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Manually guiding for short exposures?

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#1 kevinrodgers22

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Posted 03 December 2021 - 01:10 PM

I know manually guiding today is considered nuts with todays auto guiding, plate solving technology, but i was curious if anyone still does it or has advice on how to do it. 

 

I just bought an ASI294 cam and a cheap used OAG (no manufacturer markings). I plan on mostly doing EAA (live stacking), but I'de like to maybe dabble with longer exposures at some point (five minute-ish). My LX-50 f/6.3 is pretty primitive, it does have the option for auto guiding, but I hear results are hit and miss. Not to mention I've been told my vintage  OAG may be just for illuminated eyepiece use. I also dont want to invest $200 into a guide camera that may or may not work. 

 

I read that astrophotography tracking used to be done by hand control, be it via remote or knob, and the implementation of illuminated eyepiece. Is this something I can do with my setup? The mount seems to track well with a good polar alignment. Could I use a high magnification illuminated eyepiece to help with slight adjustments? Or could I even attach cross hairs to the monitor for alignment adjustments. 

 

I've attached some pictures of my OAG, ST4 slow motion joystick I currently have.

 

Any feed back would be helpful. 

 

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#2 bobzeq25

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Posted 03 December 2021 - 01:28 PM

Feedback. 

 

Hand guiding is way too labor intensive for me, for marginal results (some things really need a computer).  Not a close call.

 

If you want to do long exposures at that focal length, you need a good (and expensive) German equatorial mount.  Not the cheap SCT fork mount.

 

And, with that good mount, with an SCT, you need to autoguide with an OAG.  The minimum camera for that is a 290MM mini.

 

All things considered, I think EAA is a much better activity for you.  Traditional imaging is complicated and expensive.  Trying to get into it with an SCT (particularly on a fork), is something that generally leads to failure.  You need an equatorial mount and a small refractor.  Or use a camera tracker and a camera lens.  These experiences are not at all unusual, they're to be expected.  Thinking that you'd be different risks a lot of your time and money.

 

"I regret spending the first 6 months trying to learn imaging with an 8" Edge, with that scope it was a losing effort. Fortunately got a nice little refractor, and not only have the quality of my images improved but I'm actually enjoying the process of learning how to do it!"

 

"I put together a video of my imaging rig along with some info on how I went from years of failure trying to image with a long focal length SCT, to achieving success on my first image."

 

https://www.youtube....h?v=MNQU1hdqz4M

 

"I started out with a CPC 800 on a heavy duty wedge.  In hindsight, I'd have started with an 80mm refractor.  I would have saved a lot of money and gotten up the learning curve a lot quicker."

 

Etc.  There's a _lot_ of etc.  <smile>


Edited by bobzeq25, 03 December 2021 - 01:38 PM.


#3 OldManSky

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Posted 03 December 2021 - 01:37 PM

Back in the film, pre-ST-4 days, I used to manually guide all the time.  For hours and hours.

 

Given that you can get a very good autoguiding camera for < $100, and the software is free, I wouldn't think of doing it manually again.  Ever.

If you want to...get a 12.5mm reticle eyepiece, put it in the OAG, center a star, and spend time chasing a guide star with your joystick.  It's hard.  It requires concentration and practice.  And still the cheap guide camera and free software will beat you by a mile.  Just sayin' :)

Good luck.


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#4 Alex McConahay

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Posted 03 December 2021 - 02:04 PM

>>>>>>>I read that astrophotography tracking used to be done by hand control, be it via remote or knob, and the implementation of illuminated eyepiece. Is this something I can do with my setup? The mount seems to track well with a good polar alignment. Could I use a high magnification illuminated eyepiece to help with slight adjustments? Or could I even attach cross hairs to the monitor for alignment adjustments.

 

Sure you can do it. People did it successfully for a long time. I did it. I'm old.  Not difficult, really, just tedious. As a matter of fact, I would suggest you give it a try. You already have the OAG, and you ought to be able pick up a reticle eyepiece somewhere for relatively cheap. It is nicer if it is illuminated, but people can guide without illumination. You just have to be able to tell where your guide star is in relation to the dim black lines on a dim sky. (This gets progressively harder to do as you move to darker skies.) Illumination is much better. But if you are paying much for the illuminated reticle, it would be better to save for an autoguide camera. But, it can be done. 

 

Your joystick should work, assuming it moves the scope when you move the stick. Just be careful you learn to just tap it so that you do not overdo the guiding. If it also had pushbuttons such that one push moved a specified distance, it would be even better. 

 

Before you go out and spend money on a reticle eyepeice, be sure to put your rig together, including the main imaging camera, and the OAG, and one of your existing eyepeices. And give it a try. Can you even stick your head into the area left for it?  Does everything come into proper focus? Main imaging camera and OAG? Can you guide at all----that is, even without a reticle, you can tell if something is drifting. Don't look at the center of the image for your guide star.....pick something along the edge of the Field of View----is the guide star moving in relation to the edge? If so, what happens when you touch the joystick? 

 

If your experiment works out, then look into spending on the reticle eyepeice, and try it all again.  

 

Having said all that, I think it would be fun to do. At least once or twice. 

 

>>>>>>>>Or could I even attach cross hairs to the monitor for alignment adjustments.

I do not understand how this could happen. What are you monitoring? The image from the main camera? No, you cannot monitor it because it happens only at the end of the exposure, when the subframe is already ruined by the bad tracking.  You have to correct in near real time, like every four to six seconds.....maybe longer depending on your standards and tracking, and all that. (And if you had a camera that could do that sticking in your OAG-----you would be using autoguiding!)

 

 

>>>>>>>I read that astrophotography tracking used to be done

You make me sound so old. 

 

 

Alex


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#5 kevinrodgers22

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Posted 03 December 2021 - 02:28 PM

Back in the film, pre-ST-4 days, I used to manually guide all the time.  For hours and hours.

 

Given that you can get a very good autoguiding camera for < $100, and the software is free, I wouldn't think of doing it manually again.  Ever.

If you want to...get a 12.5mm reticle eyepiece, put it in the OAG, center a star, and spend time chasing a guide star with your joystick.  It's hard.  It requires concentration and practice.  And still the cheap guide camera and free software will beat you by a mile.  Just sayin' smile.gif

Good luck.

Thanks guys, I appreciate the candor. 

 

I dont think I was really clear on my objective-expectations. I'm definitely not chasing the magazine quality  horse head nebula image. I was just thinking that during an EAA session if the mood struck, if I could do a manual guide to bump up my exposure time a few minutes. More specifically if there is a preferred method now a days to do it, i.e the use of a live video monitor or illuminated eyepiece..

 

I have doubts my cheapy OAG would even work with a low cost guide camera. I've read posts of people having luck with asi120m's on a lot of objects with a similar setup, but most seem say a 178 is the only way to go. Most of these people use ZWO OAG's with large pickoffs though. Back in the 90's my scope was sold with a stand alone 201x auto guider, but it resulted in several suicides so they quit including it.

 

 

During visual observation of DSO's, I generally spend 10-15 minutes at the eyepiece anyways. Adding an element of concentration-focus sounds kind of interesting to me. Developing skill in manual input to increase image output might be something I enjoy, I'm weird like that. I figure if it doesn't work I can always eat the additional $28 investment in the illuminated eyepiece, or maybe just use it as a polar alignment tool. 

 

I'm sure I'll defork in the future and spend the $800 on a better mount...I'm just trying to pull the most out of what I got right now. 


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#6 Alex McConahay

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Posted 03 December 2021 - 02:35 PM

>>>>>>>More specifically if there is a preferred method now a days to do it, i.e the use of a live video monitor or illuminated eyepiece..

 

If you can see a star in the live video monitor, you can autoguide off of it by adding PHD2......Why would you think of using a manual guide at that point? 

 

Alex



#7 kevinrodgers22

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Posted 03 December 2021 - 02:55 PM

Thanks, yeah I never thought about the live stacking delay...I would have to use a separate camera which then at that point it would be more cost effective to just give auto guiding a shot. They do sell super cheap eyepiece video cameras, but Im sure they wouldn't be able to pull a star off the tiny prism.  It would be nice to sit and align in comfort 

 

I tried that route but my mount isn't ASCOM compatible (no serial port), otherwise I would use PHD2 or plate solving..very frustrating



#8 klaussius

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Posted 03 December 2021 - 02:57 PM

Back in the film, pre-ST-4 days, I used to manually guide all the time.  For hours and hours.

 

Given that you can get a very good autoguiding camera for < $100, and the software is free, I wouldn't think of doing it manually again.  Ever.

If you want to...get a 12.5mm reticle eyepiece, put it in the OAG, center a star, and spend time chasing a guide star with your joystick.  It's hard.  It requires concentration and practice.  And still the cheap guide camera and free software will beat you by a mile.  Just sayin' smile.gif

Good luck.

When I started doing guiding, I started with manual guiding, followed by semiautomatic guiding.

 

What I would do, is measure PA-error-induced drift, measure how often I had to push the button to minimize it, and I would sit next to the mount while the intervalometer snapped pictures, pressing the button like a human clockwork machine.

 

Then I built a little device that did the same automatically with a timer connected to the ST-4 port, with a bit of electronics in-between.

 

It was a nice experiment, but it was very labor intensive. Both versions.

 

The results let me take 30" or 60" subs of relatively high quality with a mount that unguided couldn't handle 15", so it's better than nothing, but I don't think you can get good results with 300" subs with that method. It's just not precise enough.



#9 Alex McConahay

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Posted 03 December 2021 - 03:30 PM

     >>>>>>tried that route but my mount isn't ASCOM compatible (no serial port), otherwise I would use PHD2 or plate solving..very frustratin

 

Guiding does require an "ST-4 port" also known as a "Guide" port or the ASCOM/Serial port. 

 

It does not require an ASCOM or serial port.

 

Does your mount have an ST-4 port?

 

Alex


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