23 replies to this topic

[TheSevenBrothers]

Hello everyone! I need advice for what telescope to get for my Sky Watcher Star Adventurer 2i. I was thinking something like the Samyang 135mm f2 or the Askar FMA180 pro, but any other suggestions would be helpful. Thanks!

[EdDixon]

The ZWO FF65 is a great little scope.  It is about 6 lb and has great optics.  With reducer, it ends up at 312mm focal length.

[mayhem13]

Hello everyone! I need advice for what telescope to get for my Sky Watcher Star Adventurer 2i. I was thinking something like the Samyang 135mm f2 or the Askar FMA180 pro, but any other suggestions would be helpful. Thanks!

Either would be a good choice for your mount if that were the only consideration…..

 

The Samyang is optically faster and has a larger aperture so it collects more light/photons than the Askar. Given economics at scale, you likely get more performance per $$  with the Samyang.

 

The Askar FOV will be smaller than that of the Samyang obviously. 
 

With the Samyang, you’d be less likely to require guiding as the required exposure time per sub would be less but honestly I wouldn’t personally guide with either in this application.

 

You don’t mention your camera either but I suspect you’re going to be grossly undersampled anyways.

 

My money would be on the Samyang at this point if it were me…it’s also an excellent portrait lens for terrestrial and likely something you’ll keep along your journey in photography. But I’m a pragmatist and not to be trusted. Lol. I like where you’ve drawn your starting line though…..very sensible.
 

Your mount CAN accommodate more of a payload if the conditions permit…..fair weather, a sturdy tripod on a solid footing with precise polar alignment. Ballast weight hanging from the tripod helps immensely too. You will likely need to guide at 250mm of focal length or more so consider the additional weight of those components and the complexity. 

[jml79]

I tend to not recommend the Samyang 135mm, not because it's a bad lens, I've never had one so I can't comment on it's quality. But because it uses a non-standard backfocus and camera mount, requires some way to mount it (scope rings or something), is difficult to mount a focuser and has no provision for a filter. All of this can be overcome but it's fiddly. The Askar FMA 180 Pro uses the standard backspace, has a provision for mounting 2" standard filters, is guaranteed to focus past infinity, has a way to mount it to the tracker or a bigger mount later and a proven track record of being easy to use. It even has an EAF mounting kit available. Some other options I would consider are the SharpStar 50EDPH and reducer, Redcat 51, SVBony SV555, Askar SQA55.

 

Nebula Photos (youtube) just did a roundup video on refractors for the Star Adventurer GTI and concluded the FMA 180 was the perfect size for it. No the same as your SA2i but pretty close.

[TheSevenBrothers]

Also, camera I am using right now is a unmodified Sony DSLR. Should I mod it or get a dedicated astro camera? I was kinda thinking about paring the QHY Minicam8 mono(only $880) with the Samyang lens. Or should I get a OSC cam like the ASI533mc pro?

[jml79]

Which Sony SLR?? I have modified an A6000 and A7R for full spectrum for free but some can't be modded.

[TheSevenBrothers]

A6000

[Celerondon]

Also, camera I am using right now is a unmodified Sony DSLR. Should I mod it or get a dedicated astro camera? I was kinda thinking about paring the QHY Minicam8 mono(only $880) with the Samyang lens. Or should I get a OSC cam like the ASI533mc pro?

Get a dedicated astro camera for the advantages and simplicity that they provide. That ASI533MC Pro has great features and impressive performance. 

 

Although I think that choosing between mono and OSC cameras is a you thing rather than an us thing, I will venture that the ASI533MC Pro is a safer bet if you have to ask.  
 

Don

[jml79]

I modified my A6000 for bare sensor and full spectrum and it is the perfect easy to mod camera. I have had no issues with the modification. It is far from the best astro camera but it can hold it's own. It is only 12 bit and suffers from the infamous sony star eater but in my opinion that issue is overblown. There is an open source driver that works perfectly with it and allows it to work with NINA and it will also work with INDI (Stellarmate) and the ASIAir. Once modified it's not terribly usable for family phots though and will require that you use a UV/IR filter as a minimum for astro. I used ISO 800 or ISO 1600. Here are some of the results (I was a processing baby back then) and the modification tutorial.

 

Tutorial - just skip the part about adding their filter, not needed. Total cost was $0

 

https://www.lifepixe...ersion-tutorial

 

 

 

[TheSevenBrothers]

Thanks jml79. I ideally don't want to mod the a6000. But I also have a old Sony NEX 5r. Could I mod that? (nice pictures)

[erictheastrojunkie]

There's nothing wrong with starting out with your Sony and the Samyang 135mm, there are lots and lots of 3rd party ring options for the Samyang 135mm that allowing easy mounting of the setup to a tracking mount as well as easy attachment of an autofocuser like the EAF with a belt. Using the Samyang 135mm with your Sony means you don't have to worry about backfocus problems, it's an easy, lightweight setup that is VERY VERY ideal for a tracking mount. I simply would NOT go beyond the 135mm for your mount, you are using a single axis motor driven mount which means you can do automatic go-to's, you can't do target centering, you can only guide in 1 axis, etc. The small trackers like your Star Adventurer were simply made for widefield/milky way imaging and believe me, pushing them beyond 135mm, maybe 200mm, is only going to yield a lot of tossed subs and mediocre results. I have put just about everything on my old trackers, up to 600mm lenses, I've done A METRIC TON of tinkering around with. Just save some money and buy a better mount if you think you're going to go further with astrophotography. With what you have now, the 135mm is a perfect choice, pair it with your Sony and do some imaging while you save some money for the next step (which will be more expensive in terms of mount investment and more important than anything else). 

 

FWIW I have had 3 different copies of the Samyang 135mm, one of them a Sony variant, 2 copies were good without much tilt/decentering, one I had to exchange because it wasn't a good copy. Buy your lens from a retailer that allows exchanges, Samyang/Rokinon lenses are notorious for decentering problems. 

Edited by erictheastrojunkie, 24 March 2025 - 11:50 AM.

[jml79]

Thanks jml79. I ideally don't want to mod the a6000. But I also have a old Sony NEX 5r. Could I mod that? (nice pictures)

Yes, the NEX 5R can be modded to bare sensor for free. Everyone will talk about focus issues but that doesn't apply to astro, that is for lenses. The AF won't work bare sensor but the cost is right and it will work just fine manual focus. I am not sure how well the ASCOM driver will work with the NEX 5R. If you buy the Samyang 135, do yourself a favour and buy it in Canon EF mount (also called EOS mount) and then buy an adapter to Sony NEX/Sony E. Later on if you buy a cooled astro camera it will be easy to adapt it to Canon EF but it is almost impossible to adapt an astro camera to a Sony E mount. I made that mistake with my Samyang 14mm. Now I can't play with it using my astro cameras.

[Notdarkenough]

Absolutely love my SQA55.

[TheSevenBrothers]

There's nothing wrong with starting out with your Sony and the Samyang 135mm, there are lots and lots of 3rd party ring options for the Samyang 135mm that allowing easy mounting of the setup to a tracking mount as well as easy attachment of an autofocuser like the EAF with a belt. Using the Samyang 135mm with your Sony means you don't have to worry about backfocus problems, it's an easy, lightweight setup that is VERY VERY ideal for a tracking mount. I simply would NOT go beyond the 135mm for your mount, you are using a single axis motor driven mount which means you can do automatic go-to's, you can't do target centering, you can only guide in 1 axis, etc. The small trackers like your Star Adventurer were simply made for widefield/milky way imaging and believe me, pushing them beyond 135mm, maybe 200mm, is only going to yield a lot of tossed subs and mediocre results. I have put just about everything on my old trackers, up to 600mm lenses, I've done A METRIC TON of tinkering around with. Just save some money and buy a better mount if you think you're going to go further with astrophotography. With what you have now, the 135mm is a perfect choice, pair it with your Sony and do some imaging while you save some money for the next step (which will be more expensive in terms of mount investment and more important than anything else). 

 

FWIW I have had 3 different copies of the Samyang 135mm, one of them a Sony variant, 2 copies were good without much tilt/decentering, one I had to exchange because it wasn't a good copy. Buy your lens from a retailer that allows exchanges, Samyang/Rokinon lenses are notorious for decentering pr

So should I get a Samyang 135mm and pair it with either an astro moded Sony camera or get the ASI533. Or, sell my old tracker, get a better one, and still buy the Samyang lens to pair with the Sony cam?

[mayhem13]

So should I get a Samyang 135mm and pair it with either an astro moded Sony camera or get the ASI533. Or, sell my old tracker, get a better one, and still buy the Samyang lens to pair with the Sony cam?

Not sure……it all depends on where you are in your AP journey now and where you want to go.

 

Can we assume you’ve been using your existing mount and Sony for widefield Milky Way landscape imaging?

 

If so, and you can afford it, keep that setup for what it is. You can effectively image up to 200mm with it consistently meaning not tossing out subs and valuable time when the conditions aren’t great. I use mine as a secondary rig all the time for MW, Orion area, Rho Opiuci, etc. 

 

It’s important to remember that if you use an Astrocam with a lens, or even a crop sensor DSLR, the focal length changes by the crop factor of the sensor so say using a 533 or smaller 585 sensor to frame smaller targets expect a need to guide and being selective as to when to image in regards to the seeing and weather

 

…..but if your heart is in long exposure deep sky AP, my suggestion is build that rig for that purpose with the proper foundation of a quality mount that will grow with you. Today’s lightweight yet compact and highly capable and affordable Harmonic Drive mounts have been a blessing. Options like a ZWO AM5 or Sky Watcher 150i can effectively guide and long exposure image with scopes such as a 9.25 SCT, 8” Newtonian Astrographs or 160 mm refractors…..or in other words….right up to the practical limit focal lengths that normal seeing and sky conditions allow without an observatory setting. 
 

So the questions are back to you now and what you hope to achieve. Almost anything CAN be done, but the questions is SHOULD it be done……the CAN is quantifiable as it pertains to time, effort, investment, etc.

[soojooko]

So should I get a Samyang 135mm and pair it with either an astro moded Sony camera or get the ASI533. Or, sell my old tracker, get a better one, and still buy the Samyang lens to pair with the Sony cam?

Why not get the Askar FMA135. It's a proper astrograph, low cost with good optics, and is considerably lighter than the Samyang. Pair it with your Sony and then save up for a better mount. 

Edited by soojooko, 25 March 2025 - 06:53 AM.

[TheSevenBrothers]

Not sure……it all depends on where you are in your AP journey now and where you want to go.

 

Can we assume you’ve been using your existing mount and Sony for widefield Milky Way landscape imaging?

I have been using the 55-210mm kit lens (usually at 210mm), for about a year now for deep sky imaging. But I really love those 'wide' angle shots for the Samyang lens, and I also think that the f2 would be nice. I would ideally want the rig to be relatively portable and small also as I plan on camping with it maybe.

[erictheastrojunkie]

So should I get a Samyang 135mm and pair it with either an astro moded Sony camera or get the ASI533. Or, sell my old tracker, get a better one, and still buy the Samyang lens to pair with the Sony cam?

You're going to have some paralysis by analysis, that's just the natural progression of this hobby for virtually everyone. It really just boils down to what you feel like you want to accomplish over the next year or two, what do you think your time allowance will be for learning and implementing an astro setup that is a little more complex vs just using the equipment you have now and making small modifications/changes. If you think you'll have plenty of time to fiddle and learn, tinker and grow, AND your budget allows for a decent step in the astro journey then I would whole heartedly recommend you look at a better mount. You mention portability being a factor, wanting to do this while you go camping (I'm also in this group, where I do camping/travel trips a few times a year and like to have a portable setup option), I would very much recommend a mount like the ZWO AM3 or a comparable strain wave from one of the other manufacturers. That will get your payload capacity up to allow for some growth into larger telescopes in the future, while giving you a lightweight mount that can be easily packed up and taken out on camping trips without needing big power supply needs. It can also be easily manipulated and kept assembled at home so all you have to do is pick up your whole rig and take it outside when you want to image. 

 

It's easy to want/desire a bigger/better telescope, but the truth of the matter is that your foundation is way too critical for this hobby and the foundation you are using now (the Star Adventurer) is not well suited for deep sky imaging. It's a mount very much designed and engineered towards basic DSLR/MILC type cameras and lighter and wider lenses, mostly for nightscape style imaging and widefield work, it has huge periodic error and can only be guided in 1 axis. Once you start getting into focal lengths above ~200mm it becomes exponentially harder to get good results, even above 135mm I found myself throwing out 30-40% of my subs just because of the periodic error and inconsistent guiding. Not to mention framing of targets at longer focal lengths without go-to in both axis is quite cumbersome. 

 

So first thing first, decide how far you want to go down the rabbit hole and how much of a budget you have to do so. If you have a decent budget (say, $1,000-1,500) then I would buy a better mount that can ensure you get consistently good results with the equipment you have. You can buy a used AM3 with the tripod and pier off the classifieds for less than $1,500, you'll be set for a while with that. If you are thinking you aren't ready for the rabbit hole and just want to see if you can eek a bit more out of the mount you have, the Samyang 135mm is probably your best option. Skip the cheap Askar scopes, they have terrible chromatic aberration, aren't as sharp, aren't as fast. The Samyang 135mm is a very proven and well supported lens in the astro community, it has a long track record of producing great results for a lot of people over the years. Just buy one from a place that has an open exchange policy that way if you get a bad copy you can quickly exchange it for another one. I would recommend getting a Nikon f-mount or Canon EF mount version and use a sony e-mount converter with it, I say that because if you end up getting a cooled astro camera in the future and want to keep the Samyang 135mm, you can easily get an adapter for the astro camera that allows you to use a filterwheel or other accessories. Sony e-mount lenses do not have enough backfocus distance to be used with an astro camera AND a filterwheel. 

[TheSevenBrothers]

You're going to have some paralysis by analysis, that's just the natural progression of this hobby for virtually everyone. It really just boils down to what you feel like you want to accomplish over the next year or two, what do you think your time allowance will be for learning and implementing an astro setup that is a little more complex vs just using the equipment you have now and making small modifications/changes. If you think you'll have plenty of time to fiddle and learn, tinker and grow, AND your budget allows for a decent step in the astro journey then I would whole heartedly recommend you look at a better mount. You mention portability being a factor, wanting to do this while you go camping (I'm also in this group, where I do camping/travel trips a few times a year and like to have a portable setup option), I would very much recommend a mount like the ZWO AM3 or a comparable strain wave from one of the other manufacturers. That will get your payload capacity up to allow for some growth into larger telescopes in the future, while giving you a lightweight mount that can be easily packed up and taken out on camping trips without needing big power supply needs. It can also be easily manipulated and kept assembled at home so all you have to do is pick up your whole rig and take it outside when you want to image. 

 

It's easy to want/desire a bigger/better telescope, but the truth of the matter is that your foundation is way too critical for this hobby and the foundation you are using now (the Star Adventurer) is not well suited for deep sky imaging. It's a mount very much designed and engineered towards basic DSLR/MILC type cameras and lighter and wider lenses, mostly for nightscape style imaging and widefield work, it has huge periodic error and can only be guided in 1 axis. Once you start getting into focal lengths above ~200mm it becomes exponentially harder to get good results, even above 135mm I found myself throwing out 30-40% of my subs just because of the periodic error and inconsistent guiding. Not to mention framing of targets at longer focal lengths without go-to in both axis is quite cumbersome. 

 

So first thing first, decide how far you want to go down the rabbit hole and how much of a budget you have to do so. If you have a decent budget (say, $1,000-1,500) then I would buy a better mount that can ensure you get consistently good results with the equipment you have. You can buy a used AM3 with the tripod and pier off the classifieds for less than $1,500, you'll be set for a while with that. If you are thinking you aren't ready for the rabbit hole and just want to see if you can eek a bit more out of the mount you have, the Samyang 135mm is probably your best option. Skip the cheap Askar scopes, they have terrible chromatic aberration, aren't as sharp, aren't as fast. The Samyang 135mm is a very proven and well supported lens in the astro community, it has a long track record of producing great results for a lot of people over the years. Just buy one from a place that has an open exchange policy that way if you get a bad copy you can quickly exchange it for another one. I would recommend getting a Nikon f-mount or Canon EF mount version and use a sony e-mount converter with it, I say that because if you end up getting a cooled astro camera in the future and want to keep the Samyang 135mm, you can easily get an adapter for the astro camera that allows you to use a filterwheel or other accessories. Sony e-mount lenses do not have enough backfocus distance to be used with an astro camera AND a filterwheel. 

Thank you! This was all very helpful.

[TheSevenBrothers]

Yes, the NEX 5R can be modded to bare sensor for free. Everyone will talk about focus issues but that doesn't apply to astro, that is for lenses. The AF won't work bare sensor but the cost is right and it will work just fine manual focus. I am not sure how well the ASCOM driver will work with the NEX 5R. If you buy the Samyang 135, do yourself a favour and buy it in Canon EF mount (also called EOS mount) and then buy an adapter to Sony NEX/Sony E. Later on if you buy a cooled astro camera it will be easy to adapt it to Canon EF but it is almost impossible to adapt an astro camera to a Sony E mount. I made that mistake with my Samyang 14mm. Now I can't play with it using my astro cameras.

Do you know of any tutorials so that I can mod it? I can't find any..

[jml79]

Do you know of any tutorials so that I can mod it? I can't find any..

Specific to the NEX like the A6000 one I posted, no.. But youtube has several videos showing the process. All you want to do is remove the what is commonly called the AA filter but is the UV/IR filter. Search for IR modify NEX or Remove IR Filter NEX.

[matt_astro_tx]

I use an Astro Tech AT60ED 60mm F/6 doublet on my SA 2i star tracker.  I have a 0.8x reducer/flattener that speeds it up to F/4.8.  I also have all the accessories - an EAF, a cooled astrocam, guidescope and camera, and the ASIAir, and with all of this equipment combined the total payload weight is 7.7lbs, well within the mount's 11lb capacity.

 

If I did it all over again and money wasn't a constraint I would get the RedCat 51 or an Askar of similar focal length.  The AT60 is a fantastic scope and a great value for $399 (I have no regrets), but I'd like a little wider FOV and a petzval design.

 

 

 

 

[TheSevenBrothers]

I use an Astro Tech AT60ED 60mm F/6 doublet on my SA 2i star tracker.  I have a 0.8x reducer/flattener that speeds it up to F/4.8.  I also have all the accessories - an EAF, a cooled astrocam, guidescope and camera, and the ASIAir, and with all of this equipment combined the total payload weight is 7.7lbs, well within the mount's 11lb capacity.

 

If I did it all over again and money wasn't a constraint I would get the RedCat 51 or an Askar of similar focal length.  The AT60 is a fantastic scope and a great value for $399 (I have no regrets), but I'd like a little wider FOV and a petzval design.

 

Wow. Amazing pictures. How much was the entire rig?

[matt_astro_tx]

Wow. Amazing pictures. How much was the entire rig?

It's been awhile since I've checked it against current retail prices but at one point I was at $2,500 all in.  I worked extremely hard to stay within a budget at the time.  My rig has limitations, and conventional wisdom along with people on this site will rightly steer you toward a true mount and not a star tracker and they would be right to do so.  I couldn't afford that so I made this work and it has served me well, but I've had to really work at it to get good.

Edited by matt_astro_tx, 27 March 2025 - 03:20 AM.