Planetary scope -Newt or Refractor?

[Dude_with_the_tube]

done with "holy grail" hunting as my next step would only be the top tier Ep`s what i cant see any reason why should i get them,specially taking into consideration of UK weather and seeing conditions.And that holy grail hunting doesnt do any good to your bank statement too!

I am happy with the set up i have,the only thing remaining is to rewamp my 14" dob.thats it.Done.Dusted.

i know,never say never.....

[John]

done with "holy grail" hunting as my next step would only be the top tier Ep`s what i cant see any reason why should i get them,specially taking into consideration of UK weather and seeing conditions.And that holy grail hunting doesnt do any good to your bank statement too!

I am happy with the set up i have,the only thing remaining is to rewamp my 14" dob.thats it.Done.Dusted.

i know,never say never.....

I think there is something in this.

Some of the most impressive observing reports I've read on here come from people who have relatively modest equipment but have spent time really getting to know how to use it and how to observe critically.

It's quite sobering to read a report of great detail being observed backed up with excellent sketches and to find that the equipment used was more or less standard, non-premium, kit but used with skill and cunning.

It's all too easy to think that throwing more £'s at the hobby will reap more rewards but it's often not the case - I'm as guilty of this as anyone 

[AlexB67]

In theory at least the VX10L is a better planetary scope over the VX10 due to smaller obstruction size as already said, but an obstruction size of 25% or even 30%, supposedly the ability to see the diff that needs very good experienced eyes coupled with excellent seeing ( not that I ever had the privy to see  for myself ) and excellent collimation of course.

Perhaps more of an serious affect that produces the less than perfect airy disks  is the effect of coma in the faster scope,  which will  deteriorate more quickly off axis in the faster scope, and reduces contrast in the faster scope of axis more quickly.  

In any case I have noticed it in my f4.7 on nights of very good seeing,  last year even and earlier this year with Jupiter when it was nice and high in the sky.  Even with very well corrected eyepieces like the TV Radian, the sweet spot is best near the centre of the view, but it is quite marginal to my eyes expect for the very outer edges and it involved long hours labouring at the eyepiece to really convince myself of that.  Also the scope was very well cooled/ collimated, as in, it  had been standing outside for several hours and it was really in the performance zone.  With even slightly less than very good seeing conditions I struggle to see that sort of thing at all however,  for example, Saturn the way it has been of late, it is just too low in the sky for me to see any of those side effects.

With the VX10L you could get by without a coma corrector for planets and be able to use most of the FOV without that worry, let drifting take care of things for a larger part of the FOV, no need for a CC and some orthos, all the little things that add up to enhance contrast, and no doubt you'd have some cracking planetary views with a high grade mirror, a fully cooled scope, excellent seeing conditions etc.      

All that said. Seeing I have never used those perfect on paper scopes for planets, high grade mirrors etc.  I am perfectly happy with what my current equipment gives me, but high quality eyepieces I have since acquired have enhanced the views, that much I can say.

[jetstream]

Well the Leica may free up some cash here..... Not sure yet,but between last night and now on solar there is a chance....The sun @ 178x is still showing faculae and plage around those 2 lonely sunspots-no other EP of mine will do this.A bit less @ 150x or so and the granulation pops back into view...So at least a part of the planetary situation is getting sorted out....

My VX was collimated very accurately and I could watch the coma smear as it drifted across the FOV-and then go sharp as a razor

I'm going to go barlow my Tak ortho now....

[Dude_with_the_tube]

I'm going to go barlow my Tak ortho now....

you took the words out of my mouth.I know Leica is superb zoom EP,but have you ever tried orthoscopic EP for planetary? try them and you might be amazed what detail you can get out of them.Yes they are not very user friendly and some hate them due to tight eye relief and narrow FOV,but i came from 82 deg,then 100 deg FOV Eps and then tried ortho on Jupiter.After i stood up from felling on my a...se from views i had,i had to get a set of orthos! Now i have even 2 sets of these little beauties.you can get 2 or even 3 orthos for a price of 1 good quality Ep Well,1 set of BGO`s cost less than TV Ethos 17mm.

Get one and try one.

[paulastro]

For visual work (NOT imaging) I would prefer  a six inch refractor of high quality.   Convenience, consistency in iffy seeing and really wow images are the reasons I say this.  It's not for nothing that that people describe scopes other than refractors as having 'refractor like' images!

Having said that, I must admit the best view ever I can recall of Mars was through a 16 inch SC at Kelling Heath a few years back in the brightening dawn sky.  Mind you, I consider this the exception that proves the rule

One scope that I haven't seen mentioned in this thread is the Maksutov - Newtonian, and in particular the longer focal length ones produced by Intes Micro.  I have owned a 7 inch f8 of this variety (and a friend of mine still does) and they really are superb planetary scopes.  I have had my best views of Jupiter through these scopes. 

Overall though, as I said at the start I would opt for a six inch refractor, the 7 inch f8 Mak-Newt would be my choice if it wasn't for the fact that it's a bit of a beast to handle.  Having said that, I am getting on a bit 

[PaulC-I]

For visual work (NOT imaging) I would prefer  a six inch refractor of high quality.   Convenience, consistency in iffy seeing and really wow images are the reasons I say this.  It's not for nothing that that people describe scopes other than refractors as having 'refractor like' images!

Having said that, I must admit the best view ever I can recall of Mars was through a 16 inch SC at Kelling Heath a few years back in the brightening dawn sky.  Mind you, I consider this the exception that proves the rule

One scope that I haven't seen mentioned in this thread is the Maksutov - Newtonian, and in particular the longer focal length ones produced by Intes Micro.  I have owned a 7 inch f8 of this variety (and a friend of mine still does) and they really are superb planetary scopes.  I have had my best views of Jupiter through these scopes. 

Overall though, as I said at the start I would opt for a six inch refractor, the 7 inch f8 Mak-Newt would be my choice if it wasn't for the fact that it's a bit of a beast to handle.  Having said that, I am getting on a bit 

I second the Mak Newt design. My Intes MN78 Quartz gives stunning views of planets and luna. Mirrors....Tiny secondary obstruction compared to most newts and no Diffraction spikes.

Best Jupiter view so far (previously owned 6" F9 ED refractor and compared both)

Paul

[John]

I had an Instes MN61 which did seem to produce superb "apochromat like" images of the Moon and planets. I compared it side by side with the ED120 for some weeks and it was more or less equal on planetary / lunar performance though the extra aperture of the mak-newt showed on deep sky objects of course. In the end I kept the ED120 and let the MN61 go to another SGL member who is very pleased with it. The slightly lighter weight and faster cool down time of the ED120 just tipped the scales in it's favour for me but the Russian mak-newtonians are really excellent lunar and planetary scopes.

[dweller25]

Gerry,

You have a very good planetary scope already

I have the OO VX8" version but modified it for extra planetary contrast.....

1. Replaced the thick OO spider with a thinner one (I actually used one from a Skywatcher), this reduced the spider vane pattern you can see coming off a bright planet.

2. Flocked directly opposite the focuser.

3. Flocked the focuser internals.

4. Painted the edge of the secondary matt black.

And finally I bought a 75% transmission ND filter which helped a lot by reducing glare.

Hope that helps

[jetstream]

David thanks for the advice.I may try to maximize my existing scope for more contrast and will try your suggestions.I have to agree that the VX10 is good on the planets,I am very satisfied with this telescope,Saturn the other night was very good,esp for being so low and the views of Jupiter and Mars were amazing at times.During a brief but exceptional bit of seeing I saw a couple of "eyes"-darkish spots on Mars that may have been some mountain structures or something and clouds,ice....

If I may ask,what is your favorite planetary telescope?

Thanks

[jetstream]

While were talking planetary,I never got any response to the Mars image that looks very close to what I saw....any ideas anyone?!Those 2 "eyes" or features there-what are they?

[dweller25]

David thanks for the advice.I may try to maximize my existing scope for more contrast and will try your suggestions.I have to agree that the VX10 is good on the planets,I am very satisfied with this telescope,Saturn the other night was very good,esp for being so low and the views of Jupiter and Mars were amazing at times.During a brief but exceptional bit of seeing I saw a couple of "eyes"-darkish spots on Mars that may have been some mountain structures or something and clouds,ice....

If I may ask,what is your favorite planetary telescope?

Thanks

Well, I alternate betwen the 8" OO Newt and the Tak FS128, the Tak is more comfortable for me to use as I have a bad back, the 8" OO gives more detailed views.

[quaoar]

While were talking planetary,I never got any response to the Mars image that looks very close to what I saw....any ideas anyone?!Those 2 "eyes" or features there-what are they?

Not sure but if I see something I often go to this site http://lunaf.com/english/live-data/mars-today/  then cross reference with a Martian topographic features map, usually helps identify the feature I'm seeing.

[Stu]

Have you thought about fitting a curved vane spider to the VX10 Gerry?

It removes diffraction spikes, the diffraction is still there but more spread out I believe. John has one on his 12" and that seems to give cracking results

Protostar make very good ones to your spec

Stu

Sent from my iPhone using Tapatalk

[Mike73]

And finally I bought a 75% transmission ND filter which helped a lot by reducing glare.

I've started to do the same David, it doesn't seem to make any real difference to the details on the planet but removes the bright glare around it. Actually I think it was you that mentioned it a while ago so thanks.

Have you thought about fitting a curved vane spider to the VX10 Gerry?

It removes diffraction spikes, the diffraction is still there but more spread out I believe. John has one on his 12" and that seems to give cracking results

Protostar make very good ones to your spec

Stu

Sent from my iPhone using Tapatalk

Removing diffraction spikes isn't going to make any difference to the detail that can be seen on the actual disk though.

If I was into splitting double stars I'd definitely add curved vanes but for a planetary scope as much as I like to try and get as much out of my scope as possible I think curved vanes would be more trouble than they are worth.

I've just replaced the OO focuser on my VX so I now have a spare curved base plate, this got me thinking about using it to add a fan to remove the boundary layer. I'II have to do lots of research into it before I get brave enough to drill a great big hole in the side of the scope though! 

[RikM]

Paul Abel uses an 8" Newtonian with an apodizing mask and he knows a bit about planetary observing.

[Mike73]

Paul Abel uses an 8" Newtonian with an apodizing mask and he knows a bit about planetary observing.

Yep he uses one of the old blue tube Skywatchers I think his book is very good aswell.

I've also noticed that a lot of what I think are the best planetary observers/sketchers use Newts from 8" to 14" and apodizing masks, something which I'II be making for the next time Jupiter shows.

[Stu]

I've started to do the same David, it doesn't seem to make any real difference to the details on the planet but removes the bright glare around it. Actually I think it was you that mentioned it a while ago so thanks.

Removing diffraction spikes isn't going to make any difference to the detail that can be seen on the actual disk though.

If I was into splitting double stars I'd definitely add curved vanes but for a planetary scope as much as I like to try and get as much out of my scope as possible I think curved vanes would be more trouble than they are worth.

I've just replaced the OO focuser on my VX so I now have a spare curved base plate, this got me thinking about using it to add a fan to remove the boundary layer. I'II have to do lots of research into it before I get brave enough to drill a great big hole in the side of the scope though!

Not totally sure I agree Mike. Admittedly I have no experience of looking through one of these but I read plenty of evidence that they help planetary viewing too.

Interesting read here...

http://www.cloudynights.com/item.php?item_id=511

I do intend to try a protostar curved vane spider in the 12" at some point.

Cheers,

Stu

Sent from my iPhone using Tapatalk

[Mike73]

We'll have to agree to differ on that one Stu but like you I've never had a chance to compare curved and straight vanes on planets either.

I still think that for all the trouble and expense of fitting a curved vane to reduce glare around a planet its simpler just to use a ND or Neodymium filter.

[recceranger]

Despite all the specs, what ifs and buts, you really need only one yard stick. When it comes to planetary viewing aperture reigns king. In the UK as a general rule of thumb you get about x35 per 1" of aperture. Fact!

You can through as much ED Glass, quality EP's and cool down time at it as you like!

So, if you got a 10" your pushing it at beyond x350

Rick

[John]

My 12" F/5.3 dob has curved vanes. No diffraction spikes although diffraction is still present but spread evenly across the field. Does it make any overall difference ? - I don't really know but my 12" F/5.3 has split Sirius and shows great planetary and lunar detail when conditions allow. I've yet to apply flocking and blacken the edge of the secondary mirror so I might be able to improve things a little further still.

The eyepiece used can make a noticeable difference to planetary glare / scatter too. Of the wide angles I find the Pentax XW's the best although I'm sure the Delos would be very similar. The Baader 6mm GO is my "low scatter" benchmark and is a little better than even the XW's on this front. The best I've ever used was a TMB Supermonocentric 5mm.

Most of my planetary / lunar viewing is done at 265x - 318x with the occasional foray higher or lower as the conditions / target demands.

[jetstream]

I've owned a few refractors in the 4.7" - 6" range Gerry. They do pretty well for lunar, planetary and binary star observing but I think an 8" F/8 newtonian with top flight mirrors would be better again though. My ED120 does deliver planetary images that are quite close to my 12" F/5.3 dob when seeing conditions are less than optimum. In terms of usable magnification and image scale the 12" starts where the ED120 begins to falter though - around 250x

As Steve says, a 10" F/6.3 with a 1/10th wave mirror would be a killer planetary instrument.

I have made an addition to the lineup that I hope will compliment my existing set up.The SW 120ED Pro went on sale and I couldn't pass up the deal-$1400.00USD delivered,from a good vendor.

I plan to use this tripod mounted scope when conditions won't allow my VX10 to excel on the planets ( quite a bit)-esp in winter with those bright,clear mediocre seeing nights.The tripod mount will also add flexibility for winter scope placement and I understand the doublet design cools fairly fast.I've read that the 120ED also works well with the prism diag for contrast (we'll see) and from what I understand should support 240x seeing considered.

The 120ED will be an addition to,not a replacement for the VX10,the dob is going to get flocked and will be used as the main scope when my infrequent great seeing comes about.My next acquisition will be a bigger dob,most likely used-still thinking of what to get.

So the planetary line up will be the 120mm frac,250mm dob + a big dob of some sort.

Thanks to all for the input and the great advice.

[Stu]

Nice one Gerry, should give you great views :-)

Sent from my iPhone using Tapatalk

[RikM]

Sounds like a great plan.

[Mike73]

Covers all bases and leaves funds for the big dob, I like it.