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New OTA or Camera - Advice Please!

Canon EOS 600D / Rebel T3i / Kiss X5 ZWO ASI533MC Equipment CMOS Buying Advice
Mark Germani
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Upgrading from a Zenithstar 61 with a Canon DSLR, which option would be best?
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Mark Germani avatar
Mark Germani avatar
Hi folks:

I'm in the fortunate position of being able to upgrade my astrophotography setup. I have two strong options at the moment, and I'm wondering if anyone would like to weigh-in and offer their thoughts.

First option, which I was all set to move forward on, was purchasing an ASI533MC-Pro for my Zenithstar 61. I'm currently using a Canon 600D DSLR which has been astro-modified. I'm happy with the camera but it has some banding, and it's noisy, especially in the summer when I'm doing long exposures with the L-eXtreme. I would opt for the ASI2600MC-Pro but it's twice my budget.

Second option, which has only just presented itself, is a used FRA400 - the very telescope I have been favouring as an eventual upgrade to my Zenithstar 61. I haven't really looked into the condition of the telescope (store says excellent) or its story, and it may end up sold before I move on it, but it's giving me some second thoughts about the dedicated camera. My Zenithstar's CA has always bugged me, and it has a tilt issue which I haven't been able to sort. Even if the used one sells, I could probably afford a new one if I sell my Zenithstar.

The new telescope is tempting, but I'm feeling like the camera is a logical next step, as the Z61 is a serviceable OTA, and the smaller sensor on the ASI533 will be more forgiving of the CA/tilt as these are worse towards the edges.

Of course, if I'm missing some other option that any of you might advise me to consider, I'd love to hear it. Thanks in advance for your help!

CS,
Mark
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A. Wegdan avatar
A. Wegdan avatar
Hey mark, if I were in your shoes I’d go for the camera first. You are going to see a significant improvement both in the quality and the ease of use of imaging. While the fra400 is an amazing little wonder, the improvement you will see in your images though considerable, will not be comparable to the jump from Dslr to dedicated. 

while DSLRs can produce amazing images, especially if modified, the amount of effort required in processing those is significantly more complicated as opposed to dedicated, and the Zenith star 61 is an excellent scope.

hope this helps 

CS
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Mark Germani avatar
Mark Germani avatar
Thanks Ahmed, that's really helpful advice. I kind of figured the jump from DSLR to dedicated camera might be more significant than from the Zenithstar to the FRA400.

Interestingly enough, the resolution of the FRA400 with my 600D is 2.21"/pixel, whereas the Zenithstar with the ASI533MC-Pro is 2.15"/pixel. so I'm not even gaining resolution with the longer FL (I know there are other factors, but apples-to-apples…)

CS!
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JohnBryantJr avatar
JohnBryantJr avatar
Having been down that road, I would go with the dedicated Pro ZWO camera 1st. After I decided to make the jump from a Canon 50D to a 183MC-Pro I was telling myself should have done this long time ago! 2600 is really the way to go, but hurts the pocket for sure!
Mark Germani avatar
Mark Germani avatar
Thanks John, this is making me feel much better about my gut instinct. And who knows, I might really want something other than an FRA400 a few years from now when I've saved up again.

Yeah, the 2600 would be ideal, but I don't often have that much money kicking around. I'd have to sell something to make it happen - maybe a lightly used ASI533? smile

Thanks a bunch!

CS,
Mark
Rob Kiefer avatar
Rob Kiefer avatar
I have a WO 61 as well plus tilt issue. Bought the Neumann CTU. Tilt was sorted. CA - interesting, not a big issue on mine. Maybe get a good UV+IR filter like Astronomik L-3. Except of the tilt, I really like the WO61. I would go for the camera upgrade and rather upgrade to an Esprit 100ED or similar. The FRA400 is too close to the WO61 in my opinion. Sort out the tilt and you will really enjoy the WO61.
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tjm8874 avatar
tjm8874 avatar
I think ASI294MC Pro is better option, more pixel size = bit more CA allowed.
Next I can recommend Askar FRA300 than FRA400 for great resolution.
300mm + m4/3 is good FOV for many deep sky objects.
Mark Germani avatar
Mark Germani avatar
Rob Kiefer:
I have a WO 61 as well plus tilt issue. Bought the Neumann CTU. Tilt was sorted. CA - interesting, not a big issue on mine. Maybe get a good UV+IR filter like Astronomik L-3. Except of the tilt, I really like the WO61. I would go for the camera upgrade and rather upgrade to an Esprit 100ED or similar. The FRA400 is too close to the WO61 in my opinion. Sort out the tilt and you will really enjoy the WO61.

Some great ideas - thanks Rob! That’s the second endorsement I’ve heart for the Neumann CTU. Expensive though!

I shoot in Bortle 7 (8 really) and I use an Optolong L-Pro. Do you think the L-3 is a better option for broadband?

The FRA is pretty close in aperture to the Z61, but I do like the f/3.9 reducer. We get a lot of cloud/rain here on the west coast of Canada, and I’d like a slightly faster system. The Esprit 100 would be amazing though!

CS!
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Mark Germani avatar
Mark Germani avatar
I think ASI294MC Pro is better option, more pixel size = bit more CA allowed.
Next I can recommend Askar FRA300 than FRA400 for great resolution.
300mm + m4/3 is good FOV for many deep sky objects.

Thanks for the suggestions!
Björn Arnold avatar
Björn Arnold avatar
Hi Mark, 

I support the idea of getting the camera. I also shot with a ZS61II and quality was excellent. You have to keep in mind that the 533 sensor is smaller and so off-axis aberrations will be less of an issue compared to an APS-C sized sensor.
If you haven’t done already try to see if the CA is inherent or an amplification through tilt or spacing to the reducer/flattener. You haven’t stated exactly how the CA appears and so I‘m just giving these general statements here.

With respect to another scope, I‘d like to recommend the ZS81 with its reducer as a possible option. Don’t know if you had considered it?

CS, Björn
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Rob Kiefer avatar
Rob Kiefer avatar
Mark Germani:
Rob Kiefer:
I have a WO 61 as well plus tilt issue. Bought the Neumann CTU. Tilt was sorted. CA - interesting, not a big issue on mine. Maybe get a good UV+IR filter like Astronomik L-3. Except of the tilt, I really like the WO61. I would go for the camera upgrade and rather upgrade to an Esprit 100ED or similar. The FRA400 is too close to the WO61 in my opinion. Sort out the tilt and you will really enjoy the WO61.

Some great ideas - thanks Rob! That’s the second endorsement I’ve heart for the Neumann CTU. Expensive though!

I shoot in Bortle 7 (8 really) and I use an Optolong L-Pro. Do you think the L-3 is a better option for broadband?

The FRA is pretty close in aperture to the Z61, but I do like the f/3.9 reducer. We get a lot of cloud/rain here on the west coast of Canada, and I’d like a slightly faster system. The Esprit 100 would be amazing though!

CS!

Hi Mark, yes, the CTU is not cheap but it works well. However, if you plan to use a smaller sensor camera like 1" or 4/3  then your tilt issue might not be a big issue anymore. I have no experience in shooting in Bortle 7-8 and how broadband works there. I assume using the L-Pro is already the right step. How are your stars looking like (CA)? Just surprised that it is so strong or filter related?
CS
AdamJ avatar
AdamJ avatar
Get the camera and a L3 filter to deal with the CA, it will improve your imaging way more than a new scope. But I would also recommend mono (183 or 533 )over OSC as that will solve your CA totally due to refocusing between filters and give you another massive increase in sensitivity even with a manual wheel and cheap filters. 

Adam
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Jens avatar
Jens avatar
Hey Mark
I was literally in your shoes. I have the exact same setup, the 600D modified and the zenithstar 61 with the L-enhance filter.
I just bought the ASI 2600mc Pro and man, best desicion ever.
you can see the difference between my most recent image (which is just 40min of exposures) to the ones before.
go for the camera!

And what made a huuuge difference as well was to get the test version of Pixinsight with the noise- blur- and star Xterminator plugins.
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Mark Ellis (PhoenixAstro) avatar
Mark Ellis (PhoenixAstro) avatar
The FRA400 you have listed is good, but not much more FL than the zenithstar that you have.  I would suggest maybe the FRA600 than later you can upgrade you camera from a canon to maybe a QHY 268M or 268C depending on if you want to go mono or stick with the OSC cameras.

It's just my 2 cents.  

Mark E.
Brian Puhl avatar
Brian Puhl avatar
I came.

I voted.

Have you thought about mono instead however?  You'll be light years ahead vs if you went OSC again.
Sean Mc avatar
Sean Mc avatar
Here’s my 2c to consider. Since the canon is astro modded, AND you’re looking to try to speed up imaging…. Maybe get a samyang 135 f/2. That’s if the focal length works for you.  

Then save up for a longer focal length and cooled astro cam later ¯\_(ツ)_/¯
Mark Germani avatar
Mark Germani avatar
Hi Mark, 

I support the idea of getting the camera. I also shot with a ZS61II and quality was excellent. You have to keep in mind that the 533 sensor is smaller and so off-axis aberrations will be less of an issue compared to an APS-C sized sensor.
If you haven’t done already try to see if the CA is inherent or an amplification through tilt or spacing to the reducer/flattener. You haven’t stated exactly how the CA appears and so I‘m just giving these general statements here.

With respect to another scope, I‘d like to recommend the ZS81 with its reducer as a possible option. Don’t know if you had considered it?

CS, Björn

Thanks for the input, Björn! Yes, it's my hope that the smaller sensor will help deal with the tilt, though it seems I have CA throughout the image, but only on certain stars - I don't know much about CA, so I'm not sure why/how that's happening. I have tried the whole split-into-RGB-restack trick, but it doesn't really seem to work. Perhaps it has something to do with the flattener backfocus? The tilt is pretty pronounced so I'm always splitting the difference between astigmatism in one corner and coma in the other.

I haven't considered the ZS81 - I figured I'd have better quality with a triplet than a doublet when it came to CA. Maybe I'll have to do some more research there. Thanks again for your thoughts!

CS,
Mark
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Mark Germani avatar
Mark Germani avatar
Rob Kiefer:
Hi Mark, yes, the CTU is not cheap but it works well. However, if you plan to use a smaller sensor camera like 1" or 4/3  then your tilt issue might not be a big issue anymore. I have no experience in shooting in Bortle 7-8 and how broadband works there. I assume using the L-Pro is already the right step. How are your stars looking like (CA)? Just surprised that it is so strong or filter related?
CS


Hi Rob! The CA seems to be throughout the image, but only for certain stars (perhaps tied to a particular colour?) Pale yellow stars appear yellow on the side of the star facing the centre of the frame, and blue on the side of the star facing away from the centre of the frame. Blue and reddish stars do not exhibit this problem. I just checked an L-eXtreme image that I didn't do RGB stars for, and I can see the same issue, so it's not the filter (or if it is, it's a problem with both filters). I always figured it was a doublet/Zenithstar thing, and better optics would help minimize it, when I could afford to upgrade.

CS!
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Mark Germani avatar
Mark Germani avatar
Get the camera and a L3 filter to deal with the CA, it will improve your imaging way more than a new scope. But I would also recommend mono (183 or 533 )over OSC as that will solve your CA totally due to refocusing between filters and give you another massive increase in sensitivity even with a manual wheel and cheap filters. 

Adam

Hi Adam! Thanks for the input. Would you recommend an L3 filter over the L-Pro? I'm getting the CA with my L-Pro AND L-eXtreme, and (I just checked) older images I took with no filters at all, so it's related to my optics rather than bad filters, I think. Would the L-3 sort that? I'd be lying if I said I hadn't been strongly considering the purchase of an L3. You've saved me from creating a new forum post on the topic

Sadly, mono isn't remotely in my price range right now, but I'll definitely consider it as the next camera after the 533MC. Could I get away with mono in Bortle 7/8 skies? I know narrowband would be fine but what about LRGB?

CS!
Mark
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Mark Germani avatar
Mark Germani avatar
Jens:
Hey Mark
I was literally in your shoes. I have the exact same setup, the 600D modified and the zenithstar 61 with the L-enhance filter.
I just bought the ASI 2600mc Pro and man, best desicion ever.
you can see the difference between my most recent image (which is just 40min of exposures) to the ones before.
go for the camera!

And what made a huuuge difference as well was to get the test version of Pixinsight with the noise- blur- and star Xterminator plugins.

Hi Jens, thanks for the reply! Yeah, if I had enough set aside for the 2600MC I wouldn't even hesitate to go that route, other than the fact that I'm using an ASIAIR-Mini with USB 2.0 and transfer speeds would be brutal, plus the tilt issues would still be present. But I can imagine that it's a huge step up!

Funny, I was hoping to have enough to buy this camera last Christmas but I was short by a considerable margin, so I bought Pixinsight instead and that was the BEST decision I could have made - I agree! It's a game-changer. I spent the summer tearing through data from the RASC Robotic Telescope so I could improve my processing skills. I'm so happy with what I'm able to do with the software. I have all Russell's plugins too

CS,
Mark
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jaydeepappas avatar
jaydeepappas avatar
Just going to pile on with all the other suggestions - get the camera. IMO it’s a no-brainer. The camera upgrade will be a HUGE upgrade to your images compared to the telescope upgrade. Someone here mentioned that your DSLR is modded, and that’s great, but the difference in picture quality between the ZS + ASI533 vs the Askar + DSLR is not even close. Get the camera and enjoy it!
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Mark Germani avatar
Mark Germani avatar
The FRA400 you have listed is good, but not much more FL than the zenithstar that you have.  I would suggest maybe the FRA600 than later you can upgrade you camera from a canon to maybe a QHY 268M or 268C depending on if you want to go mono or stick with the OSC cameras.

It's just my 2 cents.  

Mark E.

Hi Mark, thanks for your thoughts! Yeah, the FRA400 isn't a huge step up in terms of FL, but if I wanted to upgrade to the FRA600 or any of those cameras I'd have to wait 3-4 years before I could save up enough. I figure since astro gear holds its value fairly well, it's worthwhile to do incremental upgrades as I can afford them, and learn the hobby along the way. I've heard the FRA600 is an excellent telescope, though, and the QHY268/ASI2600 is my dream camera, eventually

CS!
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Mark Germani avatar
Mark Germani avatar
Brian Puhl:
I came.

I voted.

Have you thought about mono instead however?  You'll be light years ahead vs if you went OSC again.

Thanks Brian! Another vote for mono, too. Going to have to seriously consider that as the next step up! CS!
Mark Germani avatar
Mark Germani avatar
Sean Mc:
Here’s my 2c to consider. Since the canon is astro modded, AND you’re looking to try to speed up imaging…. Maybe get a samyang 135 f/2. That’s if the focal length works for you.  

Then save up for a longer focal length and cooled astro cam later ¯\_(ツ)_/¯

Sean, you've read my mind

I'm actually keeping all my older astro gear instead of selling it, and building a second rig - my old Skyguider Pro with a Canon EF 50mm f/1.8. With the camera upgrade, I can shuffle the DSLR to this rig and have something I can take camping or on the plane. Eventually I'd like to swap out the 50mm lens for the Samyang because I love the FL, but I'd miss the reach of my Z61 for galaxy season if I were to use it on my main rig.

Thanks and CS!
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Mark Germani avatar
Mark Germani avatar
Just going to pile on with all the other suggestions - get the camera. IMO it’s a no-brainer. The camera upgrade will be a HUGE upgrade to your images compared to the telescope upgrade. Someone here mentioned that your DSLR is modded, and that’s great, but the difference in picture quality between the ZS + ASI533 vs the Askar + DSLR is not even close. Get the camera and enjoy it!

Thanks Jay! That clinches it. There's a review of the ASI533MC-Pro by Damian Peach and he says it's not much better than a modded DSLR, but I have a hard time taking that at face value, as I think the improvement will be noticeable, though I've never used a dedicated camera so it's hard to know for sure. I really appreciate all the first-hand experience you and others have brought to this thread. Astrobin is a super resource!

CS,
Mark
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