Ideal magnification for planets.

[Stuu]

Hi everyone. 

I'm on the hunt for an eyepiece for my new OTA that will suit viewing planets, mainly Jupiter and Saturn. I have an F5 150/750 Newtonian. I've got a 3.2mm Starguider but after reading several threads, x234 magnification sounds like it's stretched the limit of average viewing conditions in the UK. I've not had the chance to see for myself yet but in the meantime, does anyone have any experience with the same sort of setup? I was thinking of aiming for around x170 - 180 if the Starguider doesn't work out.

Edited July 3, 2021 by Stuu

[dweller25]

X180 will be about right for Jupiter and Saturn in the UK, so a 4mm eyepiece 👍

Edited July 3, 2021 by dweller25

[Tiny Clanger]

Magnification is, once you have a theoretical limit set by your telescope, limited by the atmospheric conditions.

I've not yet found a need to go beyond 200x , and my highest useable combo (127 mak with a focal length of 1500mm and 8mm BST eyepiece) gives 187.5x . I have a 6mm ep too, but with that 'scope it shows my eye floaters so much I'd not want to use it much. 

I've used the 187.5x to view Mars when it was well placed, and the Moon too, but on most nights the conditions are just not good enough to push the magnification that high, so I'll  try a 12mm or 15mm instead,which will give a better, if less magnified, view.  That's why people buy several eyepieces  (or a zoom eyepiece) , magnification is not everything.

Wait until you have the chance to use the kit you already have to view the planet, , only you , viewing from where you are, with your 'scope on your mount will be able to decide for sure what you need or don't need.

Heather

 

[John]

I find higher powers produce more satisfying results with Saturn and Mars. If the seeing is good and your scope in decent collimation, you might find the 234x useful on those targets. For Jupiter lower powers seem to (usually) produce a sharper and more contrasty view so 140x - 180x would be more effective.

As has been said, having a range of magnification options is very useful so you can experiment and see what will give the best views on a given night. The seeing conditions are the main determining factor on what proves successful.

 

[Sunshine]

Definitely one of those subjects that is highly dependant of typical conditions in your area, trial and error over several nights of observation will narrow down your highest possible magnification for planetary. 

There really is no cut and dry answer for what magnification will be your average highest useable power as there are so many variables involved, I had to try several eyepieces before I settled on a range which

was most practical for my scope and typical conditions. It may take some time and swapping of eyepieces before you find which one is best for you.

[wookie1965]

Yes as others have said all depends on the scope and atmospheric conditions, I went out on the 22nd for a session at 2am on the 23rd I turned the scope to Saturn with my 5" Refractor it has a focal length of 1180mm my 8mm BST showed the best results at 147.5x anything more was soft. I could easily do a 4mm giving.   X295

[PeterStudz]

Some good advice here. I did get 240x on Jupiter & Saturn for a brief period on 16th June using a Skywatcher Skyliner 200p before things got mushy but I think I was lucky there. The few other times I’ve tried this year I couldn’t get more than 130x. 

[Ags]

Seeing is not the only factor. My eyes are full of glutinous floaters, so I can't go smaller than an exit pupil of around 1mm or the planet in question is obscured behind lumps of eye jelly. So in a 150mm scope, I wouldn't go above 150x, maybe 160x. 

Edited July 3, 2021 by Ags

[Zermelo]

Also bear in mind that Saturn and Jupiter are still quite low down at the moment, which doesn't help. I have a 150/750 and I've successfully gone up to x300 on a couple of very still nights, but only on double stars higher up in the sky.

[Jiggy 67]

Apart from cost, there is no reason why you can’t go for an eyepiece to provide you with the highest magnification possible for your particular scope. The main limiting factor is seeing and transparency, sometimes you can achieve x300 or even x400, sometimes no where near that. I would recommend at least one ep that Max’s out your potential…..because, sometimes, it will work great. Also you don’t need to reserve it for planets, planetary nebulae and double stars, for example, require huge magnification sometimes, but when the conditions are right, you will thank the Gods for a high mag, high quality ep 

Edited July 3, 2021 by Jiggy 67

[Stuu]

Thanks for all the input everyone. I'm hoping the clouds stay away long enough tonight to get a look at Jupiter and Saturn, so with a bit of luck I could have a better idea of what to go for. With my 3 eyepieces and powermate I have a gap in my collection between x117 and 234, so I think something around 4-5mm might be good. I looked at a couple of zooms but I'm finding I like a fairly wide afov. Fingers crossed for the weather for anyone still up and outside!

[Mr Spock]

What eyepieces and powemate do you have?

[Stuu]

x 2.5 PM, ES 68° 16mm, Panoptic 24mm, Starguider 3.2mm. 

 

 

[Mr Spock]

A good quality 10mm will go nice with the powermate and give you x187.5; same for an 11mm - x170.

Through my 250mm the moon looks great at x171. It will handle higher powers in good conditions. I like a ratio between powers of around 1.3, so, my x171, x225 and x300 are close to that.

You are right in thinking x170 - x180 complements x234. If you like Televue, maybe an 11mm DeLite?

[Stuu]

I was looking at that sort of focal length originally, it was between the 11mm DeLite, 10mm XW and 9mm Morpheus. But wasn't sure if I'm better off using something in that range with the powermate or just a shorter focal length. 

Edited July 4, 2021 by Stuu

[Mr Spock]

5 hours ago, Stuu said:

I was looking at that sort of focal length originally, it was between the 11mm DeLite, 10mm XW and 9mm Morpheus.

Either the 10mm or 11mm will be fine; the 9mm at x208 is too close to the x234. 

A single eyepiece of 4mm would be the same as the powermate + 10mm. A 5mm eyepiece would be x150 and a bit low on power. To get x170 you would need a (750/170=4.4) a 4.4mm eyepiece and there aren't any.

[Stuu]

It's a tough choice between the DeLite and XW, just need to book some weekend overtime in to fund it 😆 Thanks for your input. 

I managed to get some amazing views of Saturn and Jupiter through the powermate and 16mm. It's the first time I've seen Jupiter's cloud belts, absolutely stunning! It gave me a chance to have a play with some filters as well. The 3.2mm wasn't the sharpest of views but still fun to see at that sort of magnification. 

 

Edited July 4, 2021 by Stuu

[John]

Having owned a couple, the great thing about the TV Powermate is that it gives a totally transparent power boost. No impact on light scatter, light throughput, focuser position, field vignetting etc, etc.

Having said that, the DeLite or the XW's (and the Delos) are really excellent eyepieces as well.

The low altitude of the planets currently is the biggest "downer" for me having observed them for years when they were much higher in the sky. Still, we have to make the best of what we have !

 

 

Edited July 4, 2021 by John

[Mr Spock]

I'm fortunate enough to have seen Saturn when it was overhead. An incredible sight. At the moment it's lower than I can reach - with my 250mm it's below my garden fence level 

Given how my seeing conditions are it's likely to be mush anyway.

[Stuu]

I did look at the Delos but it's quite a jump in price, I think I'm leaning towards the XW 10. 

Having only got into this last year I don't know any different with them being low in the sky, I'm lucky that I can get a good view of them where they are at the moment. The clarity of them last night blew me away! I hadn't seen them since last year with my 90mm achro where Jupiter was just a bright white disc. Just need the weather to sort itself of out now! 

[John]

1 hour ago, Stuu said:

I did look at the Delos but it's quite a jump in price, I think I'm leaning towards the XW 10. 

Having only got into this last year I don't know any different with them being low in the sky, I'm lucky that I can get a good view of them where they are at the moment. The clarity of them last night blew me away! I hadn't seen them since last year with my 90mm achro where Jupiter was just a bright white disc. Just need the weather to sort itself of out now! 

I have the XW 10, 7, 5 and 3.5mm. They are all excellent. The 5mm would give you 150x which would be a very useful higher power.

 

 

[Stuu]

21 minutes ago, John said:

I have the XW 10, 7, 5 and 3.5mm. They are all excellent. The 5mm would give you 150x which would be a very useful higher power.

 

 

They definitely do well in all the  reviews I've read. I really like my ES68° but the delivery time on any of the ES stuff is not good at the moment. The 10 will hopefully give me a good DSO eyepiece as well after some feedback on a previous post.

[Starwatcher2001]

17 hours ago, Stuu said:

I think I'm leaning towards the XW 10.

I have the XW 10 and it's one of my favourite eyepieces: good field of view and sharp. It's a very comfortable eyepiece to use with glasses, having a 20mm eye-relief. But it's equally comfortable without glasses as the eyepiece screws upwards. The XW range are expensive (to me), but are worth every penny and with care will last a lifetime. I plan to get more as finance allows.

[Stuu]

4 hours ago, Starwatcher2001 said:

I have the XW 10 and it's one of my favourite eyepieces: good field of view and sharp. It's a very comfortable eyepiece to use with glasses, having a 20mm eye-relief. But it's equally comfortable without glasses as the eyepiece screws upwards. The XW range are expensive (to me), but are worth every penny and with care will last a lifetime. I plan to get more as finance allows.

The comfort part is a big draw as I imagine I'll be spending a lot of time peering through this one. I can manage without glasses but I don't think that will last for ever, unlike the eyepiece hopefully Well worth working the odd weekend to save up for!

[Starwatcher2001]

My thoughts entirely Stu. I'm currently doing a lot of lunar observing, which involves frequent looking at the maps to identify craters and features. Swapping glasses on/off is a real pain. The XW eps are the only two in my collection that let me see the whole field with glasses on and hardly a head movement. Also works very nicely with the Teleview 2x Barlow, which retains the eye relief.