Newcomer Advice Wanted

[Alan64]

Hello Mark,

The Sky-Watcher "P-DS" series of  Newtonians are configured for imaging, and come with 2" two-speed focussers.  They are also good for visual as well, but not ideal in that they are fitted with larger secondary mirrors, for imaging, and therefore larger secondary obstructions which reduce contrast and sharpness; larger than those equipped with Newtonians configured for visual use only, like the Sky-Watcher "P" series of Newtonians.

I can understand why you would be considering a 200mm Newtonian, and for visual, as the human eye is relatively weak and requires larger apertures, particularly under light-polluted skies.  Cameras, on the other hand, do not require large apertures, as they're much more sensitive and more efficient at collecting light.  Many image with the much smaller 130P-DS instead...

https://stargazerslounge.com/topic/210593-imaging-with-the-130pds/

...and it's not at all bad for visual use to boot.  Also, the shorter the focal-length, the faster the camera takes a photograph.  Maksutovs, which have the longest focal-lengths of all other designs, would be the slowest in taking a photograph of a celestial object.  In addition, with a Maksutov, the mount chosen must be able to hold the telescope steady, rigidly, and for a long period of time.  Maksutovs are used for imaging, but it's more of a specialty among advanced imagers, and oft requiring a very large mount in relation to the telescope; that is, for serious astrophotography, with a camera in place of an eyepiece.  For afocal and EAA imaging, the requirements are not as critical.

When imaging with a Newtonian, the collimation, the alignment of the mirrors within, becomes more critical and precise compared to what is required for visual observations.

A 200mm f/5 Newtonian should require an EQ6-class mount, at least; for serious, prime-focus astrophotography.  I would consider this kit...

https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ds-eq-5-pro-goto.html

...and as a good balance between visual and imaging.

[Dave In Vermont]

Alan is quite right regards imaging - both in regards of 'Fast' Newtonians & Maksutovs.

To your earlier query, a very good Newtonian intended primarily for visual-use, can be on a very simple mount called a Dobsonian - after the inventor & pioneer - Dobson whose goal was to get as many people into this field as possible. Within financial-reach of most everyone. Here's a very good example from the sponsor of this site:

https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-200p-dobsonian.html

The 200mm is most often suggested to folks as it's what some of us call: A Lifetime Telescope. This is as it can bring you new and amazing views of different DSO's every night for the rest of one's lifetime. And view these very well, too.

Beware of getting lured into astro-photography. It is truly a bottomless-pit for money! You  might end-up selling your children into slavery for the latest upgrades to your lenses! Remember my warning - as they put you into the Straight-Jacket!   !

Enjoy!

Dave

 

[Markh68]

Thanks Alan,

I do like the look of the 150PDS on an EQ5 mount. I will  check it some more.

[Markh68]

Having looked into the 150PDS on an EQ5 pro mount I am very tempted.

I would like some views about how good this scope is with observing and basic astrophotography.

 

[JemC]

15 minutes ago, Markh68 said:

Having looked into the 150PDS on an EQ5 pro mount I am very tempted.

I would like some views about how good this scope is with observing and basic astrophotography.

Hi Markh68

you have been given some good advice in the above threads, however given the fact that you are wanting to do some astrophotography i would recommend that you get hold of a copy of "Making every photon count" by Steve Richards and have a very good read of that book, maybe read it twice

in my own personal opinion and speaking from experience (been there tried that) , i think you need to be looking at the Heq5 mount with goto as minimum for astrophotography with the scopes you are thinking of,
don't get me wrong, photography with the 150pds on eq5 can be done BUT with limitations and frustrations

i wish you luck in which ever combo you decide to go for and look forward to seeing your first image/s

[Dave In Vermont]

I heartily 2nd. that book. It's the best read to acquaint you to this field. But I suggest taking your time at this point to learn your way about with a telescope first. Then you'll have a better idea of all this requires. Astro-Photography can be done by inexpensive means, but needing to be fluent in scopes and cameras is a necessity first.

Start saving up your £££'s!

The image below maybe a stab at humor - but that's only because it's true!

Dave

 

 

[happy-kat]

If you observe the bigger the light bucket the better for your mk1 eye balls, but a camera doesn't have the same limitation as a mk1 eye ball so fast aperture is great but you don't need need a big mount demanding telescope to get that. Observing and imaging have different drivers.

[Markh68]

Hi,

I will sort a telescope and start by observing and learning the skies and leave taking photos a bit down the line. When the time is right I will seriously consider reading the book  'Making every photon count'.

So just for observing is a Skywatcher 150 PDS any good?

[Markh68]

3 hours ago, happy-kat said:

If you observe the bigger the light bucket the better for your mk1 eye balls, but a camera doesn't have the same limitation as a mk1 eye ball so fast aperture is great but you don't need need a big mount demanding telescope to get that. Observing and imaging have different drivers.

Thanks happy-kat. I will definitely get to grips with the observing side before thinking too much about photos.

[BritAngler]

If astrophotography is going to come some time later, you might want to get the bigger SW200P/EQ5 combo, and then buy a smaller scope later on for photo's. An EQ5 Goto can easily handle the SW130 or 150 Newts and both those have the potential for excellent photo's, and as already pointed out, a good-but-not-expensive refractor would also suit.

Just a thought

John

[Markh68]

Thanks John. 

Thanks so far to everyone else who has given advice I have plenty to think about and research.

[Alan64]

6 hours ago, Markh68 said:

Having looked into the 150PDS on an EQ5 pro mount I am very tempted.

I would like some views about how good this scope is with observing and basic astrophotography.

 

 

I lived in a large city when I was younger.  At the time I had an 80mm f/11 refractor on an EQ-2.  My family and I then relocated to a rural area, but only 20 to 25 miles south of that city, and over twenty years ago.  I've had a 150mm f/5 Newtonian for almost four years now, but I didn't begin observing with it until two years later in 2015.  I had not observed with a Newtonian before, and the experience was certainly eye-opening, and most rewarding.  Over the last two years I devoted a good deal of time in observing only with that telescope...

Its performance under a semi-rural night sky was such that I was inspired to flock and blacken its interior, for improved contrast; blacker sky backgrounds and object-details...

Over time, I've also learned, and have almost mastered, the process of collimation...

http://www.forumskylive.it/Public/data/serastrof/201281510358_Astro Babys Guide to Collimation.pdf

All of these Newtonians -- the Sky-Watcher, the Celestron and Orion models -- are all manufactured by Synta Optical of China.  The Sky-Watcher 150P-DS is Synta's finest, most well-equipped model.  My Orion is the second most basic, with this Celestron model, the C6-N, being the most basic of them all...

http://www.365astronomy.com/Celestron-C6-N-Newtonian-Telescope-Advanced-OTA-only.html

My Orion has a better primary-mirror cell, but that's its only advantage over that one.

Both the Orion and the Celestron have 1.25", single-speed, wonky plastic focussers; dreadful they are indeed.  The models with the metal 2" two-speed focussers are not available in the U.S., as most imagers there use refractors for imaging.  They are available in Canada however.  The best one available in the U.S. is this Celestron model with a 2" one-speed focusser, and just like the Sky-Watcher 150P...

http://www.highpointscientific.com/celestron-omni-xlt-150-newtonian-reflector-optical-tube-assembly-ota-31057ota?utm_source=google&utm_medium=cse&utm_term=CEL-31057-OTA&gclid=CKHXxMzA4NECFQwRgQodNisFuQ

That Celestron has a 51mm secondary mirror.  That of the 150P is probably the same, and configured for visual use only.  My Orion has a 48mm secondary, as most probably does the basic Celestron model, the C6-N, and both most definitely for visual use only.

That ends the treatise on the current state of the market regarding Synta's 150mm f/5 Newtonians. 

Now, a 150mm Newtonian may not knock your socks off there in the town or city, but under darker skies a 150mm really comes into its own, and will wow and amaze, for it's quite a bright, yet compact, telescope in its own right. 

Once in awhile, I like to hold a small point-and-shoot camera up to an eyepiece and snap a shot.  Such is called "afocal" astrophotography.  I'm limited to the brighter objects, like the Moon, but I also manage shots of the Orion nebula, and M13, a globular-cluster in the constellation Hercules.  I only take these photos to illustrate what an eyepiece will show an observer during a live view...

Not bad, eh?  You can do the same yourself.  In addition, I took those photos with the 150mm f/5 on the manual alt-azimuth as illustrated above.

Other than the afocal technique, I do not image, as I prefer to see the objects in real time; albeit not as bright, colourful and detailed as those images taken over lengthy exposures to be sure.  My images are only stills, and the result of the camera's shutter opening and closing in a single instance.

[Dave In Vermont]

Alan nailed it again! A 150mm Newtonian is certainly a very nice instrument.

When I started out back in 1972 with my first shop-bought telescope (3" F/15 Achromatic-Refractor though), the 150mm (called a 6" F/8 then) was about as big an instrument as your average 'amateur' would likely have. The 200mm F/5, F/4, etc. - were a rare beast. The 8" Newts were available, but few would be seen. Larger sizes still were grounds to build an observatory around them.

I suspect that the ongoing spread of light-pollution (LP) brought the 200mm/8" telescopes into the mainstream - out of necessity. I can't prove this, of course, but I can't discount it, either. But a 150mm/6" Newt is certainly a quite capable instrument!

I'll leave you with an old advertisement -

Dave

 

 

[Markh68]

I have decided and gone for a Skywatcher Explorer 150PDS on EQ5 Pro. Should be here Monday.

I am still interested in refractors maybe get one as a second scope.

 

[Alan64]

Mark, congratulations on the new kit!

You may find that the 150mm f/5 Newtonian will be quite ample, and for quite some time, especially with it mounted on a motorised mount.  A 150mm f/5 is capable of powers ranging from a low and wide 19x, to 250x and beyond with the aid of 2x and 3x barlows, or without barlows at all but with very short focal-length eyepieces instead; 4mm and shorter, for example...

http://www.365astronomy.com/Planetary-Eyepieces/#rfplist

The focal-length of a 150mm f/5 telescope is 750mm.  Eyepieces are numbered according to their focal-lengths.  You simply divide the first by the second to find the power of any given eyepiece.  The 4mm would realise a power of...

750mm ÷ 4mm = (188x)

750mm ÷ 3.2mm = (234x)

750mm ÷ 2.5mm = (300x), and the theoretical limit of a 150mm Newtonian. 

Those oculars sport large eye-lenses, and good eye-relief for eyeglass-wearers.  They also have barlowing-elements, barlows essentially, built in.

Separate barlows, however, offer a few advantages.  An eyepiece combined with a barlow results in two powers per that one eyepiece.  With a set of three eyepieces and a barlow, you would then have six different powers at your disposal.  Another advantage is when you have an eyepiece like this 4mm(188x) orthoscopic laying about, like I do...

Powerful, and most promising it is, but note the tiny eye-lens through which to observe.  In addition, the eye-relief is very tight and in requiring placing the eye to where it almost touches the eye-lens of the eyepiece in order to see the full field-of-view.  Instead of using that one, I usually prefer this wide-field 12mm with a 2.8x barlow, and for a simulated 4.3mm(174x)...

I get practically the same magnification as the 4mm orthoscopic, but with the larger eye-lens and greater eye-relief of the more comfortable 12mm.  Note how my combination there appears very much like the Lacerta(BST) eyepieces, with the built-in barlows, listed above.

I have the previous models of these two barlows, and both are a great value for the price; extraordinary value actually...

http://www.rothervalleyoptics.co.uk/antares-x2-twist-lock-barlow-lens-125.html

http://www.rothervalleyoptics.co.uk/antares-x3-twist-lock-barlow-lens-125.html

With a motorised mount, you certainly can make use of the shorter orthoscopics, however you'd be hard-pressed in using them with a telescope on a manual mount, as they have narrow fields-of-view(40° to 43°), compared to wide-field oculars.  Orthoscopics, however, offer the sharpest views over that of any other eyepiece design, but less-expensive Plossls do give them a run for the money.  Plossls, however, have even shorter eye-relief in the shorter focal-lengths(8mm and shorter) than that of orthoscopics, but with wider fields-of-view(50° to 52°).  With a motorised mount, any object within the field of an orthoscopic(or any other ocular) will stand still, there in the center of the eyepiece even, and for as long as you'd like.

Your telescope will come with a 2" focusser.  For near to the lowest power practical, and the brightest field-of-view, this 2" 70° 38mm(20x) for example is quite popular...

https://www.firstlightoptics.com/skywatcher-eyepieces/skywatcher-panaview-2-eyepieces.html

...and for scanning the star-fields of the Milky Way in summer, and observing the galaxy of Andromeda and the Pleiades in the fall and winter, among other nocturnal delights.

Your kit will come with a 25mm(30x) Plossl, with a large eye-lens and quite good eye-relief, and very similar if not identical to the 25mm that came with my 150mm f/5...

You'll be wanting more eyepieces in future, for different powers, of course.

Cheers,

[SonnyE]

8 hours ago, Markh68 said:

I have decided and gone for a Skywatcher Explorer 150PDS on EQ5 Pro. Should be here Monday.

I am still interested in refractors maybe get one as a second scope.

 

You will most likely be getting a smaller refractor as a guide scope.

Congratulations!

 

Oh, I guess nobody mentioned. But bad weather follows new telescopes. It's OK though, I busied myself looking at a neighbors chimney cap while I waited, and distant trees. Gave me time to try and figure things out.

About a month should do it.

[barkis]

Mark, the 200pds Would be a fine Imaging telescope, no slouch in  observing mode either.
It's little sister, the 130pds proved an enormous success at Imaging. Plenty of evidence of that on the forum
for you to peruse.
In the final analysis, you yourself has to decide on the choice.
Take all the advice, analyse it, investigate it,  then you decide .