45 replies to this topic

[limeyx]

As the title says, I am just sick of messing w/focus

 

I know eventually getting a more advanced focuser would be optimal but is there any real reason why I shouldn't just buy the ZWO EAF right now and have done with it ?

 

Of course it's backordered everywhere but one has to come into stock at some point...

 

[NoDarkSkies]

I have the EAF installed on 4 of my Telescopes and So Glad That I Do!
On my 5th is the Pegasus Astro FocusCube 2 Focuser Motor - With Universal L-Bracket # FC2-UNIV only because the ZAF would not fit.

Edited by NoDarkSkies, 24 January 2021 - 07:10 PM.

[WadeH237]

What problems are you having with focus?

 

My opinion is that a hard prerequisite to adoping automatic focus, is that you must be able to manually focus accurately and easily first.  If you skip that step, then when you have problems with auto focus (and you will at some point), you will not have the skills to diagnose and correct problems.

 

I would say the same thing about automating any part of this hobby.  The way that I think of it, is that when automation doesn't do the right thing, you will be troubleshooting it after the fact, and with nothing but log files to give you clues.  This is much harder than understanding the process when doing something manually.

 

Once you have mastered something manually, then you can automate it for convenience.

[bobzeq25]

As the title says, I am just sick of messing w/focus

 

I know eventually getting a more advanced focuser would be optimal but is there any real reason why I shouldn't just buy the ZWO EAF right now and have done with it ?

 

Of course it's backordered everywhere but one has to come into stock at some point...

Another possibility is this.  I have one, like it.

 

https://www.rigelsys...eppermotor.html

[Borodog]

I use a Bahtinov mask, and even though I have relatively difficult manual focusers, they get me close enough to perfect that I cannot tell the difference. I routinely image at the diffraction (or seeing) limit for planetary and lunar and focus has essentially been removed as a source of problems in both of my serious scopes (8” SCT AND 10” Dob).

[limeyx]

I also see this... but I have no clue if any of it would work with my gear -- I need a PhD just to figure it out, but I'd love a rotator also haha

 

https://www.rigelsys.com/nFRAME.html

[limeyx]

What problems are you having with focus?

 

My opinion is that a hard prerequisite to adoping automatic focus, is that you must be able to manually focus accurately and easily first.  If you skip that step, then when you have problems with auto focus (and you will at some point), you will not have the skills to diagnose and correct problems.

 

I would say the same thing about automating any part of this hobby.  The way that I think of it, is that when automation doesn't do the right thing, you will be troubleshooting it after the fact, and with nothing but log files to give you clues.  This is much harder than understanding the process when doing something manually.

 

Once you have mastered something manually, then you can automate it for convenience.

Problems

 

1. I am never in focus because I cannot see stars in LiveView and have to take 4 second test shots over & over

2. I don't have GOTO and so I have to spend ages finding a bright star to focus on before going to my target. This then puts me out of Polar alignment

3. Big temp changes overnight in summer -- no easy way to refocus during a session

 

This is costing me a lot of images and time. Agree, learning the ropes is important but I don't get many clear nights

[limeyx]

Another possibility is this.  I have one, like it.

 

https://www.rigelsys...eppermotor.html

Thank you. I saw those but I have not a clue what I need from there and it looks harder to use than the ZWO. They do tease me with a possibility for a rotator though ! (Oh the slippery slope) but I don't need a rotator until I get a better mount

 

I'd put off the focuser, but w/out GOTO, I am just thrashing around on focus and ruining good imaging nights

[DJL]

I used to focus with a Bahtinov mask but when I took up Ha RGB combination, I found it hard to focus the Ha because it's fainter. When I got my EAF I noticed that all my subs were a lot sharper, and it made me critical of anything I had captured previously. By all means learn to focus manually, but getting an EAF will save time and provide more consistent results.

[DJL]

Thank you. I saw those but I have not a clue what I need from there and it looks harder to use than the ZWO. They do tease me with a possibility for a rotator though ! (Oh the slippery slope) but I don't need a rotator until I get a better mount

 

I'd put off the focuser, but w/out GOTO, I am just thrashing around on focus and ruining good imaging nights

Goto is probably a higher priority. However, after spending 2 hours failing to find Andromeda, this was a game changer: https://www.youtube....70L3yEu_rw&t=7s - how to star hop in an organized manner rather than flailing around.

[Borodog]

Ah; did not realize you were using a dslr. In that case I do not use a mask, as the diffraction patterns are usually too small and faint to make out. The best I can do in that case is find the brightest first magnitude star in the sky, crank up the ISO to -10000 and use the focus magnifier. All the people that tell me that more faint stars pop up when you are in focus, I have to idea what they are talking about, as faint stars are never visible under any circumstances.

[Mike in Rancho]

Problems

 

1. I am never in focus because I cannot see stars in LiveView and have to take 4 second test shots over & over

2. I don't have GOTO and so I have to spend ages finding a bright star to focus on before going to my target. This then puts me out of Polar alignment

3. Big temp changes overnight in summer -- no easy way to refocus during a session

 

This is costing me a lot of images and time. Agree, learning the ropes is important but I don't get many clear nights

We have to figure out why you can't see stars in live view, with the same camera.  Now yes some areas are too dark, this month's M78 being one example, but most targets have some stars around that should show up, especially if you can slew back and forth a bit.  Can you slew around, even if you cant GOTO?  I don't know much about small trackers, I suppose I should read up on them just to know.

[RogerM]

Problems

 

1. I am never in focus because I cannot see stars in LiveView and have to take 4 second test shots over & over

2. I don't have GOTO and so I have to spend ages finding a bright star to focus on before going to my target. This then puts me out of Polar alignment

3. Big temp changes overnight in summer -- no easy way to refocus during a session

 

This is costing me a lot of images and time. Agree, learning the ropes is important but I don't get many clear nights

For live view focusing I just ramp up the ISO on my DSLR so that I can image focus at around 1/30 sec. There's no need to suffer 4 seconds!

 

When I first started I went the live view route and suffered for a spell.  It worked well enough at extremely wide field (when I shot at prime 28mm or 14mm) but obviously wasn't the best way.  I eventually printed a Bahtinov mask and that made a huge difference in setting focus.  It also made it easier to check focus during the course of an observation period, I simply plopped the mask onto the front of the lens. More on focusing in a bit...

It's best to develop a strategy that makes good use of time (I have limited observation time on nights that I can get out) and for me it helps to prioritize steps as well as to build up a consistency that made it easier to figure out a solution when something wasn't working properly.  Really makes a difference in keeping the frustration factor at bay.  Now with having moved to my present set-up I've made a few changes to my process but essentially it applies to both my terrestrial and astro based set-ups.

 

Initial set-up (includes a rough PA, I eyeball by boresighting along my scope's dovetail plate and go right to focusing the telescope.  I typically have a choice between using Aldebaran, Capella, Deneb or Arcturus which gives me a focusing target in just about any direction in the sky.

 

Point scope towards target region.  This sets up the mount/tripod with the weight/balance in the "in use" position. Only then with the setup's overall balance static (no more RA/DEC slew movements of the telescope) do I then do my polar alignment.  Since I have the iPolar, I keep the app running in the background so that I can check PA during the course of a specific target's observation period and make adjustments as necessary.

 

During an observation period, I use APT's "Focusing Aid" tool to check/adjust focus of my astro imaging train (or Bahtinov mask for my terrestrial set-up.) Using the right tools when doing things manually makes a huge difference...be it a Bahtinov Mask/live view method or using science via FWHM/HFD tool as an essential focusing aide.  If you aren't able to buy or make a Bahtinov Mask let me know and I'll print one for you (I hate seeing someone suffer.)

 

Patience and consistency in what steps you follow are a huge asset. I take every imaging session as a classroom lesson and try to learn something new each time.  There'll always be something to counter (like freezing my butt off during winter nights ) and I've had my share (and still do) of the focusing wars but I'm getting more on top of it with each outing.  Eventually I may go the EAF route but there's something quite satisfying knowing that I can achieve this one step, manually, even when swapping between supposedly par focal filter elements.

 

As for locating targets, hopefully you have one of the astronomy apps at your disposal.  I primarily use SkySafari and the Observe--Scope Display tool to manually plate solve my target's location.  I've done this enough times now for a few of the more popular beginners targets like M42, M31, NGC7000 that I can now find them without using the app and just looking up.  It all gets easier in time.

Edited by RogerM, 24 January 2021 - 08:26 PM.

[AstroVagabond]

 

My opinion is that a hard prerequisite to adoping automatic focus, is that you must be able to manually focus accurately and easily first.  

I'm a beginner just 30 days into the journey so are you saying automated focusers are not able to achieve focus reliably and consistently? I see many people use them and the demand with associated supply chain issues seem to make them unavailable at the moment.

 

I ask because I have one on my roadmap for a purchase later this year to pair with my Zenithstar 61. I don't want to waste money if they do not work.

 

Thanks!

[jonnybravo0311]

I'm a beginner just 30 days into the journey so are you saying automated focusers are not able to achieve focus reliably and consistently? I see many people use them and the demand with associated supply chain issues seem to make them unavailable at the moment.

 

I ask because I have one on my roadmap for a purchase later this year to pair with my Zenithstar 61. I don't want to waste money if they do not work.

 

Thanks!

They work.

 

The point Wade was making was that it is essential to learn to focus manually because you don't want to be up the creek if/when that magic auto-focuser up and dies on you... or suddenly isn't working quite right... or any number of other goofy things (like a USB cable gone bad or Windows deciding it's having a bad day, and doesn't recognize your USB device any longer).

[WadeH237]

Problems
 
1. I am never in focus because I cannot see stars in LiveView and have to take 4 second test shots over & over

This isn't really a problem.  We all do this.  I can easily focus my system manually in less than a minute doing this.
 

2. I don't have GOTO and so I have to spend ages finding a bright star to focus on before going to my target. This then puts me out of Polar alignment

Do yourself a favor and get a Telrad.  Once the Telrad is adjusted to be aligned with your scope, you can easily center any bright star in the Telrad, and it will be near the center of your eyepiece.  It will allow you to point at a star suitable for focus in seconds.  Also, pointing the telescope should not affect your polar alignment, so there is some kind of issue with your process here.
 

3. Big temp changes overnight in summer -- no easy way to refocus during a session
 
This is costing me a lot of images and time. Agree, learning the ropes is important but I don't get many clear nights

Refocusing due to temperature changes is probably the best reason to go with automated focusing.

 

The thing is, if you are spending time acquiring and framing targets, including a star to focus on, then I would consider this to be a priority over anything else.  You really need to solve that problem before investing in automated focusing.

[WadeH237]

They work.

 

The point Wade was making was that it is essential to learn to focus manually because you don't want to be up the creek if/when that magic auto-focuser up and dies on you... or suddenly isn't working quite right... or any number of other goofy things (like a USB cable gone bad or Windows deciding it's having a bad day, and doesn't recognize your USB device any longer).

This.

 

Automated focusing isn't magic, and it's definitely not bullet proof.  I've been doing automatic focusing for almost 15 years and I image fully automated and hands off.  I recently made a configuration change that caused me to swap focus motors on my OTA, which invalidated the focuser settings I'd been using for a while.  I also switched from SGP to NINA to automate my sessions.

 

Between these two things, it's taken me about 2 nights of testing and adjustments (both hardware and software settings) to get the focuser dialed in so that it hits best focus in all of the conditions that I expect to see.  There were two fairly distinct phases to this.  When I ran the autofocus routine the first time, it failed to find a coherent focus curve.  This was a matter of getting the focuser step size and range set up correctly.  Once I got it to start making focus curves, I spent time fine tuning the system to get the shape of the focus curve consistently correct (I was using the shape of the curve to infer what was happening at the hardware level).  This was a matter of determining the direction that it was turning the focus knob, and then getting focuser backlash compensation set up properly.

 

Once you get it all done, it's then hands off.  I expect that I'll pretty much forget about focus from now, until I make another change to the system that invalidates the current focuser settings.  But setting up automated focus is typically not plug-and-play.  And even once it's set up, there will be the occasional glitch, and it's nice to understand what's going on, and whether it needs attention or whether it will be transient.

Edited by WadeH237, 25 January 2021 - 09:04 AM.

[limeyx]

Thank you all for your advice. 

 

Right now I use plate solving and not a RDF or similar to align, and I don't really want to invest in more stuff that won't grow into new gear (so I don't plan to get finders, better tripods etc)

 

My plan is to get a better mount in the next 1-2 months, but right now everything is backordered. I was trying to hold out for a CEM40 but thats going to take longer so I may have to get the 26 and upgrade later

 

I don't have the iPolar, but use SharpCap to do PA, so it's difficult to adjust once I am framed. Yes, I can use the reticle but the reason I don't use that is because SharpCap is in theory better.

 

My current process is

- Polar align with reticle

- Polar align with Sharpcap

- Plate solve to a bright star and use mask - I had a SLR lens with Bahtinov mask and mostly got that dialed in. Now I have a scope with a Carey Mask and this was really difficult to use. 
I use APT to plate solve because with NINA its hard(er) to see where I am in Stellarium, whereas APT makes that easy

- Focus

- Plate solve to the target with APT

- Intent is then to use NINA to image (once I get a better mount it will all be in NINA)

 

The more I touch the mount, the more I have a chance to affect PA and then I only have PHD2s reports of PA error to go on (and since I cannot guide in DEC, I can't really fix much)

 

Then, if focus changes during the night, I'd have to either try to refocus on target, or again slew manually off & back - a real pain

 

I *could* change the order of Sharpcap and focus first, then come back and use SharpCap (for when the focus star is not near my target at least) which would help a bit

 

I can afford both the focuser and a better mount, but not the mount immediately. So It seemed reasonable to get the focuser, work with that and then integrate the new mount and NINA so I can automate most of this

 

Totally appreciate the advice on learning it manually, and I definitely need to be able to diagnose.

 

However, if I had refrained from plate solving and tried to star hop (especially in my skies), I would have virtually no images because I'd spend forever finding targets (plus even with a 30sec+ exposure at high ISO, I cannot see many targets, even when stretched)

 

I really appreciate the time everyone took to respond. A lot to think about

[DubbelDerp]

I think you definitely should get the focuser, because when I eventually get one as well I can ask you how to use it! 

[limeyx]

I think you definitely should get the focuser, because when I eventually get one as well I can ask you how to use it! 

That would be a change from me asking you eleventy-eight dumb questions every week

[AstroVagabond]

They work.

 

The point Wade was making was that it is essential to learn to focus manually because you don't want to be up the creek if/when that magic auto-focuser up and dies on you... or suddenly isn't working quite right... or any number of other goofy things (like a USB cable gone bad or Windows deciding it's having a bad day, and doesn't recognize your USB device any longer).

Fortunately my scope only has two control knobs, a course one and a fine one. Seems using the bohtinov mask with the bohtinov focus aid in APT has allowed me to get an acceptable focus. And if my PC is having a bad night I'm up the creek without a paddle anyway because it controls my mount, camera, and guiding software. 

 

What learning how to focus manually does not help me with is the changes in ambient air temperature along the course of the night. As they decrease my OTA, the focuser drawtube, and other parts of the telescope and imaging train will contract as they cool as well. As this contraction occurs the focal point of light my optics make changes location relative to my camera sensor.

 

These changes impact my focus based upon my current knowledge as a beginner. It is my understanding some auto focusers can compensate for these changes. While I have much to learn if in fact ambient air temperature changes do affect my focus along the night, and there is a solution through use of an auto focuser, implementing one sooner than later may make sense even if it limits the time I get to experience manually focusing my telescope.

 

But I totally agree, in particular with me being a beginner, that it's important to understand the fundamentals. Taking the time to do so will set me up for success if I have to trouble shoot which I hope is kept to a minimum!   

Edited by AstroVagabond, 25 January 2021 - 12:26 PM.

[mrlovt]

...Then, if focus changes during the night, I'd have to either try to refocus on target, or again slew manually off & back - a real pain

 

I *could* change the order of Sharpcap and focus first, then come back and use SharpCap (for when the focus star is not near my target at least) which would help a bit

 

I can afford both the focuser and a better mount, but not the mount immediately. So It seemed reasonable to get the focuser, work with that and then integrate the new mount and NINA so I can automate most of this

 

Totally appreciate the advice on learning it manually, and I definitely need to be able to diagnose.

 

However, if I had refrained from plate solving and tried to star hop (especially in my skies), I would have virtually no images because I'd spend forever finding targets (plus even with a 30sec+ exposure at high ISO, I cannot see many targets, even when stretched)

 

I really appreciate the time everyone took to respond. A lot to think about

There's definitely a balance between learning the basics and taking advantage of available tools.  The previous comments about autofousers are spot on.  They work well, but they aren't perfect and sometimes they don't work.  In that case the more familiar you are with the fundamentals, the easier it will be for you to diagnose problems that arise.  That's true of most good equipment. 

 

Your order of operations seems good, as long as you start off pretty close to focus anyways.  SharpCap focus tools are very helpful, take full advantage of them.  I found the bahtinov mask focus tool to be the best for me.

[jonnybravo0311]

What learning how to focus manually does not help me with is the changes in ambient air temperature along the course of the night.

No, it sure doesn't, and this is one of the biggest advantages of an auto-focuser for hands-off imaging. Most, if not all, of the software allows you to set parameters like "if temperature changes X degrees" and "every Y amount of time regardless of temperature change" and "every time the filter wheel spins and changes the filter".

 

That, and let's face it, the camera and computer working in conjunction with each other to obtain the best focus is much more likely to be accurate than me using the old Mk1 eyeball looking at spike patterns

[RogerM]

Limeyx,

 

I'm not the fastest but eventually I catch on to things...

 

Thank you all for your advice. 

 

Right now I use plate solving and not a RDF or similar to align, and I don't really want to invest in more stuff that won't grow into new gear (so I don't plan to get finders, better tripods etc)

 

My plan is to get a better mount in the next 1-2 months, but right now everything is backordered. I was trying to hold out for a CEM40 but thats going to take longer so I may have to get the 26 and upgrade later

 

I don't have the iPolar, but use SharpCap to do PA, so it's difficult to adjust once I am framed. Yes, I can use the reticle but the reason I don't use that is because SharpCap is in theory better.

 

My current process is

- Polar align with reticle

- Polar align with Sharpcap

- Plate solve to a bright star and use mask - I had a SLR lens with Bahtinov mask and mostly got that dialed in. Now I have a scope with a Carey Mask and this was really difficult to use. 
I use APT to plate solve because with NINA its hard(er) to see where I am in Stellarium, whereas APT makes that easy

- Focus

- Plate solve to the target with APT

- Intent is then to use NINA to image (once I get a better mount it will all be in NINA)

 

The more I touch the mount, the more I have a chance to affect PA and then I only have PHD2s reports of PA error to go on (and since I cannot guide in DEC, I can't really fix much)

 

Then, if focus changes during the night, I'd have to either try to refocus on target, or again slew manually off & back - a real pain

 

I *could* change the order of Sharpcap and focus first, then come back and use SharpCap (for when the focus star is not near my target at least) which would help a bit

 

I can afford both the focuser and a better mount, but not the mount immediately. So It seemed reasonable to get the focuser, work with that and then integrate the new mount and NINA so I can automate most of this

 

Totally appreciate the advice on learning it manually, and I definitely need to be able to diagnose.

 

However, if I had refrained from plate solving and tried to star hop (especially in my skies), I would have virtually no images because I'd spend forever finding targets (plus even with a 30sec+ exposure at high ISO, I cannot see many targets, even when stretched)

 

I really appreciate the time everyone took to respond. A lot to think about

It finally clicked (I'm not the quickest but eventually I catch on...), you're shooting with the D5300 correct?  There was a thread not too long ago that discussed DSLR focusing,  perhaps this fellow's suggestion will help you in the interim until you get an autofocuser, its the last paragraph in his post...D5300 live view tip.

[Saganwannabe]

I'm a relative beginner myself (13 months) and I can wholeheartedly recommend getting an autofocuser.  Not only has it improved my focus, it also allows me to sleep.  With NINA, I usually set my sequence so that autofocus runs at the start, on any filter change and if HFR increases by 10%.  I used to focus with a Bahtinov mask which works fine, but it requires focusing on a bright star and also requires my presence at the telescope. If you're hooked on this hobby and think you'll be at it for a while, an autofocuser is a must in my opinion.

Tim