ES David H Levy Comet Hunter - 152mm f4.7 Maksutov-Newtonian - A Users View

[paulastro]

I'm calling this a 'Users Guide' rather than a review for a good reason.  There are two excellent reviews of this scope already which I urge people to read.  The first is by Dennis di Ciccco in the September 2011 edition of Sky & Telescope (yes, that is 2011!)       https://www.apm-telescopes.net/downloads/Sky_Tel_ES_CometHunter_review_2011_SF.PDF

and the second by Ade Ashord in the May 2018 edition of Astronomy Now.  These are both very thorough and in many ways tell you all you need to know.  However I've now owned this telescope since late June and I thought perhaps a 'Users Guide' may be of interest. What is it really like to use and is it really as good as it sounds in the reviews - it almost sounds too good to be true!

Though I was vaguely aware of this scope's existence beforehand, it was Ade Ashford's review which really got me excited - unusual for me since after over 45 years using and owning many telescopes it takes a lot to rattle my chains nowadays.  I've also know Ade for a while and know from experience that his reviews are accurate and reliable, and the fact that he was clearly enamoured of this scope made me take notice.

The story cold have ended there, excited as I was by the prospects of owning one of these scopes there was little chance of me raising the cash to buy one.  At least that was the case until I mentioned to Ade in a humerous fashion that if ever he was moving the scope on I'd be very interested in taking it off his hands .  Much to my surprise Ade indicated he was moving some items on and would be willing to sell it to me and in late June we met up and I took procession.

Part of my excitement was that I have had a really fond spot for Mak-Newts for over 20 years and owned several, mainly due to their planetary and lunar performance.  In my view MNs are the next best thing if you're not in the market for a good apochromatic refractor - they give very apo-like images when the seeing plays ball, and at a fraction of the cost.  They also give far better off-axis performance than Newtonians of the same focal ratio and no diffraction spikes from the secondary.  I would add that I'm purely a visual observer, apart from a very occasional 'snap'.   Here was something a bit different.  At f4.7 it's short enough to be an excellent deep sky wide field telescope as well as being a good planetary scope.  Too good to be true?  In a preface to Ade's review the editor asked the question - 'In four decades of observing, a lot of telescopes have passed through Ade Ashford's hands, but is his quest for the best general purpose commercial telescope now at an end?'   Well, you'll have to read Ade's review yourself to know this - I'll tell you what I think.

Planetary Performance.    I've had many opportunities to look at Mars, Saturn, Jupiter and Venus.  Of course all these planets have been rather low in the sky, and observing conditions often poor.  However despite this I've had enough views of all of them to form an opinion.  I've been able to use powers of x200 or so just about most nights in better moments, and more than x300 on some occasions.  The views have certainly been close to apo performance and certainly what I would have expected from a good Mak-Newt, and perhaps exceeding my hope for one with a focal ration of f4.7 and comparatively large secondary - previous Mak-Newt, I have used have been in the f6 to f8 range.  Mars has been compromised by the dust storm of course, but Jupiter has given me some excellent views, better than I've got with my 102mm ED and than with a 180mm Maksutov, though this was far more affected by the seeing.  In more favourable conditions and the planets at a higher altitude I'm sure the DL (David Levy Scope) would perform noticeably better.  Overall, delighted with the planetary performance.

Wide Field and Deep Sky.     I never tried the 30mm eyepiece that came with the scope and at first  used a 24mm Hyperion giving x30 and 2.2 degree field.  The views were very contrasty, more than I expected in often fairly light skies, and fabulous star fields with the six inch aperture,   Large subjects such as the Pleiades and Double Cluster easily fitted into the large field and looked spectacular.  The only downside is that the stars became distorted in the outer parts of the fields, but much less so than in a 6inch f5 Newtonian for instance.  I expected this since Hyperions are not so good in scopes f6 and faster.  I knew the scope could do better.

I sold on a couple of eyepeices I didn't use very often and bought a Morpheus 17.5mm (76 degree field) after much research and reading Bill Paolini's review of it posted on SGL.  With the DL it would give x42 and a 1.8 degree field, close enough to my ideal of around 2 degrees.  First light with it and WOW, I was blown away by the view.  The first eyepiece ever with a field greater than 70 degrees field that I could the whole view with my glasses on and without turning my head.  The contrast was noticeably better and the stars sharp right to the edge, what a revelation.  This was in another class and instantly became my favourite eyepiece ever.  The deep sky views with this eyepiece and the DL are superb.  In fact I've spend several hours just sweeping around endlessly looking at whatever comes into view.  As a wide field deep sky telescope the DL excels in my view.

Imaging.    No idea I'm afraid, it's not my field and didn't attempt any.  Dennis's and Ade's reviews talk about this.

Mounting Requirements.   The scope worked well on a Vixen GP and should be fine with anything in that class or bigger.  I prefer altazimuth though and it is easily carried on my Ercole mount with no counterweight necessary - as long as the tripod is extended high enough to increase the foot print.  Amazingly I've found that for wide field and sweeping an AZ4 mount works very well with it, I even managed to use this for planetary viewing once and it wasn't that bad!

Cool Down Time and the Carbon Fibre Construction.      I've found  for the planets the scope has been useable straight away when taken outside and used at powers up to x100.  It has taken around half an hour or more to cool enough to use  higher powers, though I have done this in less time.  It is summer though, and it will probably take longer in the colder months of course.     No doubt the carbon fibre helps to mitigate temperature variations.  On several occasions I've bought the scope in sopping wet, gone off for only about five minutes or so, returned to the scope and found that it's already bone dry and up to room temperature - apart for the metal bits which are still cold.

The Finder Scope.   Ade had parted with the finder that come with the scope before I bought it, though it came with the supplied finder holder.  I have to say I thought it was much too short, virtually tube-huggingly close.  Wearing glasses I couldn't get my eye behind it properly and it was a real pain.  I must admit in the reviews the finder sounded really good that came with it and I was disappointed I didn't have it, particularly as I have always wanted a completely correctly orientated one which it is.  I found the ES finder available on line at a rather eye watering price of over £150!!  Too much for me.  I did some research and found out that Opticstar do the same finder (unbadged) for £99!  More amazingly they did a the same finder with a long stalk -eureka!!  Bought one!  A really nice finder, love star hopping with the correct orientation.    Features of the finder include: 50mm aperture, x9, correct image orientation, illuminated cross hair and field indicators, integrated dewshield, all metal construction, separate adjustment for the focus and the focus of the reticule.  Brilliant!  Never been so overjoyed using a finder.

Tube extended to cover mirror adjusting screws.    This may not sound much, but it means you can stand the scope on end and it won't fall over, it really is a useful feature.

Stainless Steel Screws used in the construction.   Ok, not vital by any means, but it make the scope so classy looking, and no more rusty screws!  Why don't other manufactures do this?

Carbon Fibre Dew Shield Provided.   What a wonderful touch, you'd have to buy one if it wasn't provided.  Same diameter as the tube so you can keep it on and use the same end cap for the tube.  Adequate length, but I will probably make an extension for it before I go to Kelling and the autumn to come.

Large Rubberised Clips for Mirror.   Not ideal, though Ade says that in practice any diffraction they cause is not obtrusive. Ade removed these and stuck the mirror down before I had the scope so they won't bother me.

Built in 'Bobs Knobs'.    Nice brass knobs to collimate the secondary if necessary, hidden by a plastic screw on cover.

Lockable Mirror Adjusters.  The knurled mirror adjustment knobs are held in place by internal hex screws which you tighten to prevent them moving by accident,

Focuser, Two inch Crayford.    Appears well constructed and works well, doesn't slip with my binoviewer and two Baader Mk111 zooms on board.

Chunky Carrying Handle opposite Dovetail.       Makes it very easy to carry the scope around in one hand.

 

Is this the best all purpose scope commercially available?

Well, you don't expect me to say yes or no do you!  I will come clean and admit  I love it.   It's performance as an all round telescope is hard to beat when you take into account the quality of the planetary views, the wonderful wide field views and its' aperture.  After all you won't find an apochromatic 152mm refractor with a f4.7 focal ratio.  You could get an apochromatic 152mm refractor which will perform better on the planets, but off hand I can't think of  better 152mm f4.7 scope which will have such contrast and such a flat field for deep sky observing.  Put these two things together and it's a combination  that is indeed hard to beat.  If you take into account it's potential for imaging and it's relative portability I think it is certainly a strong contender for the best all round scope within its' aperture class.  I feel it is also made more attractive by some of the thoughtful considerations taken it its construction which I have mentioned.

What makes me so happy with this scope is that when I'm observing with it, whatever I'm looking at, I never think that it would better if I had a so and so telescope for any particular type of object, It does everything it does really well so you don't feel wanting in any way. Even for those people who have all bases covered with a number of different scopes, I think this scope would still be useful for those times when you don't have the time or inclination to use two or more scopes.

For me, well yes, it's the best all purpose scope I can think of for its aperture.

  

 

 

[Rob]

Nice detailed report Thanks!. Looks a super nice bit of kit.

[mikeDnight]

59 minutes ago, paulastro said:

I'm calling this a 'Users Guide' rather than a review for a good reason.  There are two excellent reviews of this scope already which I urge people to read.  The first is by Dennis di Ciccco in the September 2011 edition of Sky & Telescope (yes, that is 2011!)       https://www.apm-telescopes.net/downloads/Sky_Tel_ES_CometHunter_review_2011_SF.PDF

and the second by Ade Ashord in the May 2018 edition of Astronomy Now.  These are both very thorough and in many ways tell you all you need to know.  However I've now owned this telescope since late June and I thought perhaps a 'Users Guide' may be of interest. What is it really like to use and is it really as good as it sounds in the reviews - it almost sounds too good to be true!

Though I was vaguely aware of this scope's existence beforehand, it was Ade Ashford's review which really got me excited - unusual for me since after over 45 years using and owning many telescopes it takes a lot to rattle my chains nowadays.  I've also know Ade for a while and know from experience that his reviews are accurate and reliable, and the fact that he was clearly enamoured of this scope made me take notice.

The story cold have ended there, excited as I was by the prospects of owning one of these scopes there was little chance of me raising the cash to buy one.  At least that was the case until I mentioned to Ade in a humerous fashion that if ever he was moving the scope on I'd be very interested in taking it off his hands .  Much to my surprise Ade indicated he was moving some items on and would be willing to sell it to me and in late June we met up and I took procession.

Part of my excitement was that I have had a really fond spot for Mak-Newts for over 20 years and owned several, mainly due to their planetary and lunar performance.  In my view MNs are the next best thing if you're not in the market for a good apochromatic refractor - they give very apo-like images when the seeing plays ball, and at a fraction of the cost.  They also give far better off-axis performance than Newtonians of the same focal ratio and no diffraction spikes from the secondary.  I would add that I'm purely a visual observer, apart from a very occasional 'snap'.   Here was something a bit different.  At f4.7 it's short enough to be an excellent deep sky wide field telescope as well as being a good planetary scope.  Too good to be true?  In a preface to Ade's review the editor asked the question - 'In four decades of observing, a lot of telescopes have passed through Ade Ashford's hands, but is his quest for the best general purpose commercial telescope now at an end?'   Well, you'll have to read Ade's review yourself to know this - I'll tell you what I think.

Planetary Performance.    I've had many opportunities to look at Mars, Saturn, Jupiter and Venus.  Of course all these planets have been rather low in the sky, and observing conditions often poor.  However despite this I've had enough views of all of them to form an opinion.  I've been able to use powers of x200 or so just about most nights in better moments, and more than x300 on some occasions.  The views have certainly been close to apo performance and certainly what I would have expected from a good Mak-Newt, and perhaps exceeding my hope for one with a focal ration of f4.7 and comparatively large secondary - previous Mak-Newt, I have used have been in the f6 to f8 range.  Mars has been compromised by the dust storm of course, but Jupiter has given me some excellent views, better than I've got with my 102mm ED and than with a 180mm Maksutov, though this was far more affected by the seeing.  In more favourable conditions and the planets at a higher altitude I'm sure the DL (David Levy Scope) would perform noticeably better.  Overall, delighted with the planetary performance.

Wide Field and Deep Sky.     I never tried the 30mm eyepiece that came with the scope and at first  used a 24mm Hyperion giving x30 and 2.2 degree field.  The views were very contrasty, more than I expected in often fairly light skies, and fabulous star fields with the six inch aperture,   Large subjects such as the Pleiades and Double Cluster easily fitted into the large field and looked spectacular.  The only downside is that the stars became distorted in the outer parts of the fields, but much less so than in a 6inch f5 Newtonian for instance.  I expected this since Hyperions are not so good in scopes f6 and faster.  I knew the scope could do better.

I sold on a couple of eyepeices I didn't use very often and bought a Hyperion 17.5mm (76 degree field) after much research and reading Bill Paolini's review of it posted on SGL.  With the DL it would give x42 and a 1.8 degree field, close enough to my ideal of around 2 degrees.  First light with it and WOW, I was blown away by the view.  The first eyepiece ever with a field greater than 70 degrees field that I could the whole view with my glasses on and without turning my head.  The contrast was noticeably better and the stars sharp right to the edge, what a revelation.  This was in another class and instantly became my favourite eyepiece ever.  The deep sky views with this eyepiece and the DL are superb.  In fact I've spend several hours just sweeping around endlessly looking at whatever comes into view.  As a wide field deep sky telescope the DL excels in my view.

Imaging.    No idea I'm afraid, it's not my field and didn't attempt any.  Dennis's and Ade's reviews talk about this.

Mounting Requirements.   The scope worked well on a Vixen GP and should be fine with anything in that class or bigger.  I prefer altazimuth though and it is easily carried on my Ercole mount with no counterweight necessary - as long as the tripod is extended high enough to increase the foot print.  Amazingly I've found that for wide field and sweeping an AZ4 mount works very well with it, I even managed to use this for planetary viewing once and it wasn't that bad!

Cool Down Time and the Carbon Fibre Construction.      I've found  for the planets the scope has been useable straight away when taken outside and used at powers up to x100.  It has taken around half an hour or more to cool enough to use  higher powers, though I have done this in less time.  It is summer though, and it will probably take longer in the colder months of course.     No doubt the carbon fibre helps to mitigate temperature variations.  On several occasions I've bought the scope in sopping wet, gone off for only about five minutes or so, returned to the scope and found that it's already bone dry and up to room temperature - apart for the metal bits which are still cold.

The Finder Scope.   Ade had parted with the finder that come with the scope before I bought it, though it came with the supplied finder holder.  I have to say I thought it was much too short, virtually tube-huggingly close.  Wearing glasses I couldn't get my eye behind it properly and it was a real pain.  I must admit in the reviews the finder sounded really good that came with it and I was disappointed I didn't have it, particularly as I have always wanted a completely correctly orientated one which it is.  I found the ES finder available on line at a rather eye watering price of over £150!!  Too much for me.  I did some research and found out that Opticstar do the same finder (unbadged) for £99!  More amazingly they did a the same finder with a long stalk -eureka!!  Bought one!  A really nice finder, love star hopping with the correct orientation.    Features of the finder include: 50mm aperture, x9, correct image orientation, illuminated cross hair and field indicators, integrated dewshield, all metal construction, separate adjustment for the focus and the focus of the reticule.  Brilliant!  Never been so overjoyed using a finder.

Tube extended to cover mirror adjusting screws.    This may not sound much, but it means you can stand the scope on end and it won't fall over, it really is a useful feature.

Stainless Steel Screws used in the construction.   Ok, not vital by any means, but it make the scope so classy looking, and no more rusty screws!  Why don't other manufactures do this?

Carbon Fibre Dew Shield Provided.   What a wonderful touch, you'd have to buy one if it wasn't provided.  Same diameter as the tube so you can keep it on and use the same end cap for the tube.  Adequate length, but I will probably make an extension for it before I go to Kelling and the autumn to come.

Large Rubberised Clips for Mirror.   Not ideal, though Ade says that in practice any diffraction they cause is not obtrusive. Ade removed these and stuck the mirror down before I had the scope so they won't bother me.

Built in 'Bobs Knobs'.    Nice brass knobs to collimate the secondary if necessary, hidden by a plastic screw on cover.

Lockable Mirror Adjusters.  The knurled mirror adjustment knobs are held in place by internal hex screws which you tighten to prevent them moving by accident,

Focuser, Two inch Crayford.    Appears well constructed and works well, doesn't slip with my binoviewer and two Baader Mk111 zooms on board.

Chunky Carrying Handle opposite Dovetail.       Makes it very easy to carry the scope around in one hand.

 

Is this the best all purpose scope commercially available?

Well, you don't expect me to say yes or no do you!  I will come clean and admit  I love it.   It's performance as an all round telescope is hard to beat when you take into account the quality of the planetary views, the wonderful wide field views and its' aperture.  After all you won't find an apochromatic 152mm refractor with a f4.7 focal ratio.  You could get an apochromatic 152mm refractor which will perform better on the planets, but off hand I can't think of  better 152mm f4.7 scope which will have such contrast and such a flat field for deep sky observing.  Put these two things together and it's a combination  that is indeed hard to beat.  If you take into account it's potential for imaging and it's relative portability I think it is certainly a strong contender for the best all round scope within its' aperture class.  I feel it is also made more attractive by some of the thoughtful considerations taken it its construction which I have mentioned.

What makes me so happy with this scope is that when I'm observing with it, whatever I'm looking at, I never think that it would better if I had a so and so telescope for any particular type of object, It does everything it does really well so you don't feel wanting in any way. Even for those people who have all bases covered with a number of different scopes, I think this scope would still be useful for those times when you don't have the time or inclination to use two or more scopes.

For me, well yes, it's the best all purpose scope I can think of for its aperture.

  

 

 

That looks beautiful Paul. You mentioned a 17.5 Hyperion in your write-up, but I thought you'd bought a Morpheus? 

After observing Mars a couple of nights ago, I looked up at a wonderfully transparent sky with the milkyway running almost ovredhead. The whole sky was littered with nakedeye fuzzies. I could do with borrowing your scope for three or four years, otherwise I might have to buy my own for those fuzzy nights.

[paulastro]

Well spotted Pike, I wondered if anyone would spot that!  ?   

Of course you can borrow it for three or four years Mike, there's no-one else I'd rather deprived me of  it  .

 

[F15Rules]

Great write up Paul, and a very nice looking scope.

+1 for the Morpheus 17.5mm. Rapidly becoming a favourite and barlows well too!

Dave

[mikeDnight]

I've just looked at the price and the 49mm  secondary obstruction - EEK!  

[John]

Great write up Paul

I used to have an Intes MN61 which is a 152mm F/5.9 mak-newtonian. Superb scope and also an excellent "all rounder". One I wish I'd kept

I guess the DHL Comet Hunter and the Skywatcher 190 MN are the only mak-newts available these days ?

[Stu]

What a lovely looking setup Paul. The MN looks particularly gorgeous with its CF tube. Very nice write up too, I’m another  who has been tempted by this type of scope though I have yet to take the plunge. I’ve actually owned an MN190 before but never really gave it a chance before having to sell it. Certainly an itch that needs scratching at some point!

[paulastro]

2 hours ago, mikeDnight said:

I've just looked at the price and the 49mm  secondary obstruction - EEK!  

Have you looked at the price of your 100mm refractor recently Mike?  ?

I think the price many of us  are willing to pay for a telescope compared to  what we can actually see through it varies tremendously from one person to another .

[John]

Thats one thing that I don't quite understand - I thought that the raison d'etre of the mak-newt was a very small secondary obstruction combined with no secondary support vanes. The SW 190 and the Comet Hunter seem to have reasonably large secondary obstructions whereas the Russian Intes and Intes Micro ones had very small bordering on tiny ones. I guess the SW and the Comet Hunter were designed to serve imagers as well as visual observers ?

 

[paulastro]

1 hour ago, John said:

Great write up Paul

I used to have an Intes MN61 which is a 152mm F/5.9 mak-newtonian. Superb scope and also an excellent "all rounder". One I wish I'd kept

I guess the DHL Comet Hunter and the Skywatcher 190 MN are the only mak-newts available these days ?

Many thanks John, that's kind of you.  My first Mak-Newt was a black coloured instrument sold by Orion of the USA and I think was called the Argonaut, or something like that.  I have a feeling also that it was their version of the scope you are talking about, it was certainly a 152mm scope.  Fond memories of a long time ago

It's a shame the Intes and Intes-Micro Mak-Newts are not available now.  They were excellent optically (as were their Maks) but I think they were always unfashionable, in part to their robust battle-ship grey finish, heavy weight and pretty awful focusers.  Perhaps if they had been made with glossy white carbon fibre tubes with faster stripes and feathertouch factory fitted focusers they would have been far more popular. 

[paulastro]

1 hour ago, Stu said:

What a lovely looking setup Paul. The MN looks particularly gorgeous with its CF tube. Very nice write up too, I’m another  who has been tempted by this type of scope though I have yet to take the plunge. I’ve actually owned an MN190 before but never really gave it a chance before having to sell it. Certainly an itch that needs scratching at some point!

Thank you Stu.  If you are attending Kelling I'll be there for a week from September 6th (along with Peter Drew  and Andy from The Astronomy Centre) and you'd be most welcome to come along and put it through its paces - as would anyone else who is interested. 

[paulastro]

7 minutes ago, John said:

Thats one thing that I don't quite understand - I thought that the raison d'etre of the mak-newt was a very small secondary obstruction combined with no secondary support vanes. The SW 190 and the Comet Hunter seem to have reasonably large secondary obstructions whereas the Russian Intes and Intes Micro ones had very small bordering on tiny ones. I guess the SW and the Comet Hunter were designed to serve imagers as well as visual observers ?

 

Thanks John.  You could be correct in suggesting this as all the ones I had had extremely small obstructions - thinking of the 6 and 7 inch f8 versions.  The DL scope was certainly designed to accommodate imagers and visual observers - it says so in prefaces to the manual (which is on-line) written by David Levy and the chap who runs ES and who collaborated in the design. ?     It's rather illuminating to read about the thought and aims then went into designing the scope - and in my view it meets the aims extremely well.    Just found the link    https://www.manualslib.com/manual/825774/Explore-Scientific-David-H-Levy-Comet-Hunter.html

I also right in that the SW190 is designed with imaging in mind.

I also believe that the performance in the DL scope will not be as good on planetary as the longer focal ratio Intes-Micro MNs with the same aperture.  Then again it's still very good and I suppose it's the compromise for making it an all round general purpose scope.

I do seem to remember that in recent years I did hear of some Intes-Micro versions that were less than f6, but I'm not certain.  If someone else has some information on these, (if they exist!) it would be nice to hear more  about them.

[John]

Scopes are always about compromise of one sort or another, unless you have a practically unlimited budget and a private observatory on a mountain top somewhere very dark !

The Intes MN61 I had was the Orion Argonaut branded version - maybe it was the same scope !. Not many around over here I'd have thought.

 

 

[paulastro]

Thank you so much for posting this image John, it's  so nice to see it.  It brings back some happy memories of the telescope and also other things that were going on in my life at that time.   

Wouldn't it be funny if after all these years ago we had actually both had custody of the same scope for a while.  It looks even better than I remembered it .

The finish on your tube looks very smooth, though for some reason in my memory I thought it had a crackle finish  - but this really could be my memory.  I was just delighted to get the name of the telescope correct .

I remember finding out about it (I'd never even heard of Mak-Newts at this time) by reading a review in S&T when it was reviewed alongside an Orion Mak of the same aperture.  I haven't a copy if it, but I do remember being amazed when I read about its' planetary performance.  When I eventually had mine I remember it being even better on the planets than I expected after reading the review.  It was quite a eureka moment for me and it lit the blue touch paper for my enthusiasm for the Mak-Newt.   Perhaps it was Dennis who reviewed these two scopes all those years ago .

[paulastro]

John, off to bed now, but I couldn't resist sending you this:

http://www.company7.com/orion/catadioptric/argo6.html

[John]

1 hour ago, paulastro said:

John, off to bed now, but I couldn't resist sending you this:

http://www.company7.com/orion/catadioptric/argo6.html

Thanks Paul

I love browsing through the Company 7 website. Generally I've found that if they carried something, it was a really good quality piece of kit.