Focusing Aids? Hi all- asking for advice on how to best achieve focus for astro photos of deep sky objects (DSO). I use either Svbony 102mm refractor or Celestron C6 on separate goto...

mikedent Loc: Florida

Hi all- asking for advice on how to best achieve focus for astro photos of deep sky objects (DSO). I use either Svbony 102mm refractor or Celestron C6 on separate goto mounts. I use a Bahtinov mask to focus a bright star in the live view screen of Nikon D5300 attached to the scope tube instead of an eyepiece. Looking at resulting sub photos, stars are not elongated but things don't seem perfectly sharp. I have read that SharpCap is a good help but I try to avoid having to use a computer if I don't have to. What other options, either hardware or software based, have you all seen or used for this? Thanks-Mike

bwana Loc: Bergen, Alberta, Canada

mikedent wrote:

Hi all- asking for advice on how to best achieve f... (show quote)

I pretty much use a Bahtinov mask exclusively for focusing a scope; never had a problem.

My other approach is to simply adjust focus until I see the most stars in the field-of-view (with or without Peaking). This is normally equivalent to using a Bahtinov mask.

bwa

SonnyE Loc: Communist California, USA

In addition to the Bahtinov mask, I try to see the tiniest stars as when they are pinpricks, you will be closest to your fine focus.

I now use a focuser. And in NINA, I tend to focus a lot in my auto runs because the only cost is a little time.
So far, so good.

mikedent Loc: Florida

I now use a focuser

Is this an electronic focuser that attaches to the focus dials? How does that help achieve proper focus? I have used the Bahtinov system for a while now and even though the angles look correct, many times the stars on photos are still bit bloated looking. Thanks for responses!

SonnyE Loc: Communist California, USA

mikedent wrote:

I now use a focuser

Is this an electronic focuser that attaches to the focus dials? How does that help achieve proper focus? I have used the Bahtinov system for a while now and even though the angles look correct, many times the stars on photos are still bit bloated looking. Thanks for responses!

Hi Mike,
Bloating, in my experiances, was caused by vibrations around the mount.
I could cause it by simply tapping my foot.
So over the years I found by setting up, then going in the house and connecting my mount computer (laptop) with my main desk computer (tower) and monitoring with no activity near the mount i could tone down the vibrations causing the blotted looking stars.
Works for me anyway.
I also discovered by moving my mount off of the concrete, I could reduce vibration bloating.
I use 12X12 pavers under each leg when on dirt or grass.
I use TightVNC as my program to wifi the computers to each other.

Ballard Loc: Grass Valley, California

mikedent wrote:

Hi all- asking for advice on how to best achieve f... (show quote)

Is it just the brightest stars that are bloated or are even the dim ones bloated also. If the exposure time is very long you can saturate the pixels were on the brightest stars and this will cause some star bloating. If this is the case reduce the exposure time and stack multiple images. If not then I highly recommend connecting a laptop to your camera (Normally a USB type connection) and use it in live view mode to get a full screen image where it is much easier to check the focus. I assume Nikon has an app for that, on Canons I use the Canon EOS utility program for that purpose.

mikedent Loc: Florida

I see what I perceive as bloating around many of the stars, thye are often just not mere points of light. Exposures are 55-65 seconds, iso 800. I stack in DSS. Want to try APP trial for stretching and colors, I don't use PS. My mount legs are on concrete driveway due to how the local streetlights are and the house roof height is so I can still see Polaris. Photos are done after 9pm when nobody is walking around the neighborhood any longer. I have not tried to hook up camera to a computer screen for a larger live view image, will see if it can be done.

JBRIII

You can get a set of three anti-vibration pucks for tripods. They may be sold/made by/for Celestron. Don't remember price, but not too expensive.

mikedent Loc: Florida

pucks for tripods

yes, I have these but haven't used them. Our street is pretty quiet at night...

bwana Loc: Bergen, Alberta, Canada

mikedent wrote:

I see what I perceive as bloating around many of t... (show quote)

I quite often use an external battery powered (7") monitor when imaging. It gives me a much better view of what's happening as opposed to the liveview screen and saves my back and neck. It is easy to attach a monitor to the HDMI port of any modern camera.

bwa

(Download)

SonnyE Loc: Communist California, USA

bwana wrote:

I quite often use an external battery powered (7") monitor when imaging. It gives me a much better view of what's happening as opposed to the liveview screen and saves my back and neck. It is easy to attach a monitor to the HDMI port of any modern camera.

bwa

Brian, do you live in a volcano?
You always have that white stuff on the ground.
LOL!

At one time, Mike, I tried one of those mini computers after my first laptop died.
I almost wore a path between my inside computer, and my mount. I hated it, and it would not wifi worth bean's.
I knew I needed visual at the mount.
I also have used my DSLR (mostly for comets) but a low end Nikon D3300.
But it has a USB connector, so I got a
Cable to connect the camera to my computer laptop.
Being able to view your object on a screen really helped me, and still does.
You might even be able to use a tablet plugged into your DSLR.
Lots of options as you advance in this madness.

Welcome to the Black Hole of Astrophotography!

PS: I was referring to me walking around by my mount.
But ground vibrations of any sort can effect your outcome.
Anyway, you'll get there. Keep shootin the shootin Stars!

bwana Loc: Bergen, Alberta, Canada

SonnyE wrote:

Brian, do you live in a volcano? br You always hav... (show quote)

I've found from personal experience that a snow storm can happen at anytime in the Foothills. We had about 5" for the white stuff in mid-July a couple of years ago.

If was 27C (81F) yesterday afternoon and 1C(34F) last night.

And as you say, 'keep shootin'...

bwa

SonnyE Loc: Communist California, USA

bwana wrote:

I've found from personal experience that a snow storm can happen at anytime in the Foothills. We had about 5" for the white stuff in mid-July a couple of years ago.

If was 27C (81F) yesterday afternoon and 1C(34F) last night.

And as you say, 'keep shootin'...

bwa

I recall 50 degree swings between night and day in Wyoming in the 1970's (begining of the last Ice Age, IIRC.
We got there the end of June, and on the forth of July we woke up to an inch of snow on the ground.🤯
Yep, got your leg, pullin it.🤣