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Skywatcher Explorer 150 PDS

Markh68

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Alan64

Alan64

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I've never used one with my 150mm f/5, and all of my eyepieces were less than US$100 when purchased. 

My UO 12mm Konig II, with only four glass elements, is the only eyepiece through which I've seen coma, and even then it wasn't that bad.

If you must have one, I would choose this one, or the GSO...

https://www.firstlightoptics.com/coma-correctors/skywatcher-f4-aplanatic-coma-corrector.html

Do not consider the Baader, from what I've read and seen.  It was found that it was really only suited for hyperbolic mirrors, not parabolic as our own; for imaging at least.

Said filters... http://www.prairieastronomyclub.org/useful-filters-for-viewing-deep-sky-objects/

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mikey2000

mikey2000

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1 hour ago, Alan64 said:

Do not consider the Baader, from what I've read and seen.  It was found that it was really only suited for hyperbolic mirrors, not parabolic as our own; for imaging at least.

 

Oh no!  Don't say that!  My Baader Mark III MPCC coma corrector just arrived (for use with my 150PDS)  I've had nothing but cloud so I can't test it at all.   FLO recommended that one or the skywatcher one.  I can't have the skywatcher one as it needs to fit to a Nikon or Canon adaptor.  I use Sony E mount.  The Baader will fit directly to my E mount T adapter, no problem.

 

I will report back with some news when we get clear skies again!

 

For visual use, the coma corrector is largely unnecessary.   Maybe even for photography you can get away without one.  My Sony camera has an APS-C sensor and 'sees' a large part of the scope's mirror.  Coma is obvious towards the edges of the photo.  If you use a smaller sensor (webcam, micro-4/3 etc) the camera will only 'see' the good central part of the mirror and coma will not be so obvious.  If you use a full frame camera, it will be even more noticeable.

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RikM

RikM

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The Baader MPCC is a perfect match for this scope, at least up to APS-C size sensors. That's what I use. If you are mainly using the scope for visual use for now, just leave the coma corrector in the box until you want to delve into astrophotography. I am assuming you have the motor drives for the mount already?

image.jpeg

image.jpeg

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wimvb

wimvb

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For guiding my 150PDS (with Baader CC), I use a skywatcher ST 80 with a ZWO ASI120MM camera and Lin_guider running on a Raspberry Pi. So far it works. I don't have much experience with guiding yet, so can't really judge if it's good enough. But for the limited time I have used it (too many cloudy nights), it has worked OK. The advantage of using a Raspberry Pi is that it works as a stand alone guiding system. Even if I lose Wifi between the Pi and my laptop, that doesn't affect guiding. The most common guiding solution is PHD on a laptop, which then also controls the imaging camera and possibly even the mount.

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wimvb

wimvb

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Not mine, as far as I know. I regularly check collimation with a barlowed laser. Most of the time, collimation is ok. Only occasionaly do I have to readjust the primary slightly. I don't have a permanent setup, and I carry the tube from storage to my backyard each viewing/imaging occasion.

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mikey2000

mikey2000

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On 30/01/2017 at 23:14, Markh68 said:

Thanks I hope to start enjoying it soon  I was thinking of a red dot finder scope any recommendations?

I bought one of these cheapo red dot finders: https://www.amazon.co.uk/d/Telescope-Accessories/Finderscope-Finder-Starpointer-Astronomical-Telescopes/B01C53EI98/ref=sr_1_1?ie=UTF8&qid=1485865845&sr=8-1&keywords=red+dot+finder

It's a bit wobbly and the dot is quite big but it gets you in the right area.  I have to fine tune it each session but it's quick and easy.

 

For a few quid more, I think Celestron sell something called "Star Pointer" which sounds more like a "red circle" finder than "red dot" so the circles surround the targed (as opposed to a red dot which can obscure the target)   Had I known about that one, I'd probably ahave gone for it instead.

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mikey2000

mikey2000

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On 03/02/2017 at 21:45, Markh68 said:

Whilst waiting for some clear skies decided to check collimation.

Glad I checked as both secondary nd primary mirrors were out.

Do these scopes go out of collimation often?

Mine was definitely a bit out too.  I believe Secondaries should stay collimated pretty well in general but primaries need more regular attention (and as also the easiest bit to tune up)

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Alan64

Alan64

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An extension lined with an absorptive material, like thick felt or other, always to be flat-black in colour and sheen, can help keep dew at bay...

https://stargazerslounge.com/topic/98110-diy-dew-shields/

Now, the one in that thread doesn't appear to be lined, but lining it with self-adhesive sheets of black felt would help in addition.  I made one for a 90mm Maksutov...

C90 dew shield4a.jpg

The one in the background was my first attempt, and with brown felt, as I couldn't see the reddish tone there in the store at the time.  I then went back to the store and returned the unused pack of brown and got two of the black.  I did try the brown one, for kicks, and indeed it did seem to add some colouration whilst observing.

C90 dew shield9.jpg

I also used aluminised, or chromed, bubble-wrap for the frame; perhaps not the ideal material, but I did find the notion online...

http://www.dewbuster.com/dewshield-sct.html 

When I make more of them for some of my other telescopes I may choose something else for the frame. 

Some jacket their telescopes entirely...

https://stargazerslounge.com/uploads/monthly_03_2012/post-15675-133877742386.jpg

https://stargazerslounge.com/uploads/monthly_03_2012/post-31003-133877742378_thumb.jpg

Those are passive solutions.  You can incorporate electrified heating-strips if dew proves to be especially problematic.

As for the eyepieces, I would keep them stored in a warm, dry case when not in use.  If they're dewing up whilst inserted into the focusser, then you may need to resort to an electrified solution.

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