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

Prime focus lunar image focus looking soft. Any help would be appreciated

beginner astrophotography
  • Please log in to reply
11 replies to this topic

#1 Anirudh

Anirudh

    Lift Off

  • -----
  • topic starter
  • Posts: 6
  • Joined: 13 Jul 2018

Posted 07 December 2019 - 08:03 AM

So I just tried out prime focus on the moon with the nexstar 6se. The moon looked pretty sharp through the eyepiece but the focus was pretty soft when I hooked up my camera. I tried using a Barlow lens since I read some stuff about the focal length being too long or short but it didn't really help. I did take some shots and stacked them and edited it a bit with Lightroom mobile. 

Any help would really be appreciated

I'm using a rebel T6 btw

IMG_1114_lapl4_ap700_compress34.jpg



#2 drd715

drd715

    Mariner 2

  • -----
  • Posts: 239
  • Joined: 07 Jan 2015
  • Loc: Fort Lauderdale

Posted 07 December 2019 - 08:11 AM

Could be a focus issue. But what did you stack them with? Try looking at one shot and see if it is soft by itself.

Sent from my SM-N950U using Tapatalk
  • Anirudh likes this

#3 kathyastro

kathyastro

    Apollo

  • *****
  • Posts: 1,144
  • Joined: 23 Dec 2016
  • Loc: Nova Scotia

Posted 07 December 2019 - 08:12 AM

Two things to check: focus and motion. 

 

For focus, don't just "eyeball" it.  Buy or make a Bahtinov mask, and use it to focus precisely on a bright star.  Then slew to the Moon and begin imaging.

 

How are you triggering the shutter?  You can't use your finger.  You can't touch the camera or scope.  Make sure you are using a remote.  If you don't have one, use the camera's self-timer.

 

The problem could also be bad seeing.  Don't take one or two frames.  Put the camera into video mode if you can and shoot 15 or 20 seconds of video.  That will allow the stacking software to average out the movement of the atmosphere and give you a sharp image.  It also gives you enough frames that you can throw out the worst ones and still have enough left to process.


  • okiestarman56, drd715 and Anirudh like this

#4 Anirudh

Anirudh

    Lift Off

  • -----
  • topic starter
  • Posts: 6
  • Joined: 13 Jul 2018

Posted 07 December 2019 - 08:26 AM

Could be a focus issue. But what did you stack them with? Try looking at one shot and see if it is soft by itself.

Sent from my SM-N950U using Tapatalk

I used autostackert after the disaster of trying registax and watching it repeatedly crash

This is one of the frames I used

20191206234547_IMG_1244.JPG



#5 Anirudh

Anirudh

    Lift Off

  • -----
  • topic starter
  • Posts: 6
  • Joined: 13 Jul 2018

Posted 07 December 2019 - 08:28 AM

Two things to check: focus and motion.

For focus, don't just "eyeball" it. Buy or make a Bahtinov mask, and use it to focus precisely on a bright star. Then slew to the Moon and begin imaging.

How are you triggering the shutter? You can't use your finger. You can't touch the camera or scope. Make sure you are using a remote. If you don't have one, use the camera's self-timer.

The problem could also be bad seeing. Don't take one or two frames. Put the camera into video mode if you can and shoot 15 or 20 seconds of video. That will allow the stacking software to average out the movement of the atmosphere and give you a sharp image. It also gives you enough frames that you can throw out the worst ones and still have enough left to process.

I used the Canon app from my phone so I didn't actually press the camera button at all
And there were a few intermittent wisps I'd say drifting by
I could see the drifting though the camera but it didn't seem really bad
The mirror was kinda fogged up a bit would that affect it?
And I think I used about 50 to 70 frames I think

Edited by Anirudh, 07 December 2019 - 08:29 AM.


#6 kathyastro

kathyastro

    Apollo

  • *****
  • Posts: 1,144
  • Joined: 23 Dec 2016
  • Loc: Nova Scotia

Posted 07 December 2019 - 08:34 AM

A fogged mirror would definitely make a difference.  Get yourself a hair dryer and use it on Low to clear away any dew.

 

It sounds like focus and dew would be your main suspects.


  • Anirudh likes this

#7 Anirudh

Anirudh

    Lift Off

  • -----
  • topic starter
  • Posts: 6
  • Joined: 13 Jul 2018

Posted 07 December 2019 - 08:38 AM

A fogged mirror would definitely make a difference. Get yourself a hair dryer and use it on Low to clear away any dew.
It sounds like focus and dew would be your main suspects.

Hmmm
Problem is I set it up on my terrace and there aren't any plug points possible for the hair dryer
I'm pretty sure I can get rechargable hair dryers though

Edited by Anirudh, 07 December 2019 - 08:41 AM.


#8 nimitz69

nimitz69

    Surveyor 1

  • *****
  • Posts: 1,705
  • Joined: 21 Apr 2017
  • Loc: A barrier island 18 miles south of Cocoa Beach

Posted 07 December 2019 - 09:08 AM

extension cord?

 

focus & probably dew for sure


  • Anirudh likes this

#9 Anirudh

Anirudh

    Lift Off

  • -----
  • topic starter
  • Posts: 6
  • Joined: 13 Jul 2018

Posted 07 December 2019 - 12:57 PM

Something else I just remembered
When I was starting to set everything up I actually put the t adaptor into the star diagonal and got a few shots before realising I should do without the diagonal
Thing is the shots with the diagonal were clearer than the stacked image without diagonal what's the reason for that?
And thanks for all the help with this

Edited by Anirudh, 07 December 2019 - 02:02 PM.


#10 nimitz69

nimitz69

    Surveyor 1

  • *****
  • Posts: 1,705
  • Joined: 21 Apr 2017
  • Loc: A barrier island 18 miles south of Cocoa Beach

Posted 07 December 2019 - 06:34 PM

probably no dew had formed yet and focus hadn’t drifted



#11 OldManSky

OldManSky

    Mercury-Atlas

  • *****
  • Posts: 2,529
  • Joined: 03 Jan 2019
  • Loc: Valley Center, CA USA

Posted 07 December 2019 - 06:48 PM

1. Your camera won't focus at the same place as your eyepieces.  Once you attach the camera, you'll have to re-focus.  Use the live-view screen if possible, if not, use the viewfinder.  Take your time.

2. Use the 2-second self-timer with mirror lockup option on your camera.  That will give a couple of seconds for the vibrations of the mirror flip-up to damp down before the shutter opens.

 

Keep at it!



#12 Chuckwagon

Chuckwagon

    Viking 1

  • *****
  • Posts: 801
  • Joined: 23 Jan 2008
  • Loc: Orem, Utah, USA

Posted 07 December 2019 - 10:09 PM

Also, it wouldn't hurt to check your collimation.  If it's off your focus can appear soft.




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





Also tagged with one or more of these keywords: beginner, astrophotography



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics