17 replies to this topic

[Polaco]

Hi,

 

I was planning to acquire a telescope, btw my first telescope, so far i have just only used my camera lenses.

I own a ZWO AM5N and an ASI 2600MC and i already have a guide telescope and camera asi120mm.

 

I was planning to acquire a ZWO FF107 + autofocuser + off axis guide adapter.

 

However i noticed that near the city i live someone is selling in "mint condition" an Skywatcher Evostar 150DX + focal reducer ( 0.77 reducer/flattener f6.2 ) .

The evostar + reducer and the zwoff107 are around the same price tag.

My understanding of telescopes is quite limited. So from the specs i do notice the ZWO is a cuadruplet while the Evostar is duplet.

Also there is a considerable difference in focal length 750mm for the ZWO vs 1200mm for the Evo.

My goal would be to have some kind of "all rounder" telescope mainly for DSO/planetary astrophotography 90% of the time and maybe observational for the rest. 

According to the manual the AM5N supports up to 15kg without counterweight and 20kg with it, the Evo weights around 10kg.

 

 

So the advantages of getting the Evo as far as i can see:

extra focal lenght,

being nearby is avoiding customs and any delivery issue.

 

The possible disadvantages:

aberations for astrophoto being just a duplet?

backfocus issues?

size/handling?

any adapter needed to mount my camera or possible issues?

any other?

 

I couldnt find too much info about the Evo. So if anyone could give me some advice, would be very happy.

thanks!

 

 

https://www.highpoin...efractor-s11195

 

https://www.zwoastro.../zwo-ff107-apo/

Edited by Polaco, 16 April 2025 - 08:08 AM.

[Cliff Hipsher]

 

My goal would be to have some kind of "all rounder" telescope mainly for DSO/planetary astrophotography 90% of the time and maybe observational for the rest. 

 I hate to pop your bubble, but the truth is that other then imaging the Moon, neither of those scopes would be a good choice for planetary work WITH THAT CAMERA because they just don't have the required focal length. A "better" choice would be an 8" 2000mm FL f10 SCT with a 3X Barlow and an ASI120MC-S.  

 

To prove it yourself go to Astronomy Tools  and use the FOV Calculator in IMAGING mode.

[Cliff Hipsher]

Here is a comparison..

 

[Polaco]

 I hate to pop your bubble, but the truth is that other then imaging the Moon, neither of those scopes would be a good choice for planetary work WITH THAT CAMERA because they just don't have the required focal length. A "better" choice would be an 8" 2000mm FL f10 SCT with a 3X Barlow and an ASI120MC-S.  

 

To prove it yourself go to Astronomy Tools  and use the FOV Calculator in IMAGING mode.

hi!

not popping the bubble at all! 
so then in the future i could get a camera better suited for planetary but keep the scope? so far  my main goal is DSO, but any form of planetary would be a plus.

thats not bad at all imho, since seems easier to me ( from my zero experience though ) to switch camera than telescope.

so in the end, the evostar wouldnt be that bad, uh?

 

thanks!

[Brian Carter]

I have a 5" refractor, 952mm focal length, and I wouldn't really bother trying to image planets with it.  First of all, I would need some focal extenders (Barlows), because even Jupiter is a tiny disk at prime focus for me.  So I maybe put a 2x or 3x Barlow in front of the camera, but that would require much longer exposures to image a planet, and planetary imaging relies on hundreds of very SHORT exposures stacked together.  People use much bigger scopes for planets, even big refractors aren't really big enough.  They are fantastic for viewing planets with your eyes, just not imaging.

 

But they are awesome for deep sky.  I would recommend you go with the ZWO, if those are really your only options.  The Evostar isn't going to work well:  It is a doublet and it will show a bunch of false color in your images.  And a 6" refractor is giant, you really need to see one.

 

I haven't even seen a ZWO telescope, but there are lots of 3-4" refractors to choose from and they probably all come from the same factory these days.  A refractor this size is easy to image with on the AM5, pretty much plug and play.  And since it is smaller, you are likely to use it more often, throw it in the car and drive it somewhere.  You'll have a lot more fun with it.

 

Don't get hung up on "settling" for a smaller scope, size doesn't matter as much for imaging until you start to care about imaging tiny things (like planets, little galaxy clusters, etc).  It will take you years to run out of awesome objects to image with a 4" scope.

[Polaco]

I have a 5" refractor, 952mm focal length, and I wouldn't really bother trying to image planets with it.  First of all, I would need some focal extenders (Barlows), because even Jupiter is a tiny disk at prime focus for me.  So I maybe put a 2x or 3x Barlow in front of the camera, but that would require much longer exposures to image a planet, and planetary imaging relies on hundreds of very SHORT exposures stacked together.  People use much bigger scopes for planets, even big refractors aren't really big enough.  They are fantastic for viewing planets with your eyes, just not imaging.

 

But they are awesome for deep sky.  I would recommend you go with the ZWO, if those are really your only options.  The Evostar isn't going to work well:  It is a doublet and it will show a bunch of false color in your images.  And a 6" refractor is giant, you really need to see one.

 

I haven't even seen a ZWO telescope, but there are lots of 3-4" refractors to choose from and they probably all come from the same factory these days.  A refractor this size is easy to image with on the AM5, pretty much plug and play.  And since it is smaller, you are likely to use it more often, throw it in the car and drive it somewhere.  You'll have a lot more fun with it.

 

Don't get hung up on "settling" for a smaller scope, size doesn't matter as much for imaging until you start to care about imaging tiny things (like planets, little galaxy clusters, etc).  It will take you years to run out of awesome objects to image with a 4" scope.

ok, but in astrobin there are planetary with this scope at least thats what the equipment gear appears and they might not be the best of the world but seem to be more than acceptable to imho. 

yeah i agree is big, i dont travel much, mostly will be used from my backyard or roof.

[charles.tremblay.darveau]

I have the Askar 107PHQ, which is equivalent to the ZWO107. It is an excellent telescope for DSO with the asi2600mc. I would say the doublet is probably better for visual and may still have residual CA (though I never had one) for DSO. You can see Jupiter bands and Saturn rings, but it won't have the same results as a larger scope.

 

If you want to do planetary look for a second hand C8 as other said. The 676mc camera is a good match for planetary, and the 2600mc should give you a full moon shot.

[Cliff Hipsher]

hi!

not popping the bubble at all! 
so then in the future i could get a camera better suited for planetary but keep the scope? so far  my main goal is DSO, but any form of planetary would be a plus.

thats not bad at all imho, since seems easier to me ( from my zero experience though ) to switch camera than telescope.

so in the end, the evostar wouldnt be that bad, uh?

 

thanks!

Well, I would pick the ZWO because it has better glass than the SW has.  To be completely honest, there ain't no free lunch.  A wide field refractor is optically fast and the short focal length actually makes guiding much easier.  For planetary work you are taking short VIDEO clips and not long exposure single images so as long as the mount tracks reasonably well video stacking software like Registax will have no problem producing a single image.  IMHO This is where a long fl SCT actually shines.

[Polaco]

Well, I would pick the ZWO because it has better glass than the SW has.  To be completely honest, there ain't no free lunch.  A wide field refractor is optically fast and the short focal length actually makes guiding much easier.  For planetary work you are taking short VIDEO clips and not long exposure single images so as long as the mount tracks reasonably well video stacking software like Registax will have no problem producing a single image.  IMHO This is where a long fl SCT actually shines.

sure, no free lunch... thats for granted.

just attempting to avoid making a bad decision.

the seller includes a flatterner reducer 0.77x so for it will be around 924mm f6.2 ( seems to be an accesory for the telescope as its branded as  evostar too )

not sure if i do need to use it for planetary too or just for dso.

having the chance to use it for visual, is quite aplealling, specially to share it with my kids.

the seller has some impressive images done with this telescope and i have seen some at astrobin very nice to me.

it is quite tempting me.

[charles.tremblay.darveau]

The images I've seen on astrobin has a blue halo characteristic of doublet. You can add a fringe-killer filter but that is at the cost of a significant chunk of blue signal. Mono may work better since you can refocus separately each channel. 

 

To be fair, I'm sure the skywatcher can produce good results. All I can say is that the 107PHQ produces very good images and that not having to worry about backfocus is a game changer. It's just not much of a planetary scope .

[Cliff Hipsher]

Using a reducer for planetary or visual observations is bassackwards.  To get good planetary images you need LONG focal length not short and you need a "narrow" field not a wide field.  

For visual you are using an eyepiece and the magnification power of a given eyepiece is proportional to the focal length of the telescope.  Chop the FL with a reducer and the visual magnification goes down and things look smaller.  Here again an SCT, a Newtonian reflector or a Maksutov Cassegrain rules the night.

[Polaco]

The images I've seen on astrobin has a blue halo characteristic of doublet. You can add a fringe-killer filter but that is at the cost of a significant chunk of blue signal. Mono may work better since you can refocus separately each channel. 

 

To be fair, I'm sure the skywatcher can produce good results. All I can say is that the 107PHQ produces very good images and that not having to worry about backfocus is a game changer. It's just not much of a planetary scope .

yeah i noticed the same, however not in all the images which is a bit odd. 

 

 

 

Evostar

this one is very obvious

https://app.astrobin.com/i/209ab2

this one does not seem so much

https://app.astrobin.com/i/j3ripm

 

and for comparison, here is a  ZWO FF107 one

https://app.astrobin.com/i/xowq3k

 

Maybe is the amount of light collected or the editing, but if not were for the horrid color aberrations on the stars i would say i prefer trifid done with the Evostar.

Anyway, that blueish issue is a big concern.

[Wildetelescope]

hi!

not popping the bubble at all! 
so then in the future i could get a camera better suited for planetary but keep the scope? so far  my main goal is DSO, but any form of planetary would be a plus.

thats not bad at all imho, since seems easier to me ( from my zero experience though ) to switch camera than telescope.

so in the end, the evostar wouldnt be that bad, uh?

 

thanks!

As is always the case, much of this depends on what your expectations are as to whether either of these scopes will satisfy you.  I have imaged planets with both 4 inch and 6 inch refractors and gotten very nice images.  I have imaged planets with my IMX 294 and 571 sensors and gotten some nice images.  I get higher resolution images using my C8 or C11 and a 290 or 585 planet camera.  BUT the SCT’s suffer a bit more in terms of thermal issues, seeing issues etc..   This can be dealt with to some extent, but it takes a bit more preparation.  Some of my best images from MY perspective have been obtained with my 6 inch F9 AP refractor, my QHY IMX 290 color sensor and a 1.5x Vernon scope Barlow.   Of the two scopes that you are considering, the 150mm scope will likely give you an excellent performance on both DSO and solar system, BUT you will sacrifice overall FOV and the scope might challenge your mount.  A 6 inch scope is BIG.  The 107 will give you excellent FOV and likely take a pretty good image of Jupiter, but you will not get as much resolution and detail.   Ultimately, a 4 inch refractor and a C8 SCT are a really nice combination for imaging everything.  Matching camera resolution to your optics and the target is the next step.   DSO likes ~1”/pixel.   Planets like ~0.2-0.5”/pixel.    I like the app Astroaid to determine combinations for different targets.  Hope this helps you

 

JMD

[BKBrown]

Lots of discussion here, and some unfortunate commentary about the suitability of smaller aperture scopes for planetary imaging. Fact: you can image planets with any size scope, with the important caveat that one must seriously manage their expectations. A 6" refractor will not enable you to take the same kind of images that a 14" SCT will...obviously. But that does not mean that you cannot take satisfying images, you can. The Major & Minor Planetary Imaging and Lunar Observing and Imaging forums have several "challenge" threads that are dedicated to imaging the Moon and planets with 6" or less of aperture. I have been doing this for quite a long time alongside many other folks, and you might be amazed at what can be accomplished with smaller scopes. Below are a couple of images taken with 4" and 5.5" refractors to give you an idea of what can be done.

 

Jupiter through a 4" Skywatcher 100ED Pro (think Evostar):

 

 

And through a 5.5" TEC 140ED:

 

 

TEC 140ED with ZWO ASI585mc camera

 

 

The SW Evostar 150DX mounted beside my EdgeHD 11. That is an Evostar 72ED riding piggyback...

 

 

These obviously lack the greater resolution of images by the likes of Damien Peach and Christopher Go with their 14" SCTs, but they give you a feel for what can be done if you do not have an 8" to 14" SCT and awesome seeing. I recently acquired an SW Evostar 150DX during the late, great sale and am just starting to put it through its paces. And let me tell you, it is a big telescope at just over 4 feet in length and 22 pounds (still lighter than my EdgeHD 11). Unfortunately weather and time have precluded me from imaging Jupiter under reasonable conditions, so the acid test will have to wait for the next apparition. My early attempts indicate that the scope shows a bit more CA than I like, so for my color cameras I acquired Baader Contrast Booster and Semi-APO filters, both of which also serve as UV/IR cut filters, for the next season. I fully expect that these will level the CA playing field based on reports from other planetary imagers. These filters, in conjunction with SharpCap's Pre-processing "CA Reduction/Synthetic Blue" option, should tame the CA issue and give more true APO-like results. I will report in the imaging forums when I have some results to share.

 

Bottom line: yes, you can do planetary imaging with either of the scopes you mention, I would recommend the larger aperture option. And the earlier respondent who counseled the use of a different camera is correct, so get a dedicated planetary camera. I can personally recommend the ZWO ASI585mc or ASI715mc as being suitable for the work. If you can scare up the older ASI224mc, that might be an even better choice, but they are hard to come by now. And if you are feeling adventurous and want to try mono imaging with LRGB filters, the ZWO ASI678mm is a good option. You will also want to add a 2x Barlow to your kit to help you increase focal length, and may want to add 1.5x and 3x Barlows in the future as well. Remember to go and check out the "small bore challenge" threads over in the aforementioned forums!

 

Feel free to PM me if you have any questions. At any rate, good luck and have fun!

 

Clear Skies,

Brian 

[charles.tremblay.darveau]

Lots of discussion here, and some unfortunate commentary about the suitability of smaller aperture scopes for planetary imaging. Fact: you can image planets with any size scope, with the important caveat that one must seriously manage their expectations. A 6" refractor will not enable you to take the same kind of images that a 14" SCT will...obviously. But that does not mean that you cannot take satisfying images, you can. The Major & Minor Planetary Imaging and Lunar Observing and Imaging forums have several "challenge" threads that are dedicated to imaging the Moon and planets with 6" or less of aperture. I have been doing this for quite a long time alongside many other folks, and you might be amazed at what can be accomplished with smaller scopes. Below are a couple of images taken with 4" and 5.5" refractors to give you an idea of what can be done.

Jupiter through a 4" Skywatcher 100ED Pro (think Evostar):

Jupiter0005 10-10-12 22-24-17_003_SW100ED.jpg

And through a 5.5" TEC 140ED:

Jupiter Io shadow transit 2016.jpg

TEC 140ED with ZWO ASI585mc camera

Jup241103_ZWOASI585mc_002e.jpg

The SW Evostar 150DX mounted beside my EdgeHD 11. That is an Evostar 72ED riding piggyback...

IMG_4141sc.JPG

These obviously lack the greater resolution of images by the likes of Damien Peach and Christopher Go with their 14" SCTs, but they give you a feel for what can be done if you do not have an 8" to 14" SCT and awesome seeing. I recently acquired an SW Evostar 150DX during the late, great sale and am just starting to put it through its paces. And let me tell you, it is a big telescope at just over 4 feet in length and 22 pounds (still lighter than my EdgeHD 11). Unfortunately weather and time have precluded me from imaging Jupiter under reasonable conditions, so the acid test will have to wait for the next apparition. My early attempts indicate that the scope shows a bit more CA than I like, so for my color cameras I acquired Baader Contrast Booster and Semi-APO filters, both of which also serve as UV/IR cut filters, for the next season. I fully expect that these will level the CA playing field based on reports from other planetary imagers. These filters, in conjunction with SharpCap's Pre-processing "CA Reduction/Synthetic Blue" option, should tame the CA issue and give more true APO-like results. I will report in the imaging forums when I have some results to share.

Bottom line: yes, you can do planetary imaging with either of the scopes you mention, I would recommend the larger aperture option. And the earlier respondent who counseled the use of a different camera is correct, so get a dedicated planetary camera. I can personally recommend the ZWO ASI585mc or ASI715mc as being suitable for the work. If you can scare up the older ASI224mc, that might be an even better choice, but they are hard to come by now. And if you are feeling adventurous and want to try mono imaging with LRGB filters, the ZWO ASI678mm is a good option. You will also want to add a 2x Barlow to your kit to help you increase focal length, and may want to add 1.5x and 3x Barlows in the future as well. Remember to go and check out the "small bore challenge" threads over in the aforementioned forums!

Feel free to PM me if you have any questions. At any rate, good luck and have fun!

Clear Skies,
Brian

If the TEC didn’t get a decent picture of Jupiter I would ask for a refund

[BKBrown]

If the TEC didn’t get a decent picture of Jupiter I would ask for a refund

I totally agree, but 5.5" is still 5.5". Yuri actually sent me a congratulatory message regarding the older (first) image from 2016 

 

Clear Skies,

Brian 

[Polaco]

Finally, I decided to buy the Evostar 150ed dx. I have it since 3 weeks ago.

So far, totally amazed with it.

I have just done some astro photos using the provided  0.77 reducer flattener.

I think i still need to improve focusing, I uploaded them to my drive here ( opinions welcomed ) :

https://drive.google...?usp=drive_link

 

I also got a Skywatcher dielectric diagonal and some 1.25" oculars of 8mm, 27mm and 18mm and first tried it yesterday to observe the almost full moon, and was just fantastic.

 

The only issue so far, is that when i tried to use my ZWO2600mc in primary focus ( directly, no flattener ) to do some moon photos, i was not able to get focus at all. It seems i'm having a backfocus issue.

With the focusing tube all extended the stars appeared like big dots, so i would say im quite far from focus yet.

So, I guess i need an extension tube to overcome that issue? Any suggestions?

 

thanks!!!

 

PS: sorry i have just found the missing part of the telescope that allows me to get proper focus.

Edited by Polaco, 12 May 2025 - 08:00 PM.

[Cliff Hipsher]

1.  Rack the focus tube half way out.

2.  Take the dust plug out of the eyepiece holder and take of the dust cap off of the objective.

3.  Point the telescope at a distant object.  I prefer a group of trees.

4.  Hold a piece of white card stock or printer paper behind the eyepiece holder.

5.  Move the paper away until an image comes to focus.

6.  Measure the distance between the eyepiece holder and the paper.

7.  Add the setback distance of the imaging chip from the front of the camera (ASIs are typically 6mm or so..) .

8. Add 20mm for "grip room".

At this point you can build the extension tube.  When you have that done, mark off 20mm FROM THE FOCUS TUBE END of the extension with some tape. This will give you will give you a repeatable setup, and it also makes that first AutoFocus easier.

 

Having said that, I have 2 sets of extension tubes for each of my rigs.  One set is used when I am NOT using a focal reducer and the other set is used when I am using a focal reducer.