Does this make sense for starting EEA: zwo 585 and skywatcher explorer 200

[Temporal_Mechanic]

Hi all,

 

I've had a skywatcher explorer 200 on an eq5 with tracking motors but not goto for many years and never had much success with it.  The main problem seems to be light pollution which makes it hard to find things without goto, and then hard to see them.  I'm not keen on going to dark sites so thought EEA might be my best chance at enjoying the hobby.  I'd need a camera for that and from the reading I've done an uncooled 585 based one seems like the best option in my budget.  I'm a bit worried about fov but anything with a bigger sensor seems a lot more expensive.  I have two main questions:

 

Will this camera actually work with my scope considering things like available back focus?

 

Is there something else in the same price bracket I should be considering?

 

Thanks in advance for any thoughts or suggestions.

[bosun21]

I was just about to mention @PeterC65 and I saw he was indeed typing. I'll leave you in his capable hands.

[PeterC65]

I have a Player One Uranus-C camera which uses the IMX585 sensor and I use it without any problems with my Explorer 200PDS. I think the various IMX585 astro cameras are amongst the best all round cameras available, without breaking the bank.

To get to focus with a 35mm extension tube and a 2" to 1.25" adapter (10mm) fitted to the focuser, I need to wind the focuser out to 13mm. So there is plenty of back focus, enough to fit a filter wheel between the focuser and the camera in fact. Bear in mind though that I'm using the 200PDS, not the 200P.

The IMX585 sensor is actually oversampling when used with the Explorer 200 but that isn't a problem in practice. A better pixel size match would be 4.8um, but such a camera would then be a poor match for a shorter focal length scope.

The field of view at 0.64° x 0.36° is a little small and this will limit the objects you can observe. You will be able to plate solve with this field of view though but that would be most useful if your mount was computer controlled. Getting a wider field of view with the Explorer 200 would need a bigger sensor which would be much more expensive. It is actually cheaper to buy a shorter focal length scope (I'd suggest a 70-80mm apo refractor).

 

[PeterC65]

Just to add that doing EAA is a revelation!

I started out doing visual and was always wanting to see more. I bought more eyepieces, more filters, more scopes, and then eventually I bought a camera, and since then I've been hooked. You will see HUGELY more via EAA. Even without a computer controlled mount, plate solving will tell you exactly where the scope is pointing which should help in finding things.

Another advantage of the Explorer 200 / IMX585 combination is that if you fit a Baader Hyperion Barlow then you've got a setup suitable of observing the planets and Moon detail.

Just to wet your appetite, here are some EAA snapshots that I've taken with the Explorer 200 and Uranus-C. They are what I observed on the night, with no post processing.

M16 taken with an Optolong L-eNhance filter, 25 x 15s exposures (6.25 minutes).

Io transit of Jupiter, timelapse video.

I still do visual astronomy sometimes, but like you I only observe from home and EAA means I can stay in the warm.

EAA also copes much better with light pollution. It still has a negative effect on observations but much less so than with visual. I can still observe faint nebulae when the Moon is bright for example (provided they are not too close to the Moon).

 

[Bivanus]

24 minutes ago, PeterC65 said:

I'd suggest a 70-80mm apo refractor

From an Asi ZWO 585MC + TS APO 80mm Photoline user : Yup!  🤩

[PeterC65]

19 minutes ago, Bivanus said:

From an Asi ZWO 585MC + TS APO 80mm Photoline user : Yup!  🤩

I have the TS Optics Photoline 72mm APO for widefield (1.48° x 0.83° without a reducer) which I really like. And just for good measure, an Askar FMA135 (4.7° x 2.7°) and a Pentax 55mm camera lens (11.6° x 6.5°). Together these cost me much less than even the cheapest IMX571 based camera would have cost.

 

Edited December 26, 2024 by PeterC65

[PeterC65]

In case you have the Explorer 200P, it might be useful to know where I get eyepiece focus with my Explorer 200PDS so that you can compare the back focus.

If I'm using eyepieces, I need a 35mm extension tube and a 2" to 1.25" adapter (10mm) as I do with the camera, and I get to focus with the focuser wound out to between 27-31mm depending on the eyepiece (fixed focal length). So the camera focus point is about 14-18mm further in than the eyepiece focus point.

I expect the same is true for the Explorer 200P, so if you have to wind the focuser out by at least 20mm to get to focus with a fixed focal length eyepiece then you should be fine with a camera.

 

[Temporal_Mechanic]

That's, fantastic thanks, I'll reply in detail later (probably tomorrow) but wanted to say I really appreciate the info 🙂

[bosun21]

The focus point is further out for the 200P as opposed to the PDS. You will more than likely not need the 35mm extension piece on your 200P. The PDS is actually designed for camera use whereas the P series was primarily for visual use. The uses can certainly be interchanged however some DSLR cameras couldn't reach focus due to insufficient in focus.

[PeterC65]

49 minutes ago, bosun21 said:

The focus point is further out for the 200P as opposed to the PDS. You will more than likely not need the 35mm extension piece on your 200P. The PDS is actually designed for camera use whereas the P series was primarily for visual use. The uses can certainly be interchanged however some DSLR cameras couldn't reach focus due to insufficient in focus.

I think it's the other way around. The focus point is closer in to the focuser with the 200P and that's why it may not need an extension tube.

 

[Temporal_Mechanic]

Thank you all for the advice.  @PeterC65 that photo and video are great, if I can get even remotely close to that I'll be happy!

 

I do indeed have the P rather than the PDS, I observe visually with the 35mm extension using eyepieces from 7-26 mm which would suggest the focal plane is somewhere in the middle of the extension tube so I should be fine if I remove that.

 

Good points on using a shorter fl apo for wide field viewing, that's on my future shopping list if I get enough enjoyment out of EAA to warrant it. My main fov concern was plate solving for locating things, glad to hear that works.

 

Overall I'm very reassured and will be picking the camera up from my local astro shop this afternoon, will let you know how it goes after the next clear night.

 

Thanks again,

Tim

[bosun21]

18 hours ago, PeterC65 said:

I think it's the other way around. The focus point is closer in to the focuser with the 200P and that's why it may not need an extension tube.

 

Doh! 🙄 Of course it is. I worded it the wrong way round. You get what I meant though. My apologies.

Edited December 27, 2024 by bosun21
Typo

[Temporal_Mechanic]

8 minutes ago, bosun21 said:

Doh! 🙄 Of course it is. I worded it the wrong way round. You get what I meant though. My apologies.

No worries, I did indeed get what you meant and appreciated the contribution 🙂 

[PeterC65]

I'm sure you'll enjoy EAA. There is plenty to learn, so my advice is to be patient, try as much as possible in daylight before trying it in anger at night, and take the time to read the manuals. My EAA observation has improved massively since I first started, and my first session was very disappointing.

For software I'd recommend you get SharpCap, and pay for the pro version. SharpCap is quite complex with many features, but it is generally regarded as the best software to use for EAA. Again, read the very good manual before you use it in anger, you can try out many of the features using test modes.

Let us all know how you get on (I'm trying to encourage more people on SGL to try EAA).

 

[Temporal_Mechanic]

Thanks, you must be psychic because I had a first attempt and did feel very disheartened!  Saw your post straight after and it helped.  Having digested for a couple of hours I'm already keen to get back out with a list of things to do better, as well as quite pleased with how the session went in retrospect.

 

Pros:

The camera works and is excellent 

I was able to view Jupiter with more colour and detail than I've ever managed at the eyepiece 

Plate solving works

 

Cons:

Still couldn't find Andromeda or the Pleiades

Even finding Jupiter was hard

 

The difficulty seems to fall into two categories, knowing where to point the scope and faffing with the mount to point it where I want.  The first just needs a bit of homework on my part but the second seems trickier, will have to have a think about that one

[PeterC65]

Observing the planets via EAA is one of the more difficult things to get right, and you also need to Barlow the Explorer 200 to get any detail. Brighter DSOs are easier. M31 and M45 are too big for the field of view of the Explorer 200, you need to try for smaller DSOs, things like M15 or M51, bright but smaller.

Given that you don't have GOTO, I would point the scope as close as you can to the intended object and then plate solve, then use the plate solve result to figure out how you need to move the scope position to get where you want to be.

 

[happy-kat]

has the mount motor's handset got any ports on it?

[Temporal_Mechanic]

12 hours ago, PeterC65 said:

Observing the planets via EAA is one of the more difficult things to get right, and you also need to Barlow the Explorer 200 to get any detail. Brighter DSOs are easier. M31 and M45 are too big for the field of view of the Explorer 200, you need to try for smaller DSOs, things like M15 or M51, bright but smaller.

Given that you don't have GOTO, I would point the scope as close as you can to the intended object and then plate solve, then use the plate solve result to figure out how you need to move the scope position to get where you want to be.

 

Good to know about planets, thanks.  I tried Jupiter because I know I can find it, I did try a Barlow but didn't realise I'd knocked the tracking clutch until later so it was out of frame but I assumed I'd set something up wrong.  Thanks for the suggested targets, will give those a go next time.

 

Yes, I think plate solve then adjust is going to be the best way to find things.  I couldn't get the mapping of plate solve result to handle turning right in my head but have done some reading and think I'll be able to do it next time, that's going to be my primary objective.  One good thing about the eq mount is I should be able to do the Dec axis first and then leave it in place to do the RA.

 

8 hours ago, happy-kat said:

has the mount motor's handset got any ports on it?

Unfortunately not, just power in and the two motor cables.  I think a mount upgrade or replacement is top of my list for the future but it will be at least a year until I can afford that