Jump to content

sgl_imaging_challenge_2021_2.thumb.jpg.72789c04780d7659f5b63ea05534a956.jpg

Correcting starsense focus


Recommended Posts

Has any one had to correct the focus of a steraense?

there was a growth on the lens, which turned out to be inside - 

it didn’t affect operation, but my limitless wisdom I decided it should be cleaned before it got worse and the longer nights set in

I wasn't careful enough in reassemble I think, and the locking rings got moved 

Yes

i am and idiot

Edited by iapa
Link to post
Share on other sites

Yes, I had to do this so don’ t panic :)

Here are some user instructions from members of teamcelestron (incl. me) who have had this same scenario

 

Background info

There are 31.5 full turns on the thread. I plan to do a manual align, so the telescope waits for me to decide where to point it before each capture, but leave it pointing at the same patch of sky each time. If exact focus isn't required I'm assuming start at one end then if "too few stars" turn it 360 before trying again. Once I've identified the range where it's finding stars I guess I can try and get a more exact focus i.e. Using quarter turns...
 

Steps of original poster

Started with it screwed right in and repeated the first step of a manual align until stars were identified, each time unscrewing the lens by half a turn. Each attempt took about 15 seconds; stars appeared after 15 half turns, then disappeared at 19. Difficult to get the optimum position in terms of numbers of stars, so ended up with it midway between those two points. Took about 15 minutes in all.

What I did

based on the above info. When my camera was out of focus after I removed the lens cover for cleaning. To start, I screwed the cover all the way in then backed it out 15 half turns. I ran the camera align and noted the number of stars reported as found. Then I unscrewed a further half turn and repeated the test align. I found that unscrewing by 17 half turns reported the maximum "100 stars found" and left it at that!

HTH,

Alan

Edited by alanjgreen
  • Thanks 2
Link to post
Share on other sites
57 minutes ago, alanjgreen said:

Yes, I had to do this so don’ t panic :)

Here are some user instructions from members of teamcelestron (incl. me) who have had this same scenario

 

Background info

There are 31.5 full turns on the thread. I plan to do a manual align, so the telescope waits for me to decide where to point it before each capture, but leave it pointing at the same patch of sky each time. If exact focus isn't required I'm assuming start at one end then if "too few stars" turn it 360 before trying again. Once I've identified the range where it's finding stars I guess I can try and get a more exact focus with eg quarter turns...
 

Steps of original poster

Started with it screwed right in and repeated the first step of a manual align until stars were identified, each time unscrewing the lens by half a turn. Each attempt took about 15 seconds; stars appeared after 15 half turns, then disappeared at 19. Difficult to get the optimum position in terms of numbers of stars, so ended up with it midway between those two points. Took about 15 minutes in all.

What I did

based on the above info. When my camera was out of focus after I removed the lens cover for cleaning. I screwed the cover all the way in then backed it out 15 half turns. I ran the camera align and noted the number of stars reported as found. Then I unscrewed a further half turn and repeated the test align. I found that 17 half turns reported the "100 stars found" and left it at that!

HTH,

Alan

Many thanks,

ill give this a shot next clear non-school night - I should have posted original yesterday and be in a position to fix today

 

ah well

 

again thanks for this 

Link to post
Share on other sites
  • 2 months later...

Thanks to all for the tips, I will try re-adjusting my StarSense on the first available clear night! Thinking about it, as the StarSense is clearly a very wide-angle (short focal length) set-up, that should mean a much greater depth of field (in photographic terms) so I assume that conversely, the focus point is not that critical? That gives me more hope of getting it right!

Still not sure if I've fixed the original 'Alignment not good enough' issue - I'm actually more suspicious than ever that it's bad electrical connections. will report back!

Link to post
Share on other sites
  • 2 years later...

An older thread but a good one.  My StarSense was not seeing stars. I have a lot of light pollution, LED street lamps. Auto align kept failing. I read this thread and spent the night adjusting the StarSense camera focus as described above - thank you people.

I found the focus point to be quite critical.

I found the focus point between 15 and 24 half turns out and then narrowed it down to to around number 20. Meaning these cameras are not all the same. I then started going in quarter turns in and out and then 1/8 turns until I got maximum star count.  Whereupon I lost count of turns and simply went back and forth, I had marked the focus housing. Seeing conditions were variable so I was getting between say 65 and 87 stars at the same place on repeats. Tightening the lock ring moved the focus so the last adjustments were made with the ring locked each time.

As I got near to optimum focus the StarSense would 'solve' and complete alignment, which had to be blown away and resume the Manual Align. 

Once completed I got Auto Align to run complete successfully in about one minute. Quite amazing considering the street lighting, houses and trees in the way. Finding a target is not spot-on but it is nearby.

Once again thank you to everyone who posted on this thread - if StarSense Auto Align is not solving, refocus the camera even though it is long winded and boring. I actually had more problems with the dog prancing about and trying to eat large planter pots, which makes a change from destroying lens bags and my gloves.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.