Skywatcher 200p and AP

[ahernep]

Hey Guys,

First off let me say thanks to everyone who contributes to this forum, very informative!

Apologies if this has been answered already but I'm looking for some information on the Skywatcher 200p/1200 scope. I've been looking around for quite a while to see what I should go for as my first buy and this seems to be highly recommend. Starting out I'm looking to go for the simple manual dob version and just get into basic viewing & short exposure planetary (maybe some DSO, whatever comes out in < 20-30sec exposures I guess). The question them becomes whether I can upgrade this scope for more serious DSO AP in the future, specifically mounting it on a HEQ5 or similar? I've heard conflicting stories online, just wondering what people here thought?

Also, living in Singapore I understand the seeing will never be great but I think I can travel around to find a good spot on occasion, looking at the size and weight, maybe adding a few straps & bags to make it easier this scope seems like it should be OK (but probably at the limit) for bringing in a taxi?

Cheers,
Peter.

[kimo]

Hi,
I am also new in this field(AP). Probably its too early to use such huge scope for AP, specially 200mm Newtonian . You can have small scope like 70mm - 80mm Refractor for DSO.

Thanks
Kimo

[orly_andico]

hi,

i have written a 7-part mini series on my experiences imaging with an 8" f/4 newtonian.

http://orlygoingthirty.blogspot.com/201 ... t-vii.html

short story: don't do it!!!

now seriously... such a scope, with a Paracorr, and perfectly collimated, will produce amazing images with round stars from corner to corner. I believe Ivan is using the same setup (8" f/4) and he has posted some wonderful images.

here's mine with its custom aluminum rolled tube..



but... you'll need to do a lot of work to get there. These cheap newtonians have floppy tubes, substandard focusers, and they are quite heavy. I would not try anything less than an Atlas or EQ6.

[ahernep]

Hi Guys, thanks for getting back,

Kimo, why do you say too early? My thinking is it's within my budget now (on the dob) and in the future if I get more into it I have options to upgrade to goto dob and/or put it on a HEQ5 or better? In general everyone I can find who's reviewed them seem very happy.

Orly_andico, am I right is saying that the 200/1200 giving an F/6 would be a little more forgiving than the f/4? Also, on the AP side of things it will be a while before I go that way, initially just observing & learning the skies, thus the manual dob to begin.

I agree, it will be a heavy beast, even more so if I move to a heavy duty EQ mount, but it's just about manageable for me I think, certainly anything bigger would not be.

Thanks,
Peter.

[Clifford60]

Hi Peter,

I guess you are looking for this scope as in the link.

http://ca.skywatcher.com/_english/01_pr ... hp?sid=361

The OTA weight for this scope is 11kg, by itself as a DOB it has not problem for visual, should be very decent.

However, when you want to convert it to do AP, this weight will mean a stronger tripod and mount is required, meaning more expensive. When shopping for mount, you need to pay attention to the payload for AP to do AP and not the generic value which is normally for visual. For example a payload of 25kg for visual setup is only good for about a 16-18kg AP setup. I've a 12kg OTA and when add with other accessories, easily hit 16kg not counting the counter-weight for AP. I'll need to spend a bomb (to many) to get a decent GEM for AP, one that cost more than S$2k for a new setup.

Maybe you should look for at the Newtonian design of the same aperture and lighter. @ F/5 you can gather more light for AP but more sensitive to collimation. A faster scope will also need better performance eyepieces for visual (actually depends on how much distortions you can accept).

http://ca.skywatcher.com/_english/01_pr ... hp?sid=342

Skywatcher also sell complete with GEM setup for this scope.

I think Kimo's suggestion for a 80mm refractor is because of its small size, so an easy grab and go setup. Lighter OTA means smaller mount/tripod, easier for transport, even when using public transport. However, smaller aperture means limited magnification and light gathering power. Nevertheless, this doesn't mean you can't do good AP or have nice ob experience (many of us start with a small scope and many still using it). A good clear and dark sky is more important than a good and/or big scope.

Last but not least, there is a saying: "the best telescope is the one that you use the most". So, get a setup that you will use the most.

[ahernep]

Hi Clifford,

Thanks for the feedback. I had considered the 200DS but then I had seen that it does not have Dob option (that I could find) and that the eyepieces would need to be that bit higher spec and by default I think the DS comes with only 2" so I presumed there was a reason for that thus more expensive eyepieces again. So more expensive eyepieces and more expensive mount adds a lot to the initial cost.

maybe my logic is wrong but my thinking was get a good scope for viewing initially, thus the manual dob to keep cost down but a decent OTA (I thought) that had the capability of upgrading later on rather than being replaced (unless I get really serious in which case I will start considering specialized scopes for imaging/viewing/dso/planetary etc. though this would be a long way off).

Then if I remain really interested I have 2 options for upgrading, the GoTo dob mount and/or if I get really serious to an EQ mount though I realize for a scope this weight that the cost was going to be high.

Quick side question here, has anyone compiled a list of good sites in Singapore? I have a few ideas to check out but I'm thinking this trail would have been blazed by others already?

Cheers,
Peter.

[ivan]

Hi Peter,

I wouldn't suggest using a SW 200p as a scope to start AP with. While it is a fine instrument for visual purposes and does ok for planetary imaging, it has a long-ish focal length and has itself a substantial weight. This would require your mount to have sufficient load capacity and the ability to track well to give sufficiently round stars at 1200mm of FL. Like what the others suggested, a small refractor would be better suited to this, and will certainly be less painful to use. Although my primary imaging scope is a newtonian, the choice was made because fast newts are much cheaper than fast refractors (with the drawback of having to solve collimation and mechanical issues).

Unlike visual, the exposure depth for imaging diffuse objects (galaxies, nebulae) is dependent on the focal ratio of the scope rather than aperture. While the generous (relatively speaking) aperture of 200mm will be great for gathering fainter detail for visual observation, the focal ratio of f/6 will mean that it takes more than 200% of the exposure time as compared to say, an f/4 instrument, to gather the same exposure depth. Given a choice between an f/6 newt and an f/6 refractor, I would take the latter for its ease of use, as well as the plausibilify of applying focal reduction (focal reducers for newts are crushingly expensive).

Also, it may not be necessarily true that purchasing one scope for both visual and astrophotographic purposea will ultimately save you money. Because much of the AP performance depends on the mount's tracking ability, you may be forced to purchase a larger and more expensive mount to accomodate the large scope, and this can cost more than simply purchasing a dedicated OTA and mount for AP.

Hope this helps!

[Clifford60]

Hi Peter,

Frankly, it is difficult to have best of both world, most users use DOB, SCT, MCT for visual and RC, refractor, Newtonian for AP.

I would think a small refractor will be good for star clusters and some brighter nebulaes as well as portability for both visual and AP.

To do dimmer objects especially on AP, a bigger refractor or fast Newtonian will do a better job.

Suggest you join some ob sessions and view through the different scopes and ask those APers about their setup so that you have a better idea what you will be getting.

As for the "dark" sites in Sg, it is actually in the starting few posts in Ob section of this forum, but it was not update to date. Recently, our group goes to a site in Kranji most of the times. Anyway, Sg dark site is never real darkness, still bright for us. You should join the group for a trip to Mersing or other Malaysian dark site, then you will enjoy real darkness.

[Clifford60]

Hi Peter,

By the way, 2" focuser can take 1.25" eyepieces as it will come with a 2" to 1.25" adapter. On the other hand, a 1.25" focuser will not be able to take a 2" eyepiece.

[ahernep]

Hi Clifford,

Yeah, that's what comes with the 200P and 2x1.25" eyepieces on ca.skywatcher.com but the 200PDS leaves out the 1.25" adapter and gives 1x2" eyepiece. I thought that was a hint to stick with the 2".

I guess what I was trying to do was get a good scope initially within my budget for general viewing that could give me an entry later into both planetary & DSO AP if I upgraded to some form of EQ system, but seems that might leave me compromised later or at least needing quite an investment.

To be honest what I would like to buy straight out is the 200PDS but since it only comes on the EQ mounts it's far more than I would like to spend initially, thus the thinking on the 200P. My other thinking is that even if I upgraded to a EQ mount in the future I would still probably keep it on the dob most of the time for casual viewing. My understanding (very possibly wrong) is that the EQ mount is going to be less portable and more painful to use for casual viewing.

One more question, am I right in saying that the only differences in the 200PDS (200mm/1000mm, F5) and the 200P (200mm/1200, F6) is the focal ratio with the F5 been favorable for DSO AP and also having a weight advantage (8.7Kg Vs 11Kg) that reduces the cost of the required mount. So, if we sat these side by side in adequate mounts the F6 would mean I would have to have longer exposures to get the same quality images?

I really do want to make it to a sidewalk session but every one I've found out about is on when I'm otherwise occupied. The excursions to Malaysia sound excellent and definitely something I'd be interested in.

Cheers everyone, lots more for me to think about tonight!

Peter.