Best Scope for Lunar Observations - Advice Please?

[spaceboy]

This is all going to sound contradictory to your posted needs Rich but I can guarantee once you start exploring the night sky beyond the moon you will soon find it addictive. Not only this you may be surprised to hear that the moon isn't always about at night with it spending quite a lot of it's time up during daytime hours. This in mind I would go with an 8" dob http://www.astroboot.co.uk/AstroBoot currently has one for £180. While newts are not really the first choice for planetary scopes out there they do make up for it in far brighter images and resolution for their price than most other scopes available. The longer f/6 focal length of the 200P means it is slightly more forgiving on eyepieces than the 250PX would be but the large 8" of aperture will keep you entertained for some time to come.

I'd then go for a Cheshire collimating tube to collimate the dob again available on astroboot for £12 then get a 12,15 & 18mm BST starguider http://stores.ebay.co.uk/Skys-the-Limit-Astro-and-Optical/BST-Starguider-ED-/_i.html?_fsub=2568750014 along with a http://www.telescopehouse.com/barlows/revelation-barlows/revelation-astro-2-5x-barlow-lens.html for upping the mag for close up lunar observing.

 

A cost to you of £380 give or take leaving you plenty in reserve. Which you will no doubt want a https://www.firstlightoptics.com/finders/telrad-finder-astronomy.html & http://www.ebay.co.uk/itm/Sky-Telescopes-Pocket-Sky-Atlas-by-W-Roger-Sinnott-9781931559317/231807685217?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D0ecd9cb0f2084dc28da0d4fba7307775%26pid%3D100338%26rk%3D2%26rkt%3D20%26sd%3D131720482728 when the DSO hunting bug takes hold

[John]

Resolution increases with aperture - a 10" scope will resolve more detail than a 6" one, viewing conditions allowing.

Also the Skywatcher mak-cassegrains operate at a bit under their stated aperture, for example the 180 is actually 170mm in useable aperture. Similarly for the 150mm and the 127mm.

I've owned the 127mm and 180mm Skywatcher mak-cassegrains and they are nice scopes. The 180 did take ages to cool down and, I felt, was not very versatile with it's very long focal length. An 8" or 10" dob would be a great all round astro scope for visual observing but I don't feel a 150 or especially the 180 mak-cassegrains are that.

And eventually you will want to explore the Universe beyond our moon

 

[Rich_B]

17 minutes ago, spaceboy said:

This is all going to sound contradictory to your posted needs Rich but I can guarantee once you start exploring the night sky beyond the moon you will soon find it addictive. Not only this you may be surprised to hear that the moon isn't always about at night with it spending quite a lot of it's time up during daytime hours. This in mind I would go with an 8" dob http://www.astroboot.co.uk/AstroBoot currently has one for £180. While newts are not really the first choice for planetary scopes out there they do make up for it in far brighter images and resolution for their price than most other scopes available. The longer f/6 focal length of the 200P means it is slightly more forgiving on eyepieces than the 250PX would be but the large 8" of aperture will keep you entertained for some time to come.

I'd then go for a Cheshire collimating tube to collimate the dob again available on astroboot for £12 then get a 12,15 & 18mm BST starguider http://stores.ebay.co.uk/Skys-the-Limit-Astro-and-Optical/BST-Starguider-ED-/_i.html?_fsub=2568750014 along with a http://www.telescopehouse.com/barlows/revelation-barlows/revelation-astro-2-5x-barlow-lens.html for upping the mag for close up lunar observing.

 

A cost to you of £380 give or take leaving you plenty in reserve. Which you will no doubt want a https://www.firstlightoptics.com/finders/telrad-finder-astronomy.html & http://www.ebay.co.uk/itm/Sky-Telescopes-Pocket-Sky-Atlas-by-W-Roger-Sinnott-9781931559317/231807685217?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D0ecd9cb0f2084dc28da0d4fba7307775%26pid%3D100338%26rk%3D2%26rkt%3D20%26sd%3D131720482728 when the DSO hunting bug takes hold

Thanks for such a great informative post Starboy. At £180 for the 8" Dob in A1 condition I could not resist the value on offer there, I have just purchased it!! 

I notice you advise the 12, 15 & 18mm EP's, on the link you have provided there is a 12, 15 and 25mm but no 18?

Am I correct in thinking the Telrad you recommend replaces the finder that was stated as 'missing' from the Scope on AstroBoot?

[Paz]

I wouldn't hesitate to go for the 250mm Dobsonian - compared to a smaller Maksutov.  

 

Some advantages of say a 127-180mm Maksutov

Cheaper accessories (e.g. smaller solar filters, and if using 1.25" eyepieces instead of 2" eyepieces, don't need expensive high quality eyepieces)

Smaller storage required

Less bulk to handle

Eyepiece position doesn't move so much as the scope moves

Closed tube so less likely to get crud on the mirrors

Don;t have to collimate (but collimating isn't actually a big deal)

No spider vanes holding the secondary so no diffraction spikes on bright stars

 

Some advantages of the 250mm Dobsonian

Can do wider fields of view (due to shorter focal length)

Can do higher levels of magnification (due to larger aperture)

More detail for any given magnification (due to larger exit pupil for any given level of magnification)

More light captured for any given magnification (due to larger aperture)

No glass in the light path (so better contrast and no light splitting)

Faster set up than a Mak on an alt/az mount and much faster than an Mak on an EQ mount

Easier to collimate than a Maksutov (maybe this is unfair - you don't really have to collimate Maksutovs)

 

If you compare a 127mm Maksutov to similar aperture scopes of other designs they can be more suitable or better value for money depending on what uses one has in mind but it just can't compete with a much bigger aperture dobsonian when it comes to what you will be able to see, whether it is lunar, clusters, double stars, dso's, etc.

Adding an equatorial mount into the mix makes a dobsnian hard to beat when it comes to visual use.

[Stu]

1 hour ago, Rich_B said:

Thank you for your input Stu.

Portability is not a major concern, plus I am relatively young (36) and very fit so I can cope with lugging it around moderate distances if necessary. Besides, I am starting to realise that a Mak 180 with a suitable mount is all in all a fairly bulky piece of kit anyway, not the ultra portable option I was at first assuming it would be. 

Yes studying the Lunar 100 & 200 is of great interest.

A couple of questions if you don't mind:

1.  Are you saying that the resolution will actually be better with a 10" Dob than say a Mak 150/180? I was kind of under the impression that for lunar detail the Maks were King?
2. The EQ platform does sound a good idea, could you provide a link by any chance? I can't seem to find any to look at on the usual websites.

Cost is also a factor that works in favour of the Dob route. A Mak 180 with a solid EQ mount plus EP's is looking like circa £1250. Whereas the Dob 10" with EP's is less than half that (plus whatever the EQ platform costs). I guess the question is: "Is the Mak 180 option really TWICE as good as the Dob option?" The more I consider this I strongly suspect not.

 

Rich, resolution is a function of aperture so yes, a 10" scope should have higher resolution than an 8" scope. There are obviously other factors which come into play such as the accuracy and smoothness of the optics, the size of the secondary obstruction which will influence the contrast, diffraction spikes from the secondary support on the newt vs none on the mak, the speed of the scope and thus the amount of coma you will see. The Mak is a much longer focal ratio than the newt but at the high powers you will use on the moon it will not really be a factor.

There are convenience factors too, such as speed of cool down which should be better with the newt as it is an open tube, collimation which will likely be more stable on the mak but don't be scared by collimation, it is quite easy to master. Maks can often suffer from mirror flip when changing direction of focus adjustment. This is something I don't like, and can make critical focusing trickier. The newt would not have this problem. Setup with a newt in EQ platform would be quicker than a Mak on an EQ mount, although it would be similar if using an alt az mount such as an AZ4.

The other thing to mention is eyepiece position. This may be stating the obvious, but the Mak you observe via a diagonal at the rear of the scope, observing near the zenith can be a little awkward but then for lunar observing this won't be an issue. The Newt has the eyepiece near the top of the tube so your observing position can be very different.

Dew control is another consideration. It varies depending upon where you observe, but you need to be prepared at least to have a dew shield and quite likely a dew strap for the Mak to keep the front corrector plate clear. With a newt the primary rarely sees up, but the secondary can be an issue. A hair dryer or dew heater behind the secondary would sort this.

There are many factors at place, unfortunately many of them are personal preferences too which you will get to know. The Mak definitely won't be twice as good and diffraction spikes not withstanding the 10" should give better resolution. I don't want to complicate matters further, but there are 10" scopes from Orion optics with longer focal lengths, smaller secondaries, and higher quality optics. In theory these have better contrast and will show the more difficult targets better. Much depends upon seeing conditions though and perhaps that is something for future consideration.

Here is a link to a good EQ platform. I don't own one but they look good and a good price. Teleskop Service in Germany seem to have stopped selling a platform which I have owned and works well and now range one that is much more expensive.

http://www.sumerianoptics.com/products/eq-platform/

http://www.teleskop-express.de/shop/product_info.php/info/p2700_Geoptik-Dobsonian-platform---motor-tracking-for-telescopes-up-to.html

I hope this helps rather than hinders (by confusing matters!) I have just been surprised how much I have used my EQ Platform, how much easier it makes observing at high power.", and how easy it is to setup.

Stu

[Louis D]

3 hours ago, Rich_B said:

At £180 for the 8" Dob in A1 condition I could not resist the value on offer there, I have just purchased it!!

Good job!!  After my first scope purchase new, all the rest of my scopes were purchased used off either AstroMart or Cloudy Nights Classifieds.  I've saved thousands of dollars over the years buying used where it makes sense.  Eyepieces, Telrads, diagonals, barlows, mounts, tripods, cameras, lenses, even computers.  I'll buy new if the price is well below used which occurs during closeouts (as with the Meade 5000 SWAs) or when Amazon is trying to blow out inventory (as with the Pentax 7mm XW).

As for the Mak, I looked at an excellent condition used Orion 127 on a GEM locally.  All seemed great until I tried to pick up the assembled tripod/mount/scope/counterweights to move it to another location.  OMG, with all of the counterweights installed and it's ungainly carrying shape, it just about crushed my spine to do that.  Given that I've had two severe back injuries, I had to walk away from that sweet deal (about $300 for everything).  Despite my dob weighing about 50 pounds, I can hug it against my upright body, making it fairly easily to move around without hurting my back.

You'll really like that dob.  It's probably the most versatile scope around.  If it has a 2" focuser, get a 38-42mm SWA class eyepiece to cruise the heavens with at low power.  That's something the Mak can only dream of doing.

Unless you're doing outreach, you'll find that you don't really need tracking for visual work.

[Putaendo Patrick]

Congratulations - an 8" Dob is probably one of the most versatile scopes for all round visual observing. You're going to have a lot of fun!

By the way, if you don't have it, I do recommend the free computer program Virtual Moon Atlas, just download it from the Internet.

[Jimtheslim]

7 hours ago, Rich_B said:

Am I correct in thinking the Telrad you recommend replaces the finder that was stated as 'missing' from the Scope on AstroBoot?

No you would use a telrad alongside the finder scope. The Telrad is zero magnification and allows yo to get into the right area without the confusion of a magnified, back-to-front, upside down image when you look through the finder. So locate the area of a DSO with the Telrad, then look through the fider to see if you're in the right place. 

[Dazzyt66]

Well done Rich_B - you can't beat AstroBoot for a bargain. I got my first 'proper' scope, a 150p Dob from there and also my new HEQ5. You won't be disappointed! Enjoy!

Moon Globe is a good app to explore lunar filters and Stellarium or Sky Safari are great for when you want to widen your field.

When it arrives use a 10mm eyepiece to grab a look at Saturn... ?

You may also find this useful...

 

[Dave In Vermont]

3 hours ago, Putaendo Patrick said:

Congratulations - an 8" Dob is probably one of the most versatile scopes for all round visual observing. You're going to have a lot of fun!

By the way, if you don't have it, I do recommend the free computer program Virtual Moon Atlas, just download it from the Internet.

Just to endorse Patrick's suggestion for getting the Virtual Moon Atlas - here's the link to the SourceForge download site. SourceForge also carries Stellarium, and is safe from internet-boogeys & malware  piggybacking in on good software:

https://sourceforge.net/projects/virtualmoon/

Enjoy!

Dave

[nightfisher]

congrats on the dob, now you will want to look at eyepieces, make sure to get a decent 8 to 10mm as main workhorse

[Rich_B]

Thanks again to all who have contributed to this thread.

What I have purchased so far is as follows:

• 8" SW Skyliner 200P Dob
• Celestron Eyepiece Kit (5 x EP's, 1 x Barlow, 6 x Filters)
• Telrad Attachment
• Chester Collimating Tube

I think the Dob advert said it comes without a finder, I was assuming the Telrad replaced this but apparently not. Any tips on which finder to purchase?

Do I need anything else to get started?

I will download the Sourceforge software packages as recommended above this evening. Thank you to those who suggested these.

I must say that the amount of kit I have got here for under £375 is very pleasing.

I am expecting delivery of this lot tomorrow. Any further tips greatly appreciated.

[Stu]

For basic stuff, moon, planets and bright DSOs the TelRad may well be all you need. I would see how you get on for the moment. Best option if you do buy one would be a 9x50 RACI (Right Angle Correct Image) finder. This has a prism diagonal so it's easier to view into (saves your back!) and also presents the image the right way round so it's easier to match the views to charts etc

[Louis D]

18 minutes ago, Rich_B said:

Do I need anything else to get started?

As I said above, get a 38-42mm SWA class eyepiece to cruise the heavens with at low power and to act as a widest field finder eyepiece.

Looking at what FLO offers (since they pay the bills for this forum), they have the 40mm Aero ED SWA for £105 with a 68 degree AFOV, the 38mm PanaView SWA for £79.90 with a 70 degree AFOV, and the 42mm William Optics SWAN for £97 also with a 70 degree AFOV.  The WO SWAN appears to be back ordered right now.  All of these will suffer some amount of astigmatism at the edge of the field in your F/6 scope, but are pretty sharp over the center 50%.

If you're willing to jump up in price to 170,00 € and balance a 1.25kg eyepiece, there's the Explore Scientific Maxvision 68° Okular 40mm.  I have the Meade 5000 SWA version, and it is outstandingly sharp right to edge at F/6.  I decloaked it by removing the eyeguard.  Just pry up the rubber part from the bottom edge with a butter knife to break the glue seal.  After sliding it off, you'll be able to unscrew the single screw that holds the metal part of the eyeguard to the optics barrel.  Doing so saves almost 1/2 kg in weight.

[barkis]

A  6"  f12  spherical mirror in a tube just of a size to accommodate the mirror and cell, a low profile focuser, a secondary mirror 
tailored to a minimum size  catch the reflected light and direct it into the focused eyepiece, example 12mm which will deliver a magnification approx. 150x.
Of course you have a very long OTA, 7 feet long, but would go on to a simple Dob. But superb contrasty Lunar views guaranteed.
very easy to make an instrument like this, including making the mirror, which being spherical, is relatively easy to accomplish.
the secondary and holder would come cheap too, a single vane to hold the small flat.   A low profile focuser can be constructed from modern plastic  waste pipe fittings.
Maybe not the prettiest astronomical telescope on the planet, but those lunar views will blow you away.
Who does this sort of thing anymore, although large Dobs are being built by members on this forum and elswehere, but those are very serious instruments, this is a fun project,
but the result will guarantee it was worth the effort. 
One disadvantage, constant nudging of the scope will be need to keep your lunar target in view .

 

[Dazzyt66]

2 hours ago, Rich_B said:

Thanks again to all who have contributed to this thread.

What I have purchased so far is as follows:

• 8" SW Skyliner 200P Dob
• Celestron Eyepiece Kit (5 x EP's, 1 x Barlow, 6 x Filters)
• Telrad Attachment
• Chester Collimating Tube

I think the Dob advert said it comes without a finder, I was assuming the Telrad replaced this but apparently not. Any tips on which finder to purchase?

Do I need anything else to get started?

I will download the Sourceforge software packages as recommended above this evening. Thank you to those who suggested these.

I must say that the amount of kit I have got here for under £375 is very pleasing.

I am expecting delivery of this lot tomorrow. Any further tips greatly appreciated.

I have a 9x50 finder (that I had on my Dob) on eBay at the mo... Current bid is £20... ?

[Putaendo Patrick]

3 hours ago, Rich_B said:

Do I need anything else to get started?

Clear skies - unfortunately in buying your Dob you have enraged the gods and doomed the whole of South Yorkshire to at least a month of heavy cloud

 

[Jimtheslim]

If you have a telrad, just get going with that for the time being. I only have a 9x50 finder and I find it very difficult to use. If I had the choice I would have bought the scope without a magnified finder and a simple red dot, however this package isn't offered by the manufacturers. You can definitely get going without a magnified finder and a just a Telrad. I imagine once you have surveyed the moon you will move on to the planets and these don't require a magnified finder as long as your telrad is aligned.

[Charic]

I have two finders permanently configured on the scope,  favouring the straight through 9x50. keeping BOTH eyes open helps find the target image  much quicker?
The Telrad may get used at darker sites if the 9x50 reticule is not visible against the night sky.

Already mentioned above, a wide-field EP is another  option. 

[Davesellars]

One thing to consider with the Mak design for the larger models is the amount of cool down time they require to reach the same temperature.  For lunar viewing this will be critical to cool down properly to avoid viewing (seeing) issues.  An SCT also takes time to cool down but I believe less than a Mak.