Which one would be most helpful to improve my astrophotography, autofocuser or autoguiding ? - Forums

Topic starter

Sep 26, 2023

Hello,

My current equipment is:
Canon 600D
Samyang 135mm f/2.8
Star Adventurer GTI
Asiair plus

By the end of the year I want to get a ZWO EAF, a ASI120MM-S guiding camera with the ZWO guiding scope however on the short term I can only afford either the EAF or the autoguiding equipement…….and I can't decide which one to get, that's a nice problem to have

I have tried 5 minutes exposures but my stars aren't exactly round so I am thinking autoguiding would improve that but I am also not super good with manual focusing using a bahtinov mask so there is room for improvement there.

So I am left wondering which would help the most, longer exposures with autoguiding or better focusing with the EAF and reducing my exposures to 3 minutes ?

Engaging

Marc Monarcha

Sep 26, 2023

I would go for autoguider. You can for sure learn how to get better at manual focus! Takes practice, but also trial and error within one session to reach optimal focus.

Haakon Rasmussen

Sep 26, 2023

I agree with Marc. Autoguiding with dithering will bring your Fotos one step further.

CS Haakon

John J. DeAlessio III

Sep 26, 2023

In the short term, I also think that you should go with autoguiding. There's a lot of great choices out there, and one place I would recommend purchasing autoguiding equipment from would be Agena Astro.

Well Written

Eric Gagne

Topic starter

Sep 26, 2023

Well, the discussion won't be very long, I just ordred an ASI120MM Mini with the ZWO Guide scope. I forgot to say I am using an Optolong L-Enhance filter. I had not considered this but reducing my exposure time would actually make me lose light, at least that's what I understan from reading this article on HowToAstro.

The next few nights will have clear sky but also moon so I guess it will be the perfect time to practice my focusing.

Mark, Haakon, thank you for your answers.

Eric Gagne

Topic starter

Sep 26, 2023

John J. DeAlessio III:
In the short term, I also think that you should go with autoguiding. There's a lot of great choices out there, and one place I would recommend purchasing autoguiding equipment from would be Agena Astro.

Thanks to you too John. I know Agena Astro is a great store but I am in Canada, the extra cost of shipping and duty make it hard to order from any store in the USA. Fortunately we have a few good ones on Canada as well. And currently, only one has both items in stock so I went with them, they are listed in the dealers page in ZWO's site so I assume I can buy with confidence although I don't know them.

Jonathan Saine

Sep 26, 2023

Both will ultimately become indispensable to you but I say start with the autoguider. For focusing, you should be able to find a 3D printed Bahtinov mask to fit that lens. Yep, $10-15 on eBay. Money well spent. Good luck.

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Joe Linington

Sep 26, 2023 · Edited: Sep 26, 2023

The problem with a 135mm is it’s too short for a standard Bahtinov mask. It benefits with a custom mask with a finer pitch. Here is a link to a file to 3D print one. What province are you in?

https://www.thingiverse.com/thing:2168672l

Concise

Howard Richard

Sep 27, 2023

Try one minute exposures.

Plus one for the new Autoguider.

Eric Gagne

Topic starter

Sep 27, 2023

That seems to be the best I can do with the mask I have. I thought it was good but now I wonder.

https://telescopescanada.ca/products/w2381aa

Eric Gagne

Topic starter

Sep 27, 2023

Joe Linington:
The problem with a 135mm is it’s too short for a standard Bahtinov mask. It benefits with a custom mask with a finer pitch. Here is a link to a file to 3D print one. What province are you in?

https://www.thingiverse.com/thing:2168672l

I'm in Quebec. Unfortunately I don't have access to a 3d printer. Anyway it probably won't be long before I get the EAF, I can never go long without getting some new toys.

Marc Monarcha

Sep 27, 2023

Eric Gagne:
That seems to be the best I can do with the mask I have. I thought it was good but now I wonder.

https://telescopescanada.ca/products/w2381aa

I think it looks good! To my eye it would need just a slight adjustment where the middle spike would go a bit further to the right, but nothing too serious, so don't beat yourself too much on it if you cannot get it there

RadMan24

Sep 27, 2023

You may be better off buying a newer camera (even if used) to get better technology and image quality, while also taking shorter exposures to avoid the need for guiding and improving the overall dynamic range of your images due to less impact from sky and air glow. At 135mm focal length, you should only have to focus once and perhaps 30 minutes after for the entire night, unless the temperature drops significantly, then maybe every hour or two.

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Eric Gagne

Topic starter

Sep 27, 2023

Marc Monarcha:
Eric Gagne:
That seems to be the best I can do with the mask I have. I thought it was good but now I wonder.

https://telescopescanada.ca/products/w2381aa

I think it looks good! To my eye it would need just a slight adjustment where the middle spike would go a bit further to the right, but nothing too serious, so don't beat yourself too much on it if you cannot get it there

You're right. I didn't see it but now that you said it I can see the the middle spike is not perfectly centered.

Eric Gagne

Topic starter

Sep 27, 2023

You may be better off buying a newer camera (even if used) to get better technology and image quality, while also taking shorter exposures to avoid the need for guiding and improving the overall dynamic range of your images due to less impact from sky and air glow. At 135mm focal length, you should only have to focus once and perhaps 30 minutes after for the entire night, unless the temperature drops significantly, then maybe every hour or two.

It's in my plans but not for a while. I bought this one only 5 months ago and paid to have it modified, I'll try to use it as much as I can......though it may not be much since I found out yesterday the shutter count is over 108 000

B0bby White

Sep 28, 2023

I used a year a bit similar setup (Samyang 135 + Canon 2000D(a)+AZ-GTi).
Both of improvements (EAF & Guiding) huge step forward. But while you using DSLR you easily can done manually focusing: just using canon screen magnification (x10) and trying get a little spot as you can achieve(without or minimal red fringe). Guiding will gives you some important thing: long sub exposures (5') (especially for DLSR it's important) and dithering.
EAF makes your life a little bit easy and it's really necessary when you switch to dedicated cooled camera. Or full night session fully automated and your imaging place affected by significant night temperature fluctuations (my experience: Samyang 135mm - tolerant lens to temp shift. While it's 3-5 degrees I've don't worry about).

James Tickner

Sep 28, 2023

Just a comment on purchasing an EAF for use with the Samyang lens - you might not need it!

I recently acquired a Samyang 135 mm F/2 lens for wide-field imaging and rigged up a bracket, 3D printer gear wheel and belt to allow me to use my existing ZWO EAF. I used the EAF once and then dismantled the whole thing. I've found that the lens holds focus really well and doesn't exhibit much shift with temperature, meaning that focus doesn't really change through the night, or even from night to night. I use the star HFR report in Nina to check focus (quicker and more accurate than a Bahtinov mask) and once every few nights might need to just manually touch up the focus, but that only takes a couple of minutes.

And at the risk of straying off topic, the Astrobin Community Survey - AstroBin is always looking for volunteers with a wide-field setup (the Samyang 135 mm is perfect) to help with our whole sky imaging project. Drop me a line if you have any interest!

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dkamen

Sep 28, 2023

There is a spectrum with large reflecting scopes+metal tubes+cheap focusers and 1.25" nosepieces on one end, small lenses with helical systems and native DSLR mounting on the other, everything else in between.

I have been using the Samyang 135mm at f/2.8 with my Nikon since early June and only had to refocus once. And that was because I detached the lens to clean up a dust mote that was getting too annoying, rotating the focus ring while doing so.

Eric Gagne

Topic starter

Sep 28, 2023

James Tickner:
Just a comment on purchasing an EAF for use with the Samyang lens - you might not need it!

And at the risk of straying off topic, the Astrobin Community Survey - AstroBin is always looking for volunteers with a wide-field setup (the Samyang 135 mm is perfect) to help with our whole sky imaging project. Drop me a line if you have any interest!

It looks like an interesting project but I am afraid at this point I don't have the knowledge to participate. I only started AP a few months ago, I have no prior knowledge of astrophotography or astronomy, I still have a lot to learn. I read the following and have no idea what field size and arcsecs/pix mean.

The ABC Survey team would like as many people as possible to take part. While the quality principle drives us to a prescribed observing and processing pipeline under relatively dark skies (Bortle 4 or better), the field size (9 x 6 deg) and resolution (at least 10arcsec/pix) has been designed to be inclusive of imaging systems with focal lengths 85-250mm and both full frame and APS-C sized sensors.

I don't think I could contribute anything valuable.

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Abdul Thomas Jnr

Sep 28, 2023

Definitely an autoguider. Makes a huge difference. I've got the Rasa 8 for about a year now and I have always use a bahtinov mask at F2 but my stars are good. In my eyes anyway. Check my images to see yourself. All done with a bahtinov mask

Eric Gagne

Topic starter

Sep 28, 2023

=16pxAnyway it probably won't be long before I get the EAF, I can never go long without getting some new toys.

Some of you may have seen this..........well guess what........

I should receive everything tomorrow.

Thx everyone for all the answers, all very informative.

Abdul Thomas Jnr

Sep 28, 2023 · Edited: Sep 28, 2023

Eric Gagne:
That seems to be the best I can do with the mask I have. I thought it was good but now I wonder.

https://telescopescanada.ca/products/w2381aa

*** You are slightly out of focus. Central line could move slightly to the right***

Robert Gillette

Sep 29, 2023

Having used a Bahtinov mask for years, I’d say your focus is not quite spot-on. The central spike is not perfectly centered.

Once you do get your EAF, move to auto focusing. I’d recommend FocusMax, which is now $150, but the gold standard for auto-focus. Takes some study of the tutorials and manual, but worth the effort.

As for round stars, make sure your polar alignment is as good as you can make it, to minimize drift —and, when you start guiding, to minimize the corrections it has to make.

Astroimaging involves a long learning curve, but will reward you with increasingly better images as you climb it.

CS, Bob

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