Day time focusing - Forums

Topic starter

Jul 30, 2025

So I have my new c9.25 edge mostly set up and ready to go. I am unfortunately stuck with a couple weeks of forced night shift overtime currently. Trying to get ready ahead of a night off.

I am just wondering if a c9.25 / reducer / asi2600mc would need more than a distance of 1/2 mile to focus in the day time? That's the farthest house roof I can see from my yard. I found focus visually but so far no luck with the camera. I am exactly at 146mm backfocus in case anyone is wondering.

I am guessing that I just really need a farther target. I see waves of green from trees with zero details focusing in both directions.

Médéric Hébert

Jul 30, 2025

The main issue I'd see with focusing in day-time is that the temperature will change and your focus won't be valid anymore.

I get your woes sinci I work night shift too, my suggestion would be to get an electronic focuser and let your imaging routine focus for you once it's night outside.
I do almost all my imaging that way now.

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Himanshu Pandey

Jul 30, 2025

You should be able to get something in focus 1/2 mile out. That is way more distance to sight a finder scope with the main scope in the day time. I've done it often at about 100 yards with a C8. 880 yards is enough.

NE-FL-Astro

Jul 30, 2025

1/2 a mile will get you in the right area. I have an almost identical setup with the main difference being I have a 2600mm and focused on trees over a quarter mile away. I would actually highly recommend starting during the day with video mode or a fast exposure because it’s difficult to find initial focus otherwise. Obviously you’ll have to fine tune it at night, but it’s a great way to start. I’d also recommend checking your collimation on the first clear night. Check your out of focus star shapes, they should be perfect donuts. Enjoy the rig!

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Ryan5508

Topic starter

Jul 30, 2025

I was slowing going through small 5 step increment with the ZWO eaf. And was just seemingly unable to get focused. Hence my question with the distance in a camera. I am basically all ready to run at this point. Just swapped in the filter wheel and oag-l.

Thinking about pulling the eaf and trying by hand at some point.

Also on the topic of the 9.25 how loose is good enough for the clutches? When using the eaf. I don't want to accidentally backed them off too far. This is my first sct. Other rig is an esprit 100ed.

NE-FL-Astro

Jul 30, 2025

I was slowing going through small 5 step increment with the ZWO eaf. And was just seemingly unable to get focused. Hence my question with the distance in a camera. I am basically all ready to run at this point. Just swapped in the filter wheel and oag-l.

Thinking about pulling the eaf and trying by hand at some point.

Also on the topic of the 9.25 how loose is good enough for the clutches? When using the eaf. I don't want to accidentally backed them off too far. This is my first sct. Other rig is an esprit 100ed.

Steps of 5 is way too small. I would be using steps of 300. It wouldn't hurt to do it by hand, but if you get it dialed in on some distant trees, it'll be easy to tune it from there. For the EAF step sizes, you'll probably want to be somewhere between 200-300 to get a proper result. For the clutches, I just used some judgment and made sure the EAF didn't seem to be stressing itself. It's a pretty powerful little motor.

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Ryan5508

Topic starter

Jul 31, 2025

I found my issue.

The zwo sct bracket I installed needs the orange ring. I put it on with out it. It was allowing the focuser to slide outward slightly. This made it so I could never get focus on the camera end to end turning it.

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Wei-Hao Wang

Aug 1, 2025

The real question is not how. It's why? Why do you want to focus in day time?

To avoid focusing at night? That's not going to work, because the temperature is likely going to be very different. So you will refocus at night anyway.

To get into the ballpark so you can better balance the OTA? Then I think anything more than half mile away can be used. If the mount is set correctly and if the sky clear, you can even use a mag 1 star to focus during day time.

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Ryan5508

Topic starter

Aug 1, 2025

Wei-Hao Wang:
The real question is not how. It's why? Why do you want to focus in day time?

To avoid focusing at night? That's not going to work, because the temperature is likely going to be very different. So you will refocus at night anyway.

To get into the ballpark so you can better balance the OTA? Then I think anything more than half mile away can be used. If the mount is set correctly and if the sky clear, you can even use a mag 1 star to focus during day time.

I think if you read the post you would already have the answer to your question. I am on a 51 day straight 12.5 hr night shifts. So I only have day time before work to get things together for my first night off.

Tony Gondola

Frequent contributor

Aug 1, 2025

I think the idea is to get as close as you can. The more distant the object the better. The moon is often visible during the day so that would be ideal. Also, if you have a solar filter you could just use the sun. Sure there will be some drift due to temp but it will get you close.

Ryan5508

Topic starter

Aug 1, 2025

I installed the orange collar ring back on the focuser this morning before bed. This afternoon I was easily able to focus the camera/oag. I was also able to focus the eyepiece/planetary camera without issue.

The bracket made for the sct's from zwo is in way too many pictures online without the orange ring. This is what lead me to not using it during my install. But every thing is good now.

Read noise Astrophotography

Frequent contributor

Aug 28, 2025

Ryan5508 · Jul 30, 2025, 12:42 AM
So I have my new c9.25 edge mostly set up and ready to go. I am unfortunately stuck with a couple weeks of forced night shift overtime currently. Trying to get ready ahead of a night off.

I am just wondering if a c9.25 / reducer / asi2600mc would need more than a distance of 1/2 mile to focus in the day time? That's the farthest house roof I can see from my yard. I found focus visually but so far no luck with the camera. I am exactly at 146mm backfocus in case anyone is wondering.

I am guessing that I just really need a farther target. I see waves of green from trees with zero details focusing in both directions.

I am not sure that is going to work out. Day time focus is something you use to say roughly adjust a finder scope or make a OAG parfocal with the imaging senso. But well before astro dark you can easily find a bright star and focus on it. Before its truly dark you can use this time to align and focus so when dark hits you just press play