coma corrector for reflector?

[RayGood]

Hello fellow members.

I am wanting to buy a visual OTA for the moment, but want the ability to use it for DSLR imaging if I decide to expand, in the future. I am wanting to get a Sky Watcher 150P (f/5 750mm fl). Note that this is not the PDS version. The link below is the OTA model I want to get;

http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ota.html

I have heard that this OTA (the newer model with the 2" focusser) has been successfully used for AP with a Cannon 1000DSLR fixed straight up to the focuser at prime focus (f/5). I have a Cannon 1000D DSLR as well

I have chosen not to go with the PDS version because while it maybe better for the AP, the vignetting in the PDS OTAs -compared to the 150P is extreme, due to an undersized secondaries. Yes, flat fields will deal with this, but for visual (that is what I initially intend the OTA to be used for) I want as least vignetting as possible. Plus, the PDS is more expensive, and with the current package deals out there at the moment, I would be forced to have to buy extra eyepieces and a barlow or two as well . So yep, I am working on a tight budget.

So, at some point in the future, I will be using it for imaging and long exposure AP, la de da.....

But I have not come across any posts or other on-line info that exclusively states that the Sky Watcher Coma Corrector works with a DSLR (at the f/5 prime focus) for the 150P OTA model   I have done lots of imaging in the past before, and am fussy when it comes to the quality of my images. I definately want a nice coma-free field of stars in my images. Therefore, I need to ask;

Does anyone out there know, or knows someone who can let me know, whether the SW150P (not the PDS model) focal plane (at the default f/5 speed - i.e. no barlow lens used - just the basic hooking the DSLR straight up to the OTA's focusser) will meet up with a Cannon 1000 D DSLR's sensor, with a Sky Watcher Coma Corrector included in the optical train? i.e. the optical train would be

[OTA focusser] -- [sW Coma Corrector] -- [Cannon T-ring] -- [Cannon 1000 D DSLR Camera Body]

[Purplehayze104]

Hi There

I use the 150P even thou has a different focuser, I use the SW Coma corrector with my dslr Canon 500D with no problems an copes pretty well with it only the very edges seem to get some, you will need an adapter to fit it to the camera to but they not to expensive its an M48 adapter, the t-ring wont fit it.

http://www.firstlightoptics.com/adapters/skywatcher-dslr-m48-ring-adapter.html

there are more expensive ones out there but choice will be ures in the end.

hope this helps.

clear skies

john

[RayGood]

Ah dahn . Thanks anyway for your responnce john. Moonlite focusers are well known to take up very little backfocus. I should think the standard 2" focusser on the OTA takes up well more than your moonlight.

Unless you still have your old SW 2" focusser, and could compare the two focusses, I don't think we'll find out. If you do still have it, and have the time, please let me know. That would be the info I'm looking for. Either way, thanks

Anyone else out there who might know, or also has experience with this set-up, please let us know.

[Uranium235]

The 150P should work ok with the CC (and without) on the stock focuser, but there wont be much room for adjustment (and the drawtube will cut in a bit more). However, if im not mistaken - the PDS range of news has a slightly larger secondary (not smaller) than the P versions. Actually, if you use the SWCC your telescope will be operating @ f4.5 as it also acts as a 0.9x reducer.

You should not notice any vignetting while observing, it only comes into play when imaging - in which case you >must< use flats regardless.

[RayGood]

The 150P should work ok with the CC (and without) on the stock focuser, but there wont be much room for adjustment (and the drawtube will cut in a bit more). However, if im not mistaken - the PDS range of news has a slightly larger secondary (not smaller) than the P versions. Actually, if you use the SWCC your telescope will be operating @ f4.5 as it also acts as a 0.9x reducer.

You should not notice any vignetting while observing, it only comes into play when imaging - in which case you >must< use flats regardless.

Thanks. Do you own a SW 150P model then, or know someone who has one, and has tried it with the SW Coma Corrector and DSLR. I might be able to confirm or find out just how little room there would be left for adjustment. I need to be sure you see, before I spend the cash, because by the time I plan to do AP, I should think the return period of the sale will be over.