magnification range on planetary targets using 4"-ish refractors

[Piero]

What is the magnification range you use for each planetary target (Moon, Sun in white light, Mercury-Neptune) using a 4"-ish refractor under good-excellent seeing conditions? 

[John]

With my Tak FC100DL and assuming decently steady conditions:

- Moon: 150x - 300x. Sometimes less if I want to take in a large feature / area.

- Sun (W/L): 50x-100x, occasionally up to 150x on a particular feature.

- Mercury: not observed with this scope, yet. With other scopes I've used 150x-200x on this planet.

- Venus: 150x - 250x

- Mars: 200x - 300x

- Jupiter: 130x -220x. Occasionally more if conditions are very good but Jupiter just does not seem to reward really high magnifications.

- Saturn: 150x - 250x.

- Uranus: 150x - 300x.

- Neptune: 200x - 300x. A few times 450x just for kicks !

Hope that helps a little. Whats behind your question by the way ?

[Piero]

6 minutes ago, John said:

Hope that helps a little. Whats behind your question by the way ?

Thinking about brothers and sisters for the lone HR 2.4mm!   

[chiltonstar]

I have used 150 to 250x with my 102mm achro for Jupiter, Mars, Saturn, Uranus and Neptune.

Chris

[Timebandit]

 

On the 120 ed . I will push as much magnification as I can get away with, provided I can achieve a quality image. A complete waste of time in my opinion using a high magnification, if all you start to achieve is a blur in the image. Give me a smaller image in the eyepiece that is razor sharp any day. I have eyepiece ranging from 3.5 mm to about 8mm for planetary, depending on seeing conditions. As I say I will push it as far as I can depending on the particular seeing conditions that night, and even then they never seem to stay steady in the UK during an observation session.

Obviously it depends what 4" ish scope you are looking to use the brothers and sisters to the 2.4 HR with I suppose. I know some of the Taks can handle very high magnifications. But personally the 3.5mm Pentax XW is the highest magnification eyepiece I have. And due to the seeing conditions in the UK I don't seem to use it that much only when seeing conditions rarely allow. To me personally going below 3.5,mm would not make sense as I don't think I could justify it in the eyepiece case due to the lack of use it would probably receive.

[Highburymark]

My normal maximum with the 100DC is Nagler 3.5mm (211x) on planets and Moon but occasionally use Nagler zoom at 3mm if conditions allow. I haven't yet gone further than this with the Tak - so interested to hear how often you get to use your 2.4mm Vixen under UK skies.

[Stu]

Would love to try a 2.4mm in my Tak under good conditions, they sound pretty spectacular eyepieces. The other night I had the Nag Zoom in the Zeiss Abbe Barlow and on the moon it held up to beyond 4mm i.e. over x400. The scopes will often take it, it's the seeing conditions that won't.

[Highburymark]

3 hours ago, Piero said:

Thinking about brothers and sisters for the lone HR 2.4mm!   

So guess you'd be looking at 370x if you bought the 2mm HR Piero?

[Piero]

26 minutes ago, Highburymark said:

So guess you'd be looking at 370x if you bought the 2mm HR Piero?

Actually, I now realise my second comment was a bit misleading. No, I am not considering the HR 2mm or 1.6mm, but which longer focal lengths of TOE or HR could be handy with the Tak. Reading the above comments and Mike (MikeDNight)'s notes in his sketching, a 4mm focal length eyepiece (185x) seems useful. Same for the 3.3mm. Interestingly, combined with a 2x barlow, one can get 2mm, 1.6mm, for high power lunar observation under great seeing!  

At this stage, these are just open thoughts really.. more reviews are needed for the new TOE.

[Piero]

1 hour ago, Stu said:

Would love to try a 2.4mm in my Tak under good conditions, they sound pretty spectacular eyepieces. The other night I had the Nag Zoom in the Zeiss Abbe Barlow and on the moon it held up to beyond 4mm i.e. over x400. The scopes will often take it, it's the seeing conditions that won't.

I agree. The scope is not the limiting factor, but the seeing is unfortunately. 

.. and to me the ZAB is a powerful weapon for 1.25" eyepieces, a keeper..  

[Stu]

30 minutes ago, Piero said:

.. and to me the ZAB is a powerful weapon for 1.25" eyepieces, a keeper..  

Indeed Piero. Just had to sell mine unfortunately but will re buy when life gets easier!

[Piero]

2 hours ago, Highburymark said:

My normal maximum with the 100DC is Nagler 3.5mm (211x) on planets and Moon but occasionally use Nagler zoom at 3mm if conditions allow. I haven't yet gone further than this with the Tak - so interested to hear how often you get to use your 2.4mm Vixen under UK skies.

I would not say that the 2.4mm is used very often, but it is used on lunar and white light solar observation. I reckon it can be successfully employed on very tight double stars. Another area of use could be the detection of Moons on other planets. I have no experience with this, but this eyepiece has the lowest level of light scattering I have ever seen (well, it is basically null!), so my suspect is that it should work well. Of course a 4" refractor might not be sufficient, but who knows.. maybe Encelados  

As planetary observation is something that I really like in this hobby, I like to hear what people tend to use when observing planets.

[John]

4 hours ago, Timebandit said:

 

.... A complete waste of time in my opinion using a high magnification, if all you start to achieve is a blur in the image. Give me a smaller image in the eyepiece that is razor sharp any day.....

 

I totally agree with this. The magnifications that I quote in my earlier post (with the exception of 450x) are where the image is still retaining good contrast and image sharpness. Once that appears to be lacking I step back down the magnification straight away.

 

[Timebandit]

11 hours ago, John said:

I totally agree with this. The magnifications that I quote in my earlier post (with the exception of 450x) are where the image is still retaining good contrast and image sharpness. Once that appears to be lacking I step back down the magnification straight away.

 

 

 

This is why in my opinion if you are truly serious about planetary observing you need numerous increments of eyepieces in your armoury . It is only then you can push to maximum magnification and retain maximum sharpness in the target. I know I get flac on the site for being a bit of a collectionist of eyepieces for  planetary . But I consider you need increments of at least 1mm to achieve this. And maybe even 0.5mm at times. Due to the atmospheric/seeing conditions this really does effect what is the point you can push maximum magnification, and that 0.5 , 1mm increments can make all the difference. That's why I have the 3.5XW , 4 NLV , 5 XW, 5BGO, 6BGO, 7,XW, 7BGO, and 8 TV. I know it's a lot but this way I can push the magnificent to the point of the particular seeing conditions, while maintaining maximum sharpness to the image. As for planetary maximum magnification that retains razor sharpness of target is what I am trying to achieve in the Obs session.

[Stu]

2 minutes ago, Timebandit said:

 

 

This is why in my opinion if you are truly serious about planetary observing you need numerous increments of eyepieces in your armoury . It is only then you can push to maximum magnification and retain maximum sharpness in the target. I know I get flac on the site for being a bit of a collectionist of eyepieces for  planetary . But I consider you need increments of at least 1mm to achieve this. And maybe even 0.5mm at times. Due to the atmospheric/seeing conditions this really does effect what is the point you can push maximum magnification, and that 0.5 , 1mm increments can make all the difference. That's why I have the 3.5XW , 4 NLV , 5 XW, 5BGO, 6BGO, 7,XW, 7BGO, and 8 TV. I know it's a lot but this way I can push the magnificent to the point of the particular seeing conditions, while maintaining maximum sharpness to the image. As for planetary maximum magnification that retains razor sharpness of target is what I am trying to achieve in the Obs session.

That's why the Leica 8.9 to 17.8mm ASPH Zoom is such a good option, when combined with a top notch barlow. I used mine quite often with a 2.5x PowerMate and it covered basically all of your range above and is very sharp on axis for planetary.

[Piero]

Same here. A zoom combined with a barlow works nicely on planetary targets. 

Said this, I've got very crisp views at 308x on a few occasions, and above this sometimes. Maybe the seeing over here is a bit better? 

[Timebandit]

3 hours ago, Stu said:

That's why the Leica 8.9 to 17.8mm ASPH Zoom is such a good option, when combined with a top notch barlow. I used mine quite often with a 2.5x PowerMate and it covered basically all of your range above and is very sharp on axis for planetary.

 

Yes I can see your point of view on this?.  But for me there are a number of draw backs with a zoom.

To get a quality zoom you  do seem to need to buy something like the Leica , and these are not cheap new. Correct me if I am wrong but around £800 . This is a big chunk of cash in one go. And then you need a quality Barlow/powermate and these are not cheap.  As for second hand (my preferred route) the Leica do not seem to come up used , and even then you would be taking considerable cash in one lump sum. With something like the BGO they do come up second hand and at sensible money . Even the Pentax XW come up second hand ,and at reasonable money. This way you can spread the expenditure over a period of time , but still build up a focal range of very good quality eyepieces over a period of time as finance allow .

If you have all you money tied up in one quality zoom. A consideration I always worry about. If you have an accident. Maybe drop the eyepiece when using,or when cleaning scratch it, if it gets considerable damage then you have lost an awful  lot of money in one eyepiece. With multiple eyepieces then you spread the risk considerably . As if you damage one then you still have the remaining to use. And replacing one BGO or XW is so much cheaper than one Leica Zoom.

I also do binoviewers on planetary and lunar. Therefore the likes of high power 6, 7 ,9 mm BGO can be paired up at very reasonable cost. And the same with the 8mm TV.  Two Leica Zooms would leave me in serious trouble with the bank manager I think?  ,

I can see the advantage of a quality zoom ,but for me the collection of single focal ratio range just works for me , or maybe it just looks more impressive in the eyepiece case  when you have numerous eyepiece instead of just one zoom. Or maybe I really am a collectionist and should seek help?

[Piero]

if money are a concern I would not even get an APO refractor, but just a Skywatcher dobson 8", and maybe in the s/h market too.. 

Dropping an eyepiece is possible, but chances are reduced with proper care.. I never lost a key, never broke a mobile phone... so I WILL TOUCH WOOD that I will never drop my zoom!  

[John]

5 hours ago, Timebandit said:

 

 

This is why in my opinion if you are truly serious about planetary observing you need numerous increments of eyepieces in your armoury . It is only then you can push to maximum magnification and retain maximum sharpness in the target...

I very much agree with this.

My higher power eyepieces go: 8mm, 7mm, 6mm, 5mm, 4mm, 3.5mm, 4mm-2mm nagler zoom plus the Leica ASPH zoom and Baader VIP barlow for good measure. Those give quite a few options !

 

[Stu]

I also agree, which is why I used to have this case......

It is only finances which caused them to be sold. It was not out of any desire! I actually saved money going to the Leica Zoom/Barlow, but sadly that has gone now too. But..... I still have a full set of BGOs and a Nag Zoom so have all the options covered still, pretty much. Just lacking eye relief and fov!!!

[Timebandit]

3 hours ago, John said:

I very much agree with this.

My higher power eyepieces go: 8mm, 7mm, 6mm, 5mm, 4mm, 3.5mm, 4mm-2mm nagler zoom plus the Leica ASPH zoom and Baader VIP barlow for good measure. Those give quite a few options !

 

 

You do have most option's covered there John. Maybe I am not such a collectionist after all. Makes me feel so much better now☺

 

2 hours ago, Stu said:

I also agree, which is why I used to have this case......

It is only finances which caused them to be sold. It was not out of any desire! I actually saved money going to the Leica Zoom/Barlow, but sadly that has gone now too. But..... I still have a full set of BGOs and a Nag Zoom so have all the options covered still, pretty much. Just lacking eye relief and fov!!!

 

Lovely looking case. Just quality. 

I am glad you still have the BGO. These IMO are so much quality in optical terms for so little money( when compared with other quality optics). I have a soft spot for my BGO also, and would hate to part with them.

[alan potts]

I am pretty much in agreement with John at the top of thread. Mine is 115mm or 4 1/2 inches I never go above X266 which is 3mm in this, I do not have anything shorter. I find Saturn holds well on the top end and Mars needs this amount much of the time. The outer planets I use other scopes with more inches.

Alan.

[alan potts]

16 hours ago, Stu said:

I also agree, which is why I used to have this case......

It is only finances which caused them to be sold. It was not out of any desire! I actually saved money going to the Leica Zoom/Barlow, but sadly that has gone now too. But..... I still have a full set of BGOs and a Nag Zoom so have all the options covered still, pretty much. Just lacking eye relief and fov!!!

Did I not buy one of them Stu or was it the other wat around.

Alan

[Stu]

13 minutes ago, alan potts said:

Did I not buy one of them Stu or was it the other wat around.

Alan

I think maybe the 10mm Delos Alan?

[timwetherell]

On 13/11/2017 at 10:13, Timebandit said:

 But I consider you need increments of at least 1mm to achieve this. And maybe even 0.5mm at times. Due to the atmospheric/seeing conditions this really does effect what is the point you can push maximum magnification, and that 0.5 , 1mm increments can make all the difference.

Yep, that's exactly my experience too. I have 4,5,6,7,8,9,10mm for planets. For other targets I'm happy with 70% jumps but tweaking the image on planets is a very different matter. Though of course since the planets are now on holiday in Australia for the foreseeable future, it's all somehwat moot