First Serious Telescope - Skywatcher Explorer 150/750 vs 200/1000 on EQ-5 mount?

[Gibbous Mars]

Hi there, 

Apologies in advance for the long post.

Looking for some advise about buying my first serious telescope - ideally something that will keep me busy for several years at least! I recently dusted off a small 3" reflector which has served me well for several years but this is overdue an upgrade. 

I particularly like reflectors and note Skywatcher have some high-quality (and more importantly very positively reviewed) scopes on the market. I am looking to take up this wonderful hobby more seriously and as such from my research online, I'm torn between the Skywatcher Explorer 150/750 PDS (6") or the 200/1000 PDS (8") telescope OTA (links below), with an EQ-5 mount which could accommodate either. . 

I would be leaning towards the 200/1000 PDS due to the bigger 8" aperture, however my concern would be it would be limited in terms of getting into astrophotography down the line due to the weight of the OTA (c. 9kg) vs the max load of the EQ5 mount (10kg). Unfortunately, a higher load capacity mount (EQ-6) will be out of my budget for several years I suspect. If there are workarounds to this limitation I'm all ears!

On the other hand the 150/750 PDS OTA weighs in at 5.5kg so the mounting has capacity take the weight of a camera, coma corrector, etc.. I note the price difference between these OTAs is not huge, so my key considerations are quality of viewing, option of taking up astrophotography & portability. Is there a significant difference in terms quality of the viewing between the 150mm and 200mm apertures?

Additionally, any advice on whether I need a Go-To setup on the mount to target DSOs, etc., or if I should just get a dual-axis motor and use manual targeting and/or the RA/DEC guiding on the mount to start off? I'm having a lot of fun manually finding stars, planets, Messier objects, etc. 

Finally any recommendations for a decent camera that would suit either OTA (both have the same Crayford DS focuser) would be very much appreciated.

     150/750 P-DS (6"): https://www.astroshop.eu/telescopes/skywatcher-telescope-n-150-750-pds-explorer-bd-ota/p,19163

     200/1000 P-DS (8"): https://www.astroshop.eu/telescopes/skywatcher-telescope-n-200-1000-pds-explorer-bd-ota/p,19166

     EQ-5 Mount: https://www.astroshop.eu/equatorial-without-goto/skywatcher-mount-eq5/p,16081

 

Many thanks in advance!

 

 

 

 

 

[bosun21]

I would personally opt for the 150mm PDS simply due to the fact that the 200mm plus accessories will be the limit for the EQ5 mount. The 200mm will also be more of a wind sail. Regarding your choice of camera it all depends on what you want to photograph. Planetary, lunar or deep sky objects. The cameras are different. Although the ASI585 is having a good showing on some DSO’s. A 200mm with accessories and camera etc will be overloading the EQ5 for astrophotography IMO. HTH.

[Stickey]

I agree with Bosun21 - the 150PDS will be a better fit with the EQ5. If you're really keen on the 200PDS, you really need to consider a HEQ5  mount, especially when you add the weight of a camera and maybe a guide scope and guide camera. 

I started with a 150 f/5 and really enjoyed it. I used an EQ3/2 mount and added motor drives. But when I got a 200PDS, I also got a HEQ5  and trust me, with the 200 fully loaded with my Sony A5000 camera and 50mm guide scope with ASI120MM  guide camera,  the HEQ5 is right at its limit for astrophotography. 

I wish you good luck with whichever score you choose. 

 

Mike

[Gibbous Mars]

Thanks both for the friendly advice and quick responses too! 

While I love the idea of the 200DPS setup, I don't think I can currently justify the cost of a HEQ5 or EQ6. I think the 150 f5 on an EQ5 with motor drives is probably the best of both worlds to get going for both visual observing and first steps into photography.

As a quick aside, is there such a thing as a decent all-rounder camera suitable for general astrophotography and also 'regular'/daytime outdoors photography? Ideally something I can share the use of with my better half and justify the expense of a buying a quality camera in due course? 

[Padraic M]

Hi there @Gibbous Mars and welcome to the money pit club!

I have the 150PDS and it's a fine telescope, and I'm sure the 200PDS is in the same league. I also have an 80mm high-end refractor and can comment favourably on both and also the pros and cons of both.

Reflectors give excellent value for money in terms of aperture. You may already have checked out the astro calculators (e.g. astronomy.tools) to see the difference in resolving power and light grasp of a 150mm vs an 80mm, and it's significant. Reflectors however can also be more work to get working correctly than a 3" or 4" refractor. They're bigger and (usually) heavier, need regular collimation, and generally with longer focal lengths which makes operation that bit more difficult.

I'm sure you know that the PDS range are designed to be suitable for astrophotography (Parabolic mirror/Dual-speed focuser/Short tube) so they are a good starting position even if you don't intend to start astrophotography immediately. However you'll also know if you read around these forum pages that there's a big difference between observing and AP. 

The usual rule of thumb for AP is to halve the stated payload of your mount - so in that case, the ideal max weight of scope (plus all peripherals) on an EQ5 would be ~5kgs. HEQ5 Pro on the other hand is rated for 11kg imaging, 18kg visual. That means that where the EQ5 is pushed beyond its limits with the 150PDS, the HEQ5 gives some headroom. If you haven't already bought the EQ5, I would strongly recommend you spend the extra ~€300 and get a HEQ5. You wouldn't need to go as far as an EQ-6, although I managed to pick up a NE6-Pro second-hand on these forums, which is an excellent mount, for less than the price of a new EQ5. 

With either of these mounts, I would push for the 150 rather than the 200. These reflectors are big beasts, surprisingly heavy especially when fully loaded with AP kit, and because they are so big they respond like heavier scopes when on the mount. This is partly because they can catch a breeze very easily, but also because of their length, they act like levers.

For observing, you should consider buying some decent quality eye pieces. The 2" EP that comes with the 150PDS is not great quality. I had previously bought the Skywatcher box-set of 1.25" EPs which don't have a super reputation, but even these are better than the stock 2" EP. For the same price, you could probably get 2 or 3 good-quality EPs that will transform your viewing experience. Manual focusing will be fine, but get a Bahtinov mask to help get the sharpest focus.

For AP, I have the ZWO ASI1600MM Pro, an old workhorse camera that has been somewhat superceded by some of the newer, zero-read-noise cameras but still does a really good job. Because it's a mono camera, you would need filters and a filter wheel to construct a colour image either from a set of (L)RGB filters or from one or more narrow-band filters (Ha, SII, OIII). I'm in Bortle 8 Dublin city centre skies so I stick mostly with Ha because of the light pollution. I also have a ZWO ASI533MC Pro one-shot colour camera that I use when I'm in dark skies, and I really love how much easier it is to get good full-colour results from it. This is possibly due as much to the dark skies as it is to the camera. Few people use OSC cameras under city skies, but it can be done. If your budget can stretch to it, the newer ASI2600MC Pro really seems to have blown these other cameras out of the water but it is pricey. There's a Rising Cam cheaper version using the same sensor that is very much worth looking at. Of course you can also go down the DSLR route and even get an astro-modified DSLR but while usable they are not ideal for long-exposure DSO photography, and are harder to calibrate than dedicated cooled AP cameras.

Bear in mind that for AP you really will want to look at electronic focusing, guiding with a separate guide scope and guide camera, and a connection to a computer of some sort so that software like NINA or APT can control your imaging sequences. Of course, there are two types of AP - Planetary and DSO - and they require different scopes, cameras, techniques and software. I'm only dealing with DSO here as it's what I do, but also as you're leaning towards a Newtonian reflector you are also probably looking primarily at DSO.

The PDS scopes also leak light both from the rear (primary mirror) end and through the focuser tube. This is probably OK for observing although there will be some loss of contrast, but for AP it does cause light streaks on the images and really needs to be sorted out. Tinfoil and a swimming cap will do the job. There are also a few other mods that are highly recommended such as loosening or replacing the primary mirror clamps because they cause triangular-shaped stars. It sounds scarey but is not too bad as long as you're careful with the mirror and have some patience 🙂. You will also need a collimator whether you're doing AP or visual.

AP quickly gets very specialised and can cost a whole lot of money. Lots of people, myself included, start out by saying they want to do some observing and a little bit of AP, but if the AP bug bites, they end up head-over-heels down the rabbit hole of equipment and software. Things that sound irrelevant like image noise, poor star shapes, less-than-100% focus, poor tracking, internal reflections/star halos etc. are really frustrating once you see them in your pictures, and it's a never-ending process to eliminate them to an acceptable level. That's why many will recommend a good quality 4" reflector on a EQ-5 or better mount as a starting point for AP as an easier way to cut your teeth. A 150PDS on a HEQ5 is equally good, but is a little more difficult to fine-tune and manage.

hth and doesn't add more confusion!

[malc-c]

Some excellent advice given already.  From personal experience I would agree with what's already been stated, that a 150PDS / EQ5 combo would be better than a 200PDS on the same mount, especially if you intend or feel that you will be heading towards imaging rather than visual.  The HEQ5 has more precision and fine tuning than the EQ5, and as already mentioned has a decent load carrying ability.  I originally purchased a 200P / EQ5 set up, and after a short period of visual use ended up dipping my toe into imaging.  I purchased a second hand HEQ5 and fitted an Orion Optics secondary of the same dimensions of that fitted in the 200PDS and have been very pleased with the results.

[Louis D]

On 05/05/2023 at 17:21, Gibbous Mars said:

Thanks both for the friendly advice and quick responses too! 

While I love the idea of the 200DPS setup, I don't think I can currently justify the cost of a HEQ5 or EQ6. I think the 150 f5 on an EQ5 with motor drives is probably the best of both worlds to get going for both visual observing and first steps into photography.

As a quick aside, is there such a thing as a decent all-rounder camera suitable for general astrophotography and also 'regular'/daytime outdoors photography? Ideally something I can share the use of with my better half and justify the expense of a buying a quality camera in due course? 

My colleague at work rapidly switched from imaging with a ~5" Newtonian and DSLR to imaging with a ~80mm ED refractor and dedicated astro camera and filter wheel.  The difference in quality of results is like night and day, with the refractor winning big time.  I'm not saying to go the same route.  I'm just providing a recent anecdote of someone starting out in astrophotography like yourself.

[Gibbous Mars]

Thanks for the great advice! I just have a quick update - and new query! I've taken the advice above and bought a second hand HEQ5 Pro GoTo Mount which should future proof any future visual and AP aspirations. However, I just need to sort a power supply for the mount. 

Any advice or recommendations for a mains-fed power supply for the HEQ5 mount? I mainly plan to observe from my garden so I can power it from a mains and I understand it needs a ~12V power supply. 

I was thinking something along these lines should do the trick but any advise would be appreciated!

https://www.amazon.co.uk/dp/B0BLHGZ4QP/?coliid=I2DZJTHMYLTU2A&colid=174HHE3IM73KU&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

https://www.amazon.co.uk/dp/B08NCLCWFB/?coliid=I1EG3L6Q5AYQEX&colid=174HHE3IM73KU&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

  

Edited May 15, 2023 by Gibbous Mars

[Louis D]

18 minutes ago, Gibbous Mars said:

Thanks for the great advice! I just have a quick update - and new query! I've taken the advice above and bought a second hand HEQ5 Pro GoTo Mount which should future proof any future visual and AP aspirations. However, I just need to sort a power supply for the mount. 

Any advice or recommendations for a mains-fed power supply for the HEQ5 mount? I mainly plan to observe from my garden so I can power it from a mains and I understand it needs a ~12V power supply. 

I was thinking something along these lines should do the trick but any advise would be appreciated!

https://www.amazon.co.uk/dp/B0BLHGZ4QP/?coliid=I2DZJTHMYLTU2A&colid=174HHE3IM73KU&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

https://www.amazon.co.uk/dp/B08NCLCWFB/?coliid=I1EG3L6Q5AYQEX&colid=174HHE3IM73KU&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

  

A lot of these cheap, variable voltage power supplies are not well regulated.  Their voltage can vary while under load, not supply enough amperage, introduce electrical noise into the line by being a switched power supply, burn out prematurely due to cheap components, etc.  You just need 2A at 12V, so find a quality 12V transformer type power supply rated for at least 2A with the proper connector, and you should be good to go.

[Cosmic Geoff]

14 hours ago, Gibbous Mars said:

I was thinking something along these lines should do the trick but any advise would be appreciated!

https://www.amazon.co.uk/dp/B0BLHGZ4QP/?coliid=I2DZJTHMYLTU2A&colid=174HHE3IM73KU&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

https://www.amazon.co.uk/dp/B08NCLCWFB/?coliid=I1EG3L6Q5AYQEX&colid=174HHE3IM73KU&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

Why pay £25 for the Amazon supply, capable of delivering 24v and zapping your kit,  when  you can buy a switched-mode supply rated for astro use at 5 amps at +12v, and rated for outdoor use including low temperatures?

Lynx Astro 12v DC 5A Low Noise Power Supply | First Light Optics 

Cheaper than a battery power tank.

Edited May 16, 2023 by Cosmic Geoff

[wookie1965]

I had a 200p 9n my EQ5 and it was on the very edge of payload without adding more weight I.e cameras, guide scope and other peripherals. 

The 150 would be a better choice as others have said. 

[rl]

Hi..

Visually an 8" is noticeably better but the difference is not massive. A good site counts for more than the extra 2".

Since you *know* you are intending to go down the AP route I'd stretch the budget if at all possible, start with the mount and look out for a s/h HEQ5. There  is nothing more likely to give you problems than a substandard mount which will frustrate you and end up putting you off. It will take a decent choice of OTA including the ubiquitous ED80 and 150PDS, plus all the trimmings.

I sold my 150PDS for £120 a couple of years ago..when cash is really tight s/h is the way to go providing you check that the seller has a good reputation. 

Edited May 16, 2023 by rl

[malc-c]

14 hours ago, Louis D said:

A lot of these cheap, variable voltage power supplies are not well regulated.  Their voltage can vary while under load, not supply enough amperage, introduce electrical noise into the line by being a switched power supply, burn out prematurely due to cheap components, etc.  You just need 2A at 12V, so find a quality 12V transformer type power supply rated for at least 2A with the proper connector, and you should be good to go.

I would recommend shelling out £30 - £40 for a 12v 5amp supply form Rother Valley optics or FLO.  That way you know you have something suitable for the mounts that they sell, and should something go wrong and it stops working then you have a better change of having it replaced with as little hassle than through the Amazon return process, or direct to a Chinese supplier.  

5 Amps will give you enough headroom to cover the surge in current when the steppers start the slew.  The current draw once moving for both steppers is around 1.8 - 2.0 amps.  The mainboard only draws around 40mA so doesn't really impact the load.  The other advantage of buying form FLO etc is that you'll know it will work, and has the right barrel connector.  The mainboard lacks any real reverse voltage protection, other than blowing a large diode or inductor, which then means a repair or replacement board.