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

Greetings fellow hobbyists, seeking advice on ETX-90EC deep sky observations

  • Please log in to reply
10 replies to this topic

#1 Cky

Cky

    Lift Off

  • -----
  • topic starter
  • Posts: 3
  • Joined: 16 Dec 2018

Posted 16 December 2018 - 03:58 PM

Hello everyone my name is Ben. I’ve acquired this telescope from a local seller from CL here in Maryland and this will be my first motorized telescope. I’m hoping this setup will be a solid foundation for astrophotography that always mesmerized me for the last decade. This is where I am now with my additions to the rig looking for small additions that will make observations more enjoyable. So far I managed to equip the telescope with Nikon DSLR camera, motorized focuster, 497 remote with latest firmware, PC interface, Sony starlight board camera that’s 0000.4lux sensitivity attached to the view finder so I wouldn’t have to bend my neck 90deg when I have to observer objects directly above me, and also a diy lens hood just for testing. Perhaps some of this stuff is over the top for amateur like me, so please don’t be too harsh. Thank you for your help and time 

 

CDA1DE54-DDDD-4C63-AA03-C7A20BA33B52_zps

 

3C6319DC-CF21-40BB-BD95-18C33932447C_zps

 

13E72DFF-406B-4CDC-A8CD-00AF4B26DB69_zps

 


Edited by Cky, 16 December 2018 - 03:59 PM.

  • M57Guy likes this

#2 ShaulaB

ShaulaB

    Apollo

  • *****
  • Posts: 1256
  • Joined: 11 Oct 2012
  • Loc: Missouri

Posted 16 December 2018 - 04:48 PM

Go for it! Have fun and post some images.

 

What is your scope's focal length? DSO's usually work out well with shorter fl optics. Things called focal reducers are available and might be a consideration.


Edited by ShaulaB, 16 December 2018 - 04:50 PM.


#3 Cky

Cky

    Lift Off

  • -----
  • topic starter
  • Posts: 3
  • Joined: 16 Dec 2018

Posted 16 December 2018 - 05:08 PM

I believe its 1250mm FL with a 5x camera adapter. If im not mistaken that would be 25x Zoom ? 



#4 Foundationer

Foundationer

    Explorer 1

  • *****
  • Posts: 53
  • Joined: 23 Oct 2017
  • Loc: Central US

Posted 16 December 2018 - 09:50 PM

Be careful with the dec lock,and maybe find a way to balance, looks tail heavy.
Good luck

#5 Thrifty1

Thrifty1

    Mariner 2

  • -----
  • Posts: 205
  • Joined: 24 Feb 2006
  • Loc: Nashville, TN

Posted 17 December 2018 - 01:18 PM

I will second to be careful with that much weight from the DSLR at the back of the scope. The plastic gears in the ETX scopes are not made to handle a lot of weight / imbalance. I have an ETX-105 I had to rebuild some gears due to using a DSLR too much on it. I only use my DSLR on my larger 10” LX200 now.

Looking online it appears your scope is F/13.8 which is about the same as my ETX-105. This makes it a bit of a challenge for deep sky objects as longer exposures are needed. The longer exposure then results in more drive imperfections impacting your images. A focal reducer will help speed up the scope / reduce exposure times.

Here is a link to some ETX deep sky photos - these are somewhat dated but give you an idea of what some have done. You will definitely need to take many images and stack them.

http://www.weasner.c...ts_deepsky.html

You may also want to look into the EAA Observation & Equipment forum to see examples of what you can obtain with other smaller / lighter cameras.

Edited by Thrifty1, 17 December 2018 - 01:18 PM.


#6 REC

REC

    Voyager 1

  • *****
  • Posts: 10652
  • Joined: 20 Oct 2010
  • Loc: NC

Posted 17 December 2018 - 03:17 PM

Hello everyone my name is Ben. I’ve acquired this telescope from a local seller from CL here in Maryland and this will be my first motorized telescope. I’m hoping this setup will be a solid foundation for astrophotography that always mesmerized me for the last decade. This is where I am now with my additions to the rig looking for small additions that will make observations more enjoyable. So far I managed to equip the telescope with Nikon DSLR camera, motorized focuster, 497 remote with latest firmware, PC interface, Sony starlight board camera that’s 0000.4lux sensitivity attached to the view finder so I wouldn’t have to bend my neck 90deg when I have to observer objects directly above me, and also a diy lens hood just for testing. Perhaps some of this stuff is over the top for amateur like me, so please don’t be too harsh. Thank you for your help and time 

 

CDA1DE54-DDDD-4C63-AA03-C7A20BA33B52_zps

 

3C6319DC-CF21-40BB-BD95-18C33932447C_zps

 

13E72DFF-406B-4CDC-A8CD-00AF4B26DB69_zps

Needs a lot of counter balance. Try out the moon first without any eyepeice in it. Also, this would be good for wide field AP with an adapter to mount it on the top of the scope. Piggy Back.



#7 Cky

Cky

    Lift Off

  • -----
  • topic starter
  • Posts: 3
  • Joined: 16 Dec 2018

Posted 17 December 2018 - 04:59 PM

Thank you for everyone’s help! I sincere apologize, I was being to hasteful with the brief technical setup on the telescope. I do have a counter weight on the front lens to mitigate imbalance problems with the heavy DSLR. This configuration was used in last nights observations. Here are few more pictures of what I’m using.

EB9F2E04-6E28-4ED4-B1C8-3998E795AA28_zps

76E7EBFA-B5CD-44D6-A824-4B84F5DE9BB9_zps


Edited by Cky, 17 December 2018 - 05:09 PM.


#8 M57Guy

M57Guy

    Viking 1

  • *****
  • Posts: 786
  • Joined: 21 Jun 2015
  • Loc: On my ship the Rocinante, wheeling through the galaxies

Posted 18 December 2018 - 10:37 PM

Me thinks your 'diy lens hood' is a SCH 40 female adapter - very clever. waytogo.gif

 

Is it a snug fit or did you wrap the OTA with something?



#9 aeajr

aeajr

    Voyager 1

  • *****
  • Moderators
  • Posts: 10887
  • Joined: 26 Jun 2015
  • Loc: Long Island, New York, USA

Posted 19 December 2018 - 12:08 AM

I don't think I would want a white lens hood/dew shield.   Would tend to create reflections that would be undesirable. 



#10 JohnnyBGood

JohnnyBGood

    Vostok 1

  • -----
  • Posts: 189
  • Joined: 10 Mar 2016
  • Loc: Panama City Beach, FL

Posted 20 December 2018 - 09:49 AM

I do something similar with my slightly older ETX-90 RA, though I'm more low-tech about it. I'm not really interested in astrophotography, but only fiddle with it because my scope happened to come with a T adapter and "because why not". I borrow my wife's Nikon D3300 and use an ETX T adapter on the rear port. I have a nearly identical PVC dew shield on mine as well. I painted mine flat black and flocked the inside of it, using some extra thick felt pads on the inside so it would fit snugly on the tube and allow me to extend it out a little further. It balances the camera surprisingly well (and is too heavy to use on the scope without the camera attached). The T adapter works really well but does limit how high you can point the scope. The advantage to using the rear port is that you can use an eyepiece as well. It also gives correct (not mirror) images. I have to use an extension (an old barlow lens with the lens removed) to get it to focus while the camera is in focus, but a 26mm eyepiece gives pretty close to the same field of view as the camera. Makes it a lot easier to find what I'm looking for and make sure the image is more or less centered. I just have to remember to flip the mirror down before taking pictures. I have a lot of all black photos because of that.  I'm not using any sort of guide scope, so what I'm doing is much more simplistic what what your setup is capable of.

 

I'm not an expert, but I think your zoom level with a 5x Barlow is probably waaaay more than 25x. Prime focus through the rear port yields images that look (to me) to be about 50x, so you may be trying to take photos at 250x. I've used a 2x Barlow with my camera in the configuration you're using to attempt to take photos of Jupiter and that seemed to be about the best magnification I would be able to manage with the scope and camera. 3x might be possible in good conditions, though. I never could really get the ISO level and exposure length figured out for optimal Jupiter photos, but I only tried on two nights. DSOs are easy: figure out what setting works best and use it all the time. The planets use different settings and the moon is highly... uh... dynamic. Different setting for each night. Haven't gotten the moon figured out yet. Keep a log pf photos and camera settings to help figure out what works and doesn't. If you're having trouble, the first thing I'd do is try unscrewing the lens from your Barlow to get the magnification down to reasonable levels.

 

My wife's camera can only do 30 second exposures without buying more stuff I don't need, but 30 seconds ends up being about all the unguided ETX-90 will handle before I start getting trailing issues. Having fresh batteries makes a huge difference as well. Once you get it figured out the ETX-90 is a very versatile scope and is capable of some pretty decent pictures. Check out Mike Weasner's Mighty ETX page if you haven't found it yet.



#11 M57Guy

M57Guy

    Viking 1

  • *****
  • Posts: 786
  • Joined: 21 Jun 2015
  • Loc: On my ship the Rocinante, wheeling through the galaxies

Posted 21 December 2018 - 10:42 PM

I don't think I would want a white lens hood/dew shield.   Would tend to create reflections that would be undesirable. 

I would agree. Check out the last photo in post #7 - looks as if the interior has been painted.

 

My first dew shield was made from a piece of cardboard, rolled around the OTA and painted flat black on the inside.

 

Worked surprising well, but I had to wear a paper bag over my head while observing.




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