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Tips for a new user of a William Optics Zenithstar 73?

Sky-Watcher Star Adventurer Nikon D5100 Equipment Refractors DSLR
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Marc V avatar
Marc V avatar
Hi All!

I recently bought a WO ZS 73 (I know... I am somewhat responsible for the clouds these weeks in Québec, sorry!).

For the WO ZS users... Do you have some goods advices on how to "optimize" the use of my new toy?

I image with a stock Nikon D5100 and use it with a Star adventurer pro (I know, it is a bit heavy... my next buy will be a better mount).

@Marc Mantha je crois que tu as aussi ce refracteur... As-tu quelques trucs pour moi

Clear sky!

Merci, Marc

Grande nébuleuse d'Orion
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Mark Germani avatar
Mark Germani avatar
Hi Marc:

Congrats on the new telescope! I bear some responsibility for the clouds on the West coast, as I just bought the WO Z61 smile

I don't speak specifically from experience using WO products, as I haven't had a chance to use mine yet (sigh!) but I did play around with a 80mm achromat for a while. Looking at your M42 shot (very nice!) I wonder if you might benefit from using the Bahtinov mask built into the lens cap of your Z73 to fine-tune the focus. The stars are also slightly oval, so maybe double-check your polar-align and make sure that you're balanced with the counterweights. I've heard that balancing your mount slightly East-heavy is recommended, too.

I'm new here, so you can take the above with a grain of salt. Clear skies, and enjoy your new toy!

Cheers,
Mark
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Marc V avatar
Marc V avatar
Hi @Mark Germani !
Thanks for your advices! I'll keep that in mind.
cheers, Marc
matthew.maclean avatar
matthew.maclean avatar
WO makes excellent telescopes; I’ve been very happy with mine. As you said above, the biggest thing would be to get a larger two-axis mount. I use a CEM25p (which has just been updated to a CEM26 I think) and is also a purchase I’ve been very happy with. Others in this payload class use the HEQ5 I believe. Having a mount like one of these would definitely expand what you can accomplish with your new telescope. You will find the balance and stability to be a drastic improvement from the StarAdventurer. If I am very careful with polar alignment, I can get 4-5 minute un-guided frames from my setup before I see noticeable star trailing (if I am reckless, maybe 2 minutes). With two-axis auto-guiding, frame duration is basically unlimited.

I didn’t see if you had the WO flattener attached (there’s a special one for ZS73); if not, you will want one of those also with the DSLR.

The weather in the northeast for us has definitely been truly awful for at least a month. Hopefully we get some clearing soon. I would really like to get to see Orion this winter.
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Marc V avatar
Marc V avatar
I didn’t see if you had the WO flattener attached

Hi @matthew.maclean !

Thanks for your message. I wish I will be able to buy myself a new mount for the summer... I am thinking of a Celestron AVX, but I might take something with more payload... I have no flattener yet. Not sure I am there yet and I'm saving for the mount

I  hope we will have a couple clear nights in January to get Orion and other DSO in that region!

Clear sky! Marc
Marc V avatar
Marc V avatar
Mark Germani:
I wonder if you might benefit from using the Bahtinov mask built into the lens cap of your Z73 to fine-tune the focus.


@Mark Germani   I did use the mask that night, but it was the first time. The stars are pretty small in my dslr screen and it was windy, so it was not easy to focus! I need practice

Next night, i will try the Bahtinov Aid in APT (Astro Photography Tool). It should help. I already use APT for platesolving.

Cheers, Marc
Mark Germani avatar
Mark Germani avatar
Marc V:
The stars are pretty small in my dslr screen and it was windy, so it was not easy to focus!


The stars are tiny on my DSLR screen too (Canon), but I use digital zoom in live-view to magnify the stars, and it helps a bit. I did a bit of reading on your Nikon camera, and I think you should also be able to zoom in live-view mode.

In the interest of full disclosure, my bahtinov mask was too small for my 80mm achromat, so no matter how much I zoomed in I couldn't see anything more than tiny diffraction spikes, but it's my understanding that Bahtinov masks are quite effective, and the one you have is custom-built for your Z73. Sadly, my Z61 is an older model without the Bahtinov mask, so I'm hoping the Bahtinov mask that wouldn't work with my 80mm achromat will work with my Z61. Fingers crossed!

A quick note about the flattener - my telescope shop doesn't carry WO, so they didn't have the WO flattener for my Z61. They gave me the Orion Flattener for Short Tube Refractors (for 400-660mm focal length), which is a fair bit cheaper than the WO model. I haven't had a chance to test it yet, but I'm able to achieve focus on distant objects with it, so it might work. The Z61 is 360mm so it's a bit out-of-spec, but it might work even better with yours. I'll post to the forum if it works, and I'll include some sample images. Maybe you can save a few bucks!

Cheers,
Mark
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Marc V avatar
Marc V avatar
@Mark Germani
Hi Mark!

Thanks for your message. As you mentionned, I can zoom a bit in liveview mode with my Nikon. But the star are still very small. As I mentionned, I look forward to try to focus with APT and the Bahtniov Aid. I am positive is will help.

I just read your post about your flattener. I'm sure it will work fine. My retailer here proposed me like yours did to buy with another company than WO, but I don't recall which one since I am note ready for that move yet. Nevertheless, I look forward to see your next pictures!

I saw also that you use SVBONY CLS filter. I am thinking about buying that filter too (2inches one). I am just South of Montreal, and the light pollution is very present...Did you use it many times so far? Are you satisfied? Would you recommand that filter?

Best wishes for the New Year!

Cheers, Marc
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Mark Germani avatar
Mark Germani avatar
Marc V:
I saw also that you use SVBONY CLS filter. I am thinking about buying that filter too (2inches one). I am just South of Montreal, and the light pollution is very present...Did you use it many times so far? Are you satisfied? Would you recommand that filter?


The SVBONY filter is pretty intense - it blocks a LOT of light, and makes processing difficult. I end up with a lot of gradients that I have to remove, which didn't seem to be as much of a problem without the filter. It definitely removes a lot of skyglow, and I'm able to expose much longer without blowing out my histogram, but the jury's still out... I have the Canon clip-in version of the filter.

To be honest, I wish I'd saved up for the Optolong L-Pro or another less intense/restrictive filter. I have Bortle class 7-8 skies and I feel that the amount of LP removed by the SVBONY is overkill, and more trouble than it's worth.

You might also want to consider whether you plan on Astro-modding your camera. Getting a CLS-CCD or L-Pro filter now saves you from having to get an IR-cut filter down the road.

There are some great shoot-outs & reviews of CLS filters online. And I know that people on this site have had success with the SVBONY-CLS. Just my two-cents, though!

Cheers,
Mark

PS: Another thought on the Bahtinov mask - are you using a really bright star like Vega as your focusing star? Perhaps choosing a really bright star will result in better spikes. Anyone else care to chime in on Bahtinov masks?
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Marc V avatar
Marc V avatar
Thanks for your comments and opinions on SVBONY CLS filter. I will do some more research smile
Cheers, Marc
Mark Germani avatar
Mark Germani avatar
Marc:

Here's a good comparison of the Optolong L-Pro & Svbony CLS:

https://star-hunter.ru/en/optolong-l-pro-clip-eos-review/

I think I'm going to switch to the L-Pro as soon as I can afford it, and maybe the 2" to save a bit of money (the clip-in versions are more expensive, for some reason).

Cheers,
Mark
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Marc V avatar
Marc V avatar
I will have a look a your link. Thanks.
A 2 inch filter is a plus in my opinion, since you can use it with other équipement. A clip filter can just be used with your DSLR….
Cheers, Marc
Uwe Deutermann avatar
Uwe Deutermann avatar
Marc V:
I am thinking of a Celestron AVX, but I might take something with more payload

Hi Mark!
Depending on how far you want to go with your Astro images, I strongly recommend to buy a higher quality mount, you will not regret it (I know it is a tough one to swallow since it is quite more expensive). I started out very similarly, bought the AVX and it gave me for some time a lot of joy. But after some time I realized that this mount is just not good enough for the growing passion. From all what I read and see here on Astrobin the Skywatcher mounts 5/6 are very good, I had a Losmandy which was not (although more expensive as well!). You do not have to go crazy and buy a super expensive one (although they are GREAT), I would wait and see how far your passion grows. Read some reviews (from experienced astro photographers) about mounts and I am sure you will find one that will make you happy for the next years to come.
Uwe
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Marc V avatar
Marc V avatar
Uwe Deutermann:
I would wait and see how far your passion grows.


Hello Uwe! I entirely agree with you... With this interest/passion, it takes "a chess mind", one needs to think a couple moves ahead...

I still think that the AVX is a good choice in my situation. I can't really have a fix setup in my backyard and it is a "bit" light polluted. So I have to pack/unpack every night and every now and then I go to a darker aera a couple of kms away from the city (corn field)... So for a rig like mine and wih this in mind, the AVX is a good candidate.

But as you mentionned, I surf our forum and others and sneak at others settings

I am also looking and used equipement, every now and then, there are goods deals in my area.

Thanks for you message and suggestion!

Best wishes for the New Year! And many clear nights!

Cheers, Marc
Marc Mantha avatar
Marc Mantha avatar
Marc V:
@Marc Mantha je crois que tu as aussi ce refracteur... As-tu quelques trucs pour moi


Salut Marc, désolé du délais, je viens de voir tu que m'avais écrit!

First, congratz on your new scope, I am sure that you will love it!
Here are a couple of pointers:

- If you are still using the SA for this scope, your next upgrade should be a good mount. The SA is very good, but made more to take on hikes or do widefields. You are above the limit, especially when  you factor in an eventual field flater. Your exposures will be very short with the SA before you start seeing trailing. I have the heq5-pro and I really like it.

- From the image you posted, I think you cropped the nebula and that it was more on the top right portion of the image, is this correct?  The stars are elongated in a way that points towards field curvature from the scope. Getting the flatner would also be required for any wide tarde, basically most nebulas that we want to shoot I think the focus was probably ok, but the missing flatner gives the impression of being out of focus.

Cheers and clear skies!
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