Beginner getting a Zenithstar 73, want to make sure I have all the equipment right

[vansky]

Hi voyagers of the cosmos!

Been doing research on here and what feels like a million other places the past few days, first time posting.

I'm planning on getting a telescope for the first time since I had a Celestron compound as a kid. Been doing research the past few days and I've narrowed down my plan to get a WO Zenithstar 73 APO, for some visual astronomy but moreso astrophotography with my Nikon D5600. I know a scope that small ain't gonna do a lot for visual and I will probably follow this purchase up later this year with a compound scope for visual astronomy (was thinking the Skymax 180).

 

Anyway I'm trying to figure out all the stuff I need to use my Zenithstar for both viewing and photography so I can get everything at once.

 

So besides the Z73 I'm going to get:

- a Skywatcher EQ6-R mount: I know that is probably overkill for a small refractor but I want my mount to be able to handle a heavier compound that I'll likely get next.

- a Nikon T-ring

- I know I also need a T adaptor, diagonal, and eyepieces, but here is where I run into some questions that I want to be sure about...

 

1. Do I need a field flattener for AP? Does it make a big difference? My understanding is that without it stars at the fringes of the image will like stretch a bit or whatever. And does a field flattener take the place of a T-adaptor as the piece that connects the T ring with the telescope? If a field flattener does the job of a T-adaptor then I'll just shell out the money for the field flattener so I don't end up eventually buying both.

2. Sizes of diagonals and eyepieces, 1.25" vs 2". Does it matter in terms of image quality for my Z73? I have no idea what difference 2" vs 1.25" size makes for optics. And can you fit either size in anything? Like, the WO 73A field flattener recommended to go with the Z73 scope is 2", so I assume that means the back of the scope is 2". Does that mean I can only get 2" diagonals and eyepieces? Or do both 1.25" and 2" diagonals and eye pieces fit no matter what size the back of the scope is? Can I just get a cheaper 1.25" diagonal and it'll fit no matter what? And then presumably if I get a 1.25" diagonal there wouldn't be a point in getting 2" eye pieces (and do 2" eye pieces even fit in a 1.25" diagonal)?

3. What are your recommended starter eye piece sizes for a 73mm aperture / 430mm focal length f/5.9 telescope? Should I get two eye pieces and then a 2x Barlow so I have four magnification options? I read the rule is double the aperture (in mm) is the highest you want to magnify the view, which puts this scope's limit at 146x, and 430 FL ÷ 146x = 2.94mm so 3mm should be the smallest eye piece I get right which would give a ~143x magnification. Should I get a 25mm eye piece for viewing big things at only 17x, and then with Barlow it'd be 34x. And then maybe a medium magnification one like 9mm which would be 48x, and 96x with Barlow. So 25mm and 9mm and a 2x Barlow for a 73mm/430mm telescope?

 

Thanks in advance! :)

[WolfieGlos]

Hi, welcome to SGL 🙂

15 minutes ago, vansky said:

So besides the Z73 I'm going to get:

- a Skywatcher EQ6-R mount: I know that is probably overkill for a small refractor but I want my mount to be able to handle a heavier compound that I'll likely get next.

- a Nikon T-ring

- I know I also need a T adaptor, diagonal, and eyepieces, but here is where I run into some questions that I want to be sure about...

That's a great start, a mount like that will do you very well and future proof you for all but the heaviest scopes.

Have you considered other accessories; such as:

1. Power supply to mount (+cables)
2. Guiding scope+camera
3. Mount / camera control (ASIAIR or Laptop with software such as NINA/APT, etc)

If you're buying from FLO, they can advise the exact items you will require for your setup - i.e. which cables, etc.

15 minutes ago, vansky said:

1. Do I need a field flattener for AP? Does it make a big difference? My understanding is that without it stars at the fringes of the image will like stretch a bit or whatever. And does a field flattener take the place of a T-adaptor as the piece that connects the T ring with the telescope? If a field flattener does the job of a T-adaptor then I'll just shell out the money for the field flattener so I don't end up eventually buying both.

Absolutely, yes, you do need the flattener. Unless you intend to crop the image to just the centre portion, full-frame images (like say M33 Andromeda Galaxy at your focal length) will look really poor from the stars. Here's an example from CN from a quick search showing the effect without the flattener.

I don't own a WO scope, but the dedicated flattener also includes a built-in camera rotator to frame your target correctly, and also backfocus adjustment. You can also usually buy flattener/reducers - which flatten the field into the corners, but also reduce the focal length - and increasing the speed of the aperture. I'm not sure if this is offered for the Z73, but a faster aperture is worth considering.

I can't comment on the diagonals or eyepieces as I am purely an imager, but I'm sure other SGL members will be along to advise on those 🙂

[Elp]

Think you'll like the scope, I've got a Z61 and it does everything well visual, AP, planetary (though small), lunar, solar (with filters).

If the scope is like mine the rear of the focuser is 2 inch and there's an adaptor in the rear making it smaller to 1.25 inch. So you can use a 2 inch or 1.25 inch diagonal. Make your choice of diagonal, 1.25 typically only accept 1.25 eyepieces, 2 inch ones accept both. You get a larger FOV with 2 inch eyepieces but they're also more expensive. I standardised and settled on 1.25, eventually upgrading all my eyepieces to premium ones from budget. Good starter budget eyepieces are BST Starguiders, Vixen NPLs, Celestron Xcel LX from my experience. A lot will depend on your eyes, whether you wear glasses etc. I decided from the start to have 30/20/10mm and a Barlow and have generally stuck to that. If you've got that set there's minimal difference adding in a 15mm for example. The only exception is planetary viewing you may want higher powers as a Barlow "dims" the light due to extending the focal ratio.

Some WO flatteners are specific to certain scopes so make sure you get the right one. You'll need a Tring regardless as the standard bayonet mount on camera bodies are not an interface you find on flatteners, you need the Tring to connect the camera to a telescope thread. Typical flattener backspacing distances are 55mm from the back of the flattener to camera sensor so check this also, dslr mirrored bodies typically have 44mm from the bayonet to the sensor, the Tring typically makes up 11mm so you end up with the 55mm required for the camera sensor to be at the focal point of focus.

 

 

Edited January 31 by Elp

[Elp]

How are you going to setup, have it pre setup, setup fresh? In the future what sized scope are you looking to get?

I ask because if you're buying the mount new, consider a harmonic drive though you may need autoguiding to get reliable tracking (I haven't used mine unguided yet). You'll find the lighter weight and lack of counterweights a boon, even if you're just carrying the setup out and back in. Ones with two HD drives (Ra and Dec) also don't need balancing (obviously make sure they're not likely to topple over due to the imbalance when east and west heavy) so you save time here too.

The eq6 is a workhorse though as it's recommended a lot so not a bad choice.

Edited January 31 by Elp

[vansky]

Ah Wolfie thanks for the reply!

I do have a portable power supply so I'm good on that. if you're asking me about cables I'm guessing that means the cables don't come with the mount eh? Didn't realize that. I was figuring with something as wide field of view as a 430mm FL I wouldn't need a guiding scope? Maybe that's wrong. And I have not begun to look at software yet. I have an app that I can remotely use my camera with, but I don't know anything about software controlling the mount. Good stuff to look into. But I mean I can just control it with the controller on the mount right...but you're saying I should get some software on my laptop to do it? I don't really know how the whole AP process works haha. I figure it'll be a learning curve once I get the telescope and try it out.

 

 

Hello Elp!

Okay thats good to know about the adaptor on the scope. After I wrote my post above I looked at the Skymax 180 specs, which is the compound scope I am thinking I'll get once I get comfortable with the whole astronomy/AP thing on my ZenithStar, and its 2" so maybe I'll just get all my stuff at 2" so I can use the eye pieces on either one, though i'll check price differences between the 1.25's and the 2's.

Yeah I know I need a T ring, and then an adaptor to go from T ring to the scope, so what I wasn't sure about is if a flattener does the work of an adaptor? And I'll be getting the WO's Z73A flattener that's made to fit the scope so I'm good in that regard. It says the flattener is adjustable so I assume that means I just need to adjust it to what my camera needs.

I didn't follow much of what you said about the mount. I should research how mounts work and how to use them haha. All I know is I need one, they track stuff, and you have to balance the scope with counterweights. I have no clue what a harmonic drive is. I'll do some mount research tomorrow! I'm getting the eq6 because that should do fine with the compound scope I want to get as my second scope to compliment the refractor, and then if at some point I do a refractor upgrade the mount should handle whatever that future scope is as well.

 

 

Edited February 1 by vansky

[RT65CB-SWL]

20 hours ago, vansky said:

Hi voyagers of the cosmos!

...

3. What are your recommended starter eye piece sizes for a 73mm aperture / 430mm focal length f/5.9 telescope? Should I get two eye pieces and then a 2x Barlow so I have four magnification options? I read the rule is double the aperture (in mm) is the highest you want to magnify the view, which puts this scope's limit at 146x, and 430 FL ÷ 146x = 2.94mm so 3mm should be the smallest eye piece I get right which would give a ~143x magnification. Should I get a 25mm eye piece for viewing big things at only 17x, and then with Barlow it'd be 34x. And then maybe a medium magnification one like 9mm which would be 48x, and 96x with Barlow. So 25mm and 9mm and a 2x Barlow for a 73mm/430mm telescope?

 

Thanks in advance!

Hi @vansky and welcome to SGL. 

At the time of writing/posting, I am purely visual.

What is your budget for eyepieces? - You could start with a few BST’s fixed focal lengths. 

I have a TeleVue Ranger, which is similar specification [480mm f/l - 70mm obj]. I have and use 8, 13, & 15mm Plossl’s plus a few other brands and types. For wider FOV’s I use 6 and 8mm Radian’s and 13mm Nagler/type 6, a 6mm Svbony 6mm ‘goldline’ or ‘redline’ [image below]. For higher magnification/planetary views, I will use either the TeleVue Nagler 3-6mm zoom or Svbony 3-8mm zoom.

note: the ‘goldline’ AFOV is 66^o ...the ‘redline’ AFOV is 68^o  - they are branded by other manufacturers and dealers, so prices will vary.

Edited February 1 by RT65CB-SWL

[Cosmic Geoff]

10 hours ago, vansky said:

Okay thats good to know about the adaptor on the scope. After I wrote my post above I looked at the Skymax 180 specs, which is the compound scope I am thinking I'll get once I get comfortable with the whole astronomy/AP thing on my ZenithStar, and its 2" so maybe I'll just get all my stuff at 2" so I can use the eye pieces on either one, though i'll check price differences between the 1.25's and the 2's.

What do you mean by a 'compound scope'?

  The point about 2" eyepieces is that if you want a low-power eyepiece with a wide field of view, e.g. 30mm fl, the resulting size of the lenses means it won't fit into the 1.25" format, hence 2".   But a 10mm eyepiece will fit easily into the 1.25" format, so there is no point in making a 2" version.  2" eyepieces are generally heavier and more expensive.    Adapters that fit a 1.25" eyepiece into a 2" focuser are readily available.

[900SL]

Hi Vansky

 

For imaging on APSC like the Nikon (I have the D5600) you need a flattener, or flattener-reducer (which increases the FOV and 'speed' of capture)

 

The WO Flat 73 has adjustable ring, and when set to the correct spacing you have 55mm backfocus from the flattener to the camera sensor. This is provided by the T ring connector and the camera (the sensor is set 40 odd mm inside the camera body)

See here, it's pretty much self explanatory. I think you need a Nikon M48 T ring for the camera to flattener connection

 

[vansky]

3 hours ago, RT65CB-SWL said:

Hi @vansky and welcome to SGL. 

At the time of writing/posting, I am purely visual.

What is your budget for eyepieces? - You could start with a few BST’s fixed focal lengths. 

I have a TeleVue Ranger, which is similar specification [480mm f/l - 70mm obj]. I have and use 8, 13, & 15mm Plossl’s plus a few other brands and types. For wider FOV’s I use 6 & 8mm Radian’s and 13mm Nagler/type 6, a 6mm Svbony 6mm ‘goldline’ or ‘redline’ [image below]. For higher magnification/planetary views, I will use either the TeleVue Nagler 3-6mm zoom or Svbony 3-8mm zoom.

note: the ‘goldline’ AFOV is 66^o ...the ‘redline’ AFOV is 68^o  - they are branded by other manufacturers and dealers, so prices will vary.

Honestly I haven't yet researched what makes a difference in eye pieces yet. I see there are eye pieces for tens of dollars and ones for many hundreds of dollars. Don't have a clue how big the difference is, and don't know the difference between brands. To start I was just going to get a couple cheaper ones and a Barlow 2x so I can have a few different magnification levels.

And maybe the difference in eye piece quality is something better experienced? By starting off cheap and then later perhaps getting a higher quality one and seeing the difference I could better understand the difference than just trying to read about it? I don't have an eye piece budget per se, but I'm not looking to spend several hundred of dollars on eye pieces just to get started.

[vansky]

2 hours ago, Cosmic Geoff said:

What do you mean by a 'compound scope'?

  The point about 2" eyepieces is that if you want a low-power eyepiece with a wide field of view, e.g. 30mm fl, the resulting size of the lenses means it won't fit into the 1.25" format, hence 2".   But a 10mm eyepiece will fit easily into the 1.25" format, so there is no point in making a 2" version.  2" eyepieces are generally heavier and more expensive.    Adapters that fit a 1.25" eyepiece into a 2" focuser are readily available.

By compound scope I mean a SCT or Mak...am I getting that right? Compound and Catadioptric is the same thing? From my research, compound/catadioptric telescopes are the short fat ones with a sealed tube that use both a 'corrector plate' lens up top as well as mirrors.

Okay so larger focal length eye pieces literally just can't fit in 1.25"? Ah I'm reading now something about the field stops in eye pieces and the field stops have to be larger in larger length eye pieces so at a certain point on increasing length the field stop inside would be too wide to fit into a 1.25" and would require a 2" eye piece. And so 2" eye pieces have a wider field of view?

So is there nothing inherently better about a 2" eye piece? It just allows longer eye pieces and wider field of views, so it just depends what magnification and field of view you want? Is the generally higher cost of 2" just from the fact that they have to have larger lenses and are bigger? If so, maybe I'll just go with a couple 1.25" pieces to get started since they are cheaper. As I said in my last reply here, I'm starting to feel like figuring out differences in eye pieces is going to be an experience thing so I should probably just start cheap and experience the differences over time as I decide to pick up new eye pieces.

[vansky]

28 minutes ago, 900SL said:

Hi Vansky

 

For imaging on APSC like the Nikon (I have the D5600) you need a flattener, or flattener-reducer (which increases the FOV and 'speed' of capture)

 

The WO Flat 73 has adjustable ring, and when set to the correct spacing you have 55mm backfocus from the flattener to the camera sensor. This is provided by the T ring connector and the camera (the sensor is set 40 odd mm inside the camera body)

See here, it's pretty much self explanatory. I think you need a Nikon M48 T ring for the camera to flattener connection

 

Alright cool thanks. I'll go ahead and get the flattener, and the T ring of course.

[vansky]

Hey any opinions on refurbished telescopes? Zenithstar 73 is $730 but I just found a refurbished one for $558, $172 savings.

 

The refurbished one is being sold by William Optics, so I assume it should be fine right? Shouldn't really be any different than a new one?

[Elp]

Don't forget you'll likely get charged VAT and import tax when the item lands in your country of delivery.

[WolfieGlos]

16 hours ago, vansky said:

Ah Wolfie thanks for the reply!

I do have a portable power supply so I'm good on that. if you're asking me about cables I'm guessing that means the cables don't come with the mount eh? Didn't realize that. I was figuring with something as wide field of view as a 430mm FL I wouldn't need a guiding scope? Maybe that's wrong. And I have not begun to look at somewhere yet. I have an app that I can remotely use my camera with, but I don't know anything about software controlling the mount. Good stuff to look into. But I mean I can just control it with the controller on the mount right...but you're saying I should get some software on my laptop to do it? I don't really know how the whole AP process works haha. I figure it'll be a learning curve once I get the telescope and try it out.

It certainly is a learning curve   I'm still learning 3 years down the line....

Yes, you can control the mount with the controller that comes with it, which will allow you to use GoTo and locate your desired target - very useful for visual. If using for AP, you would then need to manually operate the camera (intervalometer or computer controlled).

However, if you intend on controlling the mount with Laptop / ASIAIR, you will need an EQDIR cable (which isn't supplied with the mount) to replace the hand-controller and allow the mount to be controlled by external software. The cable will connect into the same socket on the mount. The software will also allow control of the camera, other accessories (i.e. filter wheels, electronic focusers, rotators, etc, if you go this route down the line), as well as guiding which will allow dithering. Dithering will reduce/remove walking noise by moving the telescope by X amount of pixels - as you'll be using a DSLR, dithering is essential. Here's an example, and another, which ruins your images. Whilst dithering is taking place, the software would stop the camera from imaging, complete the dither, and then resume. Using the hand-controller, I don't believe you can do this.

You may be able to image with the EQ6 without guiding, you would be limited on sub length depending on your polar alignment accuracy but as I've got the HEQ5 and always use guiding, I can't really offer any exact knowledge on this subject.

Guiding software, PHD2, is free to download and use. Here is a cheap guide scope+camera bundle, I still use it now and it is mounted into a simple finder shoe or a carry handle if it comes with it (I think the Z73 does come with one, but check especially if buying second hand). If not, you might need to buy a separate finder shoe if the Z73 doesn't come with one, or the WO dedicated scope + camera.

[vansky]

11 minutes ago, WolfieGlos said:

It certainly is a learning curve   I'm still learning 3 years down the line....

Yes, you can control the mount with the controller that comes with it, which will allow you to use GoTo and locate your desired target - very useful for visual. If using for AP, you would then need to manually operate the camera (intervalometer or computer controlled).

However, if you intend on controlling the mount with Laptop / ASIAIR, you will need an EQDIR cable (which isn't supplied with the mount) to replace the hand-controller and allow the mount to be controlled by external software. The cable will connect into the same socket on the mount. The software will also allow control of the camera, other accessories (i.e. filter wheels, electronic focusers, rotators, etc, if you go this route down the line), as well as guiding which will allow dithering. Dithering will reduce/remove walking noise by moving the telescope by X amount of pixels - as you'll be using a DSLR, dithering is essential. Here's an example, and another, which ruins your images. Whilst dithering is taking place, the software would stop the camera from imaging, complete the dither, and then resume. Using the hand-controller, I don't believe you can do this.

You may be able to image with the EQ6 without guiding, you would be limited on sub length depending on your polar alignment accuracy but as I've got the HEQ5 and always use guiding, I can't really offer any exact knowledge on this subject.

Guiding software, PHD2, is free to download and use. Here is a cheap guide scope+camera bundle, I still use it now and it is mounted into a simple finder shoe or a carry handle if it comes with it (I think the Z73 does come with one, but check especially if buying second hand). If not, you might need to buy a separate finder shoe if the Z73 doesn't come with one, or the WO dedicated scope + camera.

Alright, well sounds like there is still a lot I need to learn about basic usage of mounts / software. Thanks for the info. I'll look into some of this stuff. I may start by buying fewer things just to keep it simpler at first and then as I start to use the telescope I can say to myself oh Wolfie was right I do need so-and-so gadget to do what I want to do haha

[vansky]

I bought the stuff!

I ended up getting BOTH the ZenithStar 73 and the Skymax 180 so I can right from the start do both wide field mostly astrophotography as well as have that greater reach of a bigger longer scope. Needless to say I'll have my hands full when these things come in!

Got the EQ6-R Mount and tripod which were actually on sale by a few hundred dollars so that was nice. Decided to just go for the cheaper 1.25" eye pieces to start so I got the Plossl 9mm and Plossl 25mm in that size. Got a 2x Barlow. Got a T ring. Got the field flattener. And got carrying bags for everything. And the Skymax comes with a diagonal and a 28mm eye piece and finder scope.

That should get me started haha!

I guess once I have used the mount a bit and gotten used to the telescopes I may also need to get those cables to go from mount to computer for photography, but I'll worry about that when I get to that point.

[WolfieGlos]

Great choices, I'm sure the bank balance isn't looking too healthy 🤣

I was going to suggest getting used to the mount with another scope for visual before going down the AP route. It's not to put you off, but I went in with eyes "half open" and made some bad choices which hampered my progress - and cost money. Best of luck, and any issues, just make a new thread, people are always happy to help 🙂

[vansky]

9 hours ago, WolfieGlos said:

Great choices, I'm sure the bank balance isn't looking too healthy 🤣

I was going to suggest getting used to the mount with another scope for visual before going down the AP route. It's not to put you off, but I went in with eyes "half open" and made some bad choices which hampered my progress - and cost money. Best of luck, and any issues, just make a new thread, people are always happy to help 🙂

Yeah ya know I'm guessing I'll use it visually for a bit first before I start trying to figure out photography with it. I'm sure it will be a learning curve with the mount, two telescopes, visual observing and photography. I'll probably just try to get a feel for both scopes and figuring out what each one is good at and getting comfortable using the mount before I strap on a camera and start learning that whole realm. I was just too excited to get started and just had to get both scopes I was interested in at once haha.

Bank account got a nice trim yes haha, definitely one of the biggest purchases of my life. Outside of schooling and car stuff it is the biggest purchase haha, but it's all for the cosmos!

 

Thanks for the help!

Edited February 2 by vansky

[RT65CB-SWL]

On 01/02/2024 at 21:39, vansky said:

I bought the stuff!

I ended up getting BOTH the ZenithStar 73 and the Skymax 180 so I can right from the start do both wide field mostly astrophotography as well as have that greater reach of a bigger longer scope. Needless to say I'll have my hands full when these things come in!

Got the EQ6-R Mount and tripod which were actually on sale by a few hundred dollars so that was nice. Decided to just go for the cheaper 1.25" eye pieces to start so I got the Plossl 9mm and Plossl 25mm in that size. Got a 2x Barlow. Got a T ring. Got the field flattener. And got carrying bags for everything. And the Skymax comes with a diagonal and a 28mm eye piece and finder scope.

That should get me started haha!

I guess once I have used the mount a bit and gotten used to the telescopes I may also need to get those cables to go from mount to computer for photography, but I'll worry about that when I get to that point.

Do a few test/dummy runs in daylight to prep yourself. That way you will know where everything goes when it is dark or under the illumination/glow of a red torch/flashlight.

Edited February 3 by RT65CB-SWL

[vansky]

1 hour ago, RT65CB-SWL said:

Do a few test/dummy runs in daylight to prep yourself. That way you will know where everything goes when it is dark or under the illumination/glow of a red torch/flashlight.

Oh thanks that's a great idea!

[900SL]

I focus main and guide scope on horizon before it gets dark, and polar align during twilight (before full astronomical darkness). This gives time for the rig and scopes to reach thermal equilibrium. 

Quick check on focus and PA later, just before kick off