Posted 29 March 2020 - 06:53 PM

Try to get focus with an eyepiece first.  In the Paracorr Type 2, the ASI183MC Pro, use as a 2" eyepiece, focuses at around the A:45 position.  That should get you close enough with any eyepiece to see the disk of a star change as you rack in and out.

My 35mm Panoptic as do my 22mm Panoptic and 6mm Delos all need my AP 2" MaxBright diagonal in place to focus.  I do have a 30mm extension I can add to the 21mm extender.  I'll try that tomorrow.  I can try through my diagonal as well just to see if it will focus.  Something to do while I'm sheltered in place.

 

Thanks to you all,  I'll keep you posted ..     Stay safe

 

Chuck



#7 Aaron Small

Aaron Small

    Explorer 1

  • *****
  • Posts: 89
  • Joined: 27 Sep 2012

Posted 29 March 2020 - 06:54 PM

I have the mono version of the ASI183.  It did seem to need about 40mm further (I used a 50 mm extension that came with something I had from Astronomics).

 

BTW, if you haven't done so already, donate for CN (link above and to right).  They're hurting with COVID-19 and CN could get shut down.



#8 ButterFly

ButterFly

    Viking 1

  • *****
  • Posts: 616
  • Joined: 07 Sep 2018

Posted 30 March 2020 - 01:18 PM

My 35mm Panoptic as do my 22mm Panoptic and 6mm Delos all need my AP 2" MaxBright diagonal in place to focus.  I do have a 30mm extension I can add to the 21mm extender.  I'll try that tomorrow.  I can try through my diagonal as well just to see if it will focus.  Something to do while I'm sheltered in place.

 

Thanks to you all,  I'll keep you posted ..     Stay safe

 

Chuck

That's a very good indication that you need some kind of extender.  Unless you have a flattener, the exact spacing is not critical if the focuser can make up the difference.  With a flattener, you need the proper spacing between the flattener and the sensor, and in your case, most likely extensions between the flattener and the end of the focuser tube.

 

Shooting through a diagonal is less than ideal, but it will tide you over.  You can look up the optical path length of the diagonal to get you in the ballpark of how much extension you need.

 

There is also a moon out after sunset, so take the time to measure how much drawtube is out at the focal plane.  Put some sort of frosty material (wax paper or a white plastic shopping bag) taught against the end of the focuser.  Point the scope at the moon and form an image on the material.  The drawtube extension at that position is a good reference to know.  Based on your comments, you probably need the extensions to do that.  You can also do it through the diagonal if you know its optical path length.  That position is exactly where the sensor needs to be.



#9 Pauls72

Pauls72

    Mercury-Atlas

  • *****
  • Posts: 2,802
  • Joined: 28 Oct 2007
  • Loc: LaPorte, IN USA

Posted 30 March 2020 - 02:00 PM

If you don't have a reducer or flattener the focal point can be pretty far back. Refractors are normally used with a diagonal which adds quite a bit of length.

Look at mt ST80 guide scope, I have two spacers to get the guide camera in focus.

On the bottom is my imaging scope and camera 98mm APO with a QHY183 and a 0.8x flattener/reducer.

 

20190923_191138-s2.jpg



#10 chuckscap

chuckscap

    Apollo

  • *****
  • topic starter
  • Posts: 1,104
  • Joined: 18 Jul 2009
  • Loc: Colorado Springs, CO USA

Posted 30 March 2020 - 03:31 PM

Thank you all so much.  The ASI183MC need a lot of extenders with my setup.  Even with the arrangement below I had to pull the last extender out about 1/2 " to have some focus travel left.   At least the camera/extenders feel very solid.

 

{ }

 

Here's my mount/telescope  (newly acquired, used, but new to me).   I sold my lovely TEC 7 Mak and some other stuff to purchase it.  Like it a lot so far.

 

{ }

 

Once again, thanks and thanks for not asking me if I had the lens cap on lol

 

Best,

 

Chuck



#11 moxican

moxican

    Viking 1

  • *****
  • Posts: 826
  • Joined: 13 Nov 2011
  • Loc: Toronto, Canada

Posted 30 March 2020 - 06:17 PM

Thank you all so much.  The ASI183MC need a lot of extenders with my setup.  Even with the arrangement below I had to pull the last extender out about 1/2 " to have some focus travel left.   At least the camera/extenders feel very solid.

 

{ }

 

Here's my mount/telescope  (newly acquired, used, but new to me).   I sold my lovely TEC 7 Mak and some other stuff to purchase it.  Like it a lot so far.

 

{ }

 

Once again, thanks and thanks for not asking me if I had the lens cap on lol

 

Best,

 

Chuck

Cool Chuck, glad you could work it out. Best of luck with imaging...cool.gif




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